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At present, the architecture modeling method of fluvial reservoirs are still developing. Traditional methods usually use grids to characterize architecture interbeds within the reservoir. Due to the thin thickness of this type of the interlayers, the number of the model grids must be greatly expanded. The number of grids in the tens of millions often makes an expensive computation; however, upscaling the model will generate a misleading model. The above confusion is the major reason that restricts the largescale industrialization of fluvial reservoir architecture models in oilfield development and production. Therefore, this paper explores an intelligent architecture modeling method for multilevel fluvial reservoirs based on architecture interface and element. Based on the superpositional relationship of different architectural elements within the fluvial reservoir, this method uses a combination of multilevel interface constraints and non-uniform grid techniques to build a high-resolution 3D geological model for reservoir architecture. Through the grid upscaling technology of heterogeneous architecture elements, different upscaling densities are given to the lateral-accretion bedding and lateral-accretion bodies to simplify the model gridding. This new method greatly reduces the number of model grids while ensuring the accuracy of lateral-accretion bedding models, laying a foundation for large-scale numerical simulation of the subsequent industrialization of the architecture model. This method has been validated in A layer of X oilfield with meandering fluvial channel sands as reservoirs and B layer of Y oilfield with braided river sands as reservoirs. The simulation results show that it has a higher accuracy of production history matching and remaining oil distribution forecast of the targeted sand body. The numerical simulation results show that in the actual development process of oilfield, the injected water will not displace oil in a uniform diffusive manner as traditionally assumed, but in a more complex pattern with oil in upper part of sand body being left behind as residual oil due to the influences of different levels of architecture interfaces. This investigation is important to guiding reservoir evaluation, remaining oil analysis, profile control and potential tapping and well pattern adjustment. [ABSTRACT FROM AUTHOR]

Siliciclastic deposits and dolostones of the Å Ä·ervelis Formation in southwestern Latvia were studied in outcrops, polished slabs, thin sections, and by geochemical methods, including stable isotope analyses. Siliciclastic fluvial deposits alternate with soils and carbonates. As the soil processes became dominant, up to 6 m thick dolocretes formed, but they still preserve remnant sedimentary structures and textures. The strong role of soil processes is indicated by the presence of ooids and pisoids together with fine laminar layers, chert and phosphatic inclusions, rhizoids, and stable isotope values. Peculiar vertical clay-dolomite structures, up to 1.7 m long, are root structures or their combination with Vertisol-like soil development. The extensive development of soil processes and formation of the vertical structures was stimulated by seasonally wet monsoon climate. The scarcity of fossils in the studied deposits does not allow their age to be determined precisely, but probably the thick dolocrete unit in the upper part of the studied succession formed during the end-Devonian glaciation and the period of related sea regression.

Late Quaternary fluvial channel deposits are notoriously difficult to date. In the midwestern United States, shells of aquatic mollusks can be found within many fluvial channel sediments and therefore can be radiocarbon (14C) dated to determine the age of the deposits. However, carbonate platform rocks are abundant in this region, potentially causing freshwater 14C reservoir effects (FRE) in mollusk shells. We 14C dated 11 aquatic gastropod and bivalve shell samples from specimens collected live from a stream in southwestern Ohio during three different years to assess the modern 14C reservoir effect. Modern samples yielded an average 14C FREmodern of 518 ± 65 14C yrs for 2020 (n=5), 640 ± 34 14C yrs for 2021 (n=2), and 707 ± 76 14C yrs for 2022 (n=4). We also 14C dated matched pairs of organic wood or charcoal and aquatic mollusk shells from late Pleistocene and Holocene deposits in the Four Mile Creek floodplain to determine the FREfossil. These samples, free of any potential influence from nuclear bomb testing, yielded an overall weighted mean FREfossil of 1029 ± 345 14C yrs. We then assess the advantages and limitations of both the FREmodern and FREfossil methods for determining freshwater reservoir effects. Finally, we apply the FREfossil correction to a series of shell ages from fluvial terrace deposits as a case study. The results indicate that although there is a 14C FRE in streams from the midwestern United States, aquatic shells can provide robust age control on fluvial channel deposits. More research is needed to understand the spatial and temporal variability of FREs, as well as any species effects, among various watersheds across the midwestern United States. [ABSTRACT FROM AUTHOR]

The Belt of Schuppen (BoS) of Nagaland is a NE-SW trending linear zone lying adjacent to the Brahmaputra Valley of Assam in Northeast India. Geomorphic, stratigraphic and chronologic data from the Dzüdza and Chathe river valleys that cut across the BoS have been studied to understand the influence of climate on landform evolution in parts of the BoS. Fluvial landforms in the Dzüdza and Chathe river valleys evolved in four major phases bracketed between 22–17 ka (Phase IV), 13–9.0 ka (Phase III), 7–5 ka (Phase II) and 3.5–1.5 ka (Phase I), indicating multi-centennial to millennial changes in monsoon intensity. Climatically, Phase-III was dominated by valley aggradation initiated by onset of the Indian Summer Monsoon (ISM) and persisted intermittently till the early Holocene-strengthened ISM. The other phases of aggradation are attributed to transient or weak ISM. The present study suggests that fluvial aggradation was associated with enhanced precipitation and sediment supply in the BoS valley, whereas the transient and weak ISM is manifested in episodic pulses of alluvial ingression from the tributaries to the trunk valleys; along with post depositional tectonic modifications of the landforms. [ABSTRACT FROM AUTHOR]

The lithological and malacological studies covered sediments forming the low terrace of the Rogoźnik Stream in the northwest part of the Podhale Basin. This terrace is characterised by a uniform structure within a significant part of the valley. Three layers of gravel and four layers of sandy and silty muds were found there. A rich and diversified malacofauna was discovered in fine-grained sediments. Its analysis allowed us to characterise environmental conditions during sediment deposition. The age of the individual components of the sedimentary sequence was determined by radiocarbon dating. A distinct change was found in the upper intervals of the sequence, corresponding to the warm phase of the Medieval Climate Optimum. This period is associated with the robust development of agriculture, and processes related to human activities became the main factor shaping the environment, influencing the course of geological processes, and changing the taxonomical and ecological structure of the fauna and flora assemblages found in this area. [ABSTRACT FROM AUTHOR]

This work focuses on litho-stratigraphic and malacological studies of the fluvial deposits of the Middle Moulouya, which are used to reconstruct the paleoenvironments and paleoclimates of Morocco during the Holocene. The objectives were to deduce environmental and climatic changes from the study of fluvial deposits known for their richness in paleontological remains and their spatial and temporal variations. The chronostratigraphic framework of the fluvial record is based on the radiocarbon dating of a dozen charcoal assemblages. Sidi Bouramdan is located in the Midelt region in the Ksabi basin (the Middle Moulouya) of Morocco. The Holocene plain morphodynamics are characterised by a cut-and-fill terrace system associated with a progressive deepening of the riverbed. At the level of Sidi Bouramdan, a geomorphological and lithological study identified five Holocene nested terraces of over 10-m sedimentary thickness, dated to between 10248 and 10649 cal BP and 782–921 cal BP. These show a strong chronostratigraphic discontinuity with formations of the middle Holocene period being locally absent, probably because they were destroyed by the evolution of the alluvial plain. Forty-four mollusc species were identified in the malacological study of this fluvial Holocene sequence, with changes in the malacological communities reflecting environmental variations in the fluvial system. The Upper Holocene terrace T0 was characterized by marshland-preferring species, thereby revealing a wet environment. In the other three lower Late Holocene terraces, aquatic species tended to disappear, and terrestrial species predominated, indicating the appearance and development of a dry environment in phase with paleoenvironmental data from various regional marine and continental sedimentary archives. [ABSTRACT FROM AUTHOR]

Pleistocene braided river deposits commonly represent long periods of non-deposition or erosion that are interrupted by rapid and short aggradation phases. When dating these sedimentary sequences with in-situ produced cosmic radionuclides (CRN), simple concentration-depth profiling approaches fall often short as they assume that the alluvial sedimentary sequence has been deposited with a constant and rapid aggradation rate and been exposed to cosmic radiations afterwards. Numerical modelling of the evolution of CRNs in alluvial sequences permits to account for aggradation, non-deposition and erosion phases, and can simulate which scenarios of aggradation and preservation are most likely representing the river dynamics. In this study, such a model was developed and applied to a Middle Pleistocene gravel sheet (Zutendaal gravels) exposed in NE Belgium. The model parameters were optimized to the observed 10Be and 26Al concentrations of 17 sediment samples taken over a depth interval of 7 m. In the sedimentary sequence, (at least) three individual aggradation phases can be distinguished that were interrupted by non-deposition or erosion lasting each ~40 kyr. The age for the onset of aggradation was further constrained to 654-62 +218 kyr, and further narrows down the anticipated age window [500;1000] Ma of the terrace gravels. This age, within error limits, does not invalidate previous correlations of this gravel sheet with the Cromerian Glacial B, and marine isotope stage (MIS) 16. The deposition of the entire sedimentary sequence likely represents more than one climatic cycle, and demonstrates the importance of accounting for the depositional modes of braided rivers when applying in-situ cosmogenic radionuclide techniques. [ABSTRACT FROM AUTHOR]

The Amazonia biome hosts upland closed and open vegetation ecosystems, in which the current biogeographical patterns relate to the evolution of the physical landscape. Therefore, understanding the origin and timing of the substrates supporting different ecosystems is indispensable for better comprehension of Amazonian biogeography. Here we used quartz optically stimulated luminescence (OSL) and thermally transferred optically stimulated luminescence (TT-OSL) for dating sandy substrates of closed and open vegetation environments in Central and Eastern Amazonia, from both outcrop and drill core samples (Autazes core: PBAT-15-43). These sandy substrates present ages ranging from 1 ka up to almost 2 Ma, that were primarily interpreted as depositional ages of fluvial terraces. Moreover, ages are discussed in terms of potential geomorphic processes leading to the formation of substrates, such as soil mixing and apparent age of quartz from the parent bedrock. The coupling between OSL and TT-OSL techniques allow us to date sedimentary deposits covering the whole Quaternary, which implies a new time window for the Amazonia history.

Multiproxy analyses performed at the Krosinko site in the Warsaw–Berlin ice marginal valley have provided data that characterize the depositional conditions, the paleofluvial regime, and the paleoclimate and help reconstruct the paleo-environment at a time of significant sediment (alluvium) accumulation (starting in central Poland ca. 45 ka BP). The sedimentological study, including sand-grain morphology and micromorphology analyses, reveals the presence at Krosinko of a meandering river and of a braided river during the Eemian (MIS 5e) and Upper Pleniweichselian (MIS 2), respectively. The fluvial regime changed over time, from low-energy, through high-energy, to low-energy, as documented by the differently formed sedimentary units A–D (vertical sedimentary succession from base to top: sandy silt, sand, gravelly sand, and sand). Sedimentary unit A and the lower part of unit B were accumulated in the Eemian interglacial (MIS 5e) by the low-energy meandering river. The high-energy fluvial environment during the Weichselian is associated with long, intense sediment transport, organic remains, and flints, as confirmed by taphonomic studies on conifer cones (Picea cf. abies) and wood remains (Juniperus). The river operated under distinct environmental conditions. First, during the accumulation of the upper part of unit B and unit C, there was a strong influence of freezing and aeolian weathering, which weakened significantly over time (unit D). This in turn indicates a change in climate from periglacial (upper part of unit B and unit C), when we also document the presence of permafrost in the subsurface or relatively deep seasonal frost, to temperate (unit D). With warming in the Holocene (MIS 1), an oxbow lake developed in Krosinko, the presence of which is recorded by peat. [ABSTRACT FROM AUTHOR]

Fluvial deposits offer Earth's best‐preserved geomorphic record of past climate change over geological timescales. However, quantitatively extracting this information remains challenging in part due to the complexity of erosion, sediment transport and deposition processes and how each of them responds to climate. Furthermore, sedimentary basins have the potential to temporarily store sediments, and rivers subsequently rework those sediments. This may introduce time lags into sedimentary signals and obscure any direct correlation with climate forcing. Here, using a numerical model that combines all three processes—and a new analytical solution—we show that the thickness of fluvial deposits at the outlet of a mountain river can be linked to the amplitude and period of rainfall oscillations but is modulated by the mountain uplift rate. For typical uplift rates of a few mm/yr, climate oscillations at Milankovitch periods lead to alluvial sediment thickness of tens of meters as observed in nature. We also explain the time lag of the order of 20%–25% of the forcing period that is commonly observed between the timing of maximum rainfall and erosion. By comparing to field datasets, our predictions for the thickness and time lag of fluvial deposits are broadly consistent with observations despite the simplicity of our modeling approach. These findings provide a new theoretical framework for quantitatively extracting information on past rainfall variations from fluvial deposits. Plain Language Summary: Climate influences the evolution of terrestrial landscapes through the amount of precipitation, which provides water to erode rocks and transport sediment in rivers. At the outlets of mountain ranges, rivers can deposit part of their sediment load; the shape of the deposits is influenced by the amount of flow in the rivers. If the climate changes such that the precipitation rate increases, rivers can cut into their own previous deposits. The remaining deposits are then abandoned above the riverbed. On the contrary, if precipitation decreases, rivers tend to deposit more sediment, leading to increases in the thickness of sediments at the outlets of mountain rivers. Thus, there is a relationship between the amount of precipitations and the thickness of sediments deposited at river outlets. We study this with a computer model that allows us to relate the variations in precipitation rates to variations in thickness of fluvial terrace deposits. This work can be used to better understand how rivers respond to climatic changes, and also to reconstruct climatic variations of the past from observed river deposits. Key Points: We use a numerical model and a new analytical solution to quantify a physical link between fluvial deposits and climate oscillationsOur method provides a theoretical framework for extracting information on past climate variations from fluvial terrace depositsOur results explain time lag of 20%–25% of forcing period commonly observed between the timing of maximum rainfall and erosion [ABSTRACT FROM AUTHOR]

The unmixing of grain-size distribution (GSD) with multivariate statistical analysis provides insight into sediment provenance, transport processes and environment conditions. In this article, we performed hierarchical clustering endmember modeling analysis (CEMMA) to identify the sedimentary environment of fluvial deposits at core HDZ04 drilled in the paleofloodplain on the north bank of the upper Yellow River. The CEMMA results show that four end members can effectively explain the variance in the dataset. End-Member 1 and End-Member 2 are polymodal and dominated by silty clay, and they are associated with the suspended load. End-Member 3 is composed of fine sand and silt, and medium-coarse sand makes up the majority of End-Member 4, corresponding to a mixed saltation load and bed load, respectively. Combined with the end-member scores, we constructed energy values to further divide the core samples into different depositional environments. Unit 2 and unit 5 have a high proportion of coarser end-member components, presenting a shallow channel and a high-energy channel environment, respectively. Unit 1 and unit 3 are composed of fine-grained silt and clay and are dominated by finer end-member components, which can be interpreted as a floodplain situation. Unit 4 is characterized by frequent fluctuations in grain-size composition and energy values, indicating the transition from a high-energy river channel to floodplain deposits. For the channel sedimentary environment, the accumulation rate was relatively low (0.32 mm/yr) due to the frequency migration of the channel. A high accumulation rate of the fluvial deposits had occurred in unit 1 during 1.6 Ka (4.35 mm/yr), which was a response to the influence of increased fluvial instability and human activity during the late Holocene. [ABSTRACT FROM AUTHOR]

Fluvial deposits are commonly abundant in groundwater resources, indicating very high potential for the application of groundwater heat pump (GWHP) systems. To better understand the geospatial variation in geothermal potential, this paper presents a multidisciplinary 3D approach to assess aquifer-based geothermal resources in the Han River area in Hubei Province, China. The geological setting was determined by collecting data from 1286 drilling holes. The thermophysical-hydraulic properties were investigated, and the geospatial variation was characterized by 3D geological modeling. A GIS-based procedure was deployed for the assessment of the geothermal potential by extracting parameters from these 3D models as input. The results show that the middle reaches have the highest potential due to the great thickness of the aquifer layers, followed by the upper reaches, and the lower reaches have the lowest potential. The validation of 3 specific cases, located in the upper, middle, and lower reaches, shows that the model has uncertainties of 6.1%, 14.7% and 5.5%, respectively. This implies that the accuracy of the estimated potential depends on both the available drilling data and geological heterogeneity. This study shows that integrated 3D modeling and the GIS-based approach could be useful in geothermal planning in fluvial deposit areas. • The geological setting and material property of a fluvial area has been investigated. • The geospatial variation of ground conditions was characterized by 3D modeling. • A GIS-based approach was deployed to evaluate the geothermal potential. • The uncertainty of the estimated geothermal potential was discussed. [ABSTRACT FROM AUTHOR]

The article depicts the problem of river system development during the Middle Pleistocene Interglacial in the Bystrzyca River Valley (Sudetic Foreland, south-western Poland). Ten research sites located within the Świdnica Plain are presented, in which the structural, grain size (granulometry), petrographic, quartz grain morphoscopy, and heavy mineral analyses were carried out. The study results show the formation of piedmont fan deposits 2–8 km to the NE of the Sudetic Marginal Fault. The location of the fluvial deposits between the Sanian and Odranian tills indicates that they were deposited during the Holsteinian Interglacial (Krzczonów Formation, Mazovian; see Table 1). According toxthe lithofacies analysis, vast alluvial plains, composed of angular gravel grains in the south and of sands in the north, were deposited in the Sudetic Foreland in the environment of a very dynamic river. They are covered with a discontinuous layer of Odranian till. The petrographic spectrum shows 90–99% of local rocks, namely, Sudetic porphyry, Sowie Mts Gneiss and milky quartz, and 1–10% of Scandinavian rocks. In the proto-Bystrzyca river system, the existence of an oxbow lake in the distal part of the Krzczonów fan has been proved, which was developing at the end of the Holsteinian Interglacial. The continuity of the alluvial deposits is interrupted in the vicinity of Świdnica due to both the tectonic movements and the formation of the narrow tectonic graben of Roztoka–Mokrzeszów.

The lower Siwalik succession in the south‐central Kumaun Himalaya records Middle Miocene fluvial sedimentation in the Himalayan foreland basin, the largest foreland basin of the world. Detailed facies analysis reveals three distinct facies associations, one of which is sand dominated channel deposits, and the other two are mudstone‐sandstone, and mudstone dominated overbank deposits. The initial sedimentation in the region was in channels and frequently/extensively flooded overbank areas of a meandering/anastomosing river system. Activities along basement structures sometimes caused upheaval of the basin so that the streams got incised, and overbank areas rose up beyond the reach of flood waters. As a result, the fluvial sedimentation in these upland areas ceased, the sediments that had already deposited there were subjected to extensive pedogenesis, and occasionally reworked and redistributed by sheet flows and shallow channels. The channel pattern in the region gradually changed to braided type due to channel adjustments in response to rejuvenated tectonic activities and monsoon intensification in the hinterland. These factors caused increased influx of coarser sediments in the channels, which led to gradual steepening of the channel, and once the steepening crossed the threshold, the channel changed from meandering to braided type. Interpretation of our results is contrary to the general belief that Siwalik fluvial system changed from meandering streams to braided streams during the Middle Siwalik times, and the fluvial system in the studied part of the Siwalik basin underwent this change much earlier, during the sedimentation of Lower Siwalik. [ABSTRACT FROM AUTHOR]

A seismic sedimentology study was performed to analyse the complex fluvial reservoirs in the Neogene Guantao Formation in Kongdian Oilfield, Huanghua Depression. Three facies associations were identified by core and logging data, including bedload channel, mixload channel, and floodplain. Widely developed floodplain deposits beds were selected as the relatively reliable reference time surfaces. Stratal slices were generated applying the stratal‐slicing principle on two isochronous reference seismic events in Kongdian Oilfield. These stratal slices were used to analyse the distribution of sediments in a relative geologic‐time domain. The variety of sediment distribution observed on the stratal slices indicated that the fluvial channel systems of study interval had evolved from straight channel, sandy‐braided channel to combined channel. Sediment dispersal patterns were controlled by the change of accommodation (A) and sediment supply (S) rate. Setting with a low A/S ratio favours the development of fluvial environment and high A/S ratio favours the development of floodplain. Braided channel sandstones formed in a low A/S ratio depositional environment were generally thought to be excellent reservoirs. However, the muddy plug could damage the lateral continuity of sandbody, impede the fluid flow, and reduce the water‐injection efficiency. [ABSTRACT FROM AUTHOR]

The unmixing of grain-size distribution (GSD) with multivariate statistical analysis provides insight into sediment provenance, transport processes and environment conditions. In this article, we performed hierarchical clustering endmember modeling analysis (CEMMA) to identify the sedimentary environment of fluvial deposits at core HDZ04 drilled in the paleofloodplain on the north bank of the upper Yellow River. The CEMMA results show that four end members can effectively explain the variance in the dataset. End-Member 1 and End-Member 2 are polymodal and dominated by silty clay, and they are associated with the suspended load. End-Member 3 is composed of fine sand and silt, and medium-coarse sand makes up the majority of End-Member 4, corresponding to a mixed saltation load and bed load, respectively. Combined with the end-member scores, we constructed energy values to further divide the core samples into different depositional environments. Unit 2 and unit 5 have a high proportion of coarser end-member components, presenting a shallow channel and a high-energy channel environment, respectively. Unit 1 and unit 3 are composed of fine-grained silt and clay and are dominated by finer end-member components, which can be interpreted as a floodplain situation. Unit 4 is characterized by frequent fluctuations in grain-size composition and energy values, indicating the transition from a high-energy river channel to floodplain deposits. For the channel sedimentary environment, the accumulation rate was relatively low (0.32 mm/yr) due to the frequency migration of the channel. A high accumulation rate of the fluvial deposits had occurred in unit 1 during 1.6 Ka (4.35 mm/yr), which was a response to the influence of increased fluvial instability and human activity during the late Holocene.

Geochemical data and their various approaches are useful to evaluate the climatic control on the depositional environments. This study aims to evaluate the paleoweathering and plaeoclimate condition that have controls on the depositional environments of the Miocene to Pliocene siliciclastic sequence at Al-Rehaili area, north of Jeddah. To achieve this aim, selected sandstone samples were geochemically (major and trace elements analysis) and petrographically examined. The results of these analyses reveal that the examined sandstones were deposited in non-marine (fluvial/alluvial-lacustrine) environments and suffered from weak to intermediate chemical weathering and intense physical induration under semi-arid to semi-humid climatic conditions. [ABSTRACT FROM AUTHOR]

Ferric and calcic palaeosols are characteristic features of the fluvial red beds of the Lower Triassic Petrohan Terrigenous Group exposed in the Western Stara Planina Mountains of northwestern Bulgaria. The detailed documentation of 34 outcrop sections enables to distinguish different types of palaeosols, and to interpret their formation during lowstand, transgressive and highstand phases of two fluvial depositional sequences. Lowstand deposits, representing braided river stages of the fluvial system, are characterised by reworked palaeosol products recorded as channel-floor lags or in-channel bars. In-situ ferric palaeosol profiles featuring good drainage are also present. With increasing accommodation space, anastomosing fluvial accumulation became dominant and immature ferric and calcic profiles formed. The profiles in proximal position to the channels evidence good drainage, while those from the interchannel flood plain in more distal position feature poor drainage which led to the development of gleyed profiles. The palaeosol maturity increases towards the top of transgressive deposits, best documented by palaeosols that formed in the overbank fines. The low accommodation rate during the highstand phase led again to intense channel reworking of the palaeosol profiles, documented in different types of accumulation in channel, levee and overbank settings. During the highstand phase abundant and mature (cumulative and multistory) palaeosol profiles developed. [ABSTRACT FROM AUTHOR]

Aeolis Dorsa is a topographic depression, ∼800 km east of Gale Crater, located along the Mars’ dichotomy boundary. This area hosts a set of fluvial sedimentary rocks displaying an exceptional record of depositional environments and fluvial channels patterns that suggest the presence of a large amount of surface and/or subsurface water. We interpreted the plain as an ancient waterlogged environment, a sedimentary basin passing into distal depositional environments. Regional mapping of the area revealed the presence of a large-scale fluvial system that points to a long-term and extensive hydrological cycle. A significant wet period with changing environmental conditions in Hesperian/Amazonian occurred in the study area diverging from the present-day climate. Our map (Main Map) contributes to the understanding of past climatic conditions on Mars. Moreover, it provides an interesting perspective for future missions looking for evidence of present-day and/or past extraterrestrial organisms as the life as we know it needs liquid water.

The present study revolves around the identification of the stratigraphical boundary between Pleistocene formations that formed prior to the first advance of the Scandinavian ice sheet (Early Pleistocene, i.e., the so-called preglacial) and the overlying, glacially derived deposits (Middle Pleistocene). In particular, it focuses on variation in heavy mineral assemblages, which are an important tool for stratigraphers. The Neogene basement, described here, was most often the source of material that was redeposited by Early Pleistocene rivers. The geological structure and Early Pleistocene palaeogeographical scenarios for various Polish regions are discussed. Moreover, comparisons with other European preglacial formations are carried out. The mineral spectrum of Lower Pleistocene deposits is largely dependent of rocks of the Neogene and Mesozoic basement. If the incision of ancient catchments was into terrigenous rocks, the stratigraphical boundary between preglacial and glacial formations is easily determined with the help of a heavy mineral analysis. As a rule, this coincides with a noticeable change from resistant to non-resistant mineral associations. Such cases are noted for successions in central Poland and eastern England. On the other hand, outcrops of igneous or metamorphic rocks exist within preglacial river catchments in most parts of Europe. They were the local sources of non-resistant heavy minerals long before their glacial supply from the Baltic Shield. In these cases, mineralogical analysis fails in the search for the Early/Middle Pleistocene transition.

In this study, the geochemistry (major, trace and rare earth elements) of fluvial deposits of the Çaybağı and Palu Formations, Eastern Elazığ, have been investigated. The basement of the studied basin is composed of the Guleman Group, Elazığ Magmatics, Hazar-Maden Group, and Kırkgeçit Formation which consist of volcanic materials derived from the Elazığ Magmatics. The Çaybağı Formation is composed of thick fluvio-lacustrine sedimentary sequence. Palu Formation consists of alluvial fan deposits and braided river, lacustrine sedimentary deposits. Samples were collected from braided river deposits of Çaybağı and Palu Formation along Hacısamdere–Çaybağı section (Ç-samples) and Hacısamdere-Palu section (PL samples). Significant positive correlation between Zr/Sc and Th/Sc ratios of two sample groups show that the siliciclastic sample groups do not represent considerable sediment recycling. Çaybağı and Palu samples have similar geochemical indices (Al2O3/TiO2, Ti/Zr, La/Th, La/Sc, Cr/Th, Co/Th, (La/Yb)N, (Gd/Yb)N, LREE/HREE ratios) and indicate derivation from intermediate-basic source rocks. In Si vs. Na/K diagram samples plot in arc field and La/Sc and Ti/Zr ratios show that samples were plotted in an oceanic island arc environment.

Bu çalışmada Elazığ’ın doğusundaki Çaybağı ve Palu Formasyonu’na ait fluvial çökellerin jeokimyası (majör, iz ve nadir toprak elementler) incelenmiştir. İnceleme alanının temel kayaçlarını Guleman Grubu, Elazığ Magmatitleri, Hazar-Maden Grubu, Elazığ Magmatit’lerinden malzeme almış olan Kırkgeçit Formasyonu oluşturmaktadır. Çaybağı Formasyonu kalın fluvial-lakustrin sedimanter istiften, Palu Formasyonu alüvyon yelpazesi, örgülü nehir çökelleri, lakustrin sedimanlardan oluşmaktadır. Örnekler Hacısamdere-Çaybağı kesiti (Ç örnekleri) ve Hacısamdere-Palu kesiti (PL örnekleri) boyunca Çaybağı ve Palu Formasyonları’nın nehir çökellerinden alınmıştır. Zr/Sc ve Th/Sc oranı arasında önemli pozitif korelasyonun görülmesi örneklerin önemli bir sedimanter çevrime maruz kalmadığını göstermektedir. Çaybağı ve Palu örneklerinin benzer jeokimyasal indisleri (Al2O3/TiO2, Ti/Zr, La/Th, La/Sc, Cr/Th, Co/Th, (La/Yb)N, (Gd/Yb)N, LREE/HREE oranları), bunların nötr-bazik kaynak kayaçlarından türediğini göstermektedir., Si’a karşı Na/K diyagramında örnekler yay alanına düşmektedir. La/Sc, Ti/Zr oranları örneklerin okyanus adayayı ortamında depolanmış kayaçlardan türediğini göstermektedir.

The study focuses on the sedimentation and stratigraphy of a large Vendian (Ediacaran) sedimentary basin in the southwestern Siberian craton, with implications for the origin of its units and subunits. Sediments are been correlated along the craton edge and inward into the craton interior using stratigraphic sequences, including glacial and post-glacial deposits. Clastic complexes in the Vendian: upper Chapa, Taseeva, Oselok, and Baikal groups composed of fluvial deposits are of special importance for correlations. The structure of the continental Aysa Fm. of the Oselok Group in the Sayany area has been characterized in detail, based on universal classification of lithofacies and their sequences, and correlated with sediments in the craton interior. There are two Ediacaran subunits: a continental-marine complex below and a continental complex above. The continental-marine subunit in the subsided craton margins was deposited mainly upon postglacial plains (sandurs) and marginal sea shelves, with contributions from intracratonic clastic sources. The deposits of the continental subunit belong to centripetal fluvial systems directed from distant craton-margin mountain upland toward the epicontinental sea in the central Siberian craton. The continental subunit is composed of large sections of red and variegated fluvial deposits from a foreland basin which was accumulated mainly in foredeeps in the over-compensation setting and partly reached the slopes of forebulges. Big deep sand rivers with large channel bars were formed at early and late during orogenic activity, while perennial anastomosing and braided mud-sand rivers with levees originate during passive stages of orogeny. The largest progradation of fluvial systems onto the Siberian craton is marked by channel deposits of the lower members from the Nemchanka, Moshakovka, Aysa, Khuzhir and Kachergat fms., as well as by the Bokhan sandstone member of the Chora Fm.

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Conifer fossil woods from the Campanian Puntudo Chico Formation were studied. The specimens were collected at the Estancia La Aurora, Cañadón Asfalto Basin, Chubut Province, Patagonia, Argentina. The parautochthonous petrified woods, which have well-preserved anatomy, were transported a short distance from their original habit and deposited within fluvial channels. The use of transmitted light and scanning electron microscopes allowed to identify the diagnostic characters. This paper corroborates the presence of Brachyoxylon currumillii and the first mention of Cupressinoxylon sp. cf. C. artabeae in the Puntudo Chico Formation. The new specimens of Podocarpoxylon mazzonii confirm that this taxon is a common and abundant element in the Cretaceous to Eocene floristic assemblages. Based on 51 growth-rings, the mean ring width, and Mean Sensitivity (MS) were 1.68 mm (0.62–2.92 mm) and 0.33 (0.27–0.40) respectively. These fossil trees indicate that they developed under temperate and humid conditions, with slightly sensitive from year to year with a terminal event representing a cessation or retardation of cambial activity. Other paleoclimatic proxies including geological and fossil data indicate that the Puntudo Chico Formation was deposited under temperate-warm and humid conditions, with some semi-arid events. [ABSTRACT FROM AUTHOR]

The Eastern Henan Basin is situated within the downstream alluvial plain of the Yellow River, harboring an impressive accumulation of over 500 m of fluviolacustrine strata since the Pliocene. However, the evolutionary characteristics and driving factors of the sedimentary environment in this region remain unclear due to a lack of reliable chronological constraints on the sedimentary sequence. Here, two cores were retrieved from Hangkonggang (HKG, 303.5 m) and Baisha (BS, 320.2 m) in the Eastern Henan Basin for comprehensive analyses of chronology and sedimentology. A combination of paleomagnetism, electron spin resonance (ESR), and optically stimulated luminescence (OSL) dating results indicates that sediments of two boreholes were accumulated spanning the last ∼3.48 Ma. Grain size distributions (GSDs) of typical sedimentary facies show that the boreholes predominantly encompass three types of sedimentary facies: riverbed, levee, and floodplain. Downcore variations of mean grain size (MGS) reveal that the sedimentary environment in this basin evolved from a dominant riverbed setting during the late Pliocene (3.48–2.72 Ma) to alternations between the floodplain and levee facies during the early Pleistocene (2.72–1.25 Ma) and subsequently between the riverbed, levee, and floodplain after 1.25 Ma. It was closely associated with the decrease in East Asian monsoon precipitation at ∼2.72 Ma and the increase at 1.25 Ma. Notably, the abrupt coarsening of MGS after ∼1.25 Ma was synchronized with the formation of the Sanmenxia terraces, implying the significant influence of the evolution of the Yellow River. Our results suggest that the sedimentary environment of the Eastern Henan Basin was predominantly affected by the stepwise evolution of the East Asian monsoon since ∼3.48 Ma and complementary landform transformation of the Yellow River since at least ∼1.25 Ma. • A An age model of fluvial deposits spanning the last 3.48 Ma in the Eastern Henan Basin is generated for the first time. • End-member composition of grain size distributions can be used as a reference for sedimentary facies identification. • Fluvial deposits are sensitive to climate change and the regional landform processes can play a key role in specific epochs. [ABSTRACT FROM AUTHOR]

Abstract New findings of well-preserved theropod dinosaur footprints from the Albian Lagarcito Formation (Sierras de Las Quijadas National Park, San Luis, Argentina) are described and its paleoenvironmental and stratigraphic context is discussed. The local succession of the formation is represented by three shallowing-upward cycles that were deposited in a lacustrine setting. The theropod footprints occur in sheet flood facies fringing the lake and probably were mostly oriented parallel to the shoreline. The footprints are assigned to Picunichnus quijadaensis Melchor nov. isp. which is distinguished from similar ichnotaxa by the degree of mesaxony, footprint elongation, digit proportions and occasional presence of a hallux impression. Based on the comparison of type material of theropod ichnotaxa, it is suggested that Picunichnus belongs to the ichnofamily Grallatoridae Lull, 1904, which is amended to include Grallator , Anchisauripus , and Prototrisauropus. This revision also suggests the potential recognition of additional ichnofamilies for theropod dinosaur footprints. Preservation of digital pads in P. quijadaensis also permits an osteological comparison with theropods from Gondwana. This comparison is based on the length of pedal bones inferred from P. quijadaensis and similar information on selected Jurassic–Cretaceous theropods. In addition, relative size, age and geographic provenance are also contrasted. There is no known Gondwanan theropod dinosaur with preserved pedal bones that match all these features. The best candidates are the smaller basal coelurosaur Aniksosaurus darwini from the Cenomanian of Patagonia and the similar-sized abelisaurid Majungasaurus crenatissimus from the Maastrichtian of Madagascar. This finding is relevant because the footprints come from a geographic area lacking skeletal or other footprint records of Cretaceous theropods and because the producer is apparently not recorded by skeletal remains in Gondwana continents. Highlights • Description and interpretation of Albian theropod footprints from central Argentina. • The footprints occur in sheetflood deposits fringing a freshwater lake. • Amended diagnosis of Grallatoridae based on mesaxony and footprint elongation. • The new ichnotaxon Picunichnus quijadaensis (Grallatoridae) is proposed. • Osteometric comparisons suggest that the trackmaker is not yet recorded as fossil. [ABSTRACT FROM AUTHOR]

A study of the trace elements distribution in sediments along the main watercourse of the Linares mining district (Jaen, Spain) was carried out. For this purpose, 56 soil samples were collected in the stream channel and floodplain. To obtain a geochemical characterisation of the soil, the pH, organic matter and the silt-clay fraction were measured and 33 elements were analysed. The results derived from these measurements were studied statistically and compared to the reference values for soils standards under two different regulations. This made it possible to recognise the dispersion patterns of the different metals and metalloids associated with the old mining activity of the district and to characterise the effects of the various pollution sources along the watercourse. An elevated Pb content was detected, which was associated with tailings ponds and waste rock dumps. Similarly, high concentrations of As in sediments were identified, which were associated with a smelter located at the headwater of the catchment area. [ABSTRACT FROM AUTHOR]

Aeolis Dorsa is a topographic depression, ∼800 km east of Gale Crater, located along the Mars' dichotomy boundary. This area hosts a set of fluvial sedimentary rocks displaying an exceptional record of depositional environments and fluvial channels patterns that suggest the presence of a large amount of surface and/or subsurface water. We interpreted the plain as an ancient waterlogged environment, a sedimentary basin passing into distal depositional environments. Regional mapping of the area revealed the presence of a large-scale fluvial system that points to a long-term and extensive hydrological cycle. A significant wet period with changing environmental conditions in Hesperian/Amazonian occurred in the study area diverging from the present-day climate. Our map (Main Map) contributes to the understanding of past climatic conditions on Mars. Moreover, it provides an interesting perspective for future missions looking for evidence of present-day and/or past extraterrestrial organisms as the life as we know it needs liquid water. [ABSTRACT FROM AUTHOR]

Studies of distributive fluvial systems and their preserved successions envisage the distribution and orientation of architectural elements to be primarily controlled by channels radiating outward from fan apices, in many cases along an elongate basin margin. Conceptual models for such systems account for the downstream dynamics of the fluvial network, but with limited consideration of temporal geomorphic variations, resulting vertical organisation of architectural elements, or of the interplay of factors controlling system dynamics. To understand the external and internal architecture of distributive fluvial systems, and the factors that influence their sequential facies organisation, a sedimentary succession of the proximal portion of an Upper Cretaceous, semiarid, distributive fluvial system, located at the north-eastern margin of the Bauru Basin (Southeast Brazil), has been analysed in detail. Three fining- and thinning-upward fluvial sequences are identified, forming an interval separated at the top and the bottom by two palaeosol profiles. Each sequence is formed of channel and floodplain deposits. Two types of channel deposits are identified. One is composed of stacked sets of small-scale dune deposits, suggesting perennial and steady fluvial regime, associated with more humid climate periods. The other is composed of large-scale sets indicative of flattened dunes associated with unsteady and fast-changing fluvial flow, formed in quasi-supercritical flow regime conditions, associated with drier climate periods. The vertical alternation of these two types of channel deposits records the accumulation of a fluvial succession that responded to high-frequency, climate-induced cyclic change in boundary conditions. Two palaeosol profiles, at the top and at the bottom of the succession, indicate temporary interruptions and cessation of the fluvial sedimentation, likely related to avulsion of the fluvial belt. Thus, the studied succession reveals high-frequency climate-induced allogenic sedimentary cycles that occur within a long-period autogenic geomorphologic-induced sedimentary cycle. This work suggests that the internal architecture of the channel deposits can be used as a climate proxy, and that climate and geomorphology act jointly as notable factors to control the vertical organisation of distributive fluvial systems. [ABSTRACT FROM AUTHOR]

The middle Eocene Koluel-Kaike Formation, located in the San Jorge Basin, Patagonia, Argentina, is a strongly pedogenically modified succession associated with volcaniclastic input in an aggrading distal eolian-dominated fluvial system, located ∼400 km downwind of the Eocene Andean volcanic arc. The coordinated study of sediments and paleosols of this unit allows (1) reconstruction of environmental conditions and landscape evolution, and (2) determination of the interplay of the main forcing factors in the evolution of the Kokuel-Kaike Formation. The landscape reconstruction attests to the existence of a loessic rolling plain drained by a subordinate fluvial system, composed of both unconfined and confined flows, with locally ponded areas. Over these, thick stacked cumulative paleo-Ultisols and vertic paleo-Ultisols developed with scarce simple and stacked compound vitric Entisols analogues and compound Inceptisols equivalents. This high-resolution sedimentological-pedological analysis of the Kokuel-Kaike Formation indicates that the interplay between episodic volcaniclastic supply and cyclic climate controlled landscape evolution and soil development. [ABSTRACT FROM AUTHOR]

In this study, the geochemistry (major, trace and rare earth elements) of fluvial deposits of the Çaybağı and Palu Formations, Eastern Elazığ, have been investigated. The basement of the studied basin is composed of the Guleman Group, Elazığ Magmatics, Hazar-Maden Group, and Kırkgeçit Formation which consist of volcanic materials derived from the Elazığ Magmatics. The Çaybağı Formation is composed of thick fluvio-lacustrine sedimentary sequence. Palu Formation consists of alluvial fan deposits and braided river, lacustrine sedimentary deposits. Samples were collected from braided river deposits of Çaybağı and Palu Formation along Hacısamdere-Çaybağı section (Ç-samples) and Hacısamdere-Palu section (PL samples). Significant positive correlation between Zr/Sc and Th/Sc ratios of two sample groups show that the siliciclastic sample groups do not represent considerable sediment recycling. Çaybağı and Palu samples have similar geochemical indices (Al2O3/TiO2, Ti/Zr, La/Th, La/Sc, Cr/Th, Co/Th, (La/Yb)N, (Gd/Yb)N, LREE/HREE ratios) and indicate derivation from intermediate-basic source rocks. In Si vs. Na/K diagram samples plot in arc field and La/Sc and Ti/Zr ratios show that samples were plotted in an oceanic island arc environment. [ABSTRACT FROM AUTHOR]

Fluvial sedimentary successions represent porous media that host groundwater and geothermal resources. Additionally, they overlie crystalline rocks hosting nuclear waste repositories in rift settings. The permeability characteristics of an arenaceous fluvial succession, the Triassic St Bees Sandstone Formation in England (UK), are described, from core-plug to well-test scale up to ~1 km depth. Within such lithified successions, dissolution associated with the circulation of meteoric water results in increased permeability (K~10−1–100 m/day) to depths of at least 150 m below ground level (BGL) in aquifer systems that are subject to rapid groundwater circulation. Thus, contaminant transport is likely to occur at relatively high rates. In a deeper investigation (> 150 m depth), where the aquifer has not been subjected to rapid groundwater circulation, well-test-scale hydraulic conductivity is lower, decreasing from K~10−2 m/day at 150–400 m BGL to 10−3 m/day down-dip at ~1 km BGL, where the pore fluid is hypersaline. Here, pore-scale permeability becomes progressively dominant with increasing lithostatic load. Notably, this work investigates a sandstone aquifer of fluvial origin at investigation depths consistent with highly enthalpy geothermal reservoirs (~0.7–1.1 km). At such depths, intergranular flow dominates in unfaulted areas with only minor contribution by bedding plane fractures. However, extensional faults represent preferential flow pathways, due to presence of high connective open fractures. Therefore, such faults may (1) drive nuclear waste contaminants towards the highly permeable shallow (< 150 m BGL) zone of the aquifer, and (2) influence fluid recovery in geothermal fields. [ABSTRACT FROM AUTHOR]

The Himalayan foreland basin originated through the India–Asia continent–continent collision driven by downward flexing of the Indian plate. It forms an ideal assemblage to delineate the role of process-controlled sedimentary fill in basin evolution. This paper provides the first comprehensive account of the lithofacies associations and architecture of the Middle Siwalik succession of the Himalayan foreland basin in the south-central Himachal Pradesh sector, India through detailed sedimentological analysis. Eight lithofacies form three distinct sand, gravel, and silt-mudstone lithofacies associations pertaining to specific depositional environments. Architectural elements have been defined together with bounding surfaces separating them. Sedimentological investigations reveal that the Middle Siwalik sequence represents a flash flood dominated piedmont fan and proximal to middle megafan. The fan expansion cycles indicate tectono-climatically controlled sedimentation in the Middle Siwalik foreland basin. Frequent flooding and a high sedimentation rate were influenced by the tectonic uplift along the reactivated thrusts in the hinterland coupled with phases of monsoonal intensification. • The studied Middle Siwalik belongs to a yet unattended Himachal sector of the Indian Himalaya. • Architectural documentation reveals different orders of fluvial hierarchy. • Sedimentation took place in the foreland basin setting solely by continental processes. • Contemporaneous piedmont fan and megafan sedimentary sequences are identified and interpreted. • The Middle Siwalik Foreland Basin of the present study is compared with foreland basins of similar tectonic settings globally. [ABSTRACT FROM AUTHOR]

Showing features associated with archaic Homo sapiens and evolved Homo erectus , the Dali skull is a key fossil for understanding human evolution in China. Various dating methods such as U-series, IRSL, TL, ESR, ESR/U-series, and stratigraphical correlation with central Loess Plateau sequence were used to estimate the antiquity the Dali Man site with varying results. In this study, a total of 12 samples were taken in the sequence in the Dali Man site, from the aeolian loess-palaeosol sequence and underlying fluvial deposit layers including the palaeoanthropological level and dated by several optically stimulated luminescence (OSL) methods: coarse-grained quartz SAR OSL, thermally transferred OSL (TT-OSL), and K-feldspar post-IR infrared (IR) stimulated luminescence (post-IR IRSL; pIRIR 290 ) methods. Results show that the TT-OSL and pIRIR 290 ages were consistent up to ∼100 ka. For older samples, the feldspar ages were significantly older. These pIRIR 290 ages increased with the stratigraphy up to 310 ka. The best age estimation of the Dali Man layer providing by the feldspar pIRIR 290 suggested that the Dali Man lived in late period of L3 (MIS 8) stage. Furthermore, correlating the pIRIR 290 ages between 267.7 ± 13.9 ka and 258.3 ± 14.2 ka and new pollen analysis, we proposed a new viewpoint that the Dali Man was likely to live during a transitional period from glacial to interglacial climate in the S2/L3 (MIS 7/8) stage. [ABSTRACT FROM AUTHOR]