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A detailed geomorphological mapping allowed to understand the complex relationships interplayed between local tectonics and sedimentation across the coastal area of the Baixo Alentejo (Portugal) all along the Quaternary. Different outcrops of coastal sediments between Sines and Vilanova de Milfontes permitted to reconstruct a general sequence of up to fifteen stair-cased marine terraces, while wide sequences of alluvial fans develop in the hinterland. The distinct geomorphological disposition of these alluvial fans together with the presence/absence of marine terraces, have allowed to define different phases of paleolandscape evolution based both in sea level changes and differential uplift. A dune system has been attributed to MIS 5e in basis of OSL, and 14C and U-series dating permitted the adscription of a beach unit to MIS 5. These data allowed to stablish the relative chronology of the entire marine terrace sequence and to determine the vertical movement rates along the studied coastal area. The results give values ranging from slight uplift (+0.015mm/a) to subtle subsidence (−0.030 mm/a), coinciding with other author's determinations. [ABSTRACT FROM AUTHOR]

The morphology of alluvial fans provides valuable information about changes in tectonic, climate, base level, and drainage basin characteristics. This study aims to evaluate the relationship between active tectonics and morphometric characteristics of alluvial fans in the less studied southern region of the Joghatay mountain, northeast Iran. The study area includes 13 alluvial fans and their corresponding catchment basins in a region with semi-arid climate. Morphometric characteristics of alluvial fans and their corresponding drainage basin including fan area, fan slope, sweep angle, fan toe length, fan radius, basin area, basin slope, fan's width-to-length ratio, asymmetry factor, and basin shape were measured. Our results revealed a negative relationship between the slope of alluvial fans and their corresponding basin area. The weak correlation between the drainage basin area and the fans area may be attributed to the lithology and active tectonics in the study area. The small sweep angle values of the studied alluvial fans can be attributed to the activity of thrust faults and presence of an uplifting anticline that resulted in formation of elongated alluvial fans in our study area. Analysis of the relationship between the morphometric characteristics of the fans and their corresponding basins indicated a negative correlation, which can be attributed to the sediment transport efficiency of the basins. [ABSTRACT FROM AUTHOR]

Alluvial fans and deltas are two environments with different hydrochemical conditions. Their junction zones, as mixing environments, are variably influenced by different processes, leading to variable environmental conditions. The purpose of this study is to investigate groundwater quality in the junction zone of these environments in the northern part of the Jazmourian depression (known as the Rudbar plain) in southeastern Iran to determine the dominant processes, assess arsenic and fluoride health risks, and evaluate irrigation water quality. A total of 33 samples from deep drilled wells were taken, and the concentrations of major ions and elements were determined. Additionally, statistical and hydrochemical analyses were undertaken. The dominant processes in the delta are evaporation and ion exchange, while the dominant process in the fan environment is silicate hydrolysis. Among the samples, 26.7% were mainly affected by the delta, and 73.3% were mainly affected by fan conditions. Although the majority of groundwater samples were suitable for irrigation based on quality standards, a significant portion exceeded the acceptable level for Na%. Non-carcinogenic health risk assessments indicated that arsenic hazard risks exceeded thresholds in 63.3% of cases for children and 36% for adults. Carcinogenic health risks associated with arsenic and fluoride exceeded acceptable levels in 4 and 2 stations, respectively. Elevated As concentrations contribute to a greater average health risk in parts of fans environment. [ABSTRACT FROM AUTHOR]

Much of what we know about terrestrial life during the Carboniferous Period comes from Middle Pennsylvanian (~315–307 Mya) Coal Measures deposited in low-lying wetland environments1–5. We know relatively little about terrestrial ecosystems from the Early Pennsylvanian, which was a critical interval for the diversification of insects, arachnids, tetrapods, and seed plants6–10. Here we report a diverse Early Pennsylvanian trace and body fossil Lagerstätte (~320–318 Mya) from the Wamsutta Formation of eastern North America, distinct from coal-bearing deposits, preserved in clastic substrates within basin margin conglomerates. The exceptionally preserved trace fossils and body fossils document a range of vertebrates, invertebrates and plant taxa (n = 131), with 83 distinct foliage morphotypes. Plant-insect interactions include what may be the earliest evidence of insect oviposition. This site expands our knowledge of early terrestrial ecosystems and organismal interactions and provides ground truth for future phylogenetic reconstructions of key plant, arthropod, and vertebrate groups. Our knowledge of life in the Carboniferous Period is largely restricted to low-lying wetlands dated to 315–310 million years ago. Here, the authors present an older Lagerstätte on an alluvial fan 320–318 million years ago, preserving a diverse ecosystem of vertebrates, invertebrates, plants, and plant-insect interactions. [ABSTRACT FROM AUTHOR]

Nummulitic Limestones deposits are preserved along the tectonic contact between the Variscan basement and Alpine units of Corsica. These marine carbonates, dated from the Late Palaeocene to the Middle Eocene, were deposited within a foreland flexural basin that is considered to be the southern continuation of the Alpine foreland basin of southeast (SE) France. However, in contrast with the Nummulitic Limestones of SE France, those of Corsica are far less documented. This field‐based study constrains the sedimentology, stratigraphy and structure of the Nummulitic Limestones of Corsica in three localities (Balagne, Corte and Sari‐Solenzara) to identify factors that controlled foreland basin development and to clarify its significance within the early alpine orogen. The microfacies, microfaunal assemblages and siliciclastic fractions are characterised throughout the succession at each locality. The results indicate the existence of an important Variscan basement relief to the west of the basin (West Corsican Massif) that supplied early alluvial fans found at the base of the foreland succession in the northernmost Balagne area. Continuous high clastic input strongly reduced the development and diversity of the overlying Nummulitic Limestones facies and fauna. Further south, limestones in the Corte and Sari‐Solenzara areas are thicker and contain richer fauna. Three depositional models corresponding to the carbonate ramp system are proposed for the Nummulitic Limestones and used to construct paleogeographic maps illustrating the transgressive evolution of the Corsican foreland basin from the Early to the Late Eocene. Based on our results and available regional tectonic data and LT thermochronological data, we propose that the Nummulitic marine transgression took place within a continuous foreland basin encompassing southern Corsica and SE France during the early development of the western alpine arc. [ABSTRACT FROM AUTHOR]

The Tian Shan is a typical active intracontinental orogenic belt that is driven by the ongoing indentation of India into Eurasia. However, the geological features of Quaternary deformation, especially in the easternmost sector near Harlik Mountain, remain elusive. Field observations, topographic analysis, and Electron Spin Resonance (ESR) dating were employed to comprehensively assess the deformation features and evaluate the deformation pattern for this region during the Quaternary period. The results disclose evidence of deformation in the northern and southern foreland basins of Harlik Mountain. In the Barkol Basin to the north, crustal shortening results in the formation of surface scarps and folds, indicating north-directed thrusting, with a shortening rate of ~0.15 mm/yr. In the Hami Basin, the north-directed thrust elevates the granites, which offset the alluvial fans, with a shortening rate of ~0.18 mm/yr. Together with the shortening along the boundary fault, the aggregated north–south shortening rate is approximately 0.69 mm/yr in the easternmost Tian Shan, corresponding with the differential motion rate between the north and south Harlik Mountain revealed by the GPS velocity. These findings imply that, distal to the collision zone, tectonic strain in the eastern Tian Shan is primarily accommodated through the reactivation of pre-existing strike–slip faults, with crustal shortening concentrated at the overlapping position of parallel northeast-trending left-lateral strike–slip faults. [ABSTRACT FROM AUTHOR]

We study the interrelations between salt karst and landscape evolution at the Ze'elim and Hever alluvial fans, Dead Sea (DS), Israel, in an attempt to characterize the ongoing surface and subsurface processes and identify future trends. Using light detection and ranging, interferometric synthetic aperture radar, drone photography, time-lapse cameras, and direct measurements of floodwater levels, we document floodwater recharge through riverbed sinkholes, subsurface salt dissolution, groundwater flow, and brine discharge at shoreline sinkholes during the years 2011–2023. At the Ze'elim fan, most of the surface floodwater drains into streambed sinkholes and discharges at shoreline sinkholes, whereas at the Hever fan, only a small fraction of the floodwater drains into sinkholes, while the majority flows downstream to the DS. This difference is attributed to the low-gradient stream profiles in Ze'elim, which enable water accumulation and recharge in sinkholes and their surrounding depressions, in contrast with the higher-gradient Hever profiles, which yield high-energy floods capable of carrying coarse gravel that eventually fill the sinkholes. The rapid drainage of floodwater into sinkholes also involves slope failure due to pore-pressure drop and cohesion loss within hours after each drainage event. Surface subsidence lineaments detected by InSAR indicate the presence of subsurface dissolution channels between recharge and discharge sites in the two fans and in the nearby Lynch straits. Subsidence and streambed sinkholes occur in most other fans and streams that flow to the DS; however, with the exception of Ze'elim, all other streams show only minor or no recharge along their course. This is due to either the high-gradient profiles, the gravelly sediments, the limited floods, or the lack of conditions for sinkhole development in the other streambeds. Thus, understanding the factors that govern the flood-related karst formation is of great importance for predicting landscape evolution in the DS region and elsewhere and for sinkhole hazard assessment. [ABSTRACT FROM AUTHOR]

Over the past decade, excessive groundwater extraction has been the leading cause of land subsidence in Taiwan's Chuoshui River Alluvial Fan (CRAF) area. To effectively manage and monitor groundwater resources, assessing the effects of varying seasonal groundwater extraction on groundwater levels is necessary. This study focuses on the CRAF in Taiwan. We applied three artificial intelligence techniques for three predictive models: multiple linear regression (MLR), support vector regression (SVR), and Long Short-Term Memory Networks (LSTM). Each prediction model evaluated the extraction rate, considering temporal and spatial correlations. The study aimed to predict groundwater level variations by comparing the results of different models. This study used groundwater level and extraction data from the CRAF area in Taiwan. The dataset we constructed was the input variable for predicting groundwater level variations. The experimental results show that the LSTM method is the most suitable and stable deep learning model for predicting groundwater level variations in the CRAF, Taiwan, followed by the SVR method and finally the MLR method. Additionally, when considering different distances and depths of pumping data at groundwater level monitoring stations, it was found that the Guosheng and Hexing groundwater level monitoring stations are best predicted using pumping data within a distance of 20 kilometers and a depth of 20 meters. [ABSTRACT FROM AUTHOR]

There has been a frequent occurrence of tailing dam failures in recent years, leading to severe repercussions. Flood overtopping is an important element contributing to these failures. Nevertheless, there is a scarcity of studies about the evolutionary mechanisms of dam breaches resulting from flood overtopping. In order to fill this knowledge vacuum, this study focused on the evolutionary characteristics and triggering mechanisms of overtopping failures, utilizing the Heshangyu tailings pond as a prototype. The process of overtopping breach evolution was revealed by the conduction of small-scale model testing. A scaled-down replica of the tailings pond was constructed at a ratio of 1:150, and a controlled experiment was conducted to simulate a breach in the dam caused by water overflowing. Based on the results, the following conclusions were drawn: (1) The rise in water level in the pond caused the tailings to become saturated, leading to liquefaction flow and local slope sliding at the initial dam. If the sediment-carrying capacity of the overflowing water exceeded the shear strength of the tailings, water erosion would accelerate landslides on the slope, generating a sand-laden water flow. (2) The breach was primarily influenced by water erosion, which subsequently resulted in both laterally widened and longitudinally deepened breach. As the breach expanded, the sand-carrying capacity of the water flow increased, leading to a faster rate of failure. The breach process of overtopping can be categorized into four distinct stages: gully formation stage, lateral broadening stage of gully, cracks and collapse on the slope surface, and stable stage of collapse. (3) The tailings from the outflow spread downstream in a radial pattern, forming an alluvial fan. Additionally, the depth of the deposited mud first increased and subsequently declined as the distance from the breach grew. The findings of this research provide an important basis for the prevention and control of tailings dam breach disasters due to overtopping. [ABSTRACT FROM AUTHOR]

Large-scale rock-ice avalanches resulting from the interaction of tectonics and climate are characterized with high mobility, huge volumes of sediment, and rapid denudation, being a major agent of landscape evolution in high altitude mountainous regions. Specifically, the extreme glaciated slope failures often transform into extraordinarily large and mobile debris flows, resulting in disastrous consequences such as sedimentation and desertification. Due to a dearth of on-site observation data and experimental data collection, our comprehension of the geomorphic and kinematic characteristics of rock-ice avalanches remains poor. Here we report a cluster of ancient rock-ice avalanches spreading along the Chomolhari range of the China-Bhutan Himalayas. By integrating remote sensing image interpretation with detailed field investigations, we demonstrate the geomorphic and sedimentary characteristics of four events among the avalanches. The estimated volumes of the four are 23.73 Mm3, 39.69 Mm3, 38.43 Mm3, and 38.25 Mm3, respectively. The presence of pre-existing moraines or alluvial fans constrained their movement, resulting in deposition features such as marginal digitated lobes at higher elevations and large depressed areas in the interior. Applying the Savage-Hutter theory, we calculate the basal friction angle and travel angle of these ancient rock-ice avalanches that are both less than 10°, affirming the similarity of these avalanches in the study area to those occurring in other regions. Our study significantly contributes to understanding the geomorphic and kinematic characteristics of rock-ice avalanches in high-altitude mountainous regions, providing valuable insights into their response to the disproportionate growth of Himalayan peaks. [ABSTRACT FROM AUTHOR]

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Due to extensive groundwater exploitation, a groundwater funnel has persisted in the Hutuo River alluvial fan in Shijiazhuang since the 1980s, lasting nearly 40 years and significantly impacting the groundwater chemical characteristics. In this study, based on the groundwater level and chemistry data, the hydrochemical evolution processes and mechanisms of the groundwater during the 1980 groundwater funnel period and the post-2015 artificial governance period were investigated using traditional hydrogeochemical methods and inverse hydrogeochemical simulations. The results show the following: (1) The ion concentrations gradually increased along the groundwater flow path, where they displayed a pattern of lower levels in the northwest and higher levels in the southeast. From 1980 to 2021, the concentrations of major ions were increased. (2) In 1980s, the groundwater hydrochemical type predominantly exhibited HCO3—Ca. From 1980 to 2015, the hydrochemical types diversified into HCO3·Cl—Ca, HCO3—Ca·Mg, and HCO3·SO4—Ca types. Following the artificial governance, the groundwater level rise led to an increase in the concentrations of SO42− and Mg2+. Post-2015, the prevailing hydrochemical type changed to HCO3·SO4—Ca·Mg. (3) The changes in the groundwater level and ion concentrations were quantitatively strongly correlated and exhibited spatial similarity. (4) In the 1980s, the groundwater hydrochemical composition was primarily controlled by the dissolution of albite, dolomite, halite, and quartz; reverse cation exchange; and groundwater exploitation. Since 2015, the hydrochemical composition has mainly been influenced by the dissolution of albite, calcite, and quartz; positive cation exchange; river–groundwater mixing; and industrial activities, with increasing intensities of both water–rock interactions and human activities. [ABSTRACT FROM AUTHOR]

A quarter of a century ago, during cartographic works using then-known field methods for measuring structural features, on the boundary of the Sudetic and Fore-Sudetic blocks, new phenomena were recognised; these were interpreted to be tectonic in nature and the result of left-lateral strike-slip movement in the subsurface. Grabens, half-grabens, shear zones and seismites in the gold-bearing sands and gravels that form the slopes of the valley of the River Kaczawa, are estimated to be of Pliocene and early Pleistocene age, having been interpreted as deposits of the pre-Kaczawa alluvial fan system. The natural exposures documented 25 years age have now all disappeared. In 2022, these levels became exposed again as a result of renewed gravel exploitation and phenomena described in the past reappeared. Field measurements were made again, this time using modern data-recording techniques, such as photogrammetry and terrestrial laser scanning. This work has enabled a comparison of field measurement methods with those obtained from the point clouds data. The results were found to be highly consistent. At the same time, precise reconstructions of the structures and their connection to the geodetic reference system make it possible to supplement previous geokinematic interpretations for this segment of the Sudetic Marginal Fault Zone (SMFZ). A formerly postulated left-lateral strike-slip regime in this zone was confirmed during the period of formation of the pre-Kaczawa alluvial fan deposits, but also probable is a kinematic inversion that must have occurred during, or just after, the early Pleistocene. [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]

Alluvial fans have been proven to have great utilisation potential in QTP, but to what extent they are suitable for agricultural development is unknown. Therefore, using the alluvial fan in the Lhasa River Basin (LRB) as a case study, this paper established an evaluation system of land suitability for agriculture (LSA). Principal component analysis (PCA) and the exhaustive method (EM) were used to define the minimum dataset (MDS) and then the LSA of the alluvial fan in the LRB was evaluated using a comprehensive index of LSA. Two scientific approaches were implemented to improve the LSA using a scenario simulation. The results showed that the MDS assessed by the EA was more representative compared to the PCA. Alluvial fans with suitable grades are mainly distributed in the Lhasa River's middle and lower reaches. Developing facility agriculture and repairing roads accessing the alluvial fans are effective approaches to improve the LSA, which can increase the suitable-grade area from 58.62% to 97.82% and 63.85%, respectively. Therefore, most alluvial fans in the LRB are suitable for developing agriculture, and under the influence of human activities, there will be more alluvial fans suitable for developing agriculture. Our research provides scientific methods for the sustainable development of land in alpine regions. [ABSTRACT FROM AUTHOR]

The Kalahari Basin in southern Africa, shaped by subsidence and epeirogeny, features the Okavango Rift Zone (ORZ) as a significant structural element characterized by diffused extensional deformation forming a prominent depocenter. This study elucidates the Pleistocene landscape evolution of the ORZ by examining the chronology of sediment formation and filling this incipient rift and its surroundings. Modeling of cosmogenic nuclide concentrations in surficial eolian sand from distinct structural blocks around the ORZ provides insights into sand's residence time on the surface. Sand formation occurred from ∼2.2 to 1.1 Ma, coinciding with regional tectonic events. Notably, provenance analyses of sand within ORZ's lowermost block where large alluvial fans are found indicate different source rocks and depositional environments than those of the eolian sands found at a higher elevation. This suggests that the major phase of rift subsidence and the following incision of alluvial systems into the rift occurred after eolian dune formation. Luminescence dating reveals that deposition in alluvial fan settings in the incised landscape began not later than ∼250 ka, and that a lacustrine environment existed since at least ∼140 ka. The established chronological framework constrains the geomorphological effects of the different tectono‐climatic forces that shaped this nascent rifting area. It highlights two pronounced stages of landscape development, with the most recent major deformation event in the evolving rift probably occurring during the middle Pleistocene transition (1.2–0.75 Ma). This event is reflected as a striking change in the depositional environments due to the configurational changes accompanying rift progression. Plain Language Summary: Early rifting stages mark the beginning of the breakup of continents, making them crucial for understanding plate tectonics and the formation of extensional landscapes. These stages involve seismic activity and create unique environments, helping to assess geological hazards and study past habitats and biodiversity. Early stages of continental rifting in the Okavango Rift Zone, centered in northern Botswana, are described in this work from the perspective of sediment dynamics by constructing a time frame for their evolution. Two major types of sediment and their corresponding time scales are studied. The older sediments are eolian sands that were formed between ∼2.2 and 1.1 million years ago and lie today on elevated structural surfaces above the incised rift. Within the subsiding rift that was significantly geomorphologically modified not earlier than 1 million years ago, sediments were deposited by alluvial fans at least since 250 thousand years ago and were followed by a lacustrine environment with alternating hydrological conditions since at least 140 thousand years ago. Key Points: Nascent continental rifting stages are reflected through sedimentological variationsEolian sand that was formed before alluvial incision into the rift is preserved on elevated surfacesDepositional environments in the incised rift have shifted into alluvial‐lacustrine conditions around the Middle Pleistocene Transition [ABSTRACT FROM AUTHOR]

The NW-SE-trending dextral strike-slip faults on the north side of the Tian Shan, e.g., the Karatau fault, Talas–Fergana fault, Dzhalair–Naiman fault, Aktas fault, Dzhungarian fault, and Chingiz fault, play an important role in accommodating crustal shortening. The classic viewpoint is that these strike-slip faults are an adjustment product caused by the difference in the crustal shortening from west to east. Another viewpoint attributes the dextral strike-slip fault to large-scale sinistral shearing. The Alakol Lake fault is a typical dextral strike-slip fault in the north Tian Shan that has not been reported. It is situated along the northern margin of the Dzhungarian gate, stretching for roughly 150 km from Lake Ebinur to Lake Alakol. Our team utilized aerial photographs, satellite stereoimagery, and field observations to map the spatial distribution of the Alakol Lake fault. Our findings provided evidence supporting the assertion that the fault is a dextral strike-slip fault. In reference to its spatial distribution, the Lake Alakol is situated in a pull-apart basin that lies between two major dextral strike-slip fault faults: the Chingiz and Dzhungarian faults. The Alakol Lake fault serves as a connecting structure for these two faults, resulting in the formation of a mega NW-SE dextral strike-slip fault zone. According to our analysis of the dating samples taken from the alluvial fan, as well as our measurement of the displacement of the riser and gully, it appears that the Alakol Lake fault has a dextral strike-slip rate of 0.8–1.2 mm/a (closer to 1.2 mm/a). The strike-slip rate of the Alakol Lake fault is comparatively higher than that of the Chingiz fault in the northern region (~0.7 mm/a) but slower than that of the Dzhungarian fault in the southern region (3.2–5 mm/a). The Chingiz–Alakol–Dzhungarian fault zone shows a gradual decrease in deformation towards the interior of the Kazakhstan platform. [ABSTRACT FROM AUTHOR]

We analyse 498 faults identified in satellite imagery and interpret the height and width of associated footwall ranges with respect to co‐seismic elastic rebound from tectonic and erosional unloading. The dynamics of footwall uplift link uplands to catchment patterns and interrelated hanging wall sedimentary fans. Height–length relations of some catchments and associated alluvial fans scale linearly whereas others, such as fault‐slope catchments and related down‐fault fans (building out from faults) show a significant scatter without an obvious trend. Perched basins abandoned in the footwalls of younger faults offer catchment‐fan height–length relations like watergap and dipslope‐related fans and, besides, hint at reduction of dip angle due to rollback of larger faults before abandonment. Analysis of the width‐to‐height ratio (W/h) of footwall ranges offer a robust linear statistical trend, h = 0.06 W and is identical between datasets. This trend is valid for both arid and tropical rifts, the latter offering smaller rebounds. Contributions of elastic rebound on fault throw in our data are simplistically considered through comparison to global trends on fault length versus throw. This allows consideration around maximum throw (Tmax) linked to the maximum height of footwall ranges (h) and to their width (W) above the reference level. Basic calculations indicate that co‐seismic rebound contributes from <1% to 17% of extensional fault throw. Width‐to‐height ratios for large faults (L > c. 50 km) show less spread than smaller faults. Such large faults expectedly dissect the brittle crust, indicating that these large faults which root in the ductile–brittle transition approach a balanced, steady‐state kinematic pattern. We speculate that significant crustal thinning associated with these large faults triggers the onset of isostatic adjustments that drive fault rotation, instigating fault abandonment and disconnected perched basins. [ABSTRACT FROM AUTHOR]

The western margins of the Lut Desert have long been a crucial hub for cultural exchange, owing to its distinctive geographical location. Dating back to the third millennium BC, Shahdad stands out as a key site in the archaeological studies of southeastern Iran. In 2011, a focused purposive survey was conducted to unveil the settlement patterns of historical and Islamic sites in the west of the Lut. The study successfully recorded 94 archaeological sites, including sites, architectural structures, cemeteries, troglodytic spaces, and rock art spanning from the 5th millennium BC to the late Islamic centuries. The primary aim of this research is to unravel how environmental and human factors shaped the distribution of these sites over time. The primary focus of the study is to analyze the spatial and temporal distribution of ancient sites in the Lut area, as well as the underlying factors shaping this particular pattern. Survey findings revealed that 70 sites were associated with historical and Islamic periods, contrasting with the predominantly prehistoric origins of the others. Furthermore, the research delved into the spatial distribution of historical and Islamic settlements across the cultural landscape of the Lut Desert. It emerged that the Shahdad alluvial fan, stretching along the desert's western edge from north to northeast, served as a dynamic crossroad facilitating exchange from the historical period to the late Islamic centuries, profoundly impacting the evolution and distribution of settlements in the area. [ABSTRACT FROM AUTHOR]

The findings gathered from the Northern Iranian Central Desert (NICD) over the past two decades suggest the significance of the region during the Pleistocene, indicating that different and fluctuating environmental conditions governed the region in the past, contrary to the hot and dry conditions of today. From an archaeological perspective, this means that human populations might have been able to live here during milder times. Based on this assumption and the escalating number of Paleolithic localities, the hypothesis of considering the NICD as a significant Pleistocene dispersal corridor was put forward. However, the available information regarding the Pleistocene human populations in the region was limited only to its eastern and western parts. Up until recently, the Pleistocene "plain dwellers" in the more central parts of the NICD (corresponding to the modern-day Alborz, Tehran, and western Semnan provinces) were not known to us. The picture took a turn when Showr-e Qazi, a paleolithic surface lithic scatter, located about 18km southwest of Eyvanekey, came to light. Following this discovery, the authors embarked on a comprehensive investigation of Eyvanekey. Doing so, a systematic intensive pedestrian field survey was conducted in the vicinity of Eyvanekey County to tackle questions regarding the role of the central parts of the NICD for the dispersal of Pleistocene human populations and the degree of connectivity and relatedness of the landscapes, and resultantly, strengthening or weakening the mentioned hypothesis. As a result, extensive Paleolithic surface scatters were recorded using a combined method of proportionate stratified random and adaptive sampling. The lithic assemblage from Boulan, one of these scatters, has been examined here using techno-typological approach. The preliminary results suggest Middle and Upper Paleolithic affinities. In addition, in general terms, the lithic tradition in Boulan is geared toward the expedient and opportunistic end of the spectrum. Lastly, the discovery of extensive Paleolithic localities in the central parts of the NICD provides additional support for the hypothesis of a Northern dispersal corridor. [ABSTRACT FROM AUTHOR]

A complete, fluvial stratigraphic record for the last glacial period of the Western Andes in Peru is not available due to preservation issues and spatial variability in sedimentation. Deposits are typically restricted to incomplete records of fluvial terraces or localised occurrences of alluvial fans and landslides. These landforms are thought to have formed under a regime of climate cyclicity controlling increases in precipitation. Because of the fragmented preservation of these deposits, as well as dating uncertainties, it remains unclear if orbital climate cycles, such as the precession cycle, or suborbital cycles, such as the wet Heinrich events, are driving Andean sedimentation. In this paper, we try to answer this question through a sedimentological–stratigraphical analysis of a much more complete sedimentary sequence than usually found in the region. We present the results of a grain size analysis of 5000 clasts and 13 new luminescence ages of a 52‐m‐long, stratigraphic section of the Lima fluvial fan in Peru. Bayesian age–depth modelling resulted in a robust chronostratigraphic framework and derived sedimentation rates. The stratigraphic record registered sedimentation from 121.7 ± 4 to 6.3−1.6+1.5 ka. Three major sedimentation periods occurred between 121.7 to 110−5+4, 87 ± 1 to 67−3+2, and 31−3+4 to 6.3−1.6+1.5 ka. These periods registered various unconformities and coarsening–fining upward sequences which chronologically correlate to suborbital pluvial periods, recognised from speleothems and lake records, that drove fluvial deposition. They also correlate with the timing of other recognised sedimentation events throughout the Western Andes. Marine regression resulted in fan progradation and not in incision. The Lima fan stratigraphy represents therefore the most complete, last glacial fluvial record for the Peruvian Western Andes to date and it highlights the potential of fluvial fans as recorders of suborbital climate variability. [ABSTRACT FROM AUTHOR]

The Choushui River Alluvial Fan (CRAF) is a major agricultural area in Taiwan with heavy groundwater usage. The extraction of groundwater here has caused land subsidence, which is now a significant global environmental issue. This study analyzes land subsidence in the CRAF by integrating hydrogeological data from 233 groundwater monitoring stations across four aquifers (CRAF Groundwater_NET) and data from 50 continuous GNSS stations (CRAF GNSS_NET). We developed an automated processing flow for GNSS static surveying within CRAF GNSS_NET, and further employed a time-series fitting method to examine the long-term trends and annual changes for both GNSS and groundwater level data. Our analysis of the time-series data from the past decade identifies areas of significant groundwater level depletion and subsidence hotspots. We explore the relationship between groundwater level variations and surface displacements within CRAF, utilizing GNSS data to analyze horizontal and vertical displacement trends, as well as annual changes. We integrate these findings with hydrogeological data to understand regional subsidence patterns. Our results indicate that CRAF is characterized by distinct hydrogeological features. The study finds that the amplitudes of annual changes in both groundwater level and vertical displacement generally increase from northeast to southwest in the analyzed region. One particular area shows significant groundwater level decline, with the most severe rate recorded at 0.54 m/year. Similarly, GNSS analysis indicates pronounced subsidence trends in the same area, with rates ranging from 4.2 to 5.2 cm/year. These findings highlight the critical need for the development of effective groundwater management strategies to ensure sustainable use of groundwater resources and to implement mitigation measures against land subsidence in similar multipleaquifer settings. [ABSTRACT FROM AUTHOR]

Autogenic feedbacks can produce large‐scale, organized stratigraphic patterns in alluvial fans, but autogenic depositional signatures of specific upstream boundary conditions remain challenging to interpret. Here, a combination of theory, experiment and field application is used to explore how autogenic lithofacies changes can be interpreted as stratigraphic indicators of upstream boundary conditions. Six experiments were conducted to test the effects of sediment supply and water discharge rates on autogenic advance and retreat of the lithofacies boundary (grain‐size transition) in an alluvial fan with two dominant grain sizes. Migration of the grain‐size transition caused a short‐term zigzag pattern in the grain‐size transition position in the dip‐directional deposit section. For each experiment, time‐lapse images and laser topographic scans of the fan surface and stratigraphic cross‐sections of the final deposits were used to quantify characteristic timescales of autogenic processes. Timescales for fan‐margin migration, surface wet‐fraction change and grain‐size transition migration generally shorten as sediment supply rate increases and water discharge rate decreases. Increasing the sediment supply rate shortens the duration of the fluvial sediment storage and release cycle, producing higher frequency zigzags in the grain‐size transition trajectory. Increasing the water discharge tends to widen channels and lengthens the duration of the fluvial sediment storage and release cycle, constructing lower frequency zigzags in the grain‐size transition trajectory. Increasing the water discharge also enables more sediment to transport further downstream during release events, leading to higher magnitude zigzags in the grain‐size transition trajectory. These relationships between upstream boundary conditions and the grain‐size transition trajectory demonstrate how autogenic stratigraphic signals could be used as a tool to infer relative changes in boundary conditions. [ABSTRACT FROM AUTHOR]

This study focused on determining the stratigraphic phenomena of the sequences of the Kirkuk group, within the Tertiary age, in the study area at the Buzurgan oil field within the Maysan governorate. In addition to various seismic lines from the completed seismic survey of the study region, data from the Buzurgan oil field wells was utilized. The stratigraphic interpretation results showed that the seismic sections of the Kirkuk Group formations are deposited in the form of a sigmoid configuration through the continuous deposition of shallow-shelf carbonates. Periodic rises in sea level led to episodes of deeper-water sedimentation, including shelf and shelf margin facies. Clastic (sandstone) was deposited as the sea receded from the Ghar formation, which represents the alluvial fan in the outer-shelf basin (slop and basin fan), through periods of sea-level (LST) and in a shallow-marine environment, leading to an overlap between sediments and the presence of sand lenses, onlap, and down lap. The current study shows the phase change in reflectors and perfect hydrocarbon indexes. The study detected a stratigraphic trap in the formation's eastern part and a large lens in the Southeast parts of the study area. [ABSTRACT FROM AUTHOR]

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Ski tourism's popularity is driving a rise in the number of ski resorts. This study aims to present the impact of ski infrastructure on soil erosion processes in the example from a small catchment in the Gubałowskie Foothills in southern Poland, where landscape changes before (since 1879) and after the construction of the ski station (2007) are presented. The analyses of changes in flow accumulation, slope morphometry, and drainage ditches were conducted in the test area. Quantitative analyses were performed using repeated DEMs derived from aerial LiDAR survey and detailed geodetic measurements, complemented by geomorphological mapping done in the field. The study has revealed that the ski infrastructure has not only directly transformed the hillslope by flattening and constructing escarpments (up to 3 m high) but has also created alternating patterns of erosion and accumulation. In the test area, the drainage ditch was poorly designed. It was filled with materials (0.1–0.5 m), and two new outlets formed. The escarpment of the analyzed ski run has been diminished by 0.5 m. An alluvial fan (0.1–0.22 m thick) has developed on the flattened surface below the escarpment with drainage ditch outlets. This fan is eroded by subsurface flow that creates a piping system. The gully below the alluvial fan has retreated upslope, accelerated by subsurface erosion. This study enables the presentation of hillslope adjustments and processes in response to the new conditions caused by ski infrastructure. Such results may support more effective land management in regions changed by ski infrastructure. [ABSTRACT FROM AUTHOR]

The 2012 satellite ASTER geoscience maps of Australia were designed to provide public, web-accessible, and spatially comprehensive surface mineralogy for improved mapping and solutions to geoscience challenges. However, a number of the 2012 products were clearly compromised by variable green and/or dry vegetation cover. Here, we show a strategy to first estimate and then unmix the contributions of both these vegetation components to leave, as residual, the target surface mineralogy. The success of this unmixing process is validated by (i) visual suppression/removal of the regional climate and/or local fire-scar vegetation patterns; and (ii) pixel values more closely matching field sample data. In this process, we also found that the 2012 spectral indices used to gauge the AlOH content, AlOH composition, and water content can be improved. The updated (new indices and vegetation unmixed) maps reveal new geoscience information, including: (i) regional "wet" and "dry" zones that appear to express "deep" geological characters often expressed through thick regolith cover, with one zone over the Yilgarn Craton spatially anti-correlated with Archaean gold deposits; (ii) a ~1000 km wide circular feature over the Lake Eyre region defined by a rim of abundant "muscovite" that appears to coincide with opal deposits; (iii) a N–S zonation across the western half of the continent defined by abundant muscovite in the south and kaolinite in the north, which appears to reflect opposing E ↔ W aeolian sediment transport directions across the high-pressure belt; (iv) various paleo-drainage networks, including those over aeolian sand covered the "lowlands" of the Canning Basin, which are characterized by low AlOH content, as well as those over eroding "uplands", such as the Yilgarn Craton, which have complicated compositional patterns; and (v) a chronological history of Miocene barrier shorelines, back-beach lagoons, and alluvial fans across the Eucla Basin, which, to date, had proved elusive to map using other techniques, with potential implications for heavy mineral sand exploration. Here, we explore the latter three issues. [ABSTRACT FROM AUTHOR]

The coastal plain of Rio Grande do Sul state, in Brazil, is highly vulnerable to expected changes in sea level, while having an increasing population and consequently increasing water demands. Adequate management is essential to restrain contamination, depletion and salinization of the region's aquifers considering current and future challenges, but geologic knowledge is essential to guide groundwater sustainable practices. To contribute to this discussion, this work integrated existing geological data from the northern coast of Rio Grande do Sul state to create a three-dimensional representation of the main hydrostratigraphical units of the region and its relation to the basement rocks, expanding the current knowledge of the coastal aquifer system. A review of existing data was carried out, consisting of 307 borehole logs from 13 municipalities inside the area of interest, as well as 19 vertical electrical soundings and 37 logs from oil and coal exploratory drillings, that resulted in 315 input points for the model. This work builds up on the conceptual model previously developed for the area, that defined four hydrostratigraphical units for the region, and was able to constrain the geometries of the main aquifers (unit 1 and 3) and aquitards (unit 2 and 4) and their relation to the basement rocks, showing them to be more heterogeneous in thicknesses and extent than previously thought. In addition, this work was able to model what could be a fifth hydrostratigraphical unit, that strongly differs from the other four and could be an indication of the alluvial fans previously described in the literature. [ABSTRACT FROM AUTHOR]

The occurrence of high-concentration turbid water due to a large landslide in the upper reaches of the Tedori River Basin in Japan in May 2015 led to a rapid decline in the groundwater levels within the alluvial fan. However, factors other than turbid water, such as changes in precipitation patterns, can have a significant impact on groundwater levels but have not been thoroughly investigated. By analyzing the relationship between river water and groundwater levels, we found that by 2018, conditions had returned to those observed prior to the turbidity events. Regarding seepage, we found that approximately 24% of the Tedori River's discharge contributed to seepage before the turbidity event. In contrast, during the post-turbidity years, seepage decreased between 2015 and 2017 and returned to the pre-turbidity levels by 2018. Furthermore, by constructing a hydrological model and examining the contributions of turbidity and precipitation, we found that in 2015, turbidity contributed to 76% of the groundwater level changes, whereas precipitation accounted for 24%. In contrast, in 2016, turbidity contributed to 67%, while precipitation contributed to 33%. In essence, the first year was characterized by a significant contribution from turbidity, while precipitation also played a significant role in groundwater level fluctuations in the second year. [ABSTRACT FROM AUTHOR]

The Kumitir site, associated with the Majapahit Empire, is a significant archeological discovery. Archeologists from the East Java Cultural Heritage Preservation Center (BPCB), uncovered a structure at this site, buried beneath boulder-sized rocks. According to historical literature, the collapse of Majapahit was caused by volcanic eruptions from the Anjasmoro, Arjuno, or Welirang complexes. Therefore, this study aimed recreate the gravity-driven mass flow covering the Kumitir Site. Geological surveys, including sediment structure analysis and grain orientation measurements, were conducted to provide new information on paleocurrent and ancient sedimentary processes at the site. Digital Elevation Map (DEM) and the Laharz simulation tool fecilitated the creation of reconstructed lahar flow maps using open-source DEM data with eight-meter resolution The results of the boulder analysis showed that a paleochannel played a significant role in the burial site, with two sources identified, namely Mount Welirang (Welirang alluvial fan) and the Anjasmoro complex (Old Jatirejo alluvial fan). Meanwhile, the combination of methods applied signified the direction of the Welirar alluvial fen (ESE-NNW) and the Jatirejo Tua alluvial fan (SSW-NNE). Volumes of 9 million m5 and 65 million m3 were the most relevant parameters for estimating the lahar flows of the western and eastern craters, respectively. [ABSTRACT FROM AUTHOR]

The Fenghe River is one of the "Eight Waters of Chang'an", and in-depth research on the status quo of its water environment, influencing factors, and the relationship between surface water and groundwater transformation is the key to the ecological restoration of the river. Based on 62 groundwater samples and 17 surface water samples collected in Fenghe River Basin in July2022, the chemical characteristics and influencing factors of groundwater and surface water were analyzed by mathematical statistics, Piper diagram, Gibbs diagram, ion ratio method and hydrogen and oxygen isotopes, and the transformation relationship between groundwater and surface water was explored. The results show that (1) the groundwater in the study area is weakly alkaline, about 50%is extremely hard water, 25%is hard water, and the total dissolved solids (TDS) is large, the maximum value is as high as 1 916mg·L-1, and NO3- concentration is high; surface water is weakly alkaline, soft or slightly hard water, with less TDS and more organic matter; the cations of surface water and groundwater are mainly Ca2+, the anions are mainly HCO3-, and the surface water is basically HCO3-Ca water; the main chemical types of groundwater are HCO3-Ca, HCO3·SO4-Ca, HCO3-Ca·Mg and HCO3·SO4-Ca·Mg types accounted for 24.19%, 24.19%, 16.13%and 9.68%, respectively, and the spatial variation of water chemistry type is large. (2) The water chemical characteristics of the study area are mainly controlled by rock weathering, and evaporation concentration and atmospheric precipitation are also affected; in addition to the dissolution of rock salt, Na+ in water should also be affected by silicate weathering, and Ca2+, Mg2+ and HCO3-mainly come from the weathering and dissolution of carbonates such as calcite and dolomite; the alternating adsorption of cations in groundwater is common, which has a great impact on Ca2+and Na+concentrations; human activities have increased the concentrations of SO42-, NO3-and Cl-in some groundwaters, while surface water is less affected by human activities. (3) The surface water is mainly used to recharge groundwater in the alluvial fan top-middle in the study area, and the recharge ratio is 46.62%; the leading edge of the alluvial fan is mainly recharged by groundwater for surface water, and the recharge ratio is13.62%; the lower plain is mainly recharged by surface water to groundwater, with a recharge ratio of 38.39%. [ABSTRACT FROM AUTHOR]

The Dunhuang Basin, situated in western China along the Altyn Tagh Fault (ATF) zone, intersects the Tethys and Paleo‐Asian Ocean tectonic domains. Influenced by both the ATF system and the far‐field effects of the Qiangtang‐Lhasa‐Eurasia collision during the Mesozoic, the mechanism of the Jurassic sedimentary migration of the basin in response to tectonic movements is unclear so far. The paper uses a comprehensive approach, including field geological surveys, lithologic and lithofacies discern, stratigraphic relationships analysis and 2D seismic profile interpretation, to examine the distribution of Jurassic residual strata in the basin. The comprehensive results of our study suggest that the Dunhuang Basin exists as an isolated block with unique tectonic and sedimentary evolution characteristics. In the Early Jurassic, the Dunhuang Basin underwent initial rifting, leading to the formation of small segmented intermontane sags. This phase was marked by the coarse particle sedimentary system of alluvial fans and braided rivers, represented the near source rapid deposition in the initial formation period of the basin. Stratigraphic distribution was primarily influenced by pre‐Jurassic basement topography and was not significantly constrained by faulting during this period. The formation of these isolated discontinuous small intermontane sags indicates the segmented activities of the ATF in the Early Jurassic period. In the Middle Jurassic period, influenced by the ATF dextral strike‐slip faulting, sedimentation extended eastward and the depocenter migrated clockwise compared with the distribution of the Middle Jurassic strata within the Dunhuang Basin. This period witnessed the development of coal measure strata at the basin's margins and lacustrine fine‐grained clastic deposition in the centre. The segmented fracture of the ATF gradually initiated a unified dextral strike‐slip tectonic movement. In the Late Jurassic period, sedimentary strata were locally present in the Wanyao Sag but absent in other sags. The depocenter migrated counterclockwise compared with the distribution of Middle Jurassic strata within the Dunhuang Basin, due to regional uplift accompanied by the ATF sinistral strike‐slip faulting caused by the collision between the Lhasa Block and the Eurasia Plate. The depocenter migration of the Dunhuang Basin constrained within the ATF system from the Early to Middle and Late Jurassic can be attributed to the transition of the ATF strike‐slip faulting in context of the stress relaxation and compression between the collision of the Qiangtang and Lhasa blocks to the Eurasia Plate, respectively. [ABSTRACT FROM AUTHOR]

The Marinoan diamictites and the overlying cap carbonates at continental margins bear key information on the paleo-environment evolution during the collapse of Snowball Earth, such as the timespan of intense chemical weathering. Such a sedimentary suite has been recently discovered in the northwestern Tarim Craton of China, but its depositional processes remain controversial. Here, we present stratigraphic and isotope geochemical studies on the diamictites of the Yuermeinak Formation and the overlying cap carbonates of the Sugetbrak Formation in the Aksu region of the northwestern Tarim Craton. Multiple unconformities in the region suggest major tectonic uplifting during the Cryogenian, probably resulting in a mountainous topography and varying dip directions of the overlying cap carbonates. The paleo-elevation of these mountains might have been higher and above sea level. We propose new depositional processes that involved four stages from glacial continental facies to neritic facies and/or alluvial fan systems. The first stage formed the massive diamictites and stratified siltstones with dropstones, recording cycles between glacier retreat and advance. The second stage involved the late transgression at the end of the deglaciation and the formation of calcareous massive diamictites with negative Î'13C. The third stage included the onset of cap carbonate deposition and the alternating precipitation of calcareous mudstones and carbonates, reflecting frequent sea-level changes. The fourth stage was related to a widespread marine regression that developed a terrestrial environment and the sedimentation of the sandstones of the Sugetbrak Formation. Furthermore, we suggest that intense chemical weathering on exposed continents after the Marinoan deglaciation likely lasted for only hundreds of thousands of years, releasing ample alkalis into the ocean and facilitating the precipitation of the cap carbonates. [ABSTRACT FROM AUTHOR]

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office 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.)

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]

The North Hebei Plain is a typical example of a deep-covered area, with a thickness of more than 200 m Quaternary loose sediments. Previous studies have tried various stratigraphic classification methods but lack an effective combination of geophysical methods. Based on the analysis of rock strata and dating tests, combined with geophysical well-logging data, shallow seismic reflection, and paleomagnetic dating, the Quaternary strata of the deep-covered area in the Hebei Plain was divided into the Lower Pleistocene series, the Middle Pleistocene series, the Upper Pleistocene series, and the Holocene series. By observing the cores of the Quaternary borehole QHJ02, this paper focused on dividing its loose sediments into eight lithological sections, according to the lithology, sediment colour, sedimentary assemblage, and sedimentary environment. The geomagnetic polarity belt is divided according to the paleomagnetic inclination of the paleomagnetic sample in borehole QHJ02. The results of the paleomagnetic test show that the interval of 0–101.3 m is Brunhes normal polarity chron, the interval from 101.3 to 219.5 m is Matuyama reversed polarity chron, and the interval from 219.5 to 350 m is Gauss normal polarity chron. The amplitude of the geophysical logging curve shows a good correspondence with the lithology of the QHJ02 borehole. The lithology changes can be identified through the abrupt abnormal positions of logging curves such as gamma ray, resistivity, and magnetization to analyze the sedimentary environment combination and determine the formation boundary. According to the combination of paleomagnetic, shallow seismic reflection, and geophysical well logging methods, we can determine the bottom boundaries of the Quaternary and middle Pleistocene are 219.5 m and 101.3 m, respectively. According to the combination of geophysical well-logging, lithostratigraphic assessment, dating experiment of Accelerator Mass Spectrometry 14C (AMS 14C), and Optically Stimulated Luminescence (OSL), we can determine the bottom of the upper Pleistocene and the lower limit of Holocene to be at 45.4 m and 21.4 m, respectively. Based on a comprehensive analysis of rock stratigraphic characteristics and well-logging curves, this study investigated the paleoenvironmental characteristics of borehole QHJ02 at different ages. The Upper Neogene was characterized by branch channels and river floodplains, with localized occurrences of alluvial fans, avulsion fans, and inter-channel lowlands. During the Early Pleistocene, branch channels and inter-channel lowlands dominated, with localized river floodplains. The Middle Pleistocene witnessed alternating branch channels and river floodplains as the main paleoenvironments. In the Late Pleistocene, branch channels and inter-channel lowlands were prevalent. The Holocene saw a combination of natural levees and river flood-plain environments. These findings enhance our understanding of the geological evolution and paleoenvironmental changes in the North Hebei Plain. [ABSTRACT FROM AUTHOR]

This paper presents the upper Cenozoic post-collisional terrestrial conglomeratic formations of the Eastern and South-Eastern Carpathian foreland subjected to sedimentological and geomorphological analyses including an in-depth review of previous investigations. These formations embrace gravels as the prominent component, together with sands and muds. The unit is up to 190 m thick. The conglomeratic formations are represented by erosional remnants in the Eastern Carpathians, whilst they occur as a continuous body (the Candejti Formation) in the South-Eastern Carpathians. The Eastern Carpathian formation ranges in age from the late Serravallian to early Tortonian stages, whilst the Candejti Formation extends from the late Early to the late Middle Pleistocene. These formations are separated by 10 Myr, supporting the view the Carpathians and their foreland from North to South evolved diachronously. Their affinity is determined by the sedimentary environment of alluvial fans within the wedge-top depozone of the foreland. This environment arose from simultaneous occurrence of rare intervals of intense floods and presence of highly erodible rocks in fan-supply catchments. Most of the fans are of hyperconcentrated flow-dominated type, whilst part of those within the Eastern Carpathians are of debris-flow-dominated type. The fans' origin was provided by uplifted orogen and stable or subsiding foreland, giving both high gradient and orographic precipitation. The fans accumulated following a time lag after the post-collisional orogen uplift. The facies and architectural differences between the formations are associated with specific sedimentation and regional tectonics. In the Eastern Carpathians thin conglomeratic formation was deposited above the regional angular unconformity by predominant progradation in conditions of the tectonic quiescence and low accommodation space. In the South-Eastern Carpathians the fluvial fine-grained sedimentation gradually passed into the thick conglomeratic Candejti Formation during the attenuated subsidence of the Focjani Depression. As the accommodation space decreased, the aggradation of the formation gave way to its progradation. [ABSTRACT FROM AUTHOR]

Theory suggests that the response time of alluvial channel long-profiles to perturbations in climate is related to the magnitude of the forcing and the length of the system. Shorter systems may record a higher frequency of forcing compared to longer systems. Empirical field evidence that system length plays a role in the climate periodicity preserved within the sedimentary record is, however, sparse. The Toro Basin in the Eastern Cordillera of NW Argentina provides an opportunity to test these theoretical relationships as this single source-to-sink system contains a range of sediment deposits, located at varying distances from the source. A suite of eight alluvial fan deposits is preserved along the western flanks of the Sierra de Pascha. Farther downstream, a flight of cut-and-fill terraces have been linked to eccentricity-driven (100-kyr) climate cycles since ca. 500 ka. We applied cosmogenic radionuclide (10Be) exposure dating to the fan surfaces to explore (1) how channel responses to external perturbations may or may not propagate downstream, and (2) the differences in landscape response to forcing frequency as a function of channel length. We identified two generations of fan surfaces: the first (G1) records surface activity and abandonment between ca. 800 and 500 ka and the second (G2) within the last 100 kyr. G1 fans record a prolonged phase of net incision, which has been recognised throughout the Central Andes, and was likely triggered by enhanced 100-kyr global glacial cycles following the Mid-Pleistocene Transition. Relative fan surface stability followed, while 100-kyr cut-and-fill cycles occurred downstream, suggesting a disconnect in behaviour between the two channel reaches. G2 fans record higher frequency climate forcing, possibly the result of precessional forcing of climate (ca. 21/40-kyr timescales). The lack of a high-frequency signal farther downstream provides field support for theoretical predictions of a filtering of high-frequency climate forcing with increasing channel length. We show that multiple climate periodicities can be preserved within the sedimentary record of a single basin. Differences in the timing of alluvial fan and fluvial terrace development in the Toro Basin appears to be associated with how channel length affects fluvial response times to climate forcing as well as local controls on net incision, such as tectonic deformation. [ABSTRACT FROM AUTHOR]

Understanding drought evolution and its driving factors is crucial for effective water resource management and forecasting. This study enhances the analysis of drought probability by constructing bivariate distributions, providing a more realistic perspective than single-characteristic approaches. Additionally, a meteorological drought migration model is established to explore spatiotemporal paths and related characteristics of major drought events in the Choushui River alluvial fan. The results reveal a significant increase in the probability of southward-moving drought events after 1981. Before 1981, drought paths were diverse, while after 1981, these paths became remarkably similar, following a trajectory from north to south. This is primarily attributed to the higher rainfall in the northern region of the Choushui River alluvial fan from February to April, leading to a consistent southward movement of drought centroids. This study proposes that climate change is a primary factor influencing changes in the spatiotemporal paths of drought. It implies that changes in rainfall patterns and climate conditions can be discerned through the meteorological drought migration model. As a result, it provides the potential for simplifying drought-monitoring methods. These research findings provide further insight into the dynamic process of drought in the Choushui River alluvial fan and serve as valuable references for future water resource management. [ABSTRACT FROM AUTHOR]

The Midcontinent Rift System of North America is one of the oldest continental rifts but rifting ceased before continental breakup. The southern segment of the Midcontinent Rift System lies in Kansas, USA, where the stratigraphic succession and rift evolution are largely unknown. This study analysed the rift basin infill in this part of the Midcontinent Rift System to propose a depositional model. The Precambrian rift succession was described in discontinuous cores drilled in the Texaco Noel Poersch#1 well in Washington County. Sixteen lithofacies were identified and grouped into four different facies associations (fluvial, aeolian, lacustrine and alluvial fan). Overall, the studied succession comprises continental deposits accumulated dominantly in alluvial and aeolian settings, with the intermittent development of lacustrine systems. The proposed depositional models for the available core intervals indicate cyclic patterns of overfilled and underfilled phases within the rift basin. These changes in the accommodation‐to‐supply ratio were controlled by tectonism and probably modulated by climate during evolution in the syn‐rift phase. This study advances our understanding of variations across the Midcontinent Rift System. [ABSTRACT FROM AUTHOR]

The spatial cover of biocrusts represents a suitable habitat for the activity of soil microorganisms in semi‐arid and arid regions. Microorganisms are one of the essential components of soil quality. Therefore, it is necessary to understand the processes of biocrust habitat formation in landforms and their mutual relationship with soil properties. We studied the spatial distribution of biocrusts and their effect on soil microbial biomass and carbon activity in a semi‐arid alluvial fan in NE Iran. A total of 72 soil samples (using plots 0.25 m2) from the topsoil layers (0–5 cm) were collected along the alluvial fan in September 2020. Soil surface properties and microbial biomass in two categories of biocrust and non‐biocrust were investigated in three classes of biocrusts coverage obtained by geostatistics. Our results revealed that biocrusts had a negative correlation with gravel coverage and elevation; in contrast, the suitable spaces for biocrusts growth were created by cobble clasts. The biocrusts have provided favourable conditions for soil microorganisms by altering the properties of the soil (such as increasing organic carbon, nitrogen and available phosphorus and decreasing pH), and thus they increased basal soil respiration and microbial biomass. Different microbial activities were led by the predominant type of biocrusts, as the chlorolichen crusts had the most significant effect on increasing the microbial biomass phosphorus while cyanolichen crusts increased the microbial biomass carbon. Moss and cyanolichen crusts increased microbial activity and respiration more than cyanobacteria crusts. Therefore, the soil quality has improved by biocrusts in semi‐arid ecosystems. [ABSTRACT FROM AUTHOR]

Due to the influence of multiple tectonic movements in rift basins, the sequence and sedimentary filling modes of continental petroleum reservoirs are complex, which makes it difficult to establish isochronous stratigraphic frameworks and thus affects the accuracy of subsequent predictions of effective sand bodies. Taking the Guantao Formation of the Binxian uplift and the surrounding areas as an example, this study established the sequence stratigraphic framework of the Guantao Formation and discussed the controlling effect of sequence stratigraphy on sedimentary filling. According to a combination method of seismic data, well log data, the wavelet transform technique (WTT), and Integrated Prediction Error Filter Analysis (INPEFA) methods, the Guantao Formation in the study area can be divided into 1 long-term cycle (LNG), 4 mid-term cycles (MNG1–MNG4, from bottom to top), and 11 short-term cycles (SNG1–SNG11, from bottom to top). Based on comprehensive analysis of geological and seismic data, three sedimentary facies can be classified: alluvial fan facies, braided fluvial facies, and meandering fluvial facies. The sequence stratigraphic style of the study area has a significant controlling effect on sedimentation and sand body distribution. Different levels of cycles have different impacts on sedimentary facies/microfacies types, the development degree of each sedimentary microfacies, and sand body distribution. The long-term cycle controls the distribution of sedimentary facies, while the mid-term and short-term cycles control the distribution of sedimentary microfacies. The bottom interface of the Guantao Formation (T1) served as the dominant migration channel in the study area, connecting the reservoir and source rocks. When the base-level was in the low stage (MNG1), a large amount of sand bodies developed, forming favorable reservoirs for petroleum. The interlayers at the top of the long- and mid-term cycles served as seal layers to prevent oil and gas from escaping. The MNG1 cycle has a good combination of reservoir and seal, resulting in the accumulation of oil and gas in the MNG1 strata, which became the main oil- and gas-producing layer in the area. These study results can provide effective guidance for future prediction of the distribution of sand bodies and high-quality reservoirs. [ABSTRACT FROM AUTHOR]

Alluvial glutenite reservoirs have obviously stronger heterogeneous and more complex control factors than sandstone reservoirs. Taking the Binxian Uplift area in the Boahi Bay Basin as an example, the aim of this study is to clarify the characteristics and control factors of the alluvial glutenite reservoir quality and the influence of reservoir properties on hydrocarbon accumulation. Pore types in the study area mainly include residual intergranular pores, intergranular dissolved pores, intragranular dissolved pores, and mold pores. The residual intergranular pores and intergranular dissolved pores are the main pore types. Most samples have porosity greater than 15% and permeability is mainly concentrated between 50 mD and 500 mD. It is shown that lithology type, microfacies, and diagenesis have significant impact on the reservoir quality. The reservoir qualities of very fine sandstone and fine sandstone are better than those of conglomerate and gravel-bearing sandstone. Instead of grain size, sorting affects the alluvial glutenite reservoir quality significantly. Oil-bearing samples commonly have sorting coefficient less than 2 while non-oil-bearing samples have sorting coefficient larger than 2. There are significant differences in reservoir physical properties of different sedimentary microfacies. The stream flow in mid-alluvial fan (SFMA) and braided channels outside alluvial fans (BCOA) have relatively weaker compaction and better reservoir quality than the overflow sand body (OFSB) and debris-flow in proximal alluvial fan (DFPA). Calcite cementation, the main cement in the study area, commonly developed at the base of SFMA and BCOA and near the sandstone-mudrock contacts. The source of calcium carbonate for calcite cement mainly came from around mudstone. High calcite cement content commonly results in low porosity and permeability. Individual glutenite thickness is also an important influencing factor on reservoir quality. Reservoirs with large thickness (>4 m) have high porosity and permeability. Dissolution occurred in the reservoir, forming secondary dissolution pores and improving reservoir quality. The dissolution fluid for formation of secondary pores is mainly meteoric waters instead of organic acid. The reservoir property has an important influence on hydrocarbon accumulation. The lower limit of physical properties of an effective reservoir is a porosity of 27% and permeability of 225 mD. The findings of this study can be utilized to predict the reservoir quality of alluvial glutenite reservoirs effectively in the Bohai Bay Basin and other similar basins. [ABSTRACT FROM AUTHOR]

Neoproterozoic strata are widely developed in the Upper Yangtze region of South China, among which the Sinian Dengying Formation has been discovered with numerous large gas fields in the Sichuan Basin, and hence they have become an essential domain for natural gas exploration and development. The early‐to‐middle Neoproterozoic Nanhua System and Doushantuo Formation are characterized by rifting deposits in the northeastern margin of Sichuan Basin, but their depositional succession and sequence architectures are still unclear, which has largely restricted our understanding of the resource potential of these strata. In this paper, based on the outcrops of the Neoproterozoic Nanhua System and Doushantuo Formation in the northeastern margin of Sichuan Basin, we describe the stratigraphic distribution and sedimentary evolutionary characteristics, and establish the regional stratigraphic framework, sedimentary cycle and evolutionary sequence of the Nanhua System and Doushantuo Formation. The results show that the lithology of the Nanhua System and Doushantuo Formation is primarily composed of conglomerate, conglomeratic sandstone, medium‐fine sandstone, siltstone, mudstone, shale and tillite; a variety of sedimentary facies including alluvial fan, river, delta, coastal shore, shelf, basin and tillite were developed; five third‐order sequences could be identified, representing multiple cycles of marine transgression and regression. The climate during the deposition of the Nanhua System and Doushantuo Formation underwent from a warm and humid pre‐glacial period through cold and arid multiple glacial periods to a warm and humid interglacial period, which consequently formed a sedimentary sequence of alluvial fan and fluvial delta to tillite during the early period, shelf basin to tillite during the middle period and slope basin to delta facies during the late period. In terms of a plan view, the depositional pattern is composed of alluvial fans and deltas at the proximal part of the rift, deep‐water shelf to slope at the middle part of the rift and slope to basin facies at the central part of the rift. Finally, we propose that large‐scale distribution of high‐quality source rocks developed in the interglacial Datangpo and Doushantuo formations, while fluvial‐deltaic reservoirs occurred in the Gucheng, Nantuo and Doushantuo formations, thus showing favourable resource potential and exploration prospects within the Sichuan Basin. [ABSTRACT FROM AUTHOR]

The Nonesuch Formation microbiota provide a window into ca. 1075 Ma life within the interior of ancient North America. The Nonesuch water body formed following the cessation of widespread volcanism within the Midcontinent Rift as the basin continued to subside. In northern Michigan and Wisconsin, USA, the Copper Harbor Conglomerate records terrestrial alluvial fan and fluvial plain environments that transitioned into subaqueous lacustrine deposition of the Nonesuch Formation. These units thin toward a paleotopographic high associated with the Brownstone Falls angular unconformity. Due to these "Brownstone Highlands," we were able to explore the paleoenvironment laterally at different depths in contemporaneous deposits. Rock magnetic data constrain that when the lake was shallow, it was oxygenated as evidenced by an oxidized mineral assemblage. Oxygen levels were lower at greater depth--in the deepest portions of the water body, anoxic conditions are recorded. An intermediate facies in depth and redox between these endmembers preserves detrital magnetite and hematite, which can be present in high abundance due to the proximal volcanic highlands. This magnetic facies enabled the development of a paleomagnetic pole based on both detrital magnetite and hematite that constrains the paleolatitude of the lake to 7.1 ± 2.8°N. Sediments of the intermediate facies preserve exquisite organic-walled microfossils, with microfossils being less diverse to absent in the anoxic facies where amorphous organic matter is more likely to be preserved. The assemblage of cyanobacteria and eukaryotes (both photoautotrophs and heterotrophs) lived within the oxygenated waters of this tropical Mesoproterozoic water body. [ABSTRACT FROM AUTHOR]

The Qiantang Sag, as one of the East China Sea Shelf Basin's sags with thick residual Mesozoic strata, has long lacked comprehensive foundational sedimentary research, significantly impeding the understanding of the region's resource potential and geological history. This study focuses on the Cretaceous strata of the Qiantang Sag, proposing a multi-phase sedimentary model for the Cretaceous Period. Through detailed analysis of the regional geological structure and sedimentary strata, this study unveils the complex sedimentary processes experienced by the Qiantang Sag during the Cretaceous. Utilizing drilling and core data combined with seismic geological interpretation, this study identifies that the western part of the Qiantang Sag predominantly developed alluvial fan and braided river deposits in an arid to semi-arid environment during the Cretaceous. Detrital zircon U-Pb dating analysis provides key information on the provenance areas and sedimentation ages, indicating that the Zhe-Min Uplift was the primary source region for the Qiantang Sag during the Cretaceous. Integrating vertical sedimentary sequences with provenance analysis, this study proposes sedimentary models and reconstructs the paleo-depositional evolution of the Qiantang Sag across different geological periods. During the Early Cretaceous Yushan Period, the region was influenced by intense volcanic activity, while also developing alluvial fan deposits in an arid environment. The Late Cretaceous Minjiang Period was characterized by semi-arid alluvial fan and braided river deposits. In contrast, the subsequent Shimentan Period saw the development of similar deposits, with the possible addition of seasonal lake deposits. [ABSTRACT FROM AUTHOR]

Laguna Verde's dome‐shaped structures are distinctive formations within the Central Andes, displaying unique geomicrobiological features. This study represents a pioneering investigation into these structures, assessing their formation, associated taxa, and ecological significance. Through a multifaceted approach that includes chemical analysis of the water body, multiscale characterization of the domes, and analysis of the associated microorganisms, we reveal the complex interplay between geology and biology in this extreme environment. The lake's alkaline waters that are rich in dissolved cations and anions such as chloride, sodium sulfate, and potassium, coupled with its location at the margin of the Antofalla salt flat, fed by alluvial fans and hydrothermal input, provide favorable conditions for mineral precipitation and support for the microorganism's activity. Laguna Verde's dome‐shaped structures are mainly composed of gypsum and halite, displaying an internal heterogeneous mesostructure consisting of three zones: microcrystalline, organic (orange and green layers), and crystalline. The green layer of the organic zone is predominantly composed of Proteobacteria, Bacteroidetes, and Cyanobacteria, while the orange layer is mostly inhabited by Cyanobacteria. The results of the study suggest that oxygenic photosynthesis performed by Cyanobacteria is the main carbon fixation pathway in the microbial community, supported by carbon isotopic ratios of specific biomarkers. This finding highlights the important role played by Cyanobacteria in this ecosystem. [ABSTRACT FROM AUTHOR]

Ragahama Formation comprises a siliciclastic continental deposits followed by marine carbonates, representing prograding alluvial fans from adjacent high hinterlands seaward into lagoons and fringing reef environments. The present work aimed to document the facies development and sedimentology of the Raghama carbonates exposed along the eastern coastal plain of the Red Sea, northwestern Saudi Arabia. Four stratigraphic sections were measured and sampled (D1–D4) and thin sections and major and trace element analyses were prepared and applied for petrographic and geochemical approaches. The carbonates were subdivided into three successive fore-reef, reef-core, and back-reef depositional facies. Sandy stromatolitic boundstone, microbial laminites, dolomitic ooidal grainstone, bioclastic coralline algal wackestone, sandy bioclastic wackestone, and coral boundstones were the reported microfacies types. Petrographic analysis reveals that the studied carbonates were affected by dissolution, dolomitization, and aggrading recrystallization, which affects both the original micrite matrix and grains or acts as fracture and veinlet filling leading to widespread vuggy and moldic porosity. No evidence of physical compaction, suggesting rapid lithification and recrystallization during early diagenesis and prior to substantial burial and intensive flushing by meteoric waters. Most of the original microstructure of corals were leached and destructed. This is indicated by the higher depletion in Sr and Ca levels and increase in Mg, Na, Fe, and Mn levels, especially in section D1, in comparison with the worldwide carbonates. [ABSTRACT FROM AUTHOR]

Langbein and Schumm (1958) connected precipitation to erosion in a right-skewed curve used in earth science textbooks for over six decades, where denudation increases with precipitation on the arid/semiarid limb and decreases in humid regions. Development of the catchment-averaged 10Be denudation method a quarter-century ago led geomorphologists to evaluate this hypothesis using data not influenced by the Anthropocene, with mixed findings. The Sonoran Desert in Arizona, USA, is optimal for investigating the longstanding hypothesis of increased erosion from arid to semiarid climates due to: (i) the modern orographic effect aligning elevated precipitation with altitude, mirroring Neotoma packrat midden paleoecology research for the Holocene and late Pleistocene; (ii) the region has been tectonically quiet for the residence times of analyzed 10Be ranging from ca. 8,000-110,000 years. Our significant finding echoes Langbein and Schumm's work, revealing heightened erosion along an elevation-precipitation gradient from arid to semiarid conditions. Notably, the significance of precipitation-elevation contrasts with the absence of significant correlation between 10Be denudation and attributes like slope, drainage area, relief, or landform type (e.g., alluvial fan, pediment, mountain watershed). Modern faunalturbation, increasing along this gradient, exposes more ground to rainsplash and overland flow at higher elevations, adding complexity to these results. Further insights unveil that (i) catchments in areas with substantial Quaternary base level reduction imitate tectonic effects, tripling 10Be denudation rates; (ii) basaltic boulders and cobbles yield an armoring influence; (iii) historical erosion acceleration due to urbanization and wildfires insignificantly affects 10Be denudation rates in the Sonoran Desert; and (iv) minute desert catchments yield anomalous erosion rates. [ABSTRACT FROM AUTHOR]