Search

Alluvial fans are rapidly evolving landforms sensitive to changes in tectonic and climatic conditions. Their study provides useful information to unravel the landscape evolution of lowlands and mountainous regions where sediment transported by rivers originates. The chronology of alluvial fan deposits is crucial for the flood risk assessment of those populations settled on this type of dynamic landform. Here we provide (1) a review of the literature concerning climatic reconstructions for the Sierra de Gredos, (2) optically stimulated luminescence (OSL) ages and (3) topographical analysis to reconstruct the recent events that built-up the alluvial fans of the southern sector of Sierra de Gredos (Central Spain). The area is tectonically active and has a relatively simple lithology given by a deformed and fractured Paleozoic granite massif that was heavily eroded by Quaternary glacial advances. Our OSL results indicate that the recent build-up events span from ca. 5 ka up to the end of the 19th century. The chronology of events is consistent with the climatic change reported for Central Spain, where humidity seems to be a primary control in the recent activity of the alluvial fans. Additionally, topographic analysis on a 5-m-resolution LIDAR DEM help us to propose that, tectonics have been a major control of Gredos alluvial fans in a long-term scale, longer than the Holocene but, since the mid-Holocene to the present, climate is a primary control on their landscape evolution. We conclude that current climatic conditions favor fan degradation for the Gredos alluvial fans rather than sediment transport and fan aggradation. The present study emphasizes the necessity of supplementing OSL chronologies with other long-term geochronological techniques to confine the constructive periods of fans for the entire Holocene. [ABSTRACT FROM AUTHOR]

We investigate the chlorine isotope disequilibrium between chlorides in pore fluids and chlorides in seawater and infer its consequences for chlorine isotope exchange between ocean sediment pore fluids and seawater. We illustrate our methodology with pore fluids from two IODP drilled to depths of ≈1000 m (U1456 and U1457) in the Indus River fan dominated by clay-detritus sediments of the western Himalayas. At these two sites, the concentrations of chloride and sodium ions do not show significant changes with depth and remain very close to those of seawater. As a function of depth, however, chlorides show a progressive decrease in 37Cl (downto −2.5 and −1.4 ‰ respectively), while Ca2+ increases and Mg2+ decreases, as commonly observed in clay-rich oceanic sediments. The rate of the δ37Cl decrease is correlated to the lithology and sedimentation rate. Examining the chlorine budget on these two sites, we conclude that: (1) Most of the chlorine (≥96% of the total Cl) is contained in the pore fluids as chlorides, while the chlorine stored in the other sinks (minerals or organochlorine) is generally very minor (representing <4% of the total Cl). (2) These other sinks are too small to sequester the lost 37Cl-enriched chlorine, which could compensate for the decreased δ37Cl of the chlorides observed in the pore fluids (assuming that the pore fluids originally had chlorides with the chlorine isotopic composition of seawater, δ37Cl = 0 ‰). (3) This lost 37Cl-enriched chlorine has been released from the sediment into the overlying seawater, with fluxes of about 20 mol of chloride per square metre per kiloyear. In order to evaluate the consequence of this unbalanced on a global scale, we extend this chlorine budget analysis to 22 other oceanic sites drilled by IODP in a variety of tectonic environments. It is estimated that worldwide oceanic sediment pore fluids contain 1 × 1020 mol of chloride with mean δ37Cl at −2.3 ± 0.1 ‰ and mean chlorinity at 0.290 ± 0.055 mol Cl- per kg of sediment. Most of the calculated values of the lost 37Cl-enriched chlorine flux are between 3.5 and 45.6 mol of chloride per square metre per kiloyear (mean value of 18.3 mol Cl.m−2.kyr−1), corresponding to a typical chloride exchange time between sediments and seawater of between 5.5 and 71 Myr with a mean value of 14 Myr. Importantly, in oceanic sediments, a relationship between the δ37Cl of the chlorides in their pore fluids and the nature of the detrital minerals (smectite, illite, kaolinite, carbonate, quartz, ...) may exists. This relationship should be modulated by the detrital input from the continents to the oceanic sediments and should therefore be a consequence of the climatic conditions on the continents (mainly rain, temperature). The δ37Cl of the seawater should vary according to these detrital inputs. The expected range of variation would be between −0.3 and +0.3 ‰. This is consistent with the range of δ37Cl in seawater predicted by the study of evaporites deposited since 2 Ga (Eggenkamp et al., 2019). [ABSTRACT FROM AUTHOR]

Cenozoic mountain building in Asia has been proposed as an important control over global climate by atmospheric CO 2 drawdown through silicate weathering and burial of organic carbon (OC) offshore. Because Asian submarine fans represent the most complete record of Asian orogenic erosion and weathering over the Cenozoic, evaluation of sediment major element chemistry and OC content can be used to estimate CO 2 sequestration rates driven by silicate chemical weathering and OC burial. From deep-sea fans in the Indian Ocean and South China Sea, weathering rates are calculated by comparison of weathered sediment to initial bedrock source compositions and then integrated with deposited volumes to derive the first regional weathering budget for India-Asia collision over the last ∼25 m.y. Results indicate the Indus is more important than previously recognized before and during the middle Miocene in sequestering CO 2 (∼76% of Asian total at 16–14 Ma). This in part reflects the more reactive mafic and ultramafic bedrock sources compared to the largest and major east Himalayan drainage, the Ganga-Brahmaputra, but also greater erosional flux from the onshore Indus drainage at that time. This regional synthesis further concludes that OC burial only represented a minority (20–25%) of the regional carbon budget but became more important after 17 Ma, peaking at ∼38% after ∼3 Ma. CO 2 sequestration rates increased from 17 to 15 Ma, coinciding with the Miocene Climatic Optimum, and remained mostly steady in Asia from ∼15–5 Ma as the climate cooled. Only one of three possible sediment flux models for the Bengal Fan predicts increased CO 2 consumption rates after 15 Ma and, even then, only predicts steady rates from 11 to 5 Ma. The timing of changes in CO 2 consumption rates are not consistent with Asian orogenic silicate weathering acting as the dominant control over late Cenozoic atmospheric CO 2. [ABSTRACT FROM AUTHOR]

Sites of ice-stream discharge to the continental slope build trough-mouth fans from glacigenic debris flows (GDFs), subglacial meltwater flows, and suspended sediment. Thus, past ice configurations may be interpreted from the sedimentological record. This study links the records in cores, high-resolution seismic profiles, and multibeam swath bathymetry of Hatton Slope and Fan to the changing glaciological history in Hudson Strait, one of the largest ice streams of the late Pleistocene Laurentide Ice Sheet. 14C-AMS dates, X-ray fluorescence geochemical profiles, and oxygen isotopes in sixteen cores document sediment supply during the last glacial cycle, and earlier history is interpreted from seismic data. The Frobisher Bay slope sector has a long record of GDF deposits from severe glacial periods between MIS 6 and 22, with little impact of meltwater discharge. Mass-transport events and aggrading gravel-floored valleys dominate the northern Hatton slope sector. The central slope sector shows the greatest shelf break progradation by till deposition, with kilometre-spaced gullies heading at 700–730 mbsl from the last major grounding of the ice-stream on the upper slope during Heinrich event 3 (H3). The gullies pass downslope into ∼5 km wide valleys, which have been sites of sediment bypass since widespread meltwater flow in MIS 6 and show little aggradation since MIS 16. Intervening >50 m high ridges show alternating levee accretion and erosion by shallow mass-transport events. Downslope on Hatton Fan, GDFs are common and fill wide erosional channels that lead to the sandy braid plain of the central Labrador Sea. The channels of the southern sector and Saglek Slope have channeled turbidity currents down the NAMOC, and stratified contourite deposits accumulated on the fan. Over the MIS 1–3 period widely represented by cores, ice was grounded in Hatton Basin and on the upper slope to 700 m water depth only immediately prior to H3. Older and younger H events had a floating ice-shelf in Hatton Basin, and sedimentation was dominated by the retreat of that ice shelf to Resolution Island. Distal cores show no systematic difference between the H1–top H3 interval and the base H3–H5 interval. Given the supply of carbonate detritus of consistent composition back to at least H5, any MIS 3 deglaciation of Hudson Bay would require improbably high growth rates of ice sheets in the centre of the continent. • First multibeam swath bathymetric and seismic profiling of the Hudson Strait Ice Stream. • Glacigenic debris flows, and mass-transport events were outlined during MIS 6 and 16. • Glacial ice was grounded in Hatton Basin and on the upper slope to 700 m over MIS 1-3. • Lack of a systematic difference between H1–H3 and H4–H5 events raises the question about the deglaciation hypothesis during MIS 3. [ABSTRACT FROM AUTHOR]

The offshore margins of Guyana, Suriname, and French Guyana (the "Guyanas Equatorial Margin") have become the focus of active hydrocarbon exploration over the last decade, with significant energy resources discovered since 2015 along both the Guyana and Suriname segments of the margin. Those discoveries are mainly associated with the Late Cretaceous series of the Guyana-Suriname Basin and they shed light to a rare situation where stratigraphic traps are particularly successful. To date, the tectono-stratigraphic evolution of the area has been primarily examined at margin-scale through seismic refraction, rare borehole data and sparse, regional long offset multichannel 2D seismic datasets. In this paper we combine the results from newly acquired high-resolution well data, 2D/3D seismic interpretation and 3D seismic geomorphology, to build a robust and consistent sequence stratigraphic framework and address the evolution of Cretaceous sedimentary landscapes offshore Suriname, with a particular emphasis on the Late Cretaceous strata. The Suriname margin displays a very specific overall sequence stratigraphic evolution marked by four main phases each characterized by distinct sedimentary fluxes and related overall geometries: 1) a margin initiation phase, 2) an aggrading phase, 3) a backstepping phase and 4) a forestepping phase. The Suriname basin initiated in the Early/Mid Jurassic after the emplacement of thick Early Jurassic volcanic series attributed to the Sierra-Leone (or Bahamas) Hotspot (phase 1). This localized early magmatic activity led to two very different configurations: a typical Volcanic Passive Margin in the east along the western border of the Demerara Plateau and a transform segment to the west (essentially along the Guyana margin). The following phase (phase 2) is characterized by the establishment of a Late Jurassic to Early Cretaceous mixed clastic‑carbonate platform with an overall aggradational stacking pattern observed until the Early Aptian. Phase 3 started by significant backstepping, that culminated during the Cenomanian-Turonian transition, coeval with widespread organic-rich marine shale deposition. This overall transgression occurred in four steps: (B) late Early Aptian flooding followed by renewed margin progradation; (C) Early Albian flooding and (D) Late Albian to Cenomanian flooding above the break-up unconformity and (E) the maximum backstep at the Cenomanian-Turonian boundary. This long-term transgressive trend is interpreted as the combination of (1) long-term eustatic rise during the early Cretaceous; (2) high rates of margin subsidence following the Aptian to Albian opening phase of the Equatorial Atlantic, and (3) relatively limited sediment supply rates along the margin at that time. The successive, backstepping shelf-margin wedges created a distinctive stepped profile (paleo shelf-margins) that greatly impacted the geometries of the overlying Late Cretaceous sequences. During this backstepping phase, clastic sediment delivery to the deep-water part of the Suriname basin in the Early Cretaceous was limited and mainly sourced from the large Berbice Canyon complex at the Guyana-Suriname border. The outlet of the Berbice drainage systems may have been anchored by an aborted section of the Jurassic rift and linked to the onshore Takutu graben which separates the Guyana shield in two parts. The fourth phase of the Jurassic to Cretaceous evolution of the Suriname margin is characterized by a dramatic increase of the sediment supply during the Santonian resulting in the accumulation of thick sequences of channel-dominated turbidite fans. This renewed clastic input is linked to a major drainage reorganization on the Guyana shield and is also coeval to the change from the point-sourced Berbice system to a line-sourced input from smaller rivers and deltas along the Suriname margin. From Early Santonian to Late Maastrichtian, the offshore sedimentary systems were then characterized by an overall regression with stacked coastal clastic systems on the shelf and continued fan deposition in the slope together with abundant slope erosion and related Mass Transport Complexes. At higher frequency this long-term forestepping Late Cretaceous trend was modulated by accelerated pulses of sediment supply (and associated margin progradation) during the Middle Santonian, Middle Campanian, and the Early Maastrichtian. From the Santonian turn-around to the Late Maastrichtian, sedimentary systems are deciphered as sequences constrained by biostratigraphic data from the latest industry wells in Block 58 in Suriname and combined with seismic interpretation of both 3D and 2D data. The multi-scale sequence stratigraphic framework built in this study highlights 1) the specific sedimentary architecture of the margin and 2) the role and the impact of external forcing on the sedimentation rate. Moreover, the results highlight the key importance of topographic inheritance (from both structural and sedimentary origin) on deep-water reservoir architecture, that led to important hydrocarbon accumulations through stratigraphic trapping in offshore Suriname. [ABSTRACT FROM AUTHOR]

Turbidites have been recognized as significant reservoir units in both marine and lacustrine basins. This study was conducted on the Eocene Dongying Sag (Bohai Bay Basin, East China) using sediment cores, well logs, seismic data, and petrography to investigate the diagenesis and reservoir quality of lacustrine turbidites controlled by climate-driven base-level changes. The early forced regression within a third-order sequence stratigraphy can be divided into rising and falling stages of fourth-order base-level changes. Throughout these stages, extrabasinal turbidites were triggered by river floods and comprised the main channel, distributary channel, lobe, and lobe fringe. Intrabasinal turbidites only occurred during the falling stage, which were caused by sediment failures and corresponded to tongue deposits. Compared to extrabasinal turbidites, intrabasinal turbidites possess enhanced anti-compaction capabilities, reduced clay matrix content, and higher carbonate cement content. Climate-driven base-level changes dominated the diagenesis of lacustrine turbidites. From the rising to falling stage, the climate transitioned from humid to arid conditions. This caused a decline in the formation of clay-sized sediments that were subsequently transported into deep-water environments, thereby enhancing mechanical compaction of extrabasinal turbidites. Stacking patterns of channel complexes changed from vertical aggradation to lateral migration, reducing the occurrence of carbonate cementation near channel amalgamation and sandstone–mudstone interfaces. Therefore, these processes controlled by base-level changes led to a decrease in carbonate cement content and mechanical compaction, simultaneously promoting dissolution in extrabasinal turbidites during burial. Additionally, falling base-level facilitated rapid progradation of clinothems and delta collapse, resulting in the development of limited-scale tongues characterized by lower sorting and clay matrix content inherited from the delta front. Tongues, despite their enhanced resistance to compaction, were surrounded by thick-layer deep-water mudstones, contributing to strong carbonate cementation during burial. This study confirms that extrabasinal turbidites during the falling base-level possessed better reservoir quality, thereby providing guidance for the exploration of gravity flow sandstone reservoirs in lacustrine basins. • There are two triggering mechanisms of gravity flows during the early forced regression. • Extrabasinal turbidites during the falling base-level possessed better reservoir quality. • Climate-driven base-level changes dominated the diagenesis of lacustrine turbidites. [ABSTRACT FROM AUTHOR]

The sedimentology of upper flow regime bedforms represents an important research topic at the present. Deposits interpreted as those of supercritical flows are widely recognized in modern fan systems, but their recovery is challenging. Most of the sedimentological information has come from channel thalwegs but supercritical bedforms are also frequently downslope from the channel mouths. Such an environment has been identified in the Paola basin, where erosive and depositional cyclic steps have been imaged and identified in a sandy submarine lobe of the Amantea Fan. High-resolution sub-bottom profiles provide insight into the bedform internal architecture and their relationships with a frontally-confining ridge. For the first time, supercritical bedforms in a submarine lobe have been interpreted in two distinct positions: in the scour of an erosional cyclic step and in the stoss side of a depositional cyclic step. Coarse to medium-grained massive sand with flame structures, indicating rapid sediment fall-out and frequently associated with the occurrence of hydraulic jumps, has been identified in the scour and at the toe of the ridge. The latter represents an example of topographically induced hydraulic jumps driven by a frontal confinement. Top-cut-out medium to fine sands with tractive structures have been interpreted as the deposits related to the stoss side of a cyclic step or small-scale antidune superimposed on the cyclic step surface. The presented data broaden the understanding of the range of processes that are driven by the interaction between turbidity currents and seafloor topography and the dip of the slope. The recognition that topography influences the density structure and the degree of criticality of the flow and, consequently, the morphodynamics and facies of the relative deposits may help to explain sediment distribution and improve depositional models of fan lobes in confined settings. • Sedimentological information about supercritical bedforms in a frontally confined submarine lobe are provided. • Observations result from the interpretation of high-resolution seismic profiles and the analysis of five gravity cores. • Sedimentary structures, generally associated with hydraulic jumps, have been identified in scour fills and at the base of a ridge. • The topography influences the distribution of supercritical bedforms and the flow criticality. [ABSTRACT FROM AUTHOR]

The Lower Cretaceous Jiufotang Formation lacustrine successions in the rift Luxi sag, Songliao Basin are characterized by mixed siliciclastic-carbonate-tuffaceous and organic-rich deposits. Ten facies were recognized and were formed in fan delta, delta, littoral-sublittoral lacustrine and deep lacustrine environments. A depositional sequence characterized by significant changes in facies and lake regime has been defined, and is divided into lowstand systems tract (LST), transgressive systems tract (TST), and highstand systems tract (HST) that are separated by sequence boundaries, initial flooding surfaces, and maximum flooding surfaces, respectively. During the LST, the delta and fan delta deposits covered the marginal area and extended into littoral-sublittoral lacustrine and deep lacustrine environments, respectively. During the TST, the areas of delta and fan delta decreased and lake areas increased, and the carbonate-dominated shoals and mixed siliciclastic-carbonate shorelines occupied the edge of the Majiapu highland belt. During the HST, the lake areas further expanded, and the fan delta deposits extended into deep lacustrine environments and formed deposits of underflows and turbidites. A depositional model in the rift lacustrine Luxi sag is proposed, incorporating the effects of tectonics and sediment supply, climate and carbonate production, hydrodynamic conditions, and lake-level fluctuations. During the LST, the active tectonic movement, high input of siliciclastic sediments, and subaerial volcanic eruptions resulted in the wide distribution of mixed siliciclastic-tuffaceous sedimentation. During the TST, the brackish lake water controlled by periodic dry and hot climate facilitated the carbonate deposition in shallow water, and tractional currents onto the lake shore carried sediments to form the mixed siliciclastic-carbonate-tuffaceous facies. During the HST, more humid climate and increased runoff allowed formation of widely distributed, mostly oil shale-rich deposits, and the gravity flows carried the sediments into the deeper part of basin to form the mixed siliciclastic-carbonate-tuffaceous facies. The depositional model of mixed deposits in this rift lacustrine basin has been proposed here in order to encourage comparison with other similar basins. • Mixed siliciclastic-carbonate-tuffaceous deposits were preserved in the rift Luxi sag. • Moderate siliciclastic influx and volcanic eruption provide the material for mixed deposits. • Tractional currents and gravity flows are favorable for formation of mixed sedimentation. • Relatively high paleosalinity and rising lake-level are benefit for carbonate production. • Three stages of depositional models of mixed sedimentation in a rift sag were proposed. [ABSTRACT FROM AUTHOR]

In the preserved successions of clastic lacustrine systems receiving substantial sediment input from fluvial sources, the boundary between delta-plain and delta-front facies belts marks the position of ancient lacustrine shorelines. Placing and predicting the position of this boundary in nearshore lacustrine deposits of the Triassic Yanchang Formation (Ordos Basin, China) is of considerable applied significance, since sandstone deposits of this succession host numerous geological resources; yet, delta-top and delta-front deposits differ fundamentally in terms of sandstone fraction, sandbody geometries, and petrophysical properties. However, established sedimentological criteria for shoreline identification relevant to marine environments are only partially applicable to this lacustrine setting. For example, in lacustrine systems, (i) water salinity can be considerably lower, (ii) tidal processes are negligible, (iii) wave activity is often limited and of local significance (e.g., distal and lateral delta-front fringes; transgressive periods of delta-lobe reworking), (iv) seasonal fluctuations in water chemistry and biogenic productivity may be common, and (v) the rate, frequency and magnitude of oscillations in base level differ from marine counterparts. Collectively, these factors hinder the differentiation of delta-plain and delta-front deposits in the Yanchang Formation. The establishment of effective criteria with which to make such distinction is important for palaeogeographic restorations, and for resource exploration and exploitation. On the basis of detailed sedimentological descriptions of well cores and outcrop exposures of the Yanchang Formation in the southeastern Ordos Basin, sedimentary facies accumulated as part of different sub-environments and facies belts are studied. Delta-plain deposits can be readily differentiated from those of delta-front origin on the basis of criteria relating to sediment texture, sedimentary structures, palaeontological content, well-log profiles, and vertical facies successions. These criteria are summarized and applied to better characterize the deltaic setting and to reconstruct the evolution of lacustrine shorelines during accumulation of the Yanchang Formation, particularly for the northeastern area of the basin. A key outcome of this study is the development of a broadly applicable model for the recognition of sub-environments in river-dominated lacustrine deltaic successions. A generalized workflow is established to demonstrate how techniques in sedimentary facies analysis can be employed to reconstruct siliciclastic lacustrine delta shorelines, and thereby predict reservoir characteristics. • Integration of subsurface and outcrop data enabled reconstruction of the evolution of lacustrine palaeoshorelines through the stratigraphy of the Triassic Yanchang Formation (Ordos Basin). • Recognition criteria of sedimentary texture and structures, palaeofauna and flora, well-log profiles, and facies successions are summarized to differentiate delta-plain and delta-front strata. • A depositional model for the Yanchang Fm. is proposed that synthesizes characteristics of reservoir architecture as a function of position relative to a time-averaged palaeoshoreline. • The results can inform exploration in the Ordos Basin, providing guidance on the potential for extending exploration basinward. • The outlined approach for delineating facies belts and palaeoshorelines can be applied to subsurface studies of similar lacustrine deltaic successions with ramp-like basin margins. [ABSTRACT FROM AUTHOR]

Holocene inner shelf mud wedges are important paleoenvironmental archives because they typically contain continuous and extensive sedimentary sequences that can document past changes in sedimentary processes at very high temporal resolution. Here we investigate the fine-scale, seismic patterns of the Late Holocene Adriatic Mud Wedge (AMW), along the western Adriatic margin, to understand the processes of river-sea interactions and their effects on sediments distribution. While analyzing high-resolution seismic reflection profiles, we documented variations in the architectural stratal stacking patterns of the AMW, largely related to short-term fluctuations in sediment supply during the last sea level high (ca. 6000 years BP). Analysis of high-resolution seismic profiles revealed that the AMW consists of five clinothems (referred to here as "seismic units" SU1 to SU5) that were roughly dated by calibration with the continuous recovery well PRAD2-4. Each seismic unit is bounded by minor floodplains (H1 to H5), reflecting periods of relative sediment starvation at the margin. Our analysis provides an interpretative tool to differentiate the fluvial contribution of marine remodeling processes during the AMW evolution on millennium to centennial timescales. In addition, small-scale geomorphic features such as erosion surfaces, small distributary channels and terminal lobes were identified to provide information on heterogeneities that may impact an unconventional fine-grained delta reservoir, both in terms of continuity and overall hydrocarbon potential. • We document the Late Holocene evolution of the AMW between Conero Promontory and Gargano Promontory. • The first internal subdivision of the AMW at the intra-clinothem scale for almost its entire extent is presented and analyzed. • Evidence of short-lived phases of advancing and retreat of the AMW at the intra-clinothem scale have been observed. • The competition between sediments from rivers and the redistribution by oceanographic processes sees a progressive increase of the latter over time. • New evidence has enlightened the presence of small-scale, shallow water distributary channels across the AMW. [ABSTRACT FROM AUTHOR]

• The lake stages in Jezero are consistent with semiarid climates • The Jezero lake was a throughflow lake driven by significant surface runoff • Hydrological conditions do not favor large-scale evaporite deposition • Similar climates at Jezero and Gale produce contrasting lacustrine environments Jezero crater, the landing site of the Perseverance rover, hosts sedimentary fan deposits, aqueously altered sedimentary rock, and an outlet breach of the crater rim, all of which indicates that a long-lived lake (or lakes) once existed within the crater. The deltaic deposits in the crater may preserve evidence of habitable conditions within the past lake system, which would have been influenced by the climate and conditions of the past hydrological system within the watersheds and basin. However, the aqueously altered sedimentary deposits within Jezero are less extensive than those found in other crater lakes on Mars, like Gale with a crater filling mound of cemented sediment. In this work we use hydrological models of the past Jezero lake system to constrain the climatic and hydrological conditions by comparing model predictions to the proposed lake stands and mineralogy in the crater observed from orbit and by the Perseverance rover thus far. We then compare these results to Gale crater to understand the influence of basin hydrology on the depositional setting found within past crater lakes. We show that a lake forming at the outlet breach elevation or higher in Jezero requires a semiarid or wetter-arid climate, consistent with previous estimates. An integrated hydrologic system with seasonal variations similar to arid and semiarid climates on Earth results in a lake system at Jezero characterized by both surface and subsurface outflow from the lake. Outflow to the subsurface and through the outlet breach will remove dissolved solids from the lake system, mitigating large-scale evaporite cementation within the Jezero basin, which is in contrast to Gale crater, where subsurface inflow constituted a larger percentage of the total inflow to the lake and all loss was through evaporation due to the setting in a deeper impact crater. Furthermore, at hyperarid climatic and/or groundwater-driven hydrological conditions, lake formation within Jezero would have ceased while a lacustrine depositional environment would have continued at Gale. This highlights the importance of considering basin hydrology, in addition to climate, when interpreting lacustrine sedimentary deposits in craters on Mars. [ABSTRACT FROM AUTHOR]

The existing traditional natural raisin drying room, although it has a high green grade rate for grape drying, the disadvantage is that long drying cycle and uneven product quality. Therefore, a wind field automatic control (WFAC) system was proposed to address the above problems. The WFAC system was built based on the traditional natural drying room by installing blowing fans and exhausting fans, the working principle of the system is to use HMI software to monitor and display the environmental information in the drying room and remotely control the operating parameters of different fans to adjust the wind field by the wireless network communication system, thus increasing the utilisation rate of natural wind in the grape drying. The CFD simulation experiments were conducted, and the simulation results showed that when the fan was combined with two blowing fans and one exhausting fan (TBI + OEO), the fan wind speed was 8 m s−1, and the fan vertical installation distance was 1206 mm, the corresponding wind field uniformity in the drying room was the best, which was 0.721. Based on the simulation optimisation results, the grape drying field experiment was conducted, and the results showed that the efficiency of grape drying in the TBI + OEO drying room was the highest and the drying cycle could be shortened by up to 7 days compared to the traditional drying room. Additionally, the green grade rate of raisin by hanging string in the TBI + OEO drying room was the highest, up to 78%, which was 4% higher than that in the traditional raisin drying room. Overall, the WFAC system designed and optimised in this study performed well in improving the efficiency and quality of grape drying. The results of this study can provide a theoretical basis for drying room structure improvement and industrial product condition control. [Display omitted] • The raisin drying room with the wind field automatic control system was developed. • The parameters controlling the wind field were optimised by fluid simulation. • The accuracy of the simulation was validated by the field experiment. • The drying cycle of the optimised raisin drying room could be shortened by 7 days. • The green grade rate dried could reach 78% in optimised raisin drying room. [ABSTRACT FROM AUTHOR]

Land-surface quantitative analysis based on digital elevation model (DEM) has been applied for improving the geomorphological mapping of piedmont alluvial fans. Indeed, these fans are frequently along a mountain front, where a series of coalescing fans may eventually occur. The margins of adjacent fans are rather difficult to map, thus preventing accurate and meaningful quantification of fan morphometric properties such as fan area, length, and slope. These morphometric properties are essential for informing on the influence of climatic conditions and tectonic factors on the fan-building processes. Therefore, in this paper, we propose a quantitative digital mapping approach along a stretch of about 50 km in the southern front of the Anti-Lebanon Mountains. Here, the Geomorphological Map of Syria at 1:1,000,000 scale (1963) reported at least nine piedmont alluvial fans, but these were poorly characterized in terms of geomorphometric characteristics and construction processes. Adopting the 1-arcsec SRTMv3 DEM, we propose a four-step workflow to analyse the feeding catchments morphology and fan morphometry. In this manner, the identification and geomorphological mapping of coalescent piedmont fans as well as the recognition of the main construction process have been improved. The proposed approach can support geomorphological investigations of wide and inaccessible areas—especially where arid and semi-arid climate conditions prevail—as well as where socio-political issues may prevent effective field work. • Land-surface quantitative analysis is suitable for geomorphological mapping and characterization of piedmont alluvial fans. • Recognition of the construction processes of the alluvial fan is challenging for a remotely-desk study. • Fluvial fans (FFs) are wider, with longer axis, gentle slope, and extended feeding catchment. • Alluvial fans (AFs) are smaller, with shorter axis, steeper slope, and small feeding catchment. [ABSTRACT FROM AUTHOR]

Pleistocene–recent transtensional forearc basins and associated island uplift could be driven by sinistral–oblique convergence along the eastern Hellenic subduction zone, Greece, or by simultaneous trench retreat attributable to subduction of Permo-Triassic Tethyan lithosphere. Structural mapping and basin analysis of the Lefkos Basin, Karpathos indicate deformation best related to oblique trench retreat in which Karpathos drifts southeastward more slowly than Rhodes. Lefkos Basin, perched on a corner of the offshore Karpathos Basin, comprised two Early Pleistocene marine sub-basins developed under northwest extension. Unusually long-wavelength hummocky cross-stratification (>10 m) and clinoforms (15–20 m high) constitute distinctive marker facies. Facies architecture reflects inter-related fault-controlled subsidence, syn -depositional uplift/tilting, glacioeustacy, and fan-delta-lobe avulsion. A 230U/234Th coral age of ∼600 ka and a deer mandible date a Middle Pleistocene transition to southwestward fan-delta progradation and basin uplift. Following ∼0.5 Ma fan-delta-plain deposition, the Lefkos Slide dropped a ∼3.7 km2 coastal plain. Subsequent steep north–south dextral–normal faults dominate Lefkos Basin, with subordinate steep east–west sinistral–normal and northeast-trending normal–oblique faults. Faults signify wrench domination based on their steepness, rare slip indicators, slip reversals and co-genetic upright isoclinal folds. These structures are integral to a forearc-scale dextral–normal shear zone, the Lefkos Shear Zone, an active crustal discontinuity spanning the southeastern forearc from eastern Crete through Kasos–Karpathos to Rhodes. Vertical coherence exists between upper-crustal dextral–normal shear in the Lefkos Shear Zone, crustal seismic anisotropy and deeper mantle processes. Hydraulic fractures, fluid-expulsion pipes, and ruptured cobbles record intermittent significant seismicity (Mw ≥5–6) that permeated the entire Lefkos basin fill spanning ∼2 million years, ultimately involving Late Roman–Early Byzantine archeological remains through ∼1000 years ago. This study encourages re-evaluation of seismic, landslide and tsunami hazards in the sector of the Hellenic forearc surrounding the Lefkos and Karpathos Basins. [Display omitted] • Lefkos and Karpathos Basins reveal Pleistocene-Recent Hellenic forearc neotectonics. • Hydraulic fracture, fluid expulsion and ruptured cobbles record ∼2 My of seismicity. • Forearc deformation in Lefkos Basin reflects the regional-scale Lefkos Shear Zone. • Basin deformation signifies oblique retreat of the eastern Hellenic subduction zone. • Seismic, landslide and tsunami hazards around Lefkos/Karpathos Basins need review. [ABSTRACT FROM AUTHOR]

[Display omitted] • The 47-Hz TPRS resolves wet gas-bearing and light oil-bearing intervals (LOI). • The 47-Hz map images a 154 km2 NEE-SWW oriented stratigraphic play. • The 47-Hz TPRS images phase reversals and seismic-doublets at 170 to 200°F and porosity of 22 to 32 % WGI. • The used workflow has strong stratigraphic implications for field development strategies. Basin floor fans (BFF) of deltaic depositional systems are important stratigraphic traps, which are sourced by the regionally developed meandering channel belts and associated deposits of point bar facies. The vertical and lateral changes in the tectonics and sea level adversely affect the temperature (θ) and porosity constraints of petroleum plays within BFF of the lowstand system tracts. These fluctuations impact the sedimentary controls on thickness, lithology-impedance contrast, phase, and frequency of BFF. As a result of the reliance on full-spectrum seismics, quantifying thin-bedded stratigraphic wet gas-bearing intervals (WGI) and light oil-bearing intervals of petroleum systems becomes extremely difficult. This study utilizes seismic attributes and instantaneous spectral analysis-based temperature-porosity reservoir simulations (TPRS) to quantify the BFF of the Early-Cretaceous delta of the Miano gas field, Central Pakistan. The 47-Hz peak-tuned frequency component of spectral decomposition [SpecDecomp] images a 154 km2 NEE-SWW traversed and regionally developed stratigraphic prospect. Linear regression of R2 > 0.80 between spectral decomposition-based tuning frequency of 47-Hz and gross reservoir thickness of BFF validates the presence of gas-bearing shales. The 47-Hz wavelet-based TPRS has resolved the phase reversals and seismic-doublet signatures for thin-bedded shale PETROS at θ of 170°F to 200°F and porosities of 22 % to 32 % of WGI within BFF. TPRS at 47-Hz SpecDecomp profile between the frequency bandwidth spectrums of 12–62-Hz has reappraised the exact morphology of the continental shelf, shelf-slope, and BFF. A 21 m thick aggradational parasequence of BFF was deposited at an angle of 2° during the onset of subsidence and rapid fall, followed by a subsequent standstill of sea-level at θ of 170 to 200°F, ∼26 to 35 % porosities, and laterally fractured subsidized regimes of WGI.. A 20 m thick retrogradational fluvial-dominated facies was deposited at an angle of 35° during a rising followed by a standstill of sea level at a θ of 140 to 165°F, ∼08 % to 18 % porosity, and poorly fractured uplifted compressional regimes of light oil-bearing intervals. The aggradational WGI of Lowstand System Tracts was completely embedded by retrogradational shales of transgressed system tracts from the top of the aggradational and laterally. The uncertainty analysis has prevailed with a moderate-to-good R2 > 0.75 for BFF and a very poor R2 < 0.1 for fluvial-dominated point bar traps. Our workflow has implications in terms of exploring the tectonics and stratigraphic frameworks within the petroleum systems for imaging the most productive zones in a single snapshot of 47-Hz tuning frequency. [ABSTRACT FROM AUTHOR]

The Butano Sandstone forms part of an Eocene submarine fan deposited in the La Honda basin in central California. The Butano submarine fan has been subdivided into three main facies associations: southern inner-fan deposits, central middle-fan deposits, and northern outer-fan deposits. In spite of homogeneous quartzofeldspathic sandstone composition, these outcrop belts have several compositional and mineralogical differences, likely caused by post-depositional events related to the complex tectonic history of the La Honda basin, and expressed in deep-burial diagenesis and possible hydrothermal alteration. Both compaction and cementation reduced the intergranular volume (lower than 19 %) and the Compactional Index (average 0.9), indicating the major role of compaction in reducing original porosity. The southern proximal-fan and northern distal-fan outcrops exhibit different relative abundance of detrital quartz (Qm 43.5 %) than the middle-fan central outcrop (Qm 50.7 %). Primarily plagioclase and subordinately K-feldspar suffered leaching and intense dissolution during burial, particularly in the central part of the basin, even showing similar and quite constant distribution of alteration degree among the three outcrop belts (dominantly Fpc, Fpd, Fka, and Fkb grain types). Plagioclase abundance decreases in the middle-fan deposits proportionally with the increase of authigenic kaolinite, even where present in moderate amount; in contrast, authigenic kaolinite of inner-fan strata probably formed after partial dissolution of K-feldspar. Diagenetic changes are most abundant in the Butano Sandstone in the central part of the La Honda basin, likely primarily due to hydrothermal effects during deep burial. • Investigating the post-depositional processes affecting the framework composition of the Butano Sandstone. • Compaction play the crucial role, rather than cementation, in reducing the original porosity. • Dissolution affects primarily plagioclase grains and subordinately k-feldspar. • Samples belonging to the central portion of the Butano sandstone exhibits a higher volume of quartz due to diagenetic evolution of composition. • Burial diagenesis and hydrothermal effects influence the detrital mode of the Butano Sandstone. [ABSTRACT FROM AUTHOR]

The long-term evolution of deep-sea turbidity current activity is closely related to climate and sea level changes; however, the impact of abrupt climate change (e.g. millennial-scale events in high northern latitudes) is poorly known. In this paper, deep-sea turbidite records in the western part of the lower Bengal Fan were identified since the Last Glacial Maximum (LGM) to investigate the effects of abrupt climate change on the development of the Earth's largest deep-sea fan. Our records show a termination of turbidite activity in the western lower fan at 16.6 ka–15.4 ka almost contemporaneous with Heinrich 1 event (a cooling stadial in high northern latitudes). The trigger of this termination in turbidite activity may have been a sharp decrease in erosion rates during a time of relatively stable sea level and rapid source-sink processes. The subsequent episodes of the Bolling/Allerod warm interstadial and Younger Dryas cold stadial and the rapid sea level rise event that followed possibly induced adjustment of turbidity current activities in the Bengal Fan, as indicated by other published records. In summary, we show that close links exist between abrupt climate changes in the high-latitude Northern Hemisphere and deep-sea turbidity current activity in the low-latitude South Asia. • Deep-sea turbidite records in the Bengal Fan since LGM were recovered. • Termination of turbidite in the western lower fan was triggered by HS1 event. • Links between high latitudes climate and low latitudes sedimentation were revealed. [ABSTRACT FROM AUTHOR]

Submarine fans play a crucial role in understanding deep-sea sedimentary processes, establishing source-to-sink linkages, and identifying deep-water hydrocarbon reservoirs. Various types of submarine fans have been documented. Here we present findings on the Guangya submarine fan in the Southwest subbasin (SWSB) of the South China Sea (SCS), by analyzing multibeam bathymetric and two-dimensional multichannel seismic data. Bathymetric data reveal that the Guangya fan, covering an area of ~22,500 km2, comprises seven leveed channels, leading to a large composite lobe off the channel mouths. Different from typical submarine fans, the Guangya fan exhibits an elongated shape, extending longitudinally from the shelf edge through the slope to the abyssal plain, while laterally confined within a trough-like morphology in the southwestern tip of the SWSB and beyond. Lacking a typical feeding canyon, the fan appears to be self-fed by the leveed channels that serve as the primary depositional element. In contrast to the radial channel pattern in typical fans, the channels within the Guangya fan form a unique braid to dendritic pattern, genetically linked to channel merging and intersecting effects. Long wavelength and low wave height cyclic steps are identified, highlighting the occurrence of energetic supercritical turbidity currents. Seismic stratigraphic analysis shows that the Guangya fan primarily consists of high-amplitude reflections, indicating its coarser-grained or sandy turbidite-dominated nature. The fan has been evolved since the Pliocene, and mainly comprises depositional elements including channel fills, levees, lobes, and mass transport deposits. The specific tectonic context at the convergence of the conjugate margins, bounding the funnel-shaped SWSB, significantly influences the development of the Guangya fan. The Guangya fan could be originated from a shelf-edge staging area predominantly fed by the Mekong River during sea-level lowstands. • We report a unique elongated channelized submarine fan in the South China Sea. • The fan extends from the shelf edge to the abyssal plain. • The fan appears to be self-fed by dendritic submarine channels. • Tectonics plays a key role in the development of the fan. [ABSTRACT FROM AUTHOR]

• Deep-sea habitats are typically food limited. • Stable carbon and nitrogen isotopes are useful tools to track food resources and trophic levels. • Isoscapes help track spatial variation in resource use across canyon and slope environments. • Deep-sea isoscapes provide avenue to understand shifting baselines with climate change. The deep sea is the largest biome on earth, but one of the least studied despite its critical role in global carbon cycling and climate buffering. Deep-sea organisms largely rely on particulate organic matter from the surface ocean for energy – these organisms in turn play critical roles in energy transport, transformation, storage, and sequestration of carbon. Within the deep sea, submarine canyons are amongst the most complex and dynamic environments in our oceans, where varied morphology, powerful currents, and variable nutrient conditions influence the distribution of species and transport of organic material throughout the water column and the seafloor. Significant habitat heterogeneity provides ideal substrates for cold-water corals, making submarine canyons of interest to conservation and management. However, how these and other topographic features in the deep ocean influence energy flow and trophic pathways is poorly known. Thus, submarine canyons serve as model systems to track variability in organic material flux and consequential utilization and assimilation by the benthos. In this study, we used an extensive stable isotope dataset to examine food-web structure in Baltimore and Norfolk submarine canyons and compared them to their adjacent slopes located along the U.S. Atlantic margin. Linear models were used to construct geospatially-explicit consumer isoscapes that predicted variation in carbon and nitrogen isotopes across the canyon-slope seascape, providing a predictive map from which to test hypotheses on the distribution and flow of energy resources, relevant to understanding whole community function. Communities were composed of isotopically diverse feeding groups with photosynthetically-derived organic carbon providing the basal food resource. Canyon communities were distinct from the slope, with canyon consumers significantly 13C-depleted, indicating a greater supply and/or utilization of fresh organic matter compared to the slope. Isoscapes for benthic and suspension feeders were distinct, possibly due to the consumption of different quality organic matter sources (fresh = suspension feeders, old = benthic feeders), each with distinct isotope composition. To our knowledge, our modeled isoscapes represent the first spatially extensive isotopic maps of deep-sea consumers, providing insights into regional-scale variation in stable carbon and nitrogen isotopes for different consumer groups. They provide a baseline for tracking climate-change induced fluctuations in the quality and availability of surface primary production and the consequential impact to benthic communities, which play critical roles in carbon cycling in our world's oceans. [ABSTRACT FROM AUTHOR]

• A three-stage alluvial fan pattern was built since MIS3. • Cold-dry conditions promote the aggradation of debris flow deposits. • Warm-humid climate leads to perennial streamflow on the fan surface. • Climate is the main factor controlling the evolution of Xiangpi fan. Alluvial fans in the piedmont zones of mountains respond most rapidly to tectonic activity, base-level conditions, and climate changes. These allogenic signals are effectively recorded by the external morphology and internal sedimentary characteristics of the fan. Based on field survey interpretation and integrated optically stimulated luminescence (OSL) chronology, we selected a case study of the modern Xiangpi Fan on the south bank of Lake Qinghai, NE Tibetan Plateau, and built a three-stage alluvial fan pattern since Marine isotope stages 3 (MIS3), namely, the debris flow lobe building stage (DFLBS), aeolian building stage (ABS), and streamflow reworking stage (SRS). The climatic indicators, such as the total organic carbon (TOC) flux, precipitation, and sediment particle size flux, are highly correlated with the above stages, indicating that the sedimentary process and changes in fan morphology effectively record orbital climate changes in the Lake Qinghai basin. During the DFLBS, the cold-dry climate accelerated the sediment yield sufficiently, leading to many coarse-grained sediments and low TOC flux being imported into the basin through debris flow processes. During the ABS, the extreme dry-cold climate caused the stagnation of fan development, and aeolian processes dominated the transport of fine sediment. In the SRS, warm-humid conditions led to limited sediment yield and perennial stream power, which promoted the transport of fine-grained material and TOC to the basin by braided–meandering channels. This study provides an excellent case showing how an alluvial fan responds to climate oscillations through changes in sedimentology and geomorphology. [ABSTRACT FROM AUTHOR]

Records of tide-reworked fan delta facies models are rare in literature, attributed to their lower abundances due to complex sediment distribution pattern by two exclusive end-member flows, viz., a seaward directed subaerial to subaqueous debris flow, and dominant tidal current system interfering with and reworking the debris flow. Lack of appropriate analogues of tide-reworked fan deltas makes the ancient examples more significant. The analysis of such rare tide-reworked fan deltas from deep-time, e.g., Mesoproterozoic, turns out to be unique due to the gap in clear understanding of the alluvial-fluvial vs marine processes in non-vegetated land parts. The lower part of the Mesoproterozoic Rajgarh Formation, Lalsot Basin, North Delhi Fold Belt, Aravalli Craton in NW India, provides a rare record of a tide-reworked fan delta depositional system. Sedimentary facies analysis reveals eleven lithofacies grouped under three major facies associations, viz., (i) gravel-rich conglomerate facies association, characterized by stacked debris flow deposits forming a subaerial alluvial fan, representing the delta topset component, followed downslope by (ii) pebbly, cross-stratifed sandstone facies association, characterized by reworking of the subaqueously emplaced debris flows by ebb-tidal currents, to produce the mouth bar and the delta front depositional systems, and finally, (iii) sandstone-mudstone heterolithic facies association, characterized by abundant tidal signatures in pebble-free thin-bedded sandstone-mudstone heteroliths with tidal bundles, herringbone cross-strata and wave ripples, characterizing a stable platformal subtidal-intertidal flat depositional system. The lower-middle part of the succession records an aggradational stratal stacking pattern of the subaerial alluvial fan changing to progradational stratal stacking of the laterally accreted debris-rich tide-led clinoforms producing the delta topset – mouth bar – delta front transiton of a tide-reworked fan-delta under successive regressive conditions, representing syn-rift deposition near the basin margin. A retrogradational stratal stacking pattern overlies the fan-delta succession, and signifies a transgression by landward encroaching tidal flat system over the fan-delta system during post-rift phase in a stable platformal setup, where debris supply is ceased. A regressive-transgressive model characterizing the transition from a fan-delta to tidal flat depositional systems portrays fluctuations in the accommodation conditons in response to complex interplay of basin tectonics and relative sea level changes in the Mesoproterozoic riftogenic Lalsot Basin. • Sedimentary facies model of tide-reworked fan-delta from Mesoproterozoic rift basin. • Syn-rift, aggrading debris flows led to a subaerial alluvial fan (the delta plain). • Progradation of fan delta by subaqueous tide-reworked debris flows (mouth bar). • Post-rift stable platformal transgression by a retrograding tidal flat on fan delta. • Transgressive-regressive cycle by interaction of autogenic vs. allogenic processes. [ABSTRACT FROM AUTHOR]

• Geological and cosmogenic data from Corsica reveal two-stage river capture events. • Clast lithologies demonstrate a progressive reduction of the Paleo-Ostriconi basin. • River capture led to the formation of a large Pliocene-Quaternary submarine fan. • Focused erosion can affect sites of former river capture after millions of years. • Corsica is still adapting to the disequilibrium caused by uplift of Alpine Corsica. Quantitative analysis of fluvial topography and sediment yield changes are often independently used to detect major river capture events and episodes of drainage reorganization. Here we use a unique set of geological and in situ 10Be cosmogenic data from Corsica, Western Mediterranean, to provide evidence of major river capture events affecting the former Paleo-Ostriconi river catchment during the Pliocene, and to illustrate how the landscape of Corsica is still reacting to the disequilibrium caused by the late Miocene uplift of Alpine Corsica. We found that ∼1280 km2 of basin area originally draining towards the Ligurian Sea were abruptly connected to the Tyrrhenian Sea by the capturing Tavignano and Golo rivers, which led to the formation of a large Pliocene-Quaternary submarine fan offshore the Tyrrhenian coast. The increased sediment yield towards the Tyrrhenian margin after river capture in the Pliocene was three times greater than the average sediment yield in the same source-to-sink system during the Holocene (410±100 t·km−2· a −1 vs ∼131±8 t·km−2· a −1) and greater magnitude than any subsequent peaks in sediment yield during late Pleistocene glaciations. 10Be-derived denudation rates reveal that focused erosion still affects retreating knickpoints near the sites of former river capture in central Corsica, suggesting persistence of landscape disequilibrium for several millions of years. Our results demonstrate the potentially large impact of river capture on the stratigraphic record and highlight the importance of full consideration of landscape response times to onshore disturbances for any reliable interpretation of the offshore sedimentary archive. [Display omitted] [ABSTRACT FROM AUTHOR]

Interactions among late Cenozoic global cooling, tectonic activity and regional climate evolution of the northeastern Tibetan Plateau remain elusive. To further understand the relative contributions of global climate change and tectonism, we conducted a comprehensive study of heavy minerals, rock magnetism, and branched glycerol dialkyl glycerol tetraethers (brGDGTs) in late Cenozoic sediments of the Laojunmiao section (ca. 12.7 Ma to 5 Ma) in the Jiuxi Basin. Our results reveal a notable increase in magnetic susceptibility (χ) and saturation isothermal remanent magnetization (SIRM) at 8.5 Ma, aligning with an accelerated decrease in temperature captured by brGDGTs. Combined with heavy mineral analysis, we propose that the profound changes in magnetic parameters and temperature are closely linked to the intensive uplift of the northern Qilian Shan since 8.5 Ma. Furthermore, this ongoing uplift has occurred simultaneously with persistent aridification in the Jiuxi Basin and its adjacent regions. The Qilian Shan might have reached a threshold elevation and began to act as a moisture barrier to northwestward moisture since 8.5 Ma. By synthesizing hydroclimate evolution records from the northeastern Tibetan Plateau, we deduce that changing topography resulting from tectonic uplift may have exerted a significant influence on regulating the moisture distribution in this region during the mid- to late Miocene. • Temperature reconstructed using brGDGTs declined at an accelerated rate at 8.5 Ma • Magnetic enhancement of lacustrine-delta fan sediments occurred at 8.5 Ma. • The northern Qilian Shan was uplifted at 8.5 Ma, simultaneous with regional drying. • Tectonic uplift was the primary driver of this climate transition at 8.5 Ma. [ABSTRACT FROM AUTHOR]

• Formation of fan barriers and landslide dam between 1.74 ± 0.33 Ga and 122 ± 34 Ma. • Impounding of liquid fluid by fans barriers and landslide dam. • The age of the last erosion responsible for the formation of the depression strandlines must have occured between 122 ± 34 Ma and 90.5 ± 20 Ma. • The minimum age of the last stage of the channel floor surface is 90.5 ± 20 Ma. The second-largest outflow system on Mars is Kasei Valles. The southern branch of Kasei Valles includes two inner channels among the best-preserved examples of glacial and/or fluvial erosion. This study focuses on the landforms formed by surface processes within the midstream part of the southern branch of the Kasei Valles. We mapped the landforms and built a morpho-stratigraphical chronology using their cross-cutting relationships, and numerical crater dating. We interpret a complex geomorphological history, with various landforms in the study area, including fans, landslides, topographic barriers, strandlines, terraces and deeply incised canyons. Two coluvaial fans and a large landslide temporarily blocked the valles, forming topographical barriers to impound fluids (e.g., lava, mudflow, water). It has been suggested that the structures observed in the channels were formed by Bingham or Newtonian fluid. However, these fluids have disappeared but they have left the terraces and strandlines as their geomorphic imprints. The surface texture of the terraces implies that they were probably formed by a very low viscosity fluid that carved the fan, valley floor and formed terrace staircases and deep canyons. Crater statistics reveal two different temporal clusters of colluvial fan formation. The age of the older fan cluster in the Early Amazonian period, and the age of the younger fan cluster in the Late-Middle Amazonian period. The landslide is much younger and estimated to have formed 122 Ma ago, allowing us to constrain the timing of the latest erosional period. The youngest studied geomorphic features are the platy-textured deposits emplaced either as lavas or mudflows, aged 90 Ma, covering the floor of the valles. The strandlines defining the limits of the youngest erosional (thermal) process within the study area truncate the landslide but not the platy-textured features. Therefore, they are older than 90 Ma but younger than 122 Ma, implying environmental conditions sufficient to have allowed a liquid fluid body at the Martian surface during the Latest Amazonian period. Our data suggest that the presence of well-developed terraces between strandlines requires the presence of a fluid (e.g. water, liquid lava, mud) that ponded and subsequently evacuated from the study area. [ABSTRACT FROM AUTHOR]

Thick frost on the evaporators of air-source heat pumps and refrigeration systems can degrade system performance. Defrosting in time based on precise frosting state recognition method is of great importance. Indirect measuring recognition method with low accuracy is widely used in commercial systems, for cheapness and simpleness, needing improvement urgently. While accurate direct measuring methods are usually expensive and complicated. Therefore, a novel frosting state recognition method with high accuracy is proposed, which can be realized with a simple current sensor. The method is based on the micro fluctuation in the evaporator fan current (rather than current amplitude) caused by the perturbed air due to frost. An experimental setup is built to obtain fan current samples. Combining three feature extraction approaches and three classifiers, four frost state recognition methods using fan current fluctuation are merged. They are compared and studied based on the experimental samples. Results show original signal + 1D-CNN method has the best identification performance, reaching 95.74 ± 1.73 % accuracy at −10 °C evaporator air temperature. It reveals 94.53 ± 1.06 % accuracy in a temperature range of −5∼-20 °C, and 94.73 ± 1.00 % accuracy for another fan with the same model. The method has significant improvement in performance and good potential for further study and application. • A novel frosting state recognition method is proposed based on evaporator fan current. • It is based on tiny fluctuation in current due to frost rather than current amplitude. • Growing frost changes the wake turbulence, causing the micro fluctuation in current. • Extracted feature + classifier make up recognition methods, four methods are studied. • Original signal+1DCNN has the best recognition accuracy of 95 % in T a range of −5∼-20 °C. [ABSTRACT FROM AUTHOR]

Northeastern Eurasia is one of the least explored regions in the world. Very little geophysical data is available for this inaccessible area. Even the exact location of the plate boundary between Eurasia and North America remains a subject of ongoing debate. The effective elastic thickness (EET) of the lithosphere is a proxy for lithospheric strength and can provide insight into the thermal regime and tectonic processes. We have computed a high-resolution map of the EET for northeastern Eurasia using the fan wavelet coherence technique applied to the Bouguer gravity anomalies and topography/bathymetry data, appropriately adjusted to account for the influence of density variations within sediments. The results obtained provide insights into different tectonic regimes within this predominantly understudied region. In particular, we identify the boundary between the Eurasian and North American plates in Siberia as a rheologically weak diffusive zone extending from the Verkhoyansk and Sette-Daban Ranges to the eastern boundary of the Chersky Range. Unlike the Sette-Daban and Verkhoyansk Ranges, which were formed by plate collision and have an EET of 30–50 km, other mountainous regions have much lower EET values, usually less than 15 km. These areas have recently experienced tectonic activity that has weakened the lithosphere. • A high-resolution map of the effective elastic thickness of the lithosphere is calculated for Northeastern Eurasia. • The boundary between the North American and Eurasian plates in Siberia represents a wide transition zone of weak lithosphere. • The origin and tectonics of various mountain belts are reflected in large variations of the effective elastic thickness. [ABSTRACT FROM AUTHOR]

Whereas the effects of high-order relative sea level change (3rd-order and higher) on the formation and architecture of submarine fan systems are relatively well established, a lack of large-scale spatial and temporal data has resulted in the impacts of low-order relative sea level change (i.e. , 2nd-order) eluding characterization. With the aim of revealing the impacts of 2nd-order relative sea level, this study applied regional-scale seismic geomorphology to examine 142 Miocene-aged (21–8.2 Ma) submarine fans in the Baiyun Sag of the Pearl River Mouth Basin (China), integrating a large 3D seismic volume (6000 km2), well logs and core data. By extracting seismic attributes calibrated to well data, architectural elements were interpreted, statistically correlated, and their evolution through time was assessed. The results were as follows: (1) architectural elements of submarine channels and lobes, as well as associated highstand deltas, shelf-margin deltas and incised valleys, were identified based on their seismic geomorphological features and location, revealing that submarine channels shift paleo-seaward from incised valleys and feed lobes; (2) there is a positive correlation between average width of submarine channels and average area of lobes, as well as between the average width of incised valleys and average width of submarine channels; (3) the size of architectural elements is inversely related to proportion of sand; and most importantly, (4) the size variation of architectural elements coincides with changes in 2nd-order relative sea level. Results also indicate that rapid tectonic subsidence played an important control on the size and sandiness of deep-water architectural elements. The findings of this study may inform reconstruction of submarine fan systems and prediction of their petroleum reservoir potential in other systems globally. • Submarine fan architectural elements were identified. • Two positive correlations between the architectural elements were revealed. • Second-order relative sea level had controlled the sizes and lithology of architectural elements. [ABSTRACT FROM AUTHOR]

The gas hydrate stability zone (GHSZ) is defined by pressure-temperature-salinity (pTS) constraints of natural gas hydrate (GH) system. It refers to a depth interval which usually extends several hundred meters into the sediment column at sufficient water depths. The lower boundary of the GHSZ often coincides in seismic reflection data with a bottom simulating reflector (BSR), which indicates the transition between the underlying free gas and the overlying no-free gas zone at the thermodynamic stability boundary. The GHSZ in geological systems is dynamic and can shift in response to sedimentation processes and/or changes in environmental conditions such as bottom water temperatures, hydrostatic pressure, and water salinity. The appearance of multiple BSRs has been interpreted as remnants of former GHSZ shifts which have persisted over geological timescales. In this study, we numerically simulate the sedimentation-driven development of multiple stacked BSRs in the Danube deep-sea fan in the Black Sea. We show that in this dynamic sediment depositional regime sufficient amounts of residual gas remain trapped in the former GHSZ, given sufficiently high initial gas hydrate saturations, so that paleo-BSRs could persist over long time scales (∼ 300 kyr). In particular, the formation and persistence of multiple BSRs in the Danube Delta is controlled by the sequence of sedimentation events of the levees induced by sea-level change. The kinetics of methane phase transitions between gas hydrate, dissolved methane, and free gas plays a key role in the coexistence, location and timing of the multiple BSRs. Thus, For a given permeability, distinct multiple BSRs appear only for a narrow range of GH formation (10 − 14 < k f mol / m 2 Pa s ≤ 10 − 12) and dissociation rates (10 − 16 < k d mol / m 2 Pa s < 10 − 14). • This study simulates the sedimentation-driven development of multiple stacked BSRs in the Danube paleo-delta, Black Sea. • Multiple BSR formation in Black Sea is controlled by the sequence of sedimentation events of levees due to sea-level changes. • Kinetics of phase transitions plays a key role in the coexistence, location, and timing of the multiple BSRs. • Development of multiple BSRs is possible only under a narrow range of parameters, unique for the Danube delta setting. [ABSTRACT FROM AUTHOR]

The purpose of this paper is (i) to re-assess the presence of submarine fan systems of Middle and Late Miocene age (Moki and Mount Messenger formations) previously mapped on the continental slope in offshore southern and central Taranaki Basin, New Zealand, and (ii), to demonstrate the occurrence of two newly mapped Late Miocene submarine fans in the deep-water part of offshore western Taranaki Basin, based on accepted seismic stratigraphic criteria for submarine fans. In our work we have found that the fans previously mapped amongst canyons and channels in the Moki and Mount Messenger formations on the upper and middle continental slope in southern and central Taranaki Basin do not fulfil established stratal criteria for submarine fan deposits. Moreover, detuning of 3D seismic reflection volumes for the Moki and Mount Messenger formation intervals ahead of amplitude attribute extraction, shows that the strata previously mapped as submarine fans based on amplitude alone, are merely artifacts of bed thickness. The two new fans systems of Late Miocene age that we map here, both attributed to the Mount Messenger Formation, principally comprise mudstone and represent a minor proportion of the Late Miocene succession that accumulated in southern and central parts of the basin. Our remapping of slope canyons and channels in the southern part of the basin and the identification of the two new fan systems in the western part of the basin are embodied in three new paloegeographic maps for the Middle and Late Miocene development of Taranaki Basin. A modern analogue for the two new Late Miocene fans in Taranaki Basin is the Hikurangi Fan at the terminus of the Hikurangi Channel, located outboard of the modern subduction zone of the Hikurangi margin along Eastern North Island. The new Taranaki Basin deep-water fans documented here, may have significance for hydrocarbon exploration in deep water parts of Taranaki Basin, which is largely unexplored. • New seismic geomorphologic mapping of the upper Moki and lower Mount Messenger formations in Taranaki Basin, New Zealand. • Critical reassessment of previously published submarine fan systems in southern and central Taranaki Basin and their dismissal on standard seismic stratigraphic criteria. • Seismic mapping of two new submarine fan systems in western Taranaki Basin. • Updated Taranaki Basin palaeogeographic maps for ∼14 Ma, ∼12 Ma and ∼6 Ma. [ABSTRACT FROM AUTHOR]

The fine siliciclastic rocks of the Early Permian Shoushangou Formation in West Ujimqin Banner, central Inner Mongolia are a hot spot for Late Paleozoic oil and gas exploration and hold key implications for the tectonic evolution during the closure of the Paleo-Asian Ocean (PAO). Therefore, the sedimentary characteristics of the Shoushangou Formation in West Ujimqin Banner, along with the geochemical and Sm–Nd isotopic characteristics of the clastic rock samples in Well MXD1, were investigated to privde additional constraints on its provenance and tectonic background. The mudstones contain large proportions of quartz, feldspars and igneous debris, and the CIAcorr (0.52–0.66), the A–CN–K plot and the lack of Ce anomalies in REE show a weakly weathered provenance and the chemically unaltered parent rocks, suggestive of the proximal deposition and rapid burial. Slip-roll beddings, gravity flow, Bouma sequences and the (trace) fossil assemblages in the profile indicate that the Shoushangou Formation is mainly a shallow- (semi-)abyssal submarine fan and the lithological information indicates the presence of microfaces including main and lesser water supply channels, interchannels, lobes, natural levees. Furthermore, a narrow continental shelf above the submarine fan and the concentrated zircon age population of the Shoushangou formation suggest that the tectonic background is most likely a retroarc basin. The Al 2 O 3 /TiO 2 ratio (19–24, average 22), the multivariable principal element source identification diagram and the plots of Th/Sc vs. Zr/Sc and Co/Th vs. La/Sc indicate that the source is mainly felsic, with a minor proportion of intermediate rocks. Trace elemental characteristics (e.g., Th, Zr, Sc, Co, Nd, and REE) deomonstrate that the tectonic setting of the Shoushangou Formation is confined by continental arcs. The whole rock Sm–Nd isotopic spectra of the Carboniferous and Permian strata indicate that the Baolidao arc is the main source of central Inner Mongolia. Additionally, the comparison of the Nd model ages and the zircon U–Pb ages of the Baolidao arc and other entities in the Central Asian Orogenic Belt (CAOB) is in support of a prolonged subduction of the PAO since ∼510 Ma, suggesting that the Baolidao arc was developed from the southern continental arc of the original South Mongolia microcontinent. Accordingly, it is suggested that the Shoushangou Formation was deposited in a retro-arc basin which was strongly influenced by the steep subduction of the PAO and the results collectively suggest that the PAO terminated no earlier than the middle to late Permian. • Proposed a submarine fan model for the gravity flow system in central Inner Mongolia. • The Shoushangou Formation is deposited in the retro arc basin semi-confined by the Baolidao continental arc. • The siliciclastic rocks in the Shoushangou Formation are mainly derived from the Baolidao arc. • Sedimentary and geochronological evidences suggest that the PAO terminated no earlier than middle-late Permian. • The Nd isotope data indicate the affinity of the Baolidao arc with other entities in the eastern Central Asian Orogenic Belt. [ABSTRACT FROM AUTHOR]

The connection between deltaic clinothem growth and the formation of down-dip deep-water systems on continental margins has been extensively discussed as a crucial component of sequence stratigraphic theory. However, in lacustrine settings, the growth of deltaic clinothems and outlying deep-water fans remains comparatively poorly understood. In the southwestern Bozhong Sag, Bohai Bay Basin, China, both lacustrine deltas and outlying sub-lacustrine fans were developed during the Oligocene, providing an opportunity to investigate the connection between lacustrine deltaic clinothem growth and the formation of outlying sub-lacustrine fans in deep-lacustrine systems. We employ 3D seismic data, well data, core data, and sandstone grainsize data to analyze the stacking patterns and internal architectures of these two sedimentary systems in the lower and upper successions of our study interval, SQE d 2 L. In addition, elemental geochemical parameters were utilized to reveal the paleoclimatic signature of the different stratigraphic successions. Our results suggest that there are two main types of deltaic clinothem stacking patterns in the lower and upper successions of SQE d 2 L, respectively: (1) in the lower succession, progradational to aggradational stacking patterns have a flat to steeply rising rollover trajectory, and (2) in the upper succession, aggradational to progradational and degradational stacking patterns have a slightly rising to flat and slightly falling trajectory. Meanwhile, the sub-lacustrine fans with straight channels and thick lobe complexes are coupled with progradational and aggradational (PA) deltaic clinothems in the lower succession. In the upper succession, small-scale sub-lacustrine fans with sinuous channels and thin lobe complexes are coupled with aggradational to progradational and degradational (APD) deltaic clinothems. The sediment connectivity between lacustrine deltas and sub-lacustrine fans stands in stark contrast to their counterparts in marine basins (such as marine APD clinothems coupled with large-scale deep-water fans, while marine PA clinothems rarely produce deep-water fans). In addition, two contrasting paleoclimatic stages have been identified in SQE d 2 L, namely the earlier humid stage in the lower succession and the later semiarid climatic stage in the upper succession. A comprehensive analysis of the differences between lacustrine and marine basins indicates that climatic variations play a pivotal role in deep-lacustrine deposition. Consequently, a climate-cycle-driven, sediment-supply-dominated sedimentary model of delta-to-fan sediment connectivity is proposed that incorporates the efficiency of terrigenous sediment dispersal into deep-lacustrine floors and the architecture of sub-lacustrine fans. The findings of this study further refine the implementation of the sequence stratigraphy paradigm and enhance the understanding of delta-to-fan sediment connectivity in deep-lacustrine depositional systems. • The scale of deep-water fans is coupled with various lacustrine deltaic clinothems. • Sediment connectivity of delta-to-fan in lacustrine basins is opposite to marine. • Climatic variations regulate sediment-supply and deep-lacustrine deposition. • Humid climates led to increased sediment connectivity between deltas and fans. [ABSTRACT FROM AUTHOR]

The western Ordos Basin is located at the intersection of multiple tectonic units and is a key area in the restoration of the palaeogeographic pattern of the East Asia region. The stability of the area and well-developed Paleozoic strata in the basin provide ideal conditions for revealing the relationships among the tectonic processes apparent there. However, within the constraints of extensive post-depositional modification, poor-quality seismic data, and a lack of wells, sediment dispersion differences, source attribution, and source-to-sink processes are still unclear. In this study, we integrated sedimentology, mineral, and geochemical data obtained from marine, continental, and marine-continental transition sedimentary environments in the study area in order to reveal the evolution from source-to-sink. The results show that the western Ordos Basin was predominantly supplied by the Alxa block, Yinshan orogenic belt, Qilian orogenic belt, and the North Qinling orogenic belt during the Late Paleozoic era. As a result of the closure of the Paleo Asian Ocean, the Alxa block and Yinshan orogenic belt became the primary source areas to the north, being composed of granite and alkaline basalt and some sedimentary rocks. In the southern area, the Qilian and the Northern Qinling orogenic belts were subjected to the PaleoTethys remnant ocean basin subduction during the Early Permian. Granite and alkaline basalt were the source rocks of the North Qinling orogenic belt, which became the source area during the Shanxi period. The Qilian orogenic belt contains some sedimentary rocks. The continuous uplift of the southern and northern orogenic belts. The tectonic setting of the northern source area transitions from a passive continental margin to an active continental margin with a mixture of continental arc. The tectonic setting of the southern source area transitions from a mixture of passive continental margin and active continental margin to an active continental margin and continental island arc. The climate changes gradually from humid to semi-arid and then to arid, and meanwhile, the sea level shows a decreasing trend, leading to an increasing distance of advancement for each source-to-sink system, and gradually converged in the central and eastern regions of the basin. Tidal and fan delta sandy sediments in the study area were transformed into fluvial delta sandy sediments in the northern two source-to-sink systems. The southern source-to-sink systems gradually changed from scattered sandbarrier and coastal sandy sediment to fluvial sandy sediment after the Shanxi Formation. • No apparent source from the North Qinling Belt before Shanxi Formation. • Subduction/collision time difference between Ocean Basins create a north-south difference in dispersal of sandy sediments. • Sandy sediments dispersal in marine-continental transition influenced by climate, sea-level, and basin accommodation space. [ABSTRACT FROM AUTHOR]

Climate change is increasingly affecting human well-being and will inevitably impact on occupational sectors in terms of costs, productivity, workers' health and injuries. Among the cooling garment developed to reduce heat strain, the ventilation jacket could be considered for possible use in workplaces, as it is wearable without limiting the user's mobility and autonomy. In this study, simulations with a sweating manikin are carried out to investigate the effects of a short-sleeved ventilation jacket on human thermophysiological responses in a warm-dry scenario. Simulations were performed in a climatic chamber (air temperature = 30.1 °C; air velocity = 0.29 m/s; relative humidity = 30.0 %), considering two constant levels of metabolic rate M (M 1 = 2.4 MET; M 2 = 3.2 MET), a sequence of these two (Work), and three levels of fan velocities (l f = 0; l f = 2 ; l f = 4). The results revealed a more evident impact on the mean skin temperature (T s k ) compared to the rectal temperature (T r e) , with significant decreases (compared to fan-off) at all M levels, for T s k from the beginning and for T r e from the 61st minute. Skin temperatures of the torso zones decreased significantly (compared to fan-off) at all M levels, and a greater drop was registered for the Back. The fans at the highest level (l f = 4) were significantly effective in improving whole-body and local thermal sensations when compared to fan-off, at all M levels. At the intermediate level (l f = 2), the statistical significance varied with thermal zone, M and time interval considered. The results of the simulations also showed that the Lower Torso needs to be monitored at M 2 level, as the drop in skin temperature could lead to local overcooling and thermal discomfort. Simulations showed the potential effectiveness of the ventilation jacket, but human trials are needed to verify its cooling power in real working conditions. • Simulations on a sweating manikin to evaluate the effectiveness of a ventilation jacket. • A more evident impact on the mean skin temperature than on the rectal temperature. • Significant decrease in trunk skin temperatures: a greater drop recorded in the Back. • Significantly improved whole-body and local sensations at the highest fan velocity. • Lower Trunk temperature drop needs to be monitored: it can lead to thermal discomfort. [ABSTRACT FROM AUTHOR]

Unusual sedimentary deposits such as stromatolites, thrombolites, dendrolites, and giant ooids are widely distributed in the Permian–Triassic boundary (PTB) successions of shallow platform facies worldwide. These microbial fabrics, however, are rarely present in the same section. The genesis of these PTB microbialites and the oceanographic conditions linking to the end-Permian mass extinction still remain disputed despite intense study. Here, we report a stromatolite-dendrolite-thrombolite-giant ooid association from the PTB beds of the Yudongzi section on the northwestern margin of the Yangtze Platform, South China, which was situated in low latitudes during the Permian-Triassic (P-Tr) transition. The Yudongzi microbialites rest on an irregular contact with underlying Permian bioclastic limestone and are comprised of lower bedded stromatolite, digitate dendrolite, upper bedded stromatolite, and thrombolite units. The bedded stromatolite is characterized by undulating laminated structures and various amalgamated and layered clots. The digitate dendrolite is made up of digitate-like branches, formed by clots distributed in an arched arrangement, and characterized by abundant branching dendroids. The thrombolite displays distinct clotted textures that comprise a mixture of dark-colored microbial fabric and light-colored interstitial sediment. In microbialite, columnar structures identified as Gakhumella -like calcimicrobe are very abundant. Each individual of Gakhumella -like structure has densely arranged segments forming a columnar- to fan-shaped micro-structure. Single segments are arch-shaped and form a thin chamber between segments. Coccoid-like, bacterial clump-like, and other spheroidal aggregates are also commonly present and suggestive of a biogenetic origin for the Yudongzi microbialites. Moreover, distinct aragonite crystal fans are also for the first time found in the PTB microbialites in South China, suggesting that the fans may have resulted from high inorganic carbon concentrations, and thus high levels of carbonate dioxide in the seawater. The Yudongzi microbialites are capped by shelly grainstone and a massive giant oolite, implying that the demise of the Yudongzi microbialites may be due to destruction by strong wave currents in a high energy setting. Some ooids are coated unevenly by micritic laminae (or envelopes) indicating the possibility of a microbe-related origin. These microbial-coated giant ooids, together with the massive microbialites, may imply the long-term of microbial bloom in the oceans immediately after the end-Permian extinction. The co-existence of abundant Gakhumella-like microorganisms and oxygen-dependent invertebrates, together with some coccoid-like spheroids, aragonite cement crystal fans, and pyrite framboids indicative of oxygen-poor conditions, implies that oxygenation state of the PTB microbialites is much more complex than previously recognized, demonstrating need for continued multidisciplinary examination of facies changes associated biotic mass extinction. [Display omitted] • PTB microbialite complex comprises bedded stromatolite, digitate dendrolite, thrombolite and giant ooids. • Microbial fabrics include undulating laminated structures, digitate-like branches, and clotted textures. • Ooids are coated by micritic laminae indicating the possibility of a microbe-related origin. • Columnar structures identified as Gakhumella are very abundant and belong to the benthic Pleurocapsale cyanobacteria. • Aragonite crystal fans are distinct, and may have resulted from high bicarbonate in the seawater. [ABSTRACT FROM AUTHOR]

The Messinian Salinity Crisis (MSC) was a major disruptive event in Earth's history involving all Earth's systems - hydrosphere, biosphere, lithosphere, and atmosphere. Approximately six million years ago, the entire Mediterranean Sea turned into a hypersaline basin when the Gibraltar gateway to the Atlantic Ocean narrowed and evaporation exceeded fresh water input. Consequently, marine fauna died and massive deposition of salt on the seafloor had led to the formation of the world's youngest salt giant. A fundamental observation related to this enigmatic period is a remarkable erosional surface, associated with 100 s-of-m deep canyons that were incised across the Mediterranean's continental margins during the crisis. Such canyons across the Levant margins were described in the 1970s and, later, in the 2000s they were shown to be the gateway for shallow, sinuous, submarine channels that continued towards deeper parts of the basin. Though it could have been assumed that these channels end as terminal sedimentary lobes in the Levant Basin, we show here that they contributed to a much wider sedimentary system in the Eastern Mediterranean Sea: farther west, they merge into a nearly 500-m-deep and ∼ 10-km-wide canyon, which we name after the nearby Eratosthenes Seamount. This remarkable canyon was excavated at the beginning of the MSC prior to salt deposition. We suggest that incision took place during Stage 1 of the MSC, but we cannot rule out faster incision (10s of ky) at the end of Stage 1 (∼5.60 Ma), or at its very beginning (∼5.97 Ma). Regardless of its exact age, we show that the Eratosthenes Canyon was excavated subaqueously and suggest that incision was caused by gravity currents, such as sediment-laden turbidites and/or dense brines. We argue that the increased salinity at the beginning of the crisis and a possibly limited sea level fall - whose amplitude should be investigated - had triggered these gravity currents, destabilizing the continental margin and carving the seabed wherever it was steep enough. • Discovery of the Messinian Eratosthenes Canyon (EC) in a deep Mediterranean basin. • The canyon is located 200–300 km away from the Levant continental margin. • Incision occurred at the beginning of the MSC before salt accumulation. • The EC formed sub-aqueously by dense gravity currents. • We describe the environmental conditions leading to halite precipitation. [ABSTRACT FROM AUTHOR]

Submarine channel mouth settings are hardly preserved in the stratigraphic record. Although they are still poorly known with respect to other segments of turbidite systems, conceptual models are being refined in the light of new discoveries in modern and ancient examples. Still, some questions such as the transition between expansion zones and the traditional Channel-Lobe Transition Zone (CLTZ) remains open in ancient systems. Upper Eocene deposits of the Colombian Caribbean (San Jacinto Fold Belt) are interpreted here as a fan-delta-fed, submarine, coarse-grained channel-lobe system. It displays a well-preserved channel inception stage in the shelf break represented by sigmoidal to lens-shaped gravels, and planar cross-stratified pebbly sandstones (foreset and backset) interpreted as cyclic steps in an expansion zone. In a later stage, a classical channel-levee complex was developed, represented by channel fill elements showing sharp- and erosional-based, fining-upward sequences that are meters thick, having basal massive matrix-supported pebble conglomerates (hard—extrabasinal—clasts, rip-up clasts, coastal bioclasts), vertically evolving to liquefied massive to planar-laminated coarse-grained sandstones with phytodetrital carbonaceous laminae. They are interpreted as concentrated flow deposits (high-density turbidites) coming from continental areas or from coastal systems (i.e., delta reworking). Undifferentiated channel belt thin-bedded turbidites associated with levees and terraces deposits are related to these confined systems. The channel-lobe transition zone is characterized by debrites from cohesionless debris flow in a channel-mouth bar setting, representing bypass processes that developed distally into low-angle, planar cross- and sigmoidally-stratified (upstream antidune) pebble-size to coarse-grained sandstones that fill low-angle scours (cut-and-fill structures) in an antidune field setting with supercritical conditions. When the currents lose channel confinement, the setting is characterized by changes from Froude supercritical to subcritical flow conditions in an inner lobe to lobe off-axis environment. Large seasonal fluctuations in precipitation favor high sediment concentrations, promoting the formation of volumetrically significant fan deltas and coarse-grained submarine channels with high erosive capacity; therefore, their record helps refine interpretations of depositional processes, providing criteria for recognizing areas of the turbiditic systems that are hardly preserved. The particular aggradational conditions for the preservation and stratigraphic characterization of the rare exhumed submarine channel mouth systems make it possible to decipher sediment dispersal patterns and thus connect the models proposed here, from supercritical systems to the traditional models of turbiditic systems. • Sedimentary facies from confined to unconfined flows • Evolution of a coarse-grained system from supercritical to subcritical flows • Depositional cyclic steps with supercritical conditions • Debrites to antidune field settings with supercritical to subcritical conditions • Inner lobe to lobe off-axis in subcritical conditions [ABSTRACT FROM AUTHOR]

• Geomorphology of the Paghman and Chaman faults were described based on fieldwork and satellite data. • A reverse fault was mapped west of and almost parallel to the left-lateral Paghman fault. • Based on field observation, the approximate length of surface rupture due to 1505 earthquake is ∼30 km. • The Paghman and Chaman faults could produce an earthquake of Mw 7.3–7.8 in the Kabul Basin. The city of Kabul, Afghanistan, lies within the Kabul Block, which is bounded by the Sarobi, Gardez and Paghman fault, the northern extension of the Chaman fault, accommodating oblique convergence between the Indian and Eurasian plates. In this paper, we describe the geologic structure and tectonic geomorphology of the northeast-striking Paghman fault and a ∼10-km-long portion of the Chaman fault using a combination of field observations and remote sensing data, and assess evidence for rupturing in the 1505 historical earthquake. The Paghman fault is predominantly a left-lateral strike-slip fault with a minor dip-slip component along the eastern margin of the Paghman Mountains. The Chaman and Paghman faults displaces Paleogene to Quaternary units with clear displacement of recent deposits. Continuous left-lateral movement of the both faults have caused stream deflection, capturing, abandonment, and finally, incision of alluvial deposits inside the Kabul Basin. We identify several stages in the alluvial fan development and displacement that were once a continuous unit displaced left-laterally as a single fan but are now incised by beheaded and offset stream channels. An approximately 30-km-long active fault trace is identified with geomorphic evidence of recent faulting and vertical offset ∼0.5–3 m, which we interpret is related to the historical 1505 earthquake in the area along the Chaman and Paghman faults. Our observations indicate significant along-strike variations in faults trace geometry. The seismic event comprises several fault segments separated by discontinuities such as stepovers. The two faults have accumulated enough elastic strain to cause a larger earthquake since the 1505 quake. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new workflow integrating intelligent inversion and lithology model is proposed. • This method improves the seismic resolution and prediction of tight sandbodies. • The results provide reliable geological information for horizontal well drilling. Lacustrine gravity-flow deposits are common in sedimentary basins, and sand bodies formed in the basin center mingled with organic rich mudstone may form excellent tight reservoirs of hydrocarbons. However, the complex architecture and intensive heterogeneities of lacustrine gravity-flow deposits commonly pose great risks for hydrocarbon exploration and development. To address this problem, a new workflow for predicting tight sandstone is proposed in this work. The workflow combines well log analysis, intelligent seismic inversion and 3D geological modelling to improve the prediction effectiveness of tight sandstone and sedimentary facies. The original 3D seismic data was firstly decomposed into three components with low, middle and high frequencies to improve the resolution of seismic inversion, and a nonlinear relationship between well logs and the decomposed 3D seismic data was then established by using an algorithm of support vector machine. A 3D lithofacies model was subsequently established integrating well logs and the seismic inversion result. The distribution of sand thickness was imaged relying on the lithofacies model. Correlations between the actual and predicted sand thickness based on the seismic attributes and the seismic inversion result was improved from 0.66 to 0.79. The prediction of sand bodies was further improved through the 3D lithofacies modelling, especially for these thin sandstone layers. Sedimentary facies of the Chang_7 member in the Qingcheng Oilfield, Ordos Basin, were characterized based on the distribution of sand bodies. Fan-shaped sand bodies are mapped in each zone of the Chang_7 member, revealing that the entire Chang_7 successions are of sub-lacustrine fan in origin. The Chang_7 member mainly contains six sedimentary architectural elements: main channel, branch channel, lobe, lobe edge, slump body and inter lobe/inter channel. The distribution of sedimentary facies is different in different zones, and appears to be largely related to the change of base-level. A horizontal well was designed according to the prediction of sand bodies, which show a higher probability of drilling into sandstone by approximately 10% compared with that of other horizontal wells. [ABSTRACT FROM AUTHOR]

[Display omitted] • The early Miocene Burqan Formation is a deep-marine syn -rift succession. • Facies analysis indicate deposition in proximal to distal fan settings. • Depositional parameters (grain size and detrital matrix) exert dominant control on reservoir quality. • Diagenesis plays only a minor role on reservoir quality. • Mid-fan channel deposits are interpreted as excellent quality reservoirs. Understanding the distribution of sedimentary facies, their texture and diagenetic alterations in deep-marine rift systems are critical for improved reservoir quality predictions in the subsurface. Syn-rift deep-marine sandstones of the Miocene Burqan Formation, deposited by various sediment gravity flow types in the Midyan Basin (Red Sea, Saudi Arabia) are characterized using detailed sedimentological and petrographic analyses. Six distinctive lithofacies (F1-F6) have been identified within the Burqan Formation and grouped into three broad facies associations namely proximal, medial, and distal facies of a submarine fan. The proximal fan facies consists of disorganized conglomerate (F1) and structureless sandstone (F2). The medial fan facies are represented by graded bedded and channelized sandstone (F3) and sandstone dominated heterolithics (F4). Deposits of distal fan facies consist of mudstone dominated heterolithics (F5) and structureless mudstone (F6). The sandstones are predominantly arkoses and lithic arkoses with a low degree of diagenetic modification (Eo- and Telo-diagenesis; ≤ 2 km and ≤ 70 °C temperature) and low to moderate volumes of carbonate cement (mean = 7%). The structureless sandstone (F2), sandstone dominated heterolithics (F4) and mudstone dominated heterolithics (F5) have poor reservoir quality due to the presence of authigenic cement and matrix. Graded bedded and channelized sandstone (F3) lithofacies consists of excellent reservoir sandstone due to the least proportion of cement and virtual absence of detrital clay. The observed variability in composition and textural parameters within Burqan Formation indicates that sedimentological transport processes control the depositional reservoir quality which in turn dictates diagenetic modification in deep-marine sandstones with important implications for prediction of reservoir quality in deep-marine systems. [ABSTRACT FROM AUTHOR]

The evolution of alluvial fans is controlled by the tectonic setting and climatic fluctuations. This study focused on the Lidian alluvial fan in the northern piedmont of Zhongtiao Shan, north China, to study the fluvial responses to paleoenvironmental changes since the late Last Glacial Maximum. In combination with series of accelerator mass spectrometry (AMS) 14C dating data on fan sediments, sedimentary analyses indicated that the primary fan accumulation was controlled by episodic millennium-scale debris and sheet flood flow related aggradation during 13.3–13.0, 12.7–11.3, 6.2–4.5, and 4.5–2.8 cal ka BP. Between the accumulation periods, the fan process was dominated by aeolian paleosol-and-loess sequence development and the reworking of fan clasts. Considering regional hydraulic conditions and sediment flux, we proposed that the millennium-scale episodic debris flow related fan aggradation during 13.3–13.0, 12.7–11.3, and 4.5–2.8 cal ka BP was controlled by high-volume sediment influx of the permafrost and physical weathering during cold events. The millennium-scale sheet flood-dominated fan aggradation event during 6.2–4.5 cal ka BP was related to the abrupt coarsening and high sediment yield forced by tectonic uplift. We also suggest that the scattered distributed channelized floods and debris backfilling sediments within the fine-grain layers indicate that the deposition of irregular fan lobe accumulation coincided with hydraulic shifts over shorter temporal scales. [ABSTRACT FROM AUTHOR]

Chemosynthetic ecosystems are scattered in the deep ocean, harbouring highly specialized communities, among which the degree of connectivity and dispersal is scarcely studied. This gap is largely due to limited range distribution, either real or due to highly partial exploration, preventing the availability of a sufficient number of samples for population genetic analysis. For the few species that escaped this gap, large-scale panmixia was often reported, raising wonders as to the evolutionary mechanisms involved in the first steps of speciation. Vesicomyid bivalves are one of the most abundant groups of chemosynthetic fauna, for which depth was proposed as an essential driver of differentiation. Early stages of speciation are thus expected to involve genetic differentiation along depth gradients. The vesicomyid bivalve Christineconcha regab was studied across widely separated localities along the Western African margin, from the cold-seeps of Regab pockmarks located at 3150 m depth on the Congo margin to the turbiditic lobes of the Congo deep-sea fan located at 5000 m depth, using mitochondrial (COI) sequences and eight microsatellite loci. Despite rather high density in relation to high organic matter availability, results obtained showed rather low levels of genetic diversity at both mtDNA and microsatellites. The main consistent pattern of differentiation was observed across depths from Regab pockmark (South-Western part) and lobe areas (Lobe B and C). This is likely due to the largest sample sizes characterizing Regab_SW and Lobe C allowing the detection of faint genetic differentiation, and possibly to a stronger signature in the demographically declining (thus acknowledgedly under sampled) Lobe B. Other significant results were not congruent among markers, suggesting low statistical power due to limited sample size or the occurrence of chaotic genetic patchiness. Altogether, the results suggest the occurrence of effective gene flow at regional scale, and departure from equilibrium in the recently discovered lobes of the Congo River, possibly resulting from unstable environmental conditions and recurrent events of extinction recolonization. [ABSTRACT FROM AUTHOR]

Tuffaceous material of the Lower Triassic Baikouquan Fm., NE Junggar Basin is closely associated with detrital particles and particularly with crenulated quartz grains and kaolinite. The amount tuff is reduced closed to the source area. The main component of the tuffaceous interstitial material is SiO 2 , followed by K 2 O, FeO, and MgO. The tuffaceous interstitial material can be further divided into three types: medium (basic) potassium-rich tuffaceous material, ultrabasic iron-magnesium tuffaceous material, and ultrabasic iron-magnesium rich tuffaceous material. Medium (basic) potassium-rich is dominated by fusiform shrinkage pores, often associated with kaolinite, while ultrabasic iron-magnesium rich tuff pores are not developed, and ultrabasic iron-magnesium tuffaceous material is dominated by dissolution pores. The solution pores have large diameters and large volume of pores and throats, but low pores and throats coordination number. The pore size and the pores and throats volume of shrinkage fractures are small, but the pores and throats coordination number are large. Dissolution pores are mainly distributed in Mbr 1, whereas shrinkage pores mainly occur in Mbr 2. However, the interlayer productivity data from a single well show that the Mbr 1 has a higher productivity than Mbr 2. However, the interlayer productivity data from a single well show that Mbr 1 has a higher productivity than Mbr 2. In addition, tuff is not responsible for wind action, but the cause of intermittent water flow transport in volcanic rocks. Distributary channels at the fan delta front comprise the dominant facies for development of tuffaceous interstitial materials. The composition of tuffaceous interstitial material clearly determines reservoir quality. Medium basic potassium-rich tuff has a high SiO 2 content and is prone to devitrification, so it is dominated by shrinkage pores, whereas ultrabasic iron-magnesium tuff contains FeO and MgO and is vulnerable to acid corrosion and the formation of corrosion pores. However, acid minerals such as kaolinite reduce reservoir connectivity. Compared with solution pores, shrinkage pores have a small pore volume, but high pores and throats coordination number, indicating that they have a high seepage capacity. Shrinkage pores are an important factor in causing production differences between single layers and should be given more attentions. • Tuff is the cause of intermittent water flow transport in volcanic rocks and not falling mechanism. • Composition of tuffaceous material determines obvious selectivity of reservoir development. • Medium basic potassium rich tuff is dominated by shrinkage pores. • Shrinkage pores not only impact reservoir performance, but also have high seepage capacity. [ABSTRACT FROM AUTHOR]

The depositional record of intermontane basins provides a valuable archive of the temporal evolution of orogenic belts; their common isolated nature may, however, hinder the efficient usage of standard approaches to constrain the age of a basin fill. In this paper the authigenic 10Be/9Be dating method is employed and tested to construct an age model of the existence and regression of Lake Turiec, which appeared during the Late Miocene in the intermontane Turiec Basin, Central Western Carpathians (Central Europe). The initial authigenic 10Be/9Be ratio, essential for the dating method, was analyzed on five sites of the Pleistocene-Holocene age, and back-calculation of the paleo-initial ratio was performed using lacustrine succession dated by magnetostratigraphy. Noteworthy, the initial ratio appears to be affected mainly by (post)depositional settings, and not by different provenance of the analyzed sediment. The sedimentological analysis of the Upper Miocene outcrops allowed the definition of the facies associations of an alluvial fan, a braided river, a fan delta and an open lake. The distribution of facies associations in the basin fill implies an increase in sediment supply to accommodation rate ratio due to the replacement of the open lake environment by the interconnected alluvial fan-braided river-fan delta system. Authigenic 10Be/9Be dating yielded ages of the lacustrine succession reaching ∼10.7–7.8 Ma, while the age of the fan delta succession, considered as the timing of the regression, was established to ∼6.7 Ma. The deposition of alluvial fans dominated the basin after the regression of the lake, possibly up to ∼4.0 Ma. The abrupt increase in sediment supply to the accommodation ratio at ∼6.7 Ma was caused by the uplift of the Malá Fatra Mts. at the western margin of the Turiec Basin, which had previously formed a moderate topography. The timing of this process generally coincides with the overall decrease in accommodation rates in the region due to the inversion of the Pannonian Basin System. The endorheic character of the basin before ∼6.7 Ma prevented the transport of the sediment denudated from the recently most uplifted parts of the Western Carpathians and carried towards the Pannonian Basin System, while the present-day source-to-sink system could only be formed later. This implies a low sediment supply and restricted denudation rate not only from the morphostructures surrounding the basin, but also from the Tatra Mts. and Nízke Tatry Mts. during the period ∼10.7–6.7 Ma. The research supports the suitability of intermontane basins for authigenic 10Be/9Be dating in a setting of high accommodation rates and limited redeposition of older muddy sediment. However, a special attention has to be paid to the depositional settings during determination of initial 10Be/9Be ratios. • Authigenic 10Be/9Be dating resolve history of a long-lived isolated late Miocene lake. • Initial 10Be/9Be affected by (post-)depositional settings, effect of provenance unnoticed. • Lake Turiec existed between ∼10.7–6.7 Ma, then filled by a fan delta-braided river-alluvial fan depositional system. • Regression due to increased sediment supply from mountains uplifting after ∼7 Ma. • Termination of endorheic character and establishment of the Váh River catchment followed. [ABSTRACT FROM AUTHOR]

Platform motions induced by wind and waves import strong nonlinear coupling effects in the aerodynamic characteristics of floating offshore wind turbines (FOWTs), which exacerbate the power instability of the wind turbine and should be considered during the preliminary platform design stage. For this reason, a platform motion-based method was proposed to estimate the power stability and successfully applied to the preliminary platform stability design in this paper. Firstly, a high-fidelity computational fluid dynamics (CFD) model of a 10 MW wind turbine was established using the oversetting grid and superposition motion technology. Then the influence laws of platform surge and pitch motions on the power characteristics of the wind turbine were summarized. Subsequently, a semi-submersible floating platform structure for supporting the 10 MW wind turbine was designed preliminarily. The power stability of the wind turbine and tilting stability of the platform were analyzed based on the hydrodynamic analysis results. Finally, a hybrid scaled model of the 10 MW FOWT was built, incorporating a six-degrees of freedom load actuation system based on multi-fans. The scaled model test was carried out in a wave basin, demonstrating that both the power stability and the tilting stability of the platform meet the proposed stability requirements. • CFD simulations of the DTU 10 MW wind turbine under platform pitch and surge motions are carried out. • A novel stability design method of a floating platform is proposed. • An aerodynamic actuation system with six degrees of freedom is designed. • A hybrid model of floating offshore wind turbine based on software in the loop is built. • Scaled model test is carried out in the wave basin. [ABSTRACT FROM AUTHOR]

Sediments deposited on the eastern continental shelf of India are studied for texture, mineralogy and their major, trace, and rare earth elemental composition in lithogenic fraction. The objective of this study was to identify the sources, and evaluate the factors affecting the erosion and weathering in the catchment area and dispersal and deposition of sediments over the shelf region. Here, we present an extensive dataset covering the entire eastern continental shelf of India from the Ganges-Brahmaputra (G-B) basin in the north including the shelf off major peninsular Indian river basins of Mahanadi, Godavari, and Krishna up to the Kaveri basin in the southern tip. Textural and geochemical studies have shown that the lithology of the source rocks plays an important role in governing the chemistry and mineralogy of the sediments. The results show that the G-B shelf sediments are primarily derived from the Higher Himalaya Crystalline sequence (HHCS) and the Tethyan sedimentary series (TSS) exposed along the peaks and drainage divide of the Himalayas. Mahanadi shelf sediments are mainly derived from the felsic rocks belonging to Precambrian metamorphic formations of the Eastern Ghats, limestones, sandstones, and shales of the Gondwanas and recent deltaic alluvium deposits, whereas the Krishna-Godavari (K-G) sediments find a part of their source in the Deccan Basalts. The shelf sediments off River Kaveri are derived from a mixture of peninsular granitic gneisses, tonalite-trondjhemite gneisses, and charnockites. The sediment geochemistry has also allowed us in assessing the weathering patterns in the source areas. The sediments have undergone a moderate degree of weathering. Weathering intensities were found to have varied with the source area lithology. The least square regression of the geochemical data allowed us to estimate the relative contribution of each of these sources and their geographic extent. Unlike the massive offshore deposition and formation of a major Fan system (the Bengal fan), the fluvial sediment dispersal of the mighty Himalayan Rivers on the continental shelf is significant only at the G-B mouth and their contribution reduces to <50% at about 18oN. The sediment dispersal from the Godavari River is seen to extend on either side of the mouth of the river which is attributed to the reversing East India Coastal Current (EICC), which plays an important role, in the sediment transport along the central and south-central part of the east coast of India. The influence of the Mahanadi, Krishna, and Kaveri River sediments is however confined to a small area near their mouths and has a limited geographic extent of influence in the shelf region. • Entire eastern continental shelf of India is geochemically mapped, hithero not done • A distinct provinciality in geochemistry commensurate with source rock lithology is witnessed. • Geographic spread of each contributory source is estimated using mixing calculations • Reversing monsoon currents with season seem to control the sediment dispersal in the area. • Unlike the large geographic spread into deep-sea, spread of G--B derived sediments on the shelf is limited to narrow extent [ABSTRACT FROM AUTHOR]

Convergent margins host more than half of all global submarine canyons. In this environment, the lack of cognition of the canyon morphology variation and their controls in two different types of marine forearcs (erosive and accretionary) remains exists. Based on shipborne bathymetric maps, we systematically analyze width, incision depth and slope gradient of 17 submarine canyons along the Chilean marine forearc. We divide the study area into an erosive northern area, a transitional central area, and an accretionary southern area based on trench sediment cover and in line with previous tectonic interpretations. In the northern and central areas, limited sediment supply and little erosion from infrequent turbidity currents form narrow and shallow canyons that arrive at the toe of margin. Subduction erosion contributes to a simple and regular slope morphology where regional subsidence and trench-parallel faulting activities lead to vertical crustal movement and a steep thalweg of canyons' lower reach. In contrast, frequent canyon flushing/filling turbidity currents and slope failures on the canyon walls result in a wider range of canyon width and incision depth in the south. Here, the formation of an accretionary prism generates fold and thrust ridges at the seafloor that reduce the slope gradient of canyons' lower reach. Canyon morphology within the prism region has a larger range than the non-prism (backstop) region due to the higher erodibility of the less consolidated sediment. In addition, convex-up step-shaped bedforms develop along 14 canyon thalwegs, also suggesting regional uplift/subsidence and normal faulting in the north and central region but folding and thrust faulting in the south. This work not only reveals the difference of canyon morphology on active marine forearcs but also may help to understand controls on submarine canyon morphologies along the Chilean margin as well as in other convergent margins. • 17 large submarine canyons are identified and investigated along the Chilean margin. • Submarine landslides and turbidity currents widen and deepen canyons. • Subsidence and normal faults caused by subduction erosion steepen canyons thalwegs. • Canyon morphology has a larger range within accretionary prism due to sediment accretion. • Step-shaped bedforms along canyon thalwegs reflect localized uplift/subsidence and folds/thrust faults. [ABSTRACT FROM AUTHOR]

Martian gullies are surface features, typically composed of an alcove, a channel and a depositional apron. They have been extensively studied since their first observations in the 2000s and were initially attributed to the action of liquid water. Later studies highlighted that their activity is spatially and temporally correlated with the seasonal presence of surface CO 2 ice, suggesting a link between seasonal frost and gully activity. However, the exact mechanisms leading to gully formation are still under debate. Establishing whether or not gullies are formed by liquid water has important implications for Mars recent climate and habitability. Here, we study the evolution of seasonal frost and its connection to gully activity in Sisyphi Cavi, located in the southern circumpolar region (68°S - 74°S; 345°E − 5°E). The high latitude of this site allows for detailed temporal monitoring, owing to the high frequency imaging by spacecraft in polar orbits, largely unavailable for other martian gullies, hence this site has the potential to reveal new insights on gullies in general. In particular, we used repeat images from MRO HiRISE (Mars Reconnaissance Orbiter, High Resolution Imaging Science Experiment) and TGO CaSSIS (Trace Gas Orbiter, Colour and Stereo Surface Imaging System). Our findings show that the general timing and characteristics of the defrosting patterns in Sisyphi Cavi follow seasonal patterns that are consistent from year to year. The timing of the start of defrosting and its temporal evolution are controlled by the overall orientation of the host hillslope, with equator-facing slopes defrosting before pole-facing ones and the steepest pole-facing slopes defrosting last. Gully alcoves defrost before channels and aprons located on the same hillslope independent of the orientation of the hillslope likely because the aprons have a lower thermal inertia than the alcoves that counteracts the orientation effect, which on pole-facing slopes would mean the alcoves should defrost last. We observe the presence of seasonal and ephemeral dark spots and flows which are interpreted to be a result of sediment deposition on top of the seasonal ice deposits, triggered by basal sublimation. Our observations suggest that the appearance of dark spots and dark flows can be spatially correlated with surface roughness, including presence of boulders, contrasts in material types, irregular lobes/levees and braiding caused by gully activity, and therefore could be used to help detect recently active gullies on Mars in areas with seasonal frost without the need of repeat imaging. Finally, we propose that presently observed gully activity in Sisyphi Cavi is driven by defrosted material flowing on to a frosted apron. We infer that the presence of a frosted apron could be common precursor for this type gully activity. We note that this activity only involves the mobilisation of loose materials and we have not observed any erosion of the wall rock present in Sisyphi Cavi. [Display omitted] • We perform detailed monitoring of gullies and seasonal frosts in Sisyphi Cavi. • Gully alcoves defrost before their aprons even on pole-facing slopes. • Early alcove defrosting is likely related to their higher thermal inertia. • Frosted aprons are common on Mars and could be a precursor to gully activity. • Dark spots/flows found on rough terrain may highlight recently active gullies. [ABSTRACT FROM AUTHOR]

Optimal gas production from marginal fields vulnerable to tidal energetic effects is exceedingly challenging. Conventional seismic analysis is insufficient for a significant understanding of the geomorphological description, volumetric calculations, and microfacies analysis of the anticipated heterogeneous gas-bearing sands. New insights into the offshore North Sinai (ONS) Field based on quantitative and geostatistical interpretations integrated with physical and geometrical attribute analyses are boosted for reconstructing diverse-scale reservoir internal architecture. Deterministic band-limited inversion using acoustic impedance logs contributed to the initial knowledge of facies migration during tidal-dominated delta progradation and revealed four 2nd-order sequence boundaries dependent on P-velocity variations with depth as a function of rock elasticity, low impedance gas content of 2500–3000 kPa s/m and overburden compressional factors. Gradual boundaries confining reservoir bases due to spatiotemporal facies discrepancies triggered the implementation of stochastic algorism as a model norm for tracing thin-bedded and internal heterogeneous reservoirs with no predictable gas-water contacts across subtle dismantled areas. Stochastic inversion with intensive layering below −1 ms along with static property reservoir modeling allowed the evaluation of both fine and coarse-scale reservoirs discovered as extensions of injector-controlled stacked mouth bars, fan-lobes, and distributary channels crosscutting tidal mudflats of delta top facies associations within a system of spatially migrated clinoforms to the north. Stream avulsion-induced and accommodation space inconsistencies across syn-sedimentary faults caused the shifting of the Late Plio-Pleistocene clinoform depocenter northward and deltaic facies variation inside each individual sand system, not eustatic sea level fall. After calculating the biogenic gas reserves occupying each reservoir, the present strategy offers an additional seven broad gas prospects within four dismantled blocks, raising the ONS initial gas in place to 967.95 Bcf. In addition, it depicts five gas shoals emplaced at shallow depths, posing considerable drilling hazards. This paper workflow is the first of its kind in the Neogene section of the OSN Basin. • A straightforward procedure for basin analysis by sequence stratigraphic approaches and structural evolution. • Geometrical attribute analysis is insufficient for gas exploration. • Enhancing gas production through post-stack inversion techniques re-simulate tide-dominated gas reservoirs. • Stepwise strategy of reservoir simulation and volumetric calculations rises ONS gas production to 967.95 Bcf. [ABSTRACT FROM AUTHOR]

The discovery of the super-giant Coral and Mamba gas fields in the offshore of Northern Mozambique provides a unique insight into the architecture of a new deep-water play-type. High-quality seismic and extensive well data from both fields shows that very clean (clay matrix-poor) sandstone reservoirs, with thickness >100 m and extended over tens of km can be formed by the syndepositional interaction of down-slope high-density turbulent gravity flows and across-slope bottom currents. This is recorded by: i) the marked asymmetry of submarine channels and lateral stacking in which top-of-fan seismic reflectors show a lateral transition from high to low amplitude response from axis to off-axis locations; ii) the occurrence of laterally-deviated lobe deposits, sediment waves and channel-associated drifts in the inferred bottom current direction; iii) the presence of very clean sandstones forming the bulk of the fan units and the consistent lack of interbedded fine-grained facies; iv) the occurrence of fine-grained and thin-bedded facies adjacent to the main fan axes, which are characterized by repeated transitions between ripples and parallel-laminated sandstones, mud-drapes, shale clasts and bi-directional cross-laminae in the same bed, indicating intense traction and velocity pulsations. This association forms a mixed depositional system, in which only the basal and coarse-grained part of the turbidity current load is deposited and preserved in the axial part of the system, whilst all the finer-grained sediments are pirated from the turbulent cloud by laterally flowing bottom currents and deposited in the adjacent sediment drifts. The inferred process results in exceptionally high quality reservoirs whose architectural and facies models were confirmed by the appraisal campaign and production well tests and incorporated into the reservoir model. The results of this study indicate a significant exploration potential in similar geological settings and the definition of a potential new play type, that could lead to the reinterpretation of existing deep-water datasets. • First insight of the Area 4 in northern Mozambique and the Coral Field. • New deep-water play-type: very thick, clean and extensive reservoir sandstones. • Deposits formed by syndepositional interaction of bottom currents and gravity flows. • High quality dataset composed of well logs, cores and 3D seismic. • A facies tract related to deposits affected by bottom currents is proposed. [ABSTRACT FROM AUTHOR]

In recent years, shallow-marine fans have attracted considerable attention because they may serve as valuable targets in hydrocarbon exploration. By integrating 3-D seismic, well log, core, and other measured data, this study analyzed the sedimentary characteristics and factors controlling the deposition of shallow-marine fans in Member #1 of the Huangliu Formation in the Yinggehai Basin. Four depositional elements were recognized in the channel-lobe complexes (CLCs), channel-fill sandy debrites, channel-fill turbidites, sand-rich lobe deposits and mud-rich lobe deposits. The channel-fill sandy debrites, which are characterized by low root-mean-square (RMS) amplitude in plan view and deep V-shaped reflections in seismic profile, are commonly located in the internal regions of CLCs. They have widths ranging from 1 to 2 km and single sandbody thicknesses exceeding 25 m. A cored interval from a channel-fill sandy debrite comprising several ungraded sand units revealed massive fine-grained sandstones with floating mud clasts and muddy rip-up clasts. In contrast, the channel-fill turbidites are characterized by low or high RMS amplitude in plan view and shallow V-shaped or vermiform-shaped reflections in profile. They have a small-size frontal splay at the terminus, thus forming a lobe-channel-lobe depositional style. The width of a channel-fill turbidite is usually less than 0.5 km, and the single sandbody thickness is no more than 20 m. A cored interval of channel-fill turbidite consisted of very fine-grained sandstones containing incomplete Bouma subdivisions T a –T b. The sand-rich and mud-rich lobe deposits are characterized by high RMS amplitude and low RMS amplitude with continuous sheet reflection patterns, respectively. The deposition of the shallow-marine fans was significantly influenced by sea-level fluctuations and paleogeomorphology. When sea level fell rapidly, gravity flows with higher erosive energy and velocity tended to form widely developed large-scale channel-fill sandy debrites and sand-rich lobe deposits. When sea level rose, small-scale channel-fill turbidites were dominant because of relatively decreased gravity flow energy. Distinct variations of reservoir characteristics, including mean grain size, mud content, and pore-throat radius, were controlled by sea-level fluctuations. From the period of rapid sea-level fall to the period of rising sea level, the gravity flows may have been increasingly diluted due to sufficient mixing with ambient seawater, resulting in a gradual transformation from sandy debris flows into turbidity currents. In addition, changes in gradient caused by irregular paleogeomorphology may have significantly triggered different depositional styles. With a steeper gradient, the CLC is dominated by a channelized-lobe depositional style; however, a lobe-channel-lobe depositional style prevails under a gentler gradient condition. Taking the reservoir characteristics and depositional styles into consideration, it is suggested that the sandy debrites, with better physical properties, constitute favorable hydrocarbon reservoir intervals. The shallow-marine fans in this study may serve as a distinctive analogue to similar gravity flow deposits in other basins worldwide. • Four depositional elements were recognized in the channel-lobe complexes. • Each depositional element shows distinctive seismic, well log, and core expressions. • Depositional variations are controlled by sea level fluctuations. • The irregular paleogeomorphology exert a fundamental control over depositional styles. • Sandy debrites represent a preferable hydrocarbon unit than turbidites. [ABSTRACT FROM AUTHOR]