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Submarine fan reservoirs are important accumulation zones for oil, gas, and natural gas hydrates, offering significant potential for hydrocarbon exploration. During the deposition period of the Sanya Formation in the southern part of the Changchang Sag of the Qiongdongnan Basin, a large submarine fan developed. However, the internal structure, source-sink system, and formation mechanism of this fan remain poorly understood, posing significant challenges to exploration in this area. This paper examines the source-to-sink sedimentary processes and deposition of submarine fans, using the Changchang Sag, in the Qiongdongnan Basin in the Northern South China Sea, as an example, which will provide valuable general guidance for deep water oil and gas exploration. Based on the theories of seismic stratigraphy and seismic sedimentology, this paper utilizes techniques such as seismic facies analysis, seismic attribute optimization, paleogeomorphology reconstruction, and source-to-sink sedimentary systemanalysis to analyze the 3D seismic data of the study area. Research indicates that the Sanya Formation in the Changchang Sag of the Qiongdongnan Basin comprises three depositional units: submarine fan, feeder channel, and Semi-deep marine to deep marine mudstone. The submarine fan is a fan formed by the coupling and convergence of submarine fans sourced from the southwest and southeast. Internally, it is divided into three sub-facies: the proximal fan of the sand-rich submarine fan, the main body of the sand-rich submarine fan lobes, and the distal lobes of the sand-rich submarine fan. The submarine fan sourced from the southwest extends nearly north-south and is primarily fed by sediment transported through three large, banded ancient valleys. The sedimentary filling is characterized by three-phase progradation. The submarine fan sourced from the southeast extends nearly east-west and is primarily fed by sediment transported through a single large, banded ancient valley. The sedimentary filling is characterized by two-phase lateral accumulation. During the deposition period of the Sanya Formation, certain areas of the southern uplift belt were exposed for extended periods and subjected to weathering and erosion. Sediments are transported to large ancient valleys through small supply channels. A large number of sediments were transported to the southern slope of the Changchang sag through the provenance channel system such as large ancient valleys and slope belts and deposited in the center of the sag. These make up a complete system of large ancient uplifts and submarine fan source-to-sink sedimentary systems. The sedimentary model is a lobed submarine fan controlled by semi-restricted ancient valleys and expansive basins. [ABSTRACT FROM AUTHOR]

Structural fracture distribution is essential in oil and gas transportation and development in passive continental margin basins. In this paper, taking as an example the clastic reservoirs in the A-Basin, a passive continental margin in northeastern South America, the paleotectonic stress field of the Late Cretaceous Maastrichtian formation in Basin A was numerically simulated by finite element technique through the integrated interpretation of seismic total data, logging data and core data, and the distribution of tectonic fractures was later predicted based on rock fracture criterion. The results of the study show that: (1) The distribution of tectonic stress and fractures during the Late Cretaceous Maastrichtian formation of Basin A is affected by the fracture zone, mechanical properties of rocks and tectonic stress, regions with extensive fracture development are susceptible to stress concentrations, resulting in significant stress gradients. (2) The development of structural fractures in the study area was predicted using the Griffiths criterion, and the tensile rupture coefficient T was introduced to quantitatively characterise the intensity of fracture development, with larger values reflecting a higher degree of fracture development. The well-developed and relatively well-developed fractures are mainly located in the fracture zones and the interior of submarine fans. (3) Fracture zones and sedimentary phases mainly control structural fractures in Basin A; within 5 km outside the fracture zones, the development of fractures is controlled by the fracture zones, beyond which the regional tectonic stress field controls them; inside the sedimentary fan, the development of fractures is controlled by the sedimentary subphase, which decreases in the order of the upper fan, the middle fan, and the lower fan; inside the subphase, they are controlled by the regional tectonic stress field, and the fractures show the increasing trend in the direction of NW-NE. [ABSTRACT FROM AUTHOR]

The mass flow-dominated fan delta complex is developed by the rapid deposition of coarse-grained materials in front of uplifted areas under the influence active tectonism. This is important for providing clues about the first opening stages of marine basins. The study aims to shed light on the fact that mass flow-dominated fan delta complexes play an active role in determining the characterization of tectonism controlling basin opening. In the study area, mass flow-dominated deposits of the Deliktaş Fan Delta Complex (DFDC) represent the first deposits of the southern part of the Middle Eocene Elazığ Marine Basin, whose development is controlled by normal block faults. The basin consists of the alluvial fan succession, the fan delta succession and the turbidite succession overlying both successions. DFDC is composed of fan delta facies assemblages deposited in the form of shallow water coastal prism in front of the multifeeder areas controlled by extensional tectonism. Conglomerates and sandstones predominate in the DFDC successions. The system forming the DFDC is a good example for high-energy, mass flow-dominated, multifeeder fan delta environments with different source areas surrounding the Elazığ Basin from the north and south. Sedimentological studies were carried out from 11 measured stratigraphic sections taken from the DFDC, and three different sequences were defined. These sequences contain the deposits belonging to fan delta plain and fan delta front facies assemblages. The facies architecture of the successions of the DFDC was defined based on measured stratigraphic sections, litho-correlation and field observations, and with the help of the obtained data, the sedimentation evolution of the sequences belonging to it was revealed with three-dimensional basin models. In this way, an approach to the primary geodynamics of the Elaziğ Basin was obtained. [ABSTRACT FROM AUTHOR]

The Bounty Channel is a large-scale submarine channel system located in the eastern continental margin of New Zealand. Extending along the axis of the Bounty Trough, the channel system comprises three main tributaries (C1–C3) at its head, which merge downstream into a trunk channel leading to a terminal submarine fan. In this study, we use high-quality two-dimensional multichannel seismic data to investigate the formation and evolution of tributary channels C1 and C2. Four types of seismic facies are identified in the tributary channels: fill-type, mounded divergent, wavy, and subparallel facies. These seismic facies are correspondingly interpreted as topographic depression or channel fills, levees, sediment waves, and hemipelagic deposits. The Late Miocene tributary channels were developed above a pre-existing NE–SW-oriented depression. The Pliocene to Quaternary tributary channels are characterized by preferential development of higher levees on their left hand, and the presence of sediment waves on the lower levees of their right-hand, signaling an effect of the Coriolis force. The formation and evolution of the tributaries are primarily linked to regional tectonics, including increased convergence rate between the Pacific and Australian plates along the Alpine Fault in the Late Miocene and enhanced uplift and erosion at the Southern Alps during the Pliocene. [ABSTRACT FROM AUTHOR]

Outburst floods from glacial Lake Missoula largely explain erosion of the Channeled Scabland, a system of overfit, basaltic channels in Washington, northwestern United States. However, it is challenging to explain Missoula flood routing into Moses Coulee due to its topographic isolation from flood routes. To clarify flood pathways into Moses Coulee, we mapped channels that delineate a radial-anastomosing network connecting to Moses Coulee. Channels consist of coulee-like features eroded mainly in basalt. Channels climb adverse slopes and cross divides, and the network is draped with eskers and recessional moraines. These channel geometries and glacial landform associations suggest a tunnel channel network. Large channel dimensions and network anastomosis indicate formation in subglacial floods. The network connects to Moses Coulee with sufficient cross-sectional area to convey megafloods, hinting that subglacial floods may have been a significant source of Moses Coulee meltwater, in addition to possible diverted Missoula floods. [ABSTRACT FROM AUTHOR]

Turbidity currents are sediment-laden gravity currents that transfer sediments to deep sea and lake floors through erosion and deposition. These deposits form subaqueous fans in deep marine environments and can reduce reservoir storage capacity, complicating management. Deep sea deposits often contain hydrocarbons like oil and gas. Field measurements of turbidity currents are challenging due to the risk of damage to measuring instruments, and laboratory experiments do not accurately simulate these currents. Thus, numerical modeling is crucial for understanding their formation and properties, and for locating oil and gas fields within deep sea turbidites.A 3D two-phase numerical model (water and solids) is used to simulate underflow turbidity currents. This model solves the Reynolds-Averaged Navier-Stokes equations and uses the Eulerian approach, with turbulence closure achieved by the RNG k-ε model. It simulates both continuous unconfined currents and surge-like confined currents. Calibration and validation against experimental data show the model accurately replicates key features of turbidity currents.Model results indicate that fine particles remain suspended longer, providing additional density that drives the current further with increasing downstream velocity. Vertical concentration profile shows two distinct layers: a denser, faster-moving bottom layer parallel to the bed, and a slower, more diluted upper layer affected by entrainment and mixing with ambient fluid. Turbidity currents are supercritical on sloped channels and subcritical on mild sloped unconfined seafloors or reservoir bottoms. In following article, hypothetical simulations using this model will further explore various characteristics and deposits of turbidity currents on a field scale.

Submarine canyons and channels are globally important pathways for sediment, organic carbon, nutrients and pollutants to the deep sea, and they form the largest sediment accumulations on Earth. However, studying these remote submarine systems comprehensively remains a challenge. In this study, we used the only complete-coverage and repeated bathymetric surveys yet for a very large submarine system, which is the Congo Fan off West Africa. Our aim is to understand channel-modifying features such as subaqueous landslides, meander-bend evolution, knickpoints and avulsions by analyzing their morphometric characteristics. We used a new approach to identify these channel-modifying features via morphometric fingerprints, which allows a systematic and efficient search in low-resolution bathymetry data. These observations have led us to identify three morphodynamic reaches within the Congo Canyon-Channel. The upper reach of the system is characterized by landslides that can locally block the channel, storing material for extended periods and re-excavating material through a new incised channel. The middle reach of the system is dominated by the sweep and swing of meander bends, although their importance depends on the channel's age, and the time since the last up-channel avulsion. In the distal and youngest part of the system, an upstream migrating knickpoint is present, which causes multi-stage sediment transport and overspill through an underdeveloped channel with shallow depths. These findings complement previous less- detailed morphometric analyses of the Congo Canyon-Channel, offering a clearer understanding of how submarine canyon-channels can store sediment (due to channel-damming landslides, meander point bars, levee building due to overspill), re-excavate that sediment (via thalweg incision, meander propagation, knickpoint migration) and finally transport it to the deep sea. This improved understanding of the morphodynamics of the Congo Canyon- Channel may help to understand the evolution of other submarine canyon- channels, and assessment of hazards faced by seabed infrastructure such as telecommunication cables. [ABSTRACT FROM AUTHOR]

The Early‐Middle Jurassic is one of the crucial coal‐forming geologic periods in the world and an important target for hydrocarbon exploration in the Turpan‐Hami Basin, China. The paleoenvironment and vegetation reconstruction of the Early‐Middle Jurassic have been investigated using elemental geochemistry and palynological analysis to reveal paleoclimate evolution. A total of 48 genera of pteridophyte spore and 35 genera of gymnosperm pollen were identified, and 5 palynological assemblages were longitudinally divided, which showed significant differences in geochemical behaviours. The paleoenvironment was a transition from suboxidation to anoxia and then to an oxidation environment under freshwater conditions. The paleowater in the northern Taibei Sag was deeper than that in the southern part during the Middle Jurassic, which coincided with the sedimentary background of the sublacustrine fan in the north and the shallow braided river delta in the south. The paleovegetation evolved from mixed lowland–upland forest in the Hettangian‐Toarcian, to lowland fern forest in the Aalenian‐Bajocian, to upland conifers forest in the early Bathonian, to upland Cheirolepidiaceae forest in the late Bathonian‐Callovian. The Toarcian and Bathonian‐Callovian arid climate and the Hettangian‐Pliensbachian and Aalenian‐Bajocian warm‐humid climate were responses to the continued global warming events and the intensification of the East Asian monsoon circulation, respectively. The influence of the Bathonian‐Callovian aridification event on the sedimentary response in the southern Taibei Sag will be delayed due to the gradual southward migration of the depositional centre. [ABSTRACT FROM AUTHOR]

The lower limits of petrophysical properties for an effective reservoir are among the key parameters for assessing hydrocarbon reserves and are therefore directly related to hydrocarbon exploration and development strategies. However, the lower limits for marine sandstone gas reservoirs are still not clear and the impact factors also remain to be discussed. This study analysed the lower petrophysical property limits of an effective sandstone reservoir in the Qiongdongnan Basin using porosity, permeability and gas testing. The results showed that the lower porosity and permeability limits of effective reservoirs developed in the deltas are 8.9% and 1.2 × 10−3 μm2, respectively, and 11.3% and 4.0 × 10−3 μm2 in the submarine canyons and fans, respectively. Sedimentary facies, sediment transport distance, grain size and burial depth of sandstone significantly influence the lower physical property limits. The lower porosity and permeability limits increase with the increase in sediment transport distance as well as the decrease in sandstone grain size and burial depth. Sediment sources and sedimentary facies determine whether sandstone can become an effective reservoir in the Qiongdongnan Basin. Specifically, the sediment source dramatically influences the petrophysical properties of sandstone. The sandstone sourced from the Red River has higher porosity and permeability, followed by the sandstone sourced from the Hainan Uplift, and the sandstone sourced from the palaeo-uplift within the basin has the lowest porosity and permeability. The feldspar dissolution by CO2 and organic acid is the primary formation mechanism of the effective reservoir in the Lingshui Formation, whereas the dissolution of glauconite is more common in the sandstone reservoirs of the Sanya and Meishan formations. [ABSTRACT FROM AUTHOR]

The significance of beach-bar reservoirs, which are intricately linked to unconventional hydrocarbon reservoirs, has gained increased attention. This study elucidates the complex mechanisms governing the formation, spatial distribution, and morphological characteristics of beach bars in Qinghai Lake, NW China, highlighting the interplay of lake-level fluctuations, wind wave dynamics, sediment provenance, and terrain gradient. Our findings reveal that large-scale lake-level fluctuations primarily dictate the initial formation settings of beach bars, while small-scale fluctuations refine their internal stratification and sedimentary features. Wind wave dynamics play a critical role in defining suitable depth zones for beach bar development, influencing their morphology and resulting in distinct sedimentary characteristics across different lake zones. Furthermore, the study categorizes beach bars into three main systems based on sediment provenance--bedrock, alluvial fan (fan delta), and braided river systems--each exhibiting unique compositional and structural attributes. Terrain gradient around the lake significantly affects beach bar formation, with areas having a gradient less than 0.7° being particularly favorable. This research advances our understanding of lacustrine beach bar dynamics, offering insights into their potential as indicators of past environmental conditions and their implications for hydrocarbon exploration. The comprehensive analysis of controlling factors provides a foundation for predicting beach bar distribution and contributes to the broader field of sedimentary geology by integrating multi-disciplinary approaches to study lacustrine sedimentary processes. [ABSTRACT FROM AUTHOR]

We discovered seafloor features such as bacterial mats and carbonate crusts typical for active methane seeps on the continental slope southwest of Svalbard. These features are associated with two main northwest-southeast trending morphological structures that are oriented parallel to the regional continental slope. Both structures occur at c. 800 m water depth, at the boundary between the Storfjorden trough mouth fan to the south and the Hornsund trough mouth fan to the north, which suggests a loading related fluid seepage. The main structure displays depressions and ridges forming a crater in its center. Other occurring features include small sediment mounds, domes often covered by bacterial mats, and hummocky seafloor colonized by siboglinid tubeworms. Free gas bubbles were spotted close to the centre and plumes along the rims of the structure. Thick carbonate crusts indicate a long seepage history in the center of the structure and on top of the ridges. The sources of the seeps are likely to be Miocene old organic-rich deposits, or Paleocene hydrocarbon reservoirs. [ABSTRACT FROM AUTHOR]

Enhanced sedimentation at glacial margins can produce submarine megaslides (>10,000 km3). We report a single megaslide in the Surveyor Fan, Gulf of Alaska. Minimum extant size is ∼16,124 km2 in area and ∼9,080 km3 in volume. Slope failure occurred ∼1.2 Ma at the onset of the mid‐Pleistocene transition (MPT). With accretion along the Aleutian‐Alaska Trench, the original volume is conservatively ∼16,280 km3, with only a 140 km run‐out due to its blocky, high shear strength nature. We suggest the megaslide was triggered by a major sediment influx at the onset of the MPT, when glacial‐interglacial cycles shifted from 41 to 100 Kyr. The absence of repeat megaslides may reflect a changing balance between seismic strengthening and sediment flux, where later sedimentation driven by cross‐shelf ice streams results in thin, fluidized, non‐cohesive slides. Continued accretion of the Surveyor Fan and megaslide also reduces critical wedge taper, further inhibiting major failure. Plain Language Summary: Sediment flux at glacial margins can produce submarine slides >10,000 km3 in size (megaslides). We report a single megaslide in the Surveyor Fan, Gulf of Alaska. Minimum extant size is ∼16,124 km2 in area and ∼9,080 km3 in volume. Failure occurred ∼1.2 Ma at the onset of the mid‐Pleistocene transition (MPT). Due to accretion along the Aleutian‐Alaska Trench, the original volume is conservatively ∼16,280 km3, but with only a 140 km run‐out due to its blocky, high shear strength nature. We suggest the megaslide was caused by the initial major sediment flux at the onset of the MPT, and that afterward only fluidized, thin, and non‐cohesive slides occurred. This is due to changing balance between seismic strengthening and sediment flux, and accretion of the Surveyor Fan and megaslide which reduces the critical wedge taper inhibiting major failure. Key Points: World's Fifth largest mapped megaslide documented beneath Surveyor Fan Gulf of AlaskaTiming of slope failure linked to onset of mid‐Pleistocene glacial intensificationAbsence of later failures due to changing balance of sediment flux/seismic strengthening and negative feedbacks from critical wedge processes [ABSTRACT FROM AUTHOR]

The diagenetic evolution of sandstone is very complicated under the conditions of high temperatures and pressures in deep-water, deep-buried regimes, which have great influence on reservoir quality. This study investigates the typical reservoir target of Neogene deep-water, submarine-fan sandstones under high-temperature, high-pressure regimes in the Qiongdongnan Basin, South China Sea. Utilizing a thin section, scanning electron microscope (SEM), mineral geochemistry combined with burial history evolution, complex diagenetic events, and main controlling factors of the sandstone in the Neogene Meishan Formation were determined. The results show that the evolution of sandstone reservoirs is initially controlled by depositional framework compositions and subsequently modified by eogenetic and mesogenetic alterations during progressive burial. Eogenetic alterations mainly include the following: (1) mechanical compaction; (2) dissolution of feldspar; (3) low-Fe calcite cementation. Mesogenetic events were identified as the following: (1) dissolution of feldspar; (2) ferroan calcite and ankerite formation; (3) precipitation of quartz and clay mineral. Mechanical compaction is greatly influenced by the original depositional framework composition, and sandstone samples enriched in high contents of detrital clay matrix always experienced extensive mechanical compaction. Different phases of carbonate cement during different diagenetic regimes lead to continuous destruction on reservoir porosity. The dissolution of unstable feldspar minerals during eogenetic and mesogenetic environments leads to the development of secondary porosities and would enhance the quality of the reservoir. Overpressure formation is pervasively developed owing to early disequilibrium compaction and subsequent natural gas charging. Only well-sorted sandstones with low contents of detrital clay matrix could resist early mechanical compaction, lead to ample residual original porosities, and then undergo extensive mineral dissolution to generate sufficient secondary porosities. Subsequently, these porosities would be effectively protected by overpressure formation. Poor-sorted sandstones with high contents of detrital clay matrix would experience strong mechanical compaction and extensive destruction of original porosities. Thus, these sandstones are difficult to have significant dissolution and are unable to be effectively protected by overpressure formation. Therefore, the interplay between the original framework composition and the corresponding diagenetic pathways coupled with overpressure formation would result in strong reservoir heterogeneity for the deep-buried sandstones during progressive burial. [ABSTRACT FROM AUTHOR]

The turbiditic succession containing exotic blocks of various sizes deposited in the Çüngüş Basin, has been previously identified as the Çüngüş Formation in front of the Southeast Anatolian Suture Belt, Türkiye. These turbiditic sediments, dated as Eocene-Early Miocene, were interpreted as the lowermost allochthonous tectono-stratigraphic unit thrust over the Lice Formation during the Miocene within the Çüngüş-Hakkari nappes. In this study, the stratigraphical, sedimentological, palaeontological, and structural features of the Çüngüş and Lice formations are examined and reinterpreted within a basin model. Both formations consist of sandstones, siltstones, mudstones, and subordinate conglomerates, indicating ramp-fringe palaeochannel, submarine fan, and basin-floor turbidite facies associations. In the northern part of the basin, just in front of the suture belt, volcanic, metamorphic, and ophiolitic rocks and nummulitic limestones are included as blocks and tectonic slices within the turbidite succession. Based on nannoplankton analysis, both Çüngüş and Lice formations are assigned an Early Miocene age. The sedimentary facies associations filling the Çüngüş Basin are transitional from proximal to distal facies. The thrust in the previous maps separating the Çüngüş and Lice formations cannot be confirmed in the field. Based on our field observations and age data, we interpret that the Lice and the Çüngüş formations deposited continuously within the Çüngüş Basin that was opened as a foreland basin by flexural subsidence of the Arabian Autochthon under the crustal load of the Pütürge-Bitlis Massifs and the Maden Complex during the Early Miocene. The turbidite deposits containing exotic blocks in the north of the basin are interpreted as wedge-top deposits of the foreland basin, while those in the south are considered foredeep deposits. [ABSTRACT FROM AUTHOR]

Tectonics play a significant role in shaping the morphology of submarine canyons, which form essential links in source-to-sink (S2S) systems. It is difficult, however, to investigate the resulting morphodynamics over the long term. For this purpose, we propose a novel experimental approach that can generate submarine canyons and hanging-wall fans on continuously evolving active faults. We utilize morphometric analysis and morphodynamic models to understand the response of these systems to fault slip rate (Vr) and inflow discharge (Q). Our research reveals several key findings. Firstly, the fault slip rate controls the merging speed of submarine canyons and hanging-wall fans, which in turn affects their quantity and spacing. Additionally, the long profile shapes of submarine canyons and hanging-wall fans can be decoupled into a gravity-dominated breaching process and an underflow-dominated diffusion process, which can be described using a constant-slope relationship and a morphodynamic diffusion model, respectively. Furthermore, both experimental and simulated submarine canyon–hanging-wall fan long profiles exhibit strong self-similarity, indicating that the long profiles are scale independent. The Hack's scaling relationship established through morphometric analyses serves as an important link between different scales in S2S systems, bridging laboratory-scale data to field-scale data and submarine-to-terrestrial relationships. Lastly, for deep-water sedimentary systems, we propose an empirical formula to estimate fan volume using canyon length, and the data from 26 worldwide S2S systems utilized for comparison show a strong agreement. Our geomorphic experiments provide a novel perspective for better understanding of the influence of tectonics on deep-water sedimentary processes. The scaling relationships and empirical formulas we have established aim to assist in estimating volume information that is difficult to obtain during long-term landscape evolution processes. [ABSTRACT FROM AUTHOR]

Control strategies for variable-air-volume (VAV) air conditioning significantly affect both the air quality within buildings and the consumption of building energy. Current control techniques effectively regulate room temperature using feedback on temperature discrepancies, yet they also elevate the wear on terminal devices and boost the energy usage of the supply fan. In this paper, the hysteresis and inertia parameters of end air valves and supply fans under two seasonal conditions are derived from experimental data. Aiming at the problems of frequent switching of the end air valve, long total switching stroke, and high energy consumption of the air supply fan, a fuzzy PI regulation method is proposed based on the original pressure-independent series PI regulation, which effectively solves the above problems. Initially, data on how room temperature reacts to changes in air supply fan speed and the position of end air valves during winter and summer were gathered. Following model identification, parameters for various seasonal conditions were determined. Secondly, the roles of different components in the variable-air-volume regulation process were investigated. Investigations revealed that within pressure-independent variable-air-volume control, the supply fan and end air valve emerged as the primary subjects of the study. A double-closed-loop control with the speed control of the supply fan as the outer loop and the opening control of the end air valve as the inner loop was adopted. Compared with the traditional serial PI regulation, the room temperature error of this method was increased, but it reduced the total stroke of the valve by more than 43%, which greatly reduced the valve's loss and noise and saved more than 2.7% of the energy consumption of the air supply fan. [ABSTRACT FROM AUTHOR]

The multicoloured 'Košna' conglomerates are investigated in the area of the Košna Voda spring, in the Brušane area of Velebit Mt., Croatia. The studied conglomerates consist of red-coloured matrix and clasts of various lithologies (sandstones, limestones, chert and quartz pebbles) and sizes, suggesting provenance from different areas. Average clast size and their percentage was determined by the Udden-Wentworth classification with estimation of the matrix content. Clasts and matrix lithological and mineralogical characteristics were determined using petrographic, ore microscopy, and X-ray diffraction analysis. Sandstone clasts in the studied conglomerates are classified as lithic arenites, subarkoses and arkoses. Limestone clasts are mostly wackestones to packstones with foraminifera, ostracods, echinoid and bryozoan fragments that derive from late Carboniferous/early Permian shallow-marine limestones. Calcispheres and incipient growth forms of Microcodium are also present, suggesting different sediment sources and resedimentation processes. Fragments of fusulinid foraminifera were identified in the matrix of the 'Košna' conglomerates. Based on the analyses performed, and field observations, the 'Košna' conglomerates are described as early Permian (Cisuralian) polymictic clast-supported to matrix-supported conglomerates and breccia-conglomerates that share structural and textural similarities with conglomerates from other areas in the Dinarides, as well as in the Eastern and Southern Alps. The 'Košna' conglomerates are younger than the Sakmarian and are comparable with the Trogkofel limestones of the Carnic Alps and the Karavanke Mts. in Slovenia. We suggest that the studied deposits originated from the uplifted Variscan Mountains during the Variscan and Saalian orogenic movements, and were finally deposited from tractive flows and occasional debris flows in a shallow marine environment of the Palaeo-Tethys, possibly in fan deltas. [ABSTRACT FROM AUTHOR]

As the core power element of a centrifugal fan, the impeller's structural parameters are important factors affecting the aerodynamic performance of the fan. Therefore, to improve the aerodynamic performance of centrifugal fans, in this study, we take the Powered Air-Purifying Respirator (PAPR) power system as the object of research and use a combination of computational fluid dynamics (CFD) and experimental validation to investigate the effects of the number of blades, blade inlet angle, blade outlet angle, blade height, and blade thickness on the aerodynamic performance of the fan. A five-factor, four-level orthogonal test table L16 (45) was selected to obtain the optimal combination of structural parameters for the impeller. In addition, in order to identify and visualize the features of the vortex, Q Criterion Normalized is applied to the simulation on the basis that the minimum pressure appears in the vortex core. In this study, Q Criterion Normalized is used to compare the internal vorticity of the prototype with that of the optimized prototype. The results show that (i) the order of influence of each parameter on the aerodynamic performance of the centrifugal fan is blade height > blade outlet angle > blade inlet angle > number of blades > blade thickness; (ii) the optimal combination of the structural parameters is number of blades 48, blade inlet angle 80°, blade outlet angle 120°, blade thickness 0.6 mm, and blade height 23 mm; the optimized prototype has an increase in air pressure of about 10%, an increase in air volume of about 31%, and an increase in efficiency from 49.61% to 53.57%; (iii) the intensity of internal vortices in the optimized prototype is weakened, the size of vortices and the number of vortices are reduced, and the homogeneity of the flow field is also improved. [ABSTRACT FROM AUTHOR]

This study is based on the detailed sedimentological analysis of eleven sections and one well through the late Eocene–Oligocene flysch formation of the Internal Ionian Zone (IIZ) in Western Greece. The sections are spread from the northern parts of Epirus to the north and Aitolokarnania to the south. Sedimentological data combined with biostratigraphic analyses resulted in a five-stage evolutionary model for the basin. Unit I corresponds to the lower part of the examined sections, indicating the onset of clastic sedimentation. Regarding depositional environments, it is regarded as a basin plain where lobe distal fringe accumulations occur. Unit II consists almost exclusively of heterolithic facies, marking the advance of a lobe complex system. Massive sandstone facies dominate unit III and can be considered a more proximal submarine fan system. Unit IV reflects a calm period of the basin, where mud-dominated heterolithics and hemipelagic mudstones were deposited. Hemipelagic mudstone facies with intervals of heterolithics, conglomerates, and deformed and massive sandstone facies characterize unit V. The architecture resembles a slope system incised by canyons and channels. The sand-rich intervals in Units III and V could act as the most favorable reservoir levels. In contrast, the sand-rich intervals in Unit II are considered less promising due to their higher heterogeneity. [ABSTRACT FROM AUTHOR]

Deep-sea eukaryotic microorganisms play a vital role in degrading organic matter and geochemically cycling elements in the deep ocean. However, the impact of sampling methods on detection of these microorganisms under high hydrostatic pressure remains uncertain. In this study, we compared a traditional water sampling method using a Niskin bottle, an in situ microbial filtration and fixation method (ISMIFF), and a multiple in situ nucleic acid collection (MISNAC) method to exhibit differences in the community structures that were collected at ~590–3100 m in the South China Sea (SCS). The classification and biodiversity indices of 18S rDNA Illumina sequencing reads from the V9 variation region revealed higher diversity for MISNAC DNA absorption column samples compared to others. Importantly, the relative abundance of Ciliophora (19.49%), Copepoda (23.31%), and Diplonemea (10.67%) was higher in MISNAC adsorption column samples, while Retaria (48.86%) were dominant in the MISNAC membrane samples. This indicates that MISNAC columns might collect more DNA in situ for the naked protists, while Retaria with a carbonate shell were more likely retained on the membrane. In conclusion, MISNAC is an effective method for DNA collection of deep-sea eukaryotic microorganisms and provides valuable materials for studying deep-sea microbial ecosystems. [ABSTRACT FROM AUTHOR]

Subaquatic channels, situated in lakes, fjords, submarine canyons and on deep-sea fan systems, exhibit diverse morphometric characteristics controlled by sediment transport processes, particularly turbidity currents. These processes play a significant role in transporting sediment, organic carbon, nutrients, and pollutants and pose hazards to critical infrastructure. This study examines a balanced set of subaquatic channels across various settings, sizes, and locations, employing novel data harmonization techniques to address biases toward larger channels. The analysis reveals consistent scaling relationships, particularly the dominant role of bankfull width, influencing bankfull depth, cross-sectional area, wavelength, and amplitude. The aspect ratio (width-to-depth) emerges as a significant parameter, reflecting a necessary channel compactness to maintain turbidity currents. Meandering development reveals relations between width, wavelength, and amplitude, with a preference for specific ratios. Meandering is most pronounced at channel beginnings, transitioning to straighter forms downstream, potentially influenced by flow dynamics and flow confinement. The study broadens the understanding of subaquatic channel evolution, emphasizing the importance of bankfull width and providing insights applicable across settings and scales. [ABSTRACT FROM AUTHOR]

Investigating the sedimentary architecture and evolution of sand-rich submarine fans is vital for comprehending deep-water sedimentary processes and enhancing the success rate of hydrocarbon resource exploration. Recent drilling activities in the Qiongdongnan Basin, northern South China Sea, have unveiled significant gas hydrate and shallow gas potential. However, exploration in this area faces substantial challenges due to the limited understanding of sandy reservoirs. Leveraging extensive newly acquired extensive 3D seismic data (~9000 km²) and well data, our study reveals five distinct deep-water depositional systems in the Quaternary Ledong Formation, including a submarine fan system, mass transport deposits, deepwater channel-levee systems, slope fans, and hemipelagic sediments. Notably, the targeted sandrich submarine fan lies within the abyssal plain, situated at a water depth of 1300-1700 m. This fan exhibits a unique tongue-shape configuration and a SW-NE flow direction within the plane and spans an expansive area of ~2800 km² with maximum length and width reaching 140 km and 35 km, respectively. Vertically, the fan comprises five stages of distributary channel-lobe complexes, progressing from Unit 1 to Unit 5. Their distribution ranges steadily increase from Unit 1 to Unit 3, followed by a rapid decrease from Unit 4 to Unit 5. Our results suggest that the occurrence and evolution of the submarine fan are primarily controlled by sea level fluctuation, confined geomorphology, and sediment supply. Specifically, sea level fluctuation and sediment supply influenced the occurrence of the submarine fan. Concurrently, the confined geomorphology in the abyssal plain provided accumulation space for sediments and shaped the fan into its distinct tongue-like form. In contrast to the deepwater channels within the deepwater channel-levee systems, the distributary turbidite channels within the submarine fan are marked by lower erosion depth with "U" shapes, greater channel width, and higher ratios of width to depth. The comparative analysis identifies turbidite channels as the focal points for offshore gas hydrate and shallow gas exploration in the Qiongdongnan Basin. Furthermore, the temporal evolution of submarine fan offers valuable insights into Quaternary deep-water sedimentary processes and hydrocarbon exploration within shallow strata of marginal ocean basins. [ABSTRACT FROM AUTHOR]

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Blowouts are integral features of coastal dune fields. Their presence enhances both geomorphological and ecological diversity and enables the movement of sand by wind. Their role as a 'transport corridor' may be, however, considered negative from a coastal management perspective in heavily touristic areas, where the existence of blowouts close to the foredune can enhance the loss of sediment from the beach. This paper investigated the relationship between airflow dynamics and patterns of sediment transport from the beach to established dunes through a trough blowout located on the foredune. Seven three-cup anemometers were used to measure wind speed and direction over a 24 h sampling period at a frequency of 1 min under onshore (parallel to the blowout axis) medium and high wind speeds (max of 17.9 ms−1). To measure sediment transport, a total of 12 vertical sand traps were located at three positions along the length of the deflation basin. The results indicated that small amounts of sediments went into the blowout from the beach and that the highest rates of sediment remobilization took place within the deflation basin. These results highlight two processes: (a) flow channelization induced by the blowout topography caused an increase in wind speed and sediment transport toward the depositional lobe, and (b) the presence of embryo dunes and herbaceous vegetation at the beach–blowout boundary effectively reduced the amount of sediment transport from the beach to the landform. The results confirmed the significant role that vegetation plays in controlling sediment movement and conserving the beach–dune system. [ABSTRACT FROM AUTHOR]

Deep‐water carbonate deposition is relatively poorly understood but an area of vigorous research in academia and industry, where these deposits are a significant component of many unconventional petroleum reservoirs. Recent studies of modern deep‐water carbonates have highlighted the wide variety of depositional processes, sediment types and resultant geomorphology; however, well‐documented outcrops of ancient systems, their rock types and architecture are relatively sparse. The Mississippian Lake Valley Formation provides world‐class exposures of slope‐basinal carbonate deposits. The Tierra Blanca and Doña Ana members comprise submarine fans that are >14 to 20 km in length, >5 km wide, and exposed in strike and dip view, affording a unique opportunity to constrain the architecture, rock types and sedimentary processes. Tierra Blanca and Doña Ana sedimentation was dominated by crinoids shed from an up‐dip platform and supplemented by sediments sourced locally from Waulsortian mounds. Depositional processes include turbidity flows, debris flows and hybrid sediment‐gravity flows. The Tierra Blanca submarine fan thins towards its lateral flanks and distal fringe, where deposits become more mud‐dominated, gravelly grain‐supported flows are less common, and fewer beds have scoured bases. In proximal settings, bed tracing complemented by measured sections allow mapping of stratal surfaces and identification of stories, elements and complexes. The Tierra Blanca evolved from more unconfined to confined deposition. Point‐sourced deposition of the Tierra Blanca fan required a funnelling mechanism, probably due to bathymetry created by Waulsortian mounds or possibly a platform margin re‐entrant. Outcrop exposures illustrate that younger Doña Ana submarine fan deposits onlap onto, and compensationally stack with, the thickest portions of the antecedent Tierra Blanca fan. These outcrops illustrate both similarities and differences between carbonate and siliciclastic gravity flow deposits. Similarities include comparable deposit types, depositional processes and architecture; differences relate to hydrodynamics of carbonate grains, funnelling mechanisms for point‐sourced deposits and sequence stratigraphic forcing. [ABSTRACT FROM AUTHOR]

This investigation documents that the Rugged Terrain Unit, the Stimson formation, and the Greenheugh sandstone were deposited in a 1200 m-deep lake that formed after the emergence of Mt. Sharp in Gale crater, Mars, nearly 4 billion years ago. In fact, the Curiosity rover traversed on a surface that once was the bottom of this lake and systematically examined the strata that were deposited in its deepest waters on the crater floor to layers that formed along its shoreline on Mt. Sharp. This provided a rare opportunity to document the evolution of one aqueous episode from its inception to its desiccation and to determine the warming mechanism that caused it. Deep water lacustrine siltstones directly overlie conglomerates that were deposited by mega floods on the crater floor. This indicates that the inception phase of the lake was sudden and took place when flood waters poured into the crater. The lake expanded quickly and its shoreline moved up the slope of Mt. Sharp during the lake-level rise phase and deposited a layer of sandstone with large cross beds under the influence of powerful storm waves. The lake-level highstand phase was dominated by strong bottom currents that transported sediments downhill and deposited one of the most distinctive sedimentological features in Gale crater: a layer of sandstone with a 3 km-long field of meter-high subaqueous antidunes (the Washboard) on Mt. Sharp. Bottom current continued downhill and deposited sandstone and siltstone on the foothills of Mt. Sharp and on the crater floor, respectively. The lake-level fall phase caused major erosion of lacustrine strata that resulted in their patchy distribution on Mt. Sharp. Eroded sediments were then transported to deep waters by gravity flows and were re-deposited as conglomerate and sandstone in subaqueous channels and in debris flow fans. The desiccation phase took place in calm waters of the lake. The aqueous episode we investigated was vigorous but short-lived. Its characteristics as determined by our sedimentological study matches those predicted by an asteroid impact. This suggests that the heat generated by an impact transformed Mars into a warm, wet, and turbulent planet. It resulted in planet-wide torrential rain, giant floods on land, powerful storms in the atmosphere, and strong waves in lakes. The absence of age dates prevents the determination of how long the lake existed. Speculative rates of lake-level change suggest that the lake could have lasted for a period ranging from 16 to 240 Ky. [ABSTRACT FROM AUTHOR]

Geomorphological and sedimentological research carried out in the vicinity of Vilnius (SW Lithuania) aimed to determine the age and stages of development of gullies in relation to climatic conditions and human activity. Two gullies located on the northern slope of the Vilnia river valley were examined in detail. The sedimentological features of the sediments which form fans at the mouths of the gullies were analysed. Three main lithological units were distinguished. On the basis of radiocarbon datings, the beginning of gully erosion was determined to be in the Middle Ages. This process began with intensive settlement in this area. Further stages of a cutting which were distinguished include early modern times and the period from the seventeenth century to the present day. [ABSTRACT FROM AUTHOR]

The most extensive coverage of surficial sediment samples collected to date on Egypt's Nile Delta coast and shelf is needed to better define sediment dispersal patterns across this setting's rapidly eroding margin. Changes in time are now induced by River Nile sediment cutoff by dams, sea level rise, marked shelf subsidence, and regional climate changes, which have altered the amounts and components of sediments; these require replacement, along with the implementation of more effective coastal protection measures. Multiple computer-generated offshore maps depict the distributions and proportions of sand, silt, and mud; the mean grain size and standard deviation (sorting); heavy mineral concentrations; and carbonate content. Heavy mineral lobes at the coast and offshore identify former Nile branch sites. Channel lobes extending seaward resulted from their progradational phase and from the delta's altered sedimentation from the early to late Holocene. The progressive deposition and erosion of these fossil fluvial lobes, and of two active Nile channels, selectively removed their quartz and less dense minerals, thus concentrating heavy minerals on the coast and inner shelf. The prolonged dispersal of original sediment effluence from relict and recent Nile tributaries induced variable depositional patterns on the present shelf. These coastal depocenters, along with extensive sand, silt, and mud from shelf sediments, were reworked further seaward and dispersed by bottom currents, thus masking most previous onshore-to-offshore transport patterns. The major surficial features document long-term responses to the diverse dispersal that influenced the shoreline to the outer shelf deposits from the Pleistocene to the present. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mine Automation is the property of Industry & Mine Automation Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The strata in the Shita Mountain, Yunkai region, are predominantly composed of clastic rocks with intercalated limestones. However, the precise stratigraphic age remains uncertain due to the scarcity of fossils. Previously, conglomerate layers in this region were considered indicative of the Yunan Orogeny during the Cambrian–Ordovician transition. However, through the identification of 12 lithofacies types and 5 lithofacies combinations in the conglomerate layers of the Shita Mountain section, it has been confirmed that these layers represent a fan delta depositional environment characterized by debris flow, traction flow, torrent, and rock flow. Based on the presence of brachiopod fossils dating to the Early–Middle Ordovician, we propose a novel two-episode model for the Yunan Orogeny. The first episode corresponds to submarine fan deposition, while the second episode involves tectonic uplift and a short-term sedimentary hiatus. Further analysis of the detrital zircon provenance reveals a strong affinity among the Yunkai area, India, Antarctica, the Lhasa, the Himalayas, Southern Qiangtang, and Western Australia during the Early–Middle Ordovician transition under the Gondwana assemblage background. [ABSTRACT FROM AUTHOR]

We use heat flux measurements colocated with seismic reflection profiles over a buried basement high on the Juan de Fuca plate ∼25 km seaward of the deformation front offshore Oregon to test for the presence of hydrothermal circulation in the oceanic crust. We also revisit heat flux data crossing a buried basement high ∼25 km seaward of the deformation front ∼150 km north, offshore Washington. Seafloor heat flux is inversely correlated with sediment thickness, consistent with vigorous hydrothermal circulation in the basement aquifer homogenizing temperatures at the top of the basement. Heat flux immediately above the summit of the basement highs is greater than expected solely from conduction. Fluid seepage at rates of ∼2.6–5.4 cm yr−1 in a 1–1.5 km‐wide conduit through ∼800–1,300 m thick sediment sections above these basement highs can explain these observations. Observations of thermally significant fluid seepage through sediment >225 m thick on oceanic crust are unprecedented. High sediment permeability, high fluid overpressure in the basement, or a combination of both is required to drive fluid seepage at the observed rates. We infer that rapid seepage occurs because the basement highs rise above the low permeability basal sediment with their tops protruding into the base of high permeability Nitinat or Astoria Fan sediment. Seepage from basement highs penetrating into the submarine fans can affect the thermal state of crust entering the subduction zone. Plain Language Summary: Fluid circulation in the oceanic crust can transport large amounts of heat, influencing the heat content and the distribution of heat within the crust. This fluid circulation primarily occurs in a high permeability aquifer composed of rapidly cooled basalt flows that comprise the upper ∼300 m of oceanic crustal rocks. Most marine sediments that accumulate on the basaltic aquifer have very low permeability and inhibit fluid flow; for sediment covered oceanic crust, fluid recharge/discharge from/to the ocean only occurs at sediment‐free basement outcrops. For most sediment types, ∼40 m of sediment accumulation is sufficient to slow fluid flow rates through them, so that fluid flow is not thermally significant. For sites offshore Oregon and Washington, we document thermally significant fluid seepage through sediment ∼800–1,300 m thick. This seepage occurs over buried basaltic hills that penetrate through low permeability sediment into a thick layer of high permeability sandy sediment that hosts the seepage. The fluid seepage, at ∼2.6–5.4 cm yr−1, is fast enough to remove heat from the underlying crust. This can affect the temperature of the crust entering the subduction zone offshore North America. Key Points: We discovered rapid fluid seepage through 1 km thick sediment on the Juan de Fuca plate 25 km seaward of the Cascadia subduction zoneBuried basement highs penetrating through basal sediments are high permeability conduits to the base of sandy submarine fan sedimentsThis previously unknown thermally significant seepage can affect the thermal state of the crust entering the subduction zone [ABSTRACT FROM AUTHOR]

As the globe warms, people will increasingly need affordable, safe methods to stay cool and minimize the worst health impacts of heat exposure. One of the cheapest cooling methods is electric fans. Recent research has recommended ambient air temperature thresholds for safe fan use in adults. Here we use hourly weather reanalysis data (1950–2021) to examine the temporal and spatial evolution of ambient climate conditions in the continental United States (CONUS) considered safe for fan use, focusing on high social vulnerability index (SVI) regions. We find that although most hours in the day are safe for fan use, there are regions that experience hundreds to thousands of hours per year that are too hot for safe fan use. Over the last several decades, the number of hours considered unsafe for fan use has increased across most of the CONUS (on average by ∼70%), with hotspots across the US West and South, suggesting that many individuals will increasingly need alternative cooling strategies. People living in high‐SVI locations are 1.5–2 times more likely to experience hotter climate conditions than the overall US population. High‐SVI locations also experience higher rates of warming that are approaching and exceeding important safety thresholds that relate to climate adaptation. These results highlight the need to direct additional resources to these communities for heat adaptive strategies. Plain Language Summary: As the globe warms, use of electric fans can help people stay cool if they can remain hydrated and if temperatures are low enough. Yet, there are limits to how hot it can be to safely use a fan because when temperatures are too high, a fan will increase the amount of heat traveling over the skin. We use data based on historical meteorological observations to study the number of hours in the continental US that exceed recommended temperature thresholds for safe fan use. We also examine where climate conditions considered unsafe for fan use overlap with socially vulnerable communities. We find that the geographic extent of temperatures too high for safe fan use is expanding, and the number of safe hours is decreasing. In the last two decades people have experienced double the number of hours with outdoor temperatures that are too hot for safe fan use compared to 50–70 years ago. Additionally, communities in socially vulnerable areas are experiencing higher rates of increases in unsafe hours than the overall population. Locations of particular concern include the southern and western US, highlighting the need to direct resources to invest in alternative forms of cooling in these regions. Key Points: Maximum temperatures are 1–2°C higher in locations in the United States with more socially vulnerable communitiesCommunities with high social vulnerability experience faster increases in hours with temperatures too high for safe fan useThe geographic extent of regions with hours with temperatures too hot for safe fan use is expanding [ABSTRACT FROM AUTHOR]

Submarine canyons enhance shelf-slope sediment exchange and influence hydrodynamic processes, with consequences for biogeochemical cycles. This work documents variations in the vertical export of biogenic matter on the northern shore of the Lower St. Lawrence Estuary (LSLE, Quebec, eastern Canada), which is characterized by the presence of an active submarine canyon system. A total of three moorings were deployed from November 2020 to September 2021. One nearshore mooring was deployed in the main axis of the Pointe-des-Monts (PDM) canyon system and was equipped with an Acoustic Doppler Current Profiler (ADCP), and two moorings equipped with sediment traps were deployed in the distal PDM canyon system and offshore Baie-Comeau (BC). The ADCP data revealed the occurrence of a minor sediment remobilization event (December 2020) and a small turbidity current (February 2021) in the canyon. Concurrent elevated fluxes of total particulate matter, particulate organic carbon, particulate nitrogen, and chloropigments showed that these events left a signature in the distal PDM sediment trap located >2.6 km further offshore. The composition of diatom and dinoflagellate assemblages was similar in the canyon system and offshore BC, but the diatom bloom occurred two weeks earlier (in mid-April) at the PDM site, where annual diatom and dinoflagellate fluxes were almost 2 times lower than at the BC site. A bloom of the potentially toxic diatom Pseudo-nitzschia seriata was also observed during the second half of September 2021 at the BC site. This study notably helps identify the relationship between near-bed canyon processes and biogenic matter export in the water column, thereby directly influencing the regional ecosystem. The study period further covered an anomalously nearly ice-free winter and thus, in the context of climate change, provides valuable insight into future trends of biogenic matter export in the LSLE. [ABSTRACT FROM AUTHOR]

Globally, deep-water reservoir systems are comprised of a variety of traps. Lateral and downdip trapping features include sand pinch-outs, truncation against salt or shale diapirs, and monoclinal dip or faulting with any combination of trapping designs; the potential for massive hydrocarbon accumulations exists, representing significant exploration prospects across the planet. However, deep-water turbidites and submarine fans are two different types of traps, which are developed along the upslope and the basin floor fans. Among these two traps, the basin floor fans are the most prolific traps as they are not influenced by sea-level rise, which distorts the seismic signals, and hence provides ambiguous seismic signatures to predict them as hydrocarbon-bearing zones for future explorations. Therefore, the deep-water channel-levee sand systems and basin floor fans sandstone define economically viable stratigraphic plays. The subsurface variability is significant, and hence, characterizing the thick (porous) channelized-basin floor fans reservoir is a challenge for the exploitation of hydrocarbons. This study aims to develop seismic-based attributes and wedge modeling tools to accurately resolve and characterize the porous and gas-bearing reservoirs using high-resolution seismic-based profiles, in SW Pakistan. The reflection strength slices better delineate the geomorphology of sand-filled channelized-basin floor fans as compared to the instant frequency magnitudes. This stratigraphic prospect has an area of 1180 km2. The sweetness magnitudes predict the thickness of channelized-basin floor fans as 33 m, faults, and porous lithofacies that complete a vital petroleum system. The wedge modeling also acts as a direct hydrocarbon indicator (DHI) and, hence, should be incorporated into conventional stratigraphic exploration schemes for de-risking stratigraphic prospects. The wedge model resolves a 26-m thick hydrocarbon-bearing channelized-basin floor fans lens with a lateral distribution of ~64 km. Therefore, this wedge model provides ~75% correlation of the thickness of the LSL as measured by sweetness magnitudes. The thickness of shale that serves as the top seal is 930 m, the lateral mud-filled canyons are 1190 m, and the thick bottom seal is ~10 m, which provides evidence for the presence of a vibrant petroleum play. Hence, their reveals bright opportunities to exploit the economically vibrant stratigraphic scheme inside the OIB and other similar global depositional systems. [ABSTRACT FROM AUTHOR]

Streams convey coarse-clastic sediments towards coasts, where interactions with deltaic and coastal processes determine their resultant sedimentology and geomorphology. Extracting hydroclimatic signals from such environments is a desired goal, and therefore studies commonly rely on interpreting available paleoclimatic proxy data, but the direct linking of depositional and geomorphic processes with the hydroclimate remains obscure. This is a consequence of the challenge of linking processes that are often studied separately and span across large spatial and temporal scales, including synoptic-scale hydroclimatic forcing, streamflows, water body hydrodynamics, fluvial and coastal sediment transport, and sedimentation. Here, we explore this chain of connected processes in the unique setting of the Dead Sea basin, where present-day hydroclimatology is closely tied with geomorphic evolution and sediment transport of streams and coasts that rapidly respond to lake-level fall. We use a 5-year (2018–2022) rich dataset of (i) high-resolution synoptic-scale circulation patterns, (ii) continuous wind-wave and rain–flood records, and (iii) storm-scale fluvial and coastal sediment transport of "smart" and marked boulders. We show the significance of Mediterranean cyclones in the concurrent activation of fluvial (floods) and coastal (wind waves) sediment conveyors. These synoptic-scale patterns drive the westerlies necessary for (i) delivering the moisture across the Judean desert, which is transformed into floods, and at the same time, (ii) the coeval, topographically funneled winds that turn into surface southerlies (>10 m s -1) along the Dead Sea rift valley. During winter, these mesoscale southerlies generate 10–30 high-amplitude, northward-propagating storm waves, with <4 m wave heights. Such waves transport cobbles for hundreds of meters alongshore, northward and away from the supplying channel mouths. Four to nine times per winter the rainfall generated by these atmospheric patterns is capable of generating floods that reach the stream mouths, delivering poorly sorted, coarse gravel. This usually occurs during the decay of the associated storm waves. This gravel is dispersed alongshore by waves during subsequent storms. As storm waves dominate and are >5 times more frequent than flash floods, coarse-clastic beach berms and fan deltas are deposited preferentially north of the delivering channel mouths. This asymmetric depositional architecture, controlled by the regional hydroclimatology, is identified for both the modern and late Pleistocene coast and delta environments, implying that the dominance of present-day Mediterranean cyclones also persisted in the region during the late Pleistocene when Lake Lisan occupied the basin. [ABSTRACT FROM AUTHOR]

Petrography of recrystallised ikaite from Ocean Drilling Program material has been presented previously from Nankai Trough and Congo (ex-Zaire) deep-sea fan. This paper expands on the Nankai Trough ikaite observations, drawing on evidence from Laptev Sea, South Georgia, Okhotsk Sea, and coastal lagoon Point Barrow. However, even though many ikaite and glendonite sites occur at high latitudes, it cannot be that ikaite forms exclusively in polar environments, as demonstrated by the occurrences in the low latitude low temperature deep sea sediments offshore Gulf of Guinea (Angola Congo) and mid-latitude deep-sea trenches offshore Japan. Recrystallised ikaite occurs as mm large, zoned calcite crystals in all samples, along with secondary phases of calcite. Our data set is unique in that the origin, storage, and recrystallisation process of natural formed ikaite is recorded in detail and confirms that glendonite petrographic characteristics are a consequence of the structure and chemistry of recrystallising ikaite and not the physical or geochemical environment. The transformation of man-made ikaite to calcite as recorded in laboratory studies, is a process very similar to the one we have observed for natural ikaite. Most significant is that there is variation in the order of the calcite types within a single sample, leading to the conclusion that the variation is a consequence of impurities and geochemical variability in the ikaite, not the external environment. Morphological observations reveal similarities in ikaite and glendonite, this and the similarity in internal textures in glendonite and recrystallised ikaite confirms that glendonite may be used as an indicator of past presence of ikaite. [ABSTRACT FROM AUTHOR]

The article presents the stages of development of the alluvial fan of the Stryi River (tributary of the Dniester River), which is the largest alluvial cone in the foreland of the Eastern Carpathians. The alluvial fan has a diverse morphology and complex structure, and its formation is the result of the accumulation and erosion activity of several rivers. In order to reconstruct the evolution of the alluvial fan, geological cross-sections of the Stryi, Svicha and Dniester river valleys were made on the basis of archival drillings and field research. The stratigraphy of the alluvial fills is based mainly on morphological (morphostratigraphic) criteria and the correlation of terrace levels with those of adjacent areas. Fluvial sediments from the Late Glacial and Holocene were dated by the radiocarbon method, which allowed the determination of the age of fan dissection. The main factor controlling the course of accumulation and erosion on the alluvial fan was climate change. The accumulation of alluvial covers was preceded by phases of erosion, which generally fell at the end of the glacial periods (late glacial) and the beginning of the interglacials. Differences in the depth of dissection of the strath and the thickness of the accumulated alluvial sediments in the northern and southern parts of the fan may be the result of different tectonic movements and/or the transport capacity and size of river discharges. In the Late Glacial (Alleröd-Younger Dryas) and the Early Holocene the alluvial fan was dissected to a depth of 10-15 m due to the erosion of the Stryi and Dniester rivers. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study is based on the detailed sedimentological analysis of eleven sections and one well through the late Eocene–Oligocene flysch formation of the Internal Ionian Zone (IIZ) in Western Greece. The sections are spread from the northern parts of Epirus to the north and Aitolokarnania to the south. Sedimentological data combined with biostratigraphic analyses resulted in a five-stage evolutionary model for the basin. Unit I corresponds to the lower part of the examined sections, indicating the onset of clastic sedimentation. Regarding depositional environments, it is regarded as a basin plain where lobe distal fringe accumulations occur. Unit II consists almost exclusively of heterolithic facies, marking the advance of a lobe complex system. Massive sandstone facies dominate unit III and can be considered a more proximal submarine fan system. Unit IV reflects a calm period of the basin, where mud-dominated heterolithics and hemipelagic mudstones were deposited. Hemipelagic mudstone facies with intervals of heterolithics, conglomerates, and deformed and massive sandstone facies characterize unit V. The architecture resembles a slope system incised by canyons and channels. The sand-rich intervals in Units III and V could act as the most favorable reservoir levels. In contrast, the sand-rich intervals in Unit II are considered less promising due to their higher heterogeneity.

The Eastern Mediterranean region, extending from the Offshore Nile Delta Cone of Egypt to the Levant Basin, is a confirmed hydrocarbon-rich territory with several giant gas discoveries. Numerous gas fields have been discovered in the Miocene reservoirs within the Nile Delta Cone, and the Levant Basin. The Miocene sedimentary sequences in this region are extremely heterogeneous, consisting mainly of turbiditic slope deposits, channels, and basin floor fans that were capped by evaporites formed during the Messinian Salinity Crisis. As a result, the seismic characteristics and interpreted properties of this heterogeneous section are ambiguous. The study area is located in the Offshore North Sinai Basin, where a thick Early Miocene section was deposited midway between the Nile Delta province, which includes the El-Fayrouz discovery, and the Levant Basin, which includes Tamar, Tanin, and several other discoveries. This study uses quantitative seismic interpretations methods, such as amplitude variations with offset and fluid replacement modeling, to assess the seismic acoustic impedance trend with depth. Also, determine the seismic amplitude response for the brine and gas sands reservoir of the Early and Late Miocene section to link the unexplored study area within the North Sinai Offshore Basin with the explored Nile Delta and Levant Basins. In addition to evaluate direct hydrocarbon indicator (DHI) of the dimming seismic amplitude that is compatible with the structure's last closed contour of the Syrian Arc anticline of the Early Miocene reservoirs (EMT-1 prospect). Different vintages of 2D and 3D seismic data, six wells, and various published data were used in this study. The quantitative interpretation shows the pitfalls of the acoustic impedance trend and seismic response dependency on depth for gas and brine sand, which led to the drilling of the EMT-1 dry well. Also, the fluid replacement, P-wave velocity (Vp), and density (ρ) modeling confirmed that the seismic dimming amplitude was due to a seismic processing artifact, which was corrected by readjusting the overburden Messinian salt processing velocity model. This research concludes that the seismic quantitative interpretations are successfully used to assess the acoustic impedance versus depth and understand DHI pitfalls, as well as the processing workflow that could enhance the seismic image. [ABSTRACT FROM AUTHOR]

The Mannar Basin extends over 45,000 km² off the western coast of Sri Lanka. It has evolved due to the multiphase rifting between Indo-Lanka landmasses during the Barremian-Paleocene time. The sediment thickness of the basin ranges from about 4 to 10 km. The northern part of the basin is a targeted area for hydrocarbon exploration in Sri Lanka. Though two natural gas discoveries were made in 2011, the basin remains a frontier due to lack of well penetration and 3D seismic coverage. As a result, the depositional features of sediment in the basin are little known. This study focuses on identifying paleo depositional features in the Albian and Aptian strata using 650 km² 3D seismic data from the Mannar Basin. Root Mean Square (RMS) amplitude was used to characterize the depositional features in three-time windows on IHS Kingdom software (v.8.3). The results show the existence of a multi-level paleo submarine fan system in the Albian and Aptian strata. They are located relatively close to the western coastline compared to the fan system in the Eocene strata. The deposition of this paleo submarine fan system has taken place in a shelf marine environment and has been influenced by relatively high sea levels during the Albian and Aptian compared to the relatively low sea levels in the Paleocene and Eocene. [ABSTRACT FROM AUTHOR]

The Portofino Conglomerate (PC) cropping out in the Eastern Liguria is an approximately 500 m thick, very gently folded succession mainly composed of poorly bedded and mostly matrix-supported conglomerates. It stratigraphically rests on the Helminthoid Flysch (UA3) thrusted onto the Antola Unit. We vertically distinguished three mostly ruditic litho/petrofacies: (i) Paraggi (fP) with carbonate clasts from an Helminthoid Flysch succession; (ii) Monte Pallone (fMP) with prevailing carbonate and meta-carbonate clasts and minor quartz-rich (meta)siliciclastic and high-pressure–low-pressure (HP-LP) metabasite clasts; and (iii) Monte Bocche (fMB) with dominant quartz-rich (meta)siliciclastic, meta-carbonate clasts, and minor granitoid elements and medium-temperature–high-temperature (MT-HT) regional metamorphic rocks. The middle-upper Eocen age of Paraggi litho/petrofacies is constrained by well-preserved microforaminifers (e.g., Globigerinatheka) recovered in the matrix. During its sedimentation, the directions of the paleocurrents would indicate that the PC underwent a counterclockwise rotation coeval with the first Cenozoic rotational phase of the Sardinia–Corsica system (50–30 Ma) and then stopped before the sedimentation of the Monte Pallone and Monte Bocche litho/petrofacies. The vertical compositional variation in the sedimentary inputs suggested that the PC is the result of a progressive deepening of the erosional level of a tectonic pile that can be located in the Ligurian Alps Chain. We considered the PC as the likely apical part of a submarine fan deposited in a piggy-back/thrust-top basin within the Alpine nappe stack. This sedimentary body was later tectonically transported eastward with its UA3 Helminthoid Flysch substrate (similarly to Epiligurian Units of the Northern Apennines) onto the Apenninic orogenic system (i.e., the Antola Unit). [ABSTRACT FROM AUTHOR]

For the first time, we have interpreted and delineated the distribution of Jurassic strata in the Chaoshan Subbasin, Pearl River Basin, in unprecedented detail using the newly collected seismic data (>17,000 km 2D seismic data and >580 km2 3D seismic data). Four major reflection surfaces and three corresponding stratigraphic-structural layers were identified by analyzing seismic sections and borehole data from the LF35-1-1 well. Five distinct facies associations were identified within the stratigraphic-structural layers, including the shoreface, shallow marine, deep marine, deep-water fan, and mass-transport deposits. Based on outcrop observation, microscopic analysis, and geochemical evaluation, the Lower and Middle Jurassic deep marine mudstone has good source rock potential, and the Middle-Upper Jurassic deltaic sandstone and turbidite silty fine sandstone may be good reservoirs. Additional assessment of the study area's hydrocarbon potential has been conducted using the aromatic hydrocarbon content of seafloor sediments, and favorable exploration areas have been identified using BTEP (benzene, toluene, ethylbenzene, and xylene) content anomalies. Further simulations indicate that the Middle Jurassic hydrocarbon migration is primarily controlled by sand body distribution and faults. In summary, we propose that the most promising exploration targets should be structural (fault blocks), stratigraphic (sandstone lenses), and a combination of both. [ABSTRACT FROM AUTHOR]

With potential hydrocarbon source rocks, the Mesozoic Lower Cretaceous interval in the Aitegle Sag of the Yingen-Ejinaqi Basin in China has a bright petroleum exploration prospect. Considering the scarcity of wells in Aitegle Sag, we have systematically carried out the research on the sequence structure and sedimentary system evolution of the Lower Cretaceous based on seismic, core, and logging data, guided by the Vail classic sequence stratigraphy, and innovatively introduced the self-organizing mapping neural network (SOM) learning algorithm to assist in seismic geological analysis. The results are as follows: (1) after RMSAmp, LyapIndex, FrctDim, and InfoEntr clustering, five zones are divided, which are corresponding to five seismic facies (showing medium-strong amplitude and parallel-subparallel reflection; medium-strong amplitude and wedge-shaped divergent reflection; medium-strong amplitude and continuous-relatively continuous, parallel-subparallel reflection; strong amplitude and continuous sheet-like or blank reflection; and weak amplitude and mound-shaped chaotic reflection, respectively), and interpreted as five subfacies including delta plain front, prodelta-shallow lake, semideep lake, deep lake, and sublacustrine fan. (2) The Lower Cretaceous formation includes one second-order sequence, three third-order sequences (SQ2–SQ4), and six system tracts. In the SQ2–SQ4 circle, the delta system formed by sediments from southeast varies remarkably in the progradational zones in different system tracts, and tectonic movements and sediment supply control the sequence stratigraphy in the study area as major factors. (3) It is feasible to apply SOM learning algorithm to seismic attribute clustering analysis. This method effectively realizes the combination of geophysical methods based on big data analysis and geological problem analysis, which not only strengthens the use of seismic data but also ensures the effectiveness and reliability of clustering results. These findings offer basic data and scientific supports for the exploration and development of unconventional reservoirs (e.g., shale and tight oil/gas reservoirs) in the Aitegle Sag and also provide new ideas for studying the sequence-sediment in the target zones in the fault basin regions with scarce wells. [ABSTRACT FROM AUTHOR]

The present study aims to investigate petrography characteristics and sedimental environments of upper Olenekian-middle Anisian deposits of Nakhlak group in the sedimentary-structural zone of central Iran. To this end, a section of these deposits with a thickness of 720 meters was first selected, and 190 samples were taken from this section for preparing thin sections. Also, quantitative and qualitative laboratory tests were performed and 25 samples of sandstone were selected for point counter analysis. The results indicated that the major deposits of this formation are related to siliciclastic, carbonate, and pyroclastic types, which are in the form of two facies associations. The facies association A at the bottom of the studied section with the thickness of 90 meters has a periodicity of clastic, carbonate, and pyroclastic facies. The clastic facies of this association consists of fine-grained sandstone. In addition, the carbonate facies in association A are characterized by two microfacies consisting of intraclast oolitic grainstone and oolitic grainstone. Further, tuffite is the only pyroclastic facies related to association A, which has a laminate structure, cross-bedding lamination, herringbone bedding, and upward-thinning and thickening cycles. The facies association, B which is deposited later, is more in the middle and top part of the section. The facies association B is 660 meters thick and has a periodicity of clastic and limestone facies. Clastic facies of this association includes four lithofacies such as conglomerate, pebble coarsegrained sandstone, medium-grained sandstone to thin layer siltstone and shale. The carbonate facies consists of four microfacies such as sandy intraclastic wackestone and mudstone. Furthermore, slumping structures, cross bedding, turbulence, boudinage structure, and convolute of sediments, along with the effects of erosional channels are observed in facies B. Field and laboratory studies conducted on this succession indicate the structure of facies association A was deposited in a mixed siliciclastic carbonate ramp. Finally, submarine canyons and submarine fan environments were left by increasing the depth of the facies association B in the deep part of sea and turbidity systems. [ABSTRACT FROM AUTHOR]

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Deep-marine two-part strata consisting of a sand-rich basal part overlain sharply by a mud-rich upper part have been termed linked debrites, hybrid event beds, transitional flow deposits, and bipartite facies. In continental slope and proximal basin floor strata of the Neoproterozoic Windermere Supergroup (western North America) and distal basin-floor strata of the Ordovician Cloridorme Formation (eastern North America), bipartite facies form the middle of a depositional continuum hundreds of meters long consisting upflow of thick-bedded, matrix-poor sandstone (<20% detrital mud matrix) to thin-bedded, sandy mudstone (50%–90% mud matrix). This consistent lithofacies change is interpreted to reflect particle settling in a rapidly but systematically evolving, negligibly sheared sand-mud suspension developed along the margins (Windermere) and downflow terminus (Cloridorme) of a high-energy, mud-enriched avulsion jet. In both study areas, beds of similar lithofacies type succeed one another vertically and transform to the next facies in the depositional continuum at about the same along-strike position, forming stratal units two to nine beds thick whose grain-size distribution gradually decreases upward. This spatial and temporal regularity is interpreted to be caused by multiple surges of a single, progressively waning turbidity current, with sufficient lag between successive surges for the deposition of a traction-structured sandstone overlain by mudstone cap. Furthermore, the systematic back-stepping or side-stepping recognized at the stratal unit scale is interpreted to have been driven by a combination of knickpoint migration and local topographic steering of the flows, which continued until the supply of mud from local seafloor erosion became exhausted, the main channel avulsed elsewhere, or a new stratal element developed. [ABSTRACT FROM AUTHOR]

In this study, we present evidence of a Paleocene-Eocene Thermal Maximum (PETM) record within a 543-m-thick (1780 ft) deep-marine section in the Gulf of Mexico (GoM) using organic carbon stable isotopes and biostratigraphic constraints. We suggest that climate and tectonic perturbations in the upstream North American catchments can induce a substantial response in the downstream sectors of the Gulf Coastal Plain and ultimately in the GoM. This relationship is illustrated in the deep-water basin by (1) a high accommodation and deposition of a shale interval when coarse-grained terrigenous material was trapped upstream at the onset of the PETM, and (2) a considerable increase in sediment supply during the PETM, which is archived as a particularly thick sedimentary section in the deep-sea fans of the GoM basin. Despite other thick PETM sections being observed elsewhere in the world, the one described in this study links with a continentalscale paleo-drainage, which makes it of particular interest for paleoclimate and source-to-sink reconstructions. [ABSTRACT FROM AUTHOR]

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The Paleogene Shahejie and Dongying formations of the eastern Bohai Bay Basin contain >500 m fluvial-deltaic deposits and >600 m deltaic-lacustrine deposits, both of which are important for oil and gas exploration. This study aims to figure out the deposition system distribution within the sequence stratigraphy and predict the exploration target. Sequence boundaries are recognized by unconformities in the seismic profiles and abrupt changes in the well-logging curves (acoustic, spontaneous potential, natural gamma-ray and resistivity), and two second-order and five third-order sequences (SQs1, SQs3 in the Shahejie Formation and SQd1-SQd3 in Dongying Formation) are identified. Four types of depositional system and distribution are determined by well-logging profiles, cores, relative sand content and root-mean-square seismic attributes. The SQs3 sequence is predominantly fan deltas and lacustrine deposits, the SQs1 sequence is predominantly shallow lacustrine deposits, the SQd3 sequence is predominantly braided-river delta, semi-deep lacustrine, and turbidite fan, and the SQd2 sequence is predominantly braided-river delta deposits, whereas the SQd1 sequence is predominantly braided-river deposits. The controlling factors are determined by basin subsidence simulation and fossil data of biological palynology, indicating that tectonic activity is the main controlling factor in SQs3 and SQd3 while climate is the main controlling factor in the SQs1, SQd2 and SQd1 sequences. Combined with the physical properties of sandstone, it is concluded that the beach bar in the SQs1 sequence, turbidite fan in the SQs3 and SQd3 sequences, and thick sandstone in the SQd2 sequence are the important exploration targets. [ABSTRACT FROM AUTHOR]