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The Burdigalian/Langhian (B/L) boundary has not yet been designated as a Global Stratotype Section and Point (GSSP), despite various proposed zonal schemes. In the Gulf of Suez region of Egypt, the Burdigalian-Langhian successions are notable for hosting significant hydrocarbon reservoirs within a tectonic rift setting. Therefore, biostatigraphy plays a crucial role in exploration endeavors in this area. The nannofossil biostratigraphy is investigated in two sections, Wadi Baba and Wadi Gharandel, of the lower-middle Miocene from west-central Sinai. Three biozones, NN3 (Sphenolithus belemnos) Zone, NN4 (Helicosphaera ampliaperta) Zone, and NN5 (Sphenolithus heteromorphus) Zone, are identified from the studied interval. The NN4 Zone could be divided into MNN4a/b and MNN4c. Important biovents are discussed, such as the S. heteromorphus paracme interval and the first occurrence and evolution of the Discoaster exilis and Discoaster variabilis groups. Based on the cluster analysis, the recorded taxa can be subdivided into four groups that reflect their palaeoclimatic preferences. The paleoecological interpretation of the studied Rudies Formation indicates prevailing cool and eutrophic nutrient conditions based on the dominance of taxa such as Coccolithus pelagicus, Reticulofenestra minuta, and Cyclicargolithus floridanus. The nannofossil taxa responses to sea level curve are interpreted. Fluctuations in taxa abundance and diversity indicate a slight rise in the sea level at the base of the Burdigalian followed by sudden drop in the sea level at the middle Burdigalian. High sea-level conditions prevailed again until the B/L boundary. During the Langhian period, many small-scale fluctuations in sea-level curve are detected. [ABSTRACT FROM AUTHOR]

During the Rhuddanian–Aeronian interglacial period, global geological events such as glacial melting, synsedimentary volcanic activity, biological resurgence, and large-scale marine transgressions caused frequent fluctuations in paleoproductivity, climate changes, and sea level variations. These paleoenvironmental transitions directly influenced the development characteristics of shale lithofacies. This study investigates the Longmaxi Formation shale in the Changning area in the Southern Sichuan basin, focusing on 28 core samples from Well N1. Using scanning electron microscopy, QEMSCAN, TOC, XRD, and major and trace element analyses, we reconstructed the paleoenvironmental transitions of this period and explored their control over shale lithofacies types and mineral compositions. Four shale lithofacies were identified: carbonate rich lithofacies (CRF), biogenic quartz-rich lithofacies (BQRF), detrital clay-rich lithofacies (CRDF), and detrital quartz-rich lithofacies (DQRF). During the Rhuddanian period, rising global temperatures caused glacial melting and rapid marine transgressions. The low oxygen levels in bottom waters, combined with upwelling and abundant volcanic material, led to high paleoproductivity. This period primarily developed BQRF and CRF. Rich nutrients and abundant siliceous organisms, along with anoxic to anaerobic conditions, provided the material basis and preservation conditions for high biogenic quartz and organic matter content. High paleoproductivity and anoxic conditions also facilitated the precipitation of synsedimentary calcite and supplied Mg2+ and SO42− for the formation of iron-poor dolomite via sulfate reduction. From the Late Rhuddanian to the Mid-Aeronian, the Guangxi orogeny caused sea levels to fall, increasing water oxidation and reducing upwelling and volcanic activity, which lowered paleoproductivity. Rapid sedimentation rates, stepwise global temperature increases, and the intermittent intensification of weathering affected terrigenous clastic input, resulting in the alternating deposition of CRF, CRDF, and DQRF. Two favorable shale gas reservoirs were identified from the Rhuddanian–Aeronian period: Type I (BQRF) in the L1–L3 Layers, characterized by high TOC and brittleness, and Type II (DQRF) in the L4 Layer, with significant detrital quartz content. The Type I-favorable reservoir supports ongoing gas production, and the Type II-favorable reservoir offers potential as a future exploration target. [ABSTRACT FROM AUTHOR]

Middle and Late Holocene sediments have not been extensively sampled in Lake Tanganyika, and much remains unknown about the response of the Rift Valley's largest lake to major environmental shifts during the Holocene, including the termination of the African Humid Period (AHP). Here, we present an integrated study (sedimentology, mineralogy, and geochemistry) of a radiocarbon-dated sediment core from the Kavala Island Ridge (KIR) that reveals paleoenvironmental variability in Lake Tanganyika since the Middle Holocene with decadal to centennial resolution. Massive blue-gray sandy silts represent sediments deposited during the terminal AHP (~5880–4640 cal yr BP), with detrital particle size, carbon concentrations, light stable isotopes, and mineralogy suggesting an influx of river-borne soil organic matter and weathered clay minerals to the lake at that time. Enhanced by the AHP's warm and wet conditions, chemical weathering and erosion of Lake Tanganyika's watershed appears to have promoted considerable nutrient recharge to the lake system. Following a relatively gradual termination of the AHP over the period from ~4640 cal yr BP to ~3680 cal yr BP, laminated and organic carbon-rich sediments began accumulating on the KIR. δ15Nbulk, C/N, and hydrogen index data suggest high relative primary production from a mix of algae and cyanobacteria, most likely in response to nutrient availability in the water column under a cooler and seasonally dry climate from ~3680 to 1100 cal yr BP. Sediments deposited during the Common Era show considerable variability in magnetic susceptibility, total organic carbon content, carbon isotopes, and C/N, consistent with dynamic hydroclimate conditions that affected the depositional patterns, including substantial changes around the Medieval Climate Anomaly and Little Ice Age. Data from this study highlight the importance of sedimentary records to constrain boundary conditions in hydroclimate and nutrient flux that can inform long-term ecosystem response in Lake Tanganyika. [ABSTRACT FROM AUTHOR]

The rich micromammal fossils from Early, Middle, and Late Miocene horizons of the Damiao sequence in Nei Mongol provide an opportunity to study Miocene biostratigraphy and faunal turnover in Asia. In this study, we describe thirteen dipodid species from the Damiao sequence, including two new species, Sinozapus damiaoensis sp. nov. and Lophocricetus parvus sp. nov. Sinozapus damiaoensis sp. nov. is characterized by the metaloph connecting to the central hypocone on M1-M2, the absence of the anterior arm of the protoconid, and the posterior arm of the protoconid merging with the metaconid on m2. Lophocricetus parvus sp. nov. displays a set of transitional morphological traits between Heterosminthus and Lophocricetus. It resembles Heterosminthus in its small size, the presence of the mesocone and mesoloph on M1-M2, the vestigial pseudomesolophid, and the posterior crest of the protoconid on m1. Meanwhile, it has the characteristics of Lophocricetus, including the protostyle on M1 and the hypoconid-entoconid connection on the m1. These two new species represent the earliest records of their respective genera. The Damiao dipodid fossil records improve our understanding of Neogene dipodid diversity, and refine the biostratigraphic framework in the central Nei Mongol. The new fossil records reveal a shift from small, low-crowned, humid-adapted early taxa to ecologically diverse late Middle Miocene forms, including desert-adapted jerboas, indicating a trend towards regional aridification. Nonetheless, relict sicistines and zapodines suggest localized persistence of humid refugia within broader dry environments during the late Middle Miocene, which sheltered pliopithecids in the Mongolia Plateau. [ABSTRACT FROM AUTHOR]

The Koum Basin is a North Cameroonian intracontinental basin that is part of the upper Benue Trough, notably the Yola arm. The sediments of this basin were examined to determine paleoenvironmental and paleoclimatic interpretations, which were based mostly on sedimentology and mineralogical evolution in its central part. The examined materials are dominated by claystone and siltstones of varied colours, which are, for the most part, carbonated, and a few layers of fine to medium sandstone and conglomerate. The bulk organic geochemistry enabled the designation of type III kerogen, indicating a terrestrial origin of organic matter, which shows predominantly immature issues. The bulk mineralogy development exhibits no significant changes and is dominated by phyllosilicate (25.66%), calcite (24.5%), plagioclase (19.36%), and quartz (19.31%). Smectite, illite, and vermiculite dominate clay mineral fraction, with only low quantities of kaolinite and chlorite. The diagenesis influence is low to moderate, as shown by moderate illitization and chloritization as well as Tmax values. The deposition occurred in a globally semi-arid climate, as evidenced by the permanent occurrence of smectite, punctuated by short periods of drier and humid weather. [ABSTRACT FROM AUTHOR]

Surajkund Formation of Central Narmada Basin exhibits fining upward sequences of pebbly conglomerate, coarse-fine grained sandstone, siltstone and association of seven lithofacies, namely massive pebbly conglomerate, coarse-medium grained sandstone with large scale tabular cross bedding, massive coarse grained sandstone, coarse to medium grained sandstone with horizontal parallel bedding, fine grained sandstone with parallel lamination, fine grained sandstone with ripple lamination and siltstone, indicates their deposition in mixed load meandering river. Granulometric studies of Surajkund sediments also support the fluvial depositional environment. Soft sediment deformation structures documented in the siltstones suggest sediment liquification due to earthquake shocks. Abundant development of nodular, bedded calcretes and rhizoliths within these sediments are indicative of semi-arid climate and related subaerial exposure. These sediments are prominently lithic arenites, and clay mineralogy as well as geochemistry indicate deposition in the proximity of source, short distance of transport and mixed provenance of a variety of pre-Quaternary rocks such as Precambrian metamorphic rocks and granites, Vindhyan and Gondwana Supergroups, Deccan Trap basalt and laterite. Evidences of fresh water phreatic as well as vadose zone diagenesis linked to the semi-arid climatic conditions, together with subaerial exposure of these sediments, are seen in thin sections, which are supported by δ13C (av. −5.67%) and δ18O (av. −3.88%) values of calcretes. These values also suggest calcretes formed due to pedogenic and shallow groundwater processes in warm climate with C4-dominated vegetation. OSL date of one sample from Surajkund Formation gave an Ionian Age of Pleistocene Epoch. [ABSTRACT FROM AUTHOR]

The Jurassic–Cretaceous boundary is the only Phanerozoic period-level boundary that lacks a golden spike on the geological timescale despite significant global geological and environmental change during this time related to the opening of the Atlantic Ocean. Paleoenvironmental proxy profiles (total organic carbon, δ34S, δ15N, Fe, Mn, Ce/Ce*, Th/U, δ13Corg, P, Ni, Zn, Cu, and B/Ga) for core 3 of the Baccalieu I-78 well in the Flemish Pass Basin, offshore eastern Canada, exhibit a geochemical anomaly between 3288.5 and 3289 m, overlapping with the biostratigraphic placement of the Jurassic–Cretaceous boundary. Collectively the geochemical analyses are interpreted to indicate that the anomaly is associated with a fall in relative sea level, followed by a rise, which led to restricted circulation, stratification, and widespread anoxia. This anoxia, coupled with an arid climate, further resulted in reduced weathering, limited nutrient supply, and an overall reduction in primary productivity. The results of this study, in conjunction with previous biostratigraphic studies on core 3, suggest that the Jurassic–Cretaceous boundary in Baccalieu I-78 likely falls within the geochemical anomaly, specifically between 3228.5 and 3288.85 m. Furthermore, the paleoenvironmental interpretations derived in this study agree with published reports on global sea level and climate trends around the Jurassic–Cretaceous boundary, implying the influence of global, rather than regional, factors on deposition. This suggests that geochemical proxies may be useful in providing additional paleoenvironmental insights and helping to constrain stratigraphic boundaries, particularly in intervals that lack significant lithological or biological change. [ABSTRACT FROM AUTHOR]

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The Permian Lucaogou Formation represents one of the most important hydrocarbon source rock intervals in the Junggar Basin, although the sedimentary paleoenvironment and organic matter enrichment mechanism of the Lucaogou Formation remain controversial. We studied the temporal evolution of the sedimentary paleoenvironment in the Lucaogou Formation by analyzing the elemental composition and total organic carbon content of 27 hydrocarbon source rock samples from the J305 well in the Jimsar Sag. Using these data, we found that the Lucaogou Formation overall was deposited in a semisaline to saline, reducing lake basin under an arid climate. We identified five organic matter-enriched intervals, which can be correlated with the parameters that indicate a wetter climate and a more anoxic lake environment. To compare sedimentary environments spatially, we compiled environmental indicators from 10 cores and outcrops in three sags around the Bogda Mountains. The compilation shows that the organic matter-enriched Jimsar Sag experienced a more arid climate and a more saline and anoxic lake environment during the deposition of the Lucaogou Formation, which was possibly controlled by the paleogeographic position. We conclude that the spatially arid climate and anoxic environment induced organic matter burial in the Jimsar Sag, while temporal events of a more humid climate and more anoxic environment triggered the enrichment of organic matter in some intervals of the Lucaogou Formation. [ABSTRACT FROM AUTHOR]

Worldwide, Quaternary loess-paleosol sequences archive terrestrial paleoenvironmental information. The Palouse loess in the northwestern USA is one such deposit representing at least a million years of sediment accumulation. Loess paleosol sequences are often studied via the magnetic susceptibility of sediments and the changes in susceptibility with depth. However, since variations in magnetic susceptibility can have different underlying causes, the interpretation of the magnetic susceptibility of loess depends on factors specific to each major loess region. We measured the magnetic susceptibility of sediments along depth profiles in a well-studied exposure of the Palouse loess in eastern Washington, USA (the "CLY-2 site," 46.3131° N, 118.4874° W, WGS84). Our measurements show that the magnetic susceptibility of sediments in the Palouse loess varies systematically and predictably with depth and can be correlated with other magnetic susceptibility profiles at the outcrop scale and at the regional scale. We also measured changes in grain size, elemental abundance, mineralogy, and other magnetic properties to determine the most likely cause of the magnetic susceptibility signal. Based on these results, variations in magnetic susceptibility in the Palouse are likely driven mostly by changes in coarse sediment supply and accumulation of tephra rather than changes in weathering. Magnetic susceptibility is useful as an inexpensive, non-destructive tool for stratigraphic correlation of Quaternary loess deposits in the Palouse, especially in combination with paleosol stratigraphic markers and known tephra deposits. [ABSTRACT FROM AUTHOR]

This study provides an updated quantitative analysis and prospective paleoenvironment reconstruction of the Tut oilfield, Shushan Basin, North Egypt to evaluate the hydrocarbon reservoirs in space and times for further development plans and modeling in the Tethyan region. Two sporomorph interval zones (Classopollis brasiliensis and Afropollis jardinus), and one total foraminiferal Range Zone (Thomasinella punica) are proposed. Three palynofacies assemblages are differentiated using cluster analysis of the different palynofacies parameters. The paleoenvironmental conditions during the Cenomanian were reconstructed. Palynofacies assemblage I of the Baharyia Formation suggests a marginally dysoxic-oxic basin environment with a common occurrence of ostracods and terrestrial organic matter, while palynofacies assemblage II reflects the high abundance of dinoflagellate cysts, suggesting a suboxic-anoxic middle neritic environment. Palynofacies assemblage III of the upper part of the Abu Roash G Member represents a relatively deep water inner-middle neritic environment. Three 3rd order significant sequences separated by two hiatus surfaces (Ce3 and Ce4) are described and correlated with the global eustatic sea-level. The hydrocarbon evaluation results show that the samples from the Abu Roash G Member contain oil-prone material of kerogen type II, while the samples of the Baharyia Formation are characterized by kerogen type III (gas-prone). Spore coloration analysis reveals that the samples from the studied units are too immature to produce gas or oil and are ineffective as sources of hydrocarbons. [ABSTRACT FROM AUTHOR]

The Guadix-Baza Basin (southern Spain) displays one of the best continental records from the Late Miocene to the Middle Pleistocene in western Europe, with many localities of fossil small mammals in a quite complete and continuous stratigraphic sequence. The Late Miocene continentalization of the Guadix-Baza Basin was firstly mentioned in the 1980s based on the presumed presence of Hipparion gromovae granatensis at the site of Abla (Almería province). Subsequent discoveries of late Turolian deposits confirmed the Late Miocene continentalization of the basin. The interest in the Abla site led to a second sampling campaign to look for microvertebrate fossils, which proved successful. In this paper, a complete taxonomic study of the novel microvertebrate fauna from Abla is presented, providing updated information on the age of the locality. Representatives of the vertebrate families Cyprinidae, Alytidae, Anguidae, Soricidae, Cricetidae, and Muridae have been identified. The presence of Stephanomys specimens exceeding the size of latest Miocene-earliest Pliocene species allows us to correlate the Abla site with the Early Pliocene (Ruscinian), a younger age than initially stated. A qualitative paleoecological interpretation based on the herpetofauna suggests the dominance of open environments with presence of permanent water bodies during the deposition of the Abla site, under warmer and more humid climate conditions than today in the Guadix-Baza Basin. A revision of the Hipparion remains from this locality showed that the sample is closer to Hipparion fissurae than to the initially assigned species. [ABSTRACT FROM AUTHOR]

The Cenozoic topographic development of the Himalaya‐Tibet orogen (HTO) substantially affected the paleoenvironment and biodiversity patterns of High Asia. However, concepts on the evolution and paleoenvironmental history of the HTO differ massively in timing, elevational increase and sequence of surface uplift of the different elements of the orogen. Using target enrichment of a large set of transcriptome‐derived markers, ancestral range estimation and paleoclimatic niche modelling, we assess a recently proposed concept of a warm temperate paleo‐Tibet in Asian spiny frogs of the tribe Paini and reconstruct their historical biogeography. That concept was previously developed in invertebrates. Because of their early evolutionary origin, low dispersal capacity, high degree of local endemism, and strict dependence on temperature and humidity, the cladogenesis of spiny frogs may echo the evolution of the HTO paleoenvironment. We show that diversification of main lineages occurred during the early to Mid‐Miocene, while the evolution of alpine taxa started during the late Miocene/early Pliocene. Our distribution and niche modelling results indicate range shifts and niche stability that may explain the modern disjunct distributions of spiny frogs. They probably maintained their (sub)tropical or (warm)temperate preferences and moved out of the ancestral paleo‐Tibetan area into the Himalaya as the climate shifted, as opposed to adapting in situ. Based on ancestral range estimation, we assume the existence of low‐elevation, climatically suitable corridors across paleo‐Tibet during the Miocene along the Kunlun, Qiangtang and/or Gangdese Shan. Our results contribute to a deeper understanding of the mechanisms and processes of faunal evolution in the HTO. [ABSTRACT FROM AUTHOR]

Changing climatic conditions is a perpetual circumstance for mankind. In this study, we investigate local environmental and climatic changes near Kangerlussuaq, west Greenland. Our reconstruction is based on a lake sediment core and methods include chemical proxies and a palynological analysis. The investigated site is located 15 km from the Aasivissuit Inuit summer hunting ground, which has been in use for caribou hunting for more than 2000 years. The presented climatic reconstruction covers the time from c. 560 CE to present time. We identify three distinct periods of climate regimes: From c. 560–1100 CE conditions were stable, warm and humid, and summer temperatures were 1.5–2°C warmer than today. 1100–1600 was a period of cooler and very arid conditions with more sea ice, corresponding to the Neoglacial cooling. In this period, we detect two wildfire events and subsequent temporary caribou abandonment of the area. From 1600 to present we find increasingly warmer conditions with more precipitation and less extensive sea ice cover, gradually approaching today's climate regime in Kangerlussuaq. We review the existing literature regarding the Aasivissuit summer hunting ground, which was first used concurrently with the detected cooling. Despite climatic deterioration, the hunting ground was regularly in use throughout the Neoglacial and onwards, with peak hunting intensity in the early 1700s. The detected wildfires and reindeer abandonment are interpreted to be localized events at the coring site and did not affect the hunting ground. Our findings highlight the resilience of the Inuit hunters to climatic changes as well as the advantages and limitations of local environmental reconstructions. [ABSTRACT FROM AUTHOR]

Under the background of global climate change, the evolution of climate in the future is the focus of geoscience. The Nanri Channel is an important passage connecting the Xinghua Bay and the Taiwan Strait, in China, and the study of its provenance and paleoenvironmental alternation is of great significance to the climate evolution in the eastern coast of China. The grain size and X-ray diffraction analyses of sediments from ZK1 in Nanri Channel and ZK5 in Xinghua Bay, were used to study the variation of grain size and clay mineral characteristics and to analyze the changes in hydrodynamic characteristics, provenance, and paleoenvironmental evolution in the regions since the Last Glacial Maximum. The results show that the sedimentary environment of ZK1 varies from the nearshore tidal flat facies with strong hydrodynamic conditions and the neighboring rivers as the main provenance, to the littoral facies with weak hydrodynamic conditions and the Yangtze River-like type sediments as the main provenance. The sedimentary environment of ZK5 is from the nearshore tidal flat facies with strong hydrodynamic conditions to the littoral facies with weak hydrodynamic conditions, and the provenance of both facies is mainly Yangtze River-like type sediments. The clay mineral characteristics of ZK1 show that the climate in the Nanri Channel has experienced a change from cool and wet, to mild and dry, to mild and wet since the Last Glacial Maximum, while the climate in the Xinghua Bay has experienced a change from warm and humid, to moderate and dry, to warm and humid since the early-middle Holocene, which provides scientific theoretical support for the provenance and paleoenvironment of sediments in the study area and neighboring areas. [ABSTRACT FROM AUTHOR]

Microorganisms have inhabited the oceans since the dawn of Earth. Some of them have organic walls and some produce mineral tests that are usually composed of carbonate minerals or silica. They can therefore be preserved with original parts during sedimentary deposition or fossilized through permineralization or carbonization processes. The most common marine fossil groups studied by micropaleontologists are cyanobacteria, coccolithophores, dinoflagellates, diatoms, silicoflagellates, radiolarians, foraminifers, red and green algae, ostracods, and pteropods. Dormant or reproductive cysts can also be used for determinations of the fossil microbiota. Microfossils can be studied in petrographic slides prepared from rocks or separated from loosely consolidated rocks by disaggregation or dissolution and wet sieving. Their presence is sometimes recognized by biomarkers. Transmitted light microscopy and reflected light stereomicroscopy are necessary for micropaleontological studies whereas scanning electronic microscopy (SEM) aids research on the tiniest fossils and reveals fine skeletal details. Microorganisms have influenced the oxygenation of water and the atmosphere, as well as Earth's carbon cycle and have contributed to the formation of sedimentary rocks. By studying microfossils, paleontologists depict the age of the rock and identify depositional environments. Such studies help us recognize periods of stress in Earth's history and understand their influence on living organisms. Biogenic rocks, made of microfossils, can be used as raw materials, such as fossil fuels, building stone, or additives for the food industry, agricultural, or cosmetic purposes.

Abstract The Gongola sub-basin is a frontier inland sedimentary basin consisting of Cretaceous to Tertiary sediments, believed to have been deposited in continental to coastal shallow marine complex. The Kanawa Member of Pindiga Formation is a sequence of limestone and shale. Sedimentology, facies analysis, biostratigraphy, thermal maturity assessment and kerogen typing were conducted on these strata to determine the facies, facies associations, facies successions, paleoenvironment, age, and hydrocarbon generation potential. The studied sequences are of Turonian–Santonian age, deposited due to a major transgression of the basal part of the Pindiga Formation. The shale-limestone series of the Kanawa Member is interpreted as lagoon-to-shallow marine deposits of a carbonate ramp depositional system. The sediments consist of mainly wackestone and packstone facies and shallow marine foraminiferal, suggesting that the Kanawa Member was deposited under low-energy condition. The presence of Ammobaculites subcretacea, Haplophragmoides bauchensis, Haplophragmoides pindigensis, Haplophragmoides excavata, Ammobaulites pindigensis, Ammobaculites bauchensis, Ammobaculites gombensis, Ammobaculites benuensis Ammoastuta nigeriana, Reophax guineana and Miliammina pindigensis foraminiferal assemblages, indicating Late Cretaceous age. Hydrocarbon potential is interpreted to be gas prone although, minor oil could be expected. These correspond to temperature range (TAI values) of 60 to 75 indicating thermally matured for both oil and gas generation.

The first systematic sediment survey by the icebreaker Shirase (AGB-5003) was conducted during the 61st Japanese Antarctic Research Expedition (JARE-61). Sediment samples were obtained from a total of 28 sites in 3 areas of the Totten Glacier front–Dalton polynya, Lützow-Holm Bay and Cape Darnley polynya using a large-bore gravity corer and GSJ-type K-grab sampler. In this paper, details of the survey operation are described as a reference for the future experience. In addition, preliminary results of the obtained sediments are reported as a fundamental information for future analysis using these samples.

Abstract Salt deposits are indicative of relatively extreme climate events. However, due to insufficient independent temperature proxies, paleotemperature records obtained from salt deposition are still lack. The Paleocene evaporite sequence deposited in the Hongze Depression of Subei Basin of eastern China provides an important terrestrial sediment record during this period. In this study we present total of 488 homogenization temperature (Th) data of halite fluid inclusions from drilling core with different stratigraphic depth after detailed petrological observation. The obtained Th ranged from 17.7 °C to 52.3 °C, with the mean Th value of 34.1 °C that in good agreement with the previous studies of climatic proxies. Our study shows that primary fluid inclusions of halite can serve as a robust tool to construct the ancient earth surface temperature.

In paleolimnological studies, rotifers are usually a very rare component in multiproxy research. These small invertebrates are identified from sediments by their loricas. Analysis of subfossil rotifers was conducted for sediment cores collected from three peatlands in within Poland: the Grel raised bog (S Poland, Carpathians, Orawa-Nowy Targ Basin), the Imszar raised bog (NE Poland, Podlasie Region), and the Podemszczyzna peatland (SE Poland, Sandomierz Basin). Results were compared with multiproxy analyses of peat deposits: pollen of aquatic and mire plants, non-pollen palynomorphs (NPPs), and geochemical analyses. Analysis of the rotifers indicated the occurrence of the bdelloid species Habrotrocha angusticollis (Murray, 1905). In all profiles of the studied peatlands, the occurrence of rotifers was not correlated with pollen of aquatic or mire plants or NPPs; they seem to be more related to geochemical indices. The highest densities of rotifers were found in profile sections without significant fluctuations of geochemical variables, i.e. those with higher Na/K (chemical denudation) ratios and stable redox conditions (Fe/Mn ratio). The study of subfossil rotifers supported by multiproxy analysis of peat deposits could be a useful tool for indication of periods with stable palaeohydrological conditions during the Late Glacial and Holocene. [ABSTRACT FROM AUTHOR]

Quaternary geomorphological dynamics in the lowland tropics of South America can be described from the stratigraphy of hillslope colluvium and alluvial deposits. The analysis of sediments through the identification of depositional microfeatures and biomineralized microfossils, combined with their absolute dating by optically stimulated luminescence (OSL), allow the reconstruction of paleoenvironmental conditions. The objective of this work was to investigate the dynamics of depositional processes leading to colluvial deposition in the Araripe Plateau, Northeastern Brazil, from the analysis of stratigraphic sections, using phytoliths as indicators of paleovegetation and sediment micromorphology in the identification of depositional processes. The correlation of sediments ages, ranging from the OS3 to the OS2 (Last Glacial Maximum) with phytophysiognomy indices indicated the contribution and deposition of phytoliths from an arboreal/shrubby vegetation, replaced on the surface by grass vegetation. Periods of drier climates were correlated with LGM ages, with more open vegetation composed of grasses, in synchronously with less intense geomorphological events. The micromorphological analysis revealed that the characteristics of the deposits reflect more the action of depositional processes than pedogenetic ones. The correlation of phytolithic indices with micromorphology corroborated the environmental and geomorphological dynamics of the periods dated in the stratigraphic sections. [ABSTRACT FROM AUTHOR]

Bianfudong (pinyin for Bat Cave) is a paleolithic site that was recently discovered in Heqing, Yunnan in southwestern China. Several hominin fossils, stone artifacts and more than 69,000 mammal fossils were unearthed in 2019. The hominin fossils and stone artifacts were excavated from the upper part (layers 1–12) of the section with an age range of 180–70 ka BP. Some large mammal fossils and micromammalian remains were collected from the lower part of the section (layers 22–30), which has an age >180 ka BP. This paper describes the micromammalian fossils collected from layers 25–30 and analyzes the fauna composition and paleohabitats. A total of 638 micromammal specimens represent 12 species, including 11 extant species i.e. Euroscaptor longirostris , Blarinella wardi , Anourosorex squamipes , Crocidura vorax , Eothenomys (Anteliomys) chinensis , E. (A.) proditor , Apodemus chevrieri , Ap. draco , Ap. latronum , Micromys minutus , and Niviventer confucianus , and one extinct species Anourosorex qianensis. The two arvicolid Eothenomys species dominate, both in the number of identified specimens and the minimum number of individuals. The composition of the Bianfudong micromammalian fauna can be compared with the faunas of Sanjiacun in Chenggong of Yunnan Province, Mawokoudong in Bijie and Xinglongdong in Fengjie, Guizhou Province. Using the random forest model with modern meteorological data, we calculated the mean annual precipitation (MAP) and the mean annual temperature (MAT) for all 11 living species in the Bianfudong. The MAP was inferred as 1008.04 mm, close to modern data in the Heqing area, while the MAT was slightly lower at 12.84 °C. The dominance of Eothenomys also supports a slightly cooler climate during the late Middle Pleistocene in the Heqing area. [ABSTRACT FROM AUTHOR]

Although Maya scholars have referenced coastal settlements in the more general discourse on past landscapes, coastal landscapes have only rarely been the explicit focus of research programs. Coastal peoples, however, faced distinct challenges and opportunities not shared by their inland neighbors. These had material ramifications in terms of the specific decisions coastal inhabitants made over time while trying to take advantage of opportunities and manage risks. The north coast of the Yucatan Peninsula is a complex physiographic mosaic that is categorically distinct from the inland expanses of the Maya lowlands. No doubt, the physically delimiting aspects of the north coast's diverse environment played a major role in shaping more localized concepts of landscape. Here, we employ an historical ecology framework to integrate the interdisciplinary studies conducted by the Proyecto Costa Escondida along the Yucatan's north coast. Specifically, we focus on the ancient Maya port site of Vista Alegre and what our research has revealed about the dynamic interplay of social and natural processes that shaped life at this ancient Maya port over the past three millennia. [ABSTRACT FROM AUTHOR]

Paleoenvironmental conditions significantly influence the distribution patterns and organic matter enrichment of shale. This study investigated the vertical variations of major elements, trace elements, and total organic carbon (TOC) in the Lower Carboniferous marine shale from the Yaziluo Rift Trough, South China, to understand the paleoenvironmental conditions, including redox conditions, terrigenous detrital input, paleoproductivity, and paleo-seawater depth. The Lower Carboniferous formation consists of three sedimentary facies: basin facies, lower slope facies, and upper slope facies. From the basin to the lower slope and then to the upper slope facies, TOC, quartz, and pyrite contents gradually decrease, whereas the carbonate mineral content shows an increasing trend. A continuous decline in paleo-seawater depth transformed a deep-water anoxic environment with high paleoproductivity and low detrital input in the basin facies into a semi-deep-water environment with dysoxic-oxic conditions and moderate detrital influx in the lower slope facies, evolving further into a suboxic environment with high detrital flux in the upper slope facies. The geochemistry results suggest that anoxic conditions and high paleoproductivity were the primary controls on organic matter enrichment in the siliceous shale of the basin facies. In contrast, redox conditions significantly influenced organic matter accumulation in the mixed shale of the lower slope facies, attributed to relatively low paleoproductivity in a more restricted marine setting. Additionally, the adsorption of carbon components by clay minerals facilitated the preservation of organic matter in the calcareous shale of the upper slope facies. [ABSTRACT FROM AUTHOR]

Clay mineral proxies have been widely used to reconstruct changes in provenance and the paleoclimate. However, high-altitude clay mineral indications and long-term and orbital variations have not been fully explored. Herein, we present an 800-ka clay-mineral record from a lacustrine sediment core (ZB13-C2) from the Zoige Basin on the eastern Tibetan Plateau (TP). X-ray diffraction and scanning electron microscopy were used to identify the clay mineral assemblages and their micro-morphological characteristics of core ZB13-C2. The results revealed that the clay minerals in core ZB13-C2 are mainly illite, with small amounts of chlorite, kaolinite, and smectite (including irregular mixed-layers of illite-smectite (I/S) and chlorite-smectite (C/S)). The clay mineral assemblages and proxies exhibit three stages of change, which are mainly controlled by the Zoige watershed range under different climate conditions. The watershed was limited to the southeastern region with altitudes ranging from ∼3500 to ∼4200 meters above sea level (m a.s.l.), and glacial-interglacial hydraulic erosion controlled the input of bedrock debris during 800–621 ka BP. It expanded to higher altitudes (∼1200 to ∼4700 m a.s.l.) due to stronger seasonal freeze-thaw weathering without significant glacial-interglacial variations under a cooling and drying climate during 621–100 ka BP. Finally, it expanded to its highest altitudes of ∼4700 to ∼5200 m a.s.l. northwest of the watershed after 100 ka BP, and hydraulic erosion increased obviously under a warm climate of the interstadial MIS 3 on the TP. The watershed underwent two major expansions under different climatic conditions at ∼621 ka and 100 ka BP, with the wet/dry alternation became strong at ∼621 ka BP. These results reveal that long-term temperature changes and the wet/dry alternation at high altitudes controlled the watershed range and degree of the physical erosion, and that the indications of clay minerals should be carefully clarified before they are used as climate indicators, especially on the TP. [ABSTRACT FROM AUTHOR]

The paleoenvironment of shales can be reconstructed to some extent using the combinations or concentrations of elements that correlate strongly with environmental conditions. In this study, we analyzed rare earth elements (REEs), major elements, and trace elements in the marine-continental transitional shales (transitional shales for short) of the Shan 2³ submember of the Shanxi Formation in the southeastern Ordos Basin. The purpose is to deduce the paleoenvironmental conditions of the shales, encompassing paleoredox, paleoclimate, paleoproductivity, and paleo-provenance. The Shan 2³ submember comprises four sections, namely Shan 2³-1, Shan 2³-2, Shan 2³-3, and Shan 2³-4. The Ba/Al, P/Al, and Cu/Al ratios, along with biogenic barium (Babio), indicate that the paleoproductivity of the submember peaked during the Shan 2³-1 deposition and exhibited a downtrend upward in other sections. Trends in the Uau and the Ni/Co, V/Cr, U/Th, and V/Sc ratios suggest that suboxic conditions prevailed during the Shan 2³-1 deposition, with the oxidation level gradually increasing from Shan 2³-1 to Shan 2³- 4. C-value and the Sr/Cu vs. Ga/Rb cross-plot indicate a warm and arid paleoclimate during the Shan 2³-1 deposition, which transitioned to cooler, drier conditions during the deposition of other sections. Indicators sensitive to paleoclimate, such as the K/Rb and Th/U ratios, along with the ICV, PIA, and Chemical Index of Alteration (CIA), highlight elevated weathering from Shan 2³-2 to Shan 2³-4, with Shan 2³-1 exhibiting the weakest weathering during its deposition. As suggested by the REE data, the Zr/Sc vs. Th/Sr cross-plot, provenance discriminant functions, and the cross-plots of Hf vs. La/Th, Th vs. HfeCo, and PREE vs. La/Yb, the sedimentary provenance for the transitional shales of the Shan 2³ submember is of multiple origins, with significant contributions from the Upper Continental Crust (UCC). Discriminant diagrams, including those of TheCoeZr/10, TheSceZr/10, LaeTheSc, and K2O/Na2O vs. SiO2, suggest that the transitional shales of the Shan 2³ submember were primarily deposited under tectonic settings such as continental island arcs (CIAs) and passive continental margins (PCMs). [ABSTRACT FROM AUTHOR]

Organic matter and metal elements are commonly co-enriched in marine black shales. However, the element types vary among different shales and the relevant mechanisms of organo-metal co-enrichment are still unclear. The super-enrichment of organic matter and nickel in the ore bed of Early Cambrian marine black shale of southern China provides an ideal opportunity to investigate this mechanism. Herein, to clarify the coenrichment mechanism of organic matter and, the laminated structure of this ore bed was characterized and the geochemical and mineralogical proxies of different laminae were analyzed. The results indicated that there are four types of laminae in this ore bed, namely, siliceous laminae, calcareous laminae, clay minerals laminae, and organic-rich laminae. Clay minerals laminae and organic-rich laminae were deposited under anoxic environments, while siliceous laminae were deposited under strong oxidizing to anoxic environments. Neither organic matter nor are distributed homogeneously in the ore bed; organic matter is mainly concentrated in organic-rich laminae, while is largely enriched in clay minerals laminae. Clay minerals and organic matter have strong adsorption capacity for, and the adsorption capacity of clay minerals (such as illite) for is stronger than that of organic matter. Hydrothermal events and terrestrial input are key factors affecting the paleoenvironment and laminated structure during the deposition of the ore bed. Although organic matter and are co-enriched in the ore bed, their enrichment stages and conditions vary according to the geochemical differences among laminae. [ABSTRACT FROM AUTHOR]

Research of the depositional environment using geological mapping, petrography, gamma-ray (GR) log, palynology, and foraminifera fossils of the Bojongmanik Formation has led to the formation of several different conclusions about the transition to the marine environment, which are attractive to revisit. The expected results of this research are to determine the paleoenvironment of the Bojongmanik and Serpong Formations based on elemental geochemistry, the development of paleoenvironment proxies based on portable X-ray fluorescence (pXRF) in fluvial to transitional environments studies, and the contribution of paleoenvironment analysis to GR-log facies interpretation. The research methodology starts with GR-log facies analysis, Pearson's correlation, paleoenvironment analysis based on elemental affinity and elemental ratio, and comparing the paleoenvironment with GR-log-based facies. The paleoenvironment analysis based on elemental geochemistry resulted in the Bojongmanik Formation in the research area deposited at the tidal point bar, lagoon, and shoreface, while the Serpong Formation was deposited at the fluvial point bar and floodplain. Compared to previous research, the Bojongmanik Formation in the research area could be stratigraphically related to the upper Bojongmanik Formation. Proxies based on elemental geochemical affinities of carbonate-associated, carbonate-productivity, terrigenous-associated elements, and redox-sensitive trace elements show contrast changes between facies. Proxies based on the specific ratio show a detailed paleoenvironment for paleoclimate (Sr/Cu), paleosalinity (Sr/Ba), paleoredox (Cu/Zn), paleo-hydrodynamics and water depth (Zr/Rb and Fe/Mn), sediment provenance (Cr/Zr), and siliciclastic-dominated (Zr + Rb)/Sr. Adding a geochemistry element-based paleoenvironment analysis benefits from a more specific justification for GR-log facies interpretation. [ABSTRACT FROM AUTHOR]

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Microorganisms have inhabited the oceans since the dawn of Earth. Some of them have organic walls and some produce mineral tests that are usually composed of carbonate minerals or silica. They can therefore be preserved with original parts during sedimentary deposition or fossilized through permineralization or carbonization processes. The most common marine fossil groups studied by micropaleontologists are cyanobacteria, coccolithophores, dinoflagellates, diatoms, silicoflagellates, radiolarians, foraminifers, red and green algae, ostracods, and pteropods. Dormant or reproductive cysts can also be used for determinations of the fossil microbiota. Microfossils can be studied in petrographic slides prepared from rocks or separated from loosely consolidated rocks by disaggregation or dissolution and wet sieving. Their presence is sometimes recognized by biomarkers. Transmitted light microscopy and reflected light stereomicroscopy are necessary for micropaleontological studies whereas scanning electronic microscopy (SEM) aids research on the tiniest fossils and reveals fine skeletal details. Microorganisms have influenced the oxygenation of water and the atmosphere, as well as Earth's carbon cycle and have contributed to the formation of sedimentary rocks. By studying microfossils, paleontologists depict the age of the rock and identify depositional environments. Such studies help us recognize periods of stress in Earth's history and understand their influence on living organisms. Biogenic rocks, made of microfossils, can be used as raw materials, such as fossil fuels, building stone, or additives for the food industry, agricultural, or cosmetic purposes. [ABSTRACT FROM AUTHOR]

Marine shale gas has emerged as a prominent unconventional petroleum resource in recent years, known for its abundant reserves and energy potential. Based on the database of geochemical, mineralogy and physical lab measurements, this study investigates the paleoenvironmental conditions and shale gas potential of the Carboniferous Dawuba and Cambrian Niutitang shales in the Upper Yangtze Platform, South China. Analysis of the paleoclimate and water conditions reveals that the Dawuba shale was deposited under a warm and arid climate with reducing conditions that favored organic matter (OM) preservation, transitioning towards marine conditions with increasing salinity. The Niutitang shale experienced a cooler, arid climate with prevalent saltwater and reducing conditions, also conducive to OM preservation. Both formations have reached the post-mature stage, displaying good to excellent source rock potential. The Dawuba shales are characterized by Type II2 kerogens, while the Niutitang shales predominantly contain Type I kerogens, indicating high gas generation potentials for both. The formations are composed of mixed and argillaceous shales, exhibiting ultra-low porosity and permeability but featuring development of dissolution pores, OM pores, and micro-fractures essential for gas storage. Comparative analysis shows the Dawuba shales have superior BETspecific surface areas, total pore volumes, and average pore diameters than the Niutitang shales. However, gas contents in both formations are relatively low, underscoring the necessity for further research on shale gas preservation conditions. The Qiannan Depression in Guizhou, particularly the Shangyuan and Zongdi areas of the Dawuba Formation, are identified as promising regions for shale gas exploration due to favorable geological characteristics. This study highlights the significant shale gas potential in the Upper Yangtze Platform and calls for focused research to optimize exploration and extraction efforts. [ABSTRACT FROM AUTHOR]

Iron isotope compositions, along with the partial extraction of iron in its various forms, can be utilized to investigate the complex interplay of iron migration and transformation with respect to iron isotope patterns. This study investigated the iron composition of a typical loess-paleosol sequence in Northeast China and aimed to understand the influence of iron migration and transformation of the typical loess-paleosol sequence on iron isotopes and environmental and climatic changes that occurred in the region over time by analyzing the distribution and characteristics of iron compositions in sedimentary layers. Samples were collected from Chaoyang in Northeast China, and the iron isotopic composition was analyzed using the multi-receiver inductively coupled plasma mass spectrometer (MC-ICP-MS). The findings revealed depth-dependent variations in the content of different iron forms, reflecting paleoclimatic shifts primarily through pedogenic transformation processes. Notably, iron migration within the section was observed to be limited. The variations in the reddening index and magnetic susceptibility of the loess-paleosol were primarily influenced by the presence of free iron (Fed), exhibiting a range of colors from yellow to red-yellow and red. The δ56Fe values for loess and paleosols ranged from 0.097 ± 0.035‰ to 0.167 ± 0.010‰, with an average of 0.133 ± 0.024‰ and a coefficient of variation (CV) of 15.66% at the stratum scale. These values indicated a systematic enrichment of heavy iron isotopes and a significant negative correlation with the slightly fluctuating total iron content. Specifically, our analysis highlighted distinct differences in δ56Fe values between paleosol (0.126 ± 0.024‰) and loess (0.146 ± 0.021‰). The δ56Fe in Fed was negative, averaging −0.101 ± 0.022‰, while the δ56Fe in silicate-bound iron was positive, averaging 0.156 ± 0.032‰. Intense pedogenesis, driven by warm and wet climates, facilitated iron transformations and migrations, resulting in the accumulation of light iron isotopes in the paleosols. These transformations and migrations were predominantly observed in microdomains characterized by iron depletions and concentrations, as reflected in the profile morphologies. However, the limited iron transformations and migrations did not result in significant Fe redistribution within the soil section, as evidenced by the limited variations in δ56Fe with soil depth at the stratum scale. Sampling from the stratum or pedogenic horizon could potentially create the illusion of the minimal fractionation of iron isotopes within the sequence. Therefore, a detailed examination of the iron isotope composition in the micro-domains of the loess-paleosol sequence is crucial to elucidate the fractionation processes and mechanisms of iron isotopes during the formation of these sequences. [ABSTRACT FROM AUTHOR]

Pyrite is an important proxy used to reflect the redox state of a sedimentary environment. Currently available studies on pyrite focus on the process of sulfur cycles between an ocean and sediment. However, our understanding of the biogeochemical cycle of sulfur in terrestrial lake basins remains unclear, and the growth patterns of different types of pyrite are poorly understood. In this paper, we used samples from the 34 section of the Qianjiang depression in the Jianghan Basin as direct research objects by combining pyrite and sulfur isotope determination. The one-dimensional diffusion–advection–reaction simulation (1D-DAR) model was applied to simulate the changes in the pyrite content and sulfur isotope values in the sediment. The results show that the sediments in the saline lake basin environment contain a high organic matter content, a high sedimentation rate, and a high H2S diffusion oxidation rate, reflecting the strong reducing background and high productivity of this ancient lake. Sensitivity tests revealed that the organic matter content and H2S diffusion oxidation rate at the sediment–water interface are sensitive to the pyrite content. The sedimentation rate, organic matter content, and sulfate concentration are sensitive to the pyrite's sulfur isotope values. However, the variation in the active iron content had little effect on the pyrite content or sulfur isotope value. [ABSTRACT FROM AUTHOR]

The profound impact of the Khmer Empire on Southeast Asia renders the Angkor Period particularly significant in guiding contemporary societies to advocate and promote policies that respond to climate change. We present a new continuous multi-proxy speleothem dataset from Tonle Sap Lake Basin, investigating hydroclimate variability and the paleoenvironment of Cambodia during the Angkor Period from the 9th to 15th centuries. In addition, two important climatic events on a decadal scale are clearly reconstructed. The first is the reduction of precipitation between 800 and 1000 AD and the relatively significant drought that the regional environment may have experienced from 950 to 1000 AD. The second is the anomalous wet period between 1000 and 1200 AD, during which the Southern Oscillation Index also reached its negative peak after a thousand years. The wet and dry conditions are highly consistent with the El Niño-dominated and northward Intertropical Convergence Zone. [ABSTRACT FROM AUTHOR]

This research article presents a comprehensive work on sedimentological study of the Yamama Formation in the Saudi Arabia, aiming to enhance understanding of its depositional environments, diagenetic evolution, and reservoir properties of the formation. Integrated field and petrographic studies are used to interpret microfacies, depositional environment and diagenetic history of the Yamama Formation near Riyadh, Saudi Arabia. Field investigations show that the formation is thin- to thick-bedded, massive to nodular limestone with small patches of shale and marl. Petrographic studies show four distinct microfacies, i.e., mudstone MF-I, wackestone MF-II, packstone MF-III, grainstone MF-IV. The microfacies and their associations represent homoclinal ramp depositional setting designated on the basis of the relative percentage of allochems and orthochems. The diagenetic history, which includes eogenetic, mesogenetic, and telogenetic stages, is discussed as follows: The eogenetic stage includes burrowing, micrtization, neomorphism, and drusy mosaic cementation; the mesogenetic stage includes compaction (mechanical and chemical) and dissolution. The telogenetic stage is evident from calcite-filled fracture veins crosscutting the rock unit. The reservoir properties are directly dependent on both depositional and diagenetic processes. The reservoir quality of the formation has been significantly reduced by the precipitation of different types of cements during the diagenetic processes, as observed in the detailed paragentic sequence; however, during the late stage, fracturing has enhanced the reservoir quality significantly during the late stage. [ABSTRACT FROM AUTHOR]

Late Cretaceous-Miocene foraminiferas were recovered from the BG-1 well in the offshore Eastern Dahomey Basin. Four (4) lithostratigraphic units comprising Ogwashi-Asaba, Upper Araromi, Lower Araromi and Afowo Formations have been delineated and assigned based on the textural characteristics of the sediments. Forty-nine (49) foraminiferal species were identified, with a total count of 47 calcareous species (96%) comprising both planktonic and benthic forms and two arenaceous forms (3%). Seven (7) foraminiferal zones were recognised and dated from the Upper Cenomanian to Late Miocene age. The Globotruncana aegyptica zone, marked by the disappearance of the Maastrichtian forms at 3060 ft, coincided with the appearance of the Early Paleocene benthic forms such at the Anomalinoides umboniferus- Anomalinoides midwayensis zone. The Cretaceous-Paleogene (K-Pg) boundary was recognised at 3060 ft. Seven MFSs and SBs dated from the Upper Cenomanian and Upper Miocene ages were identified in the sequence stratigraphic analysis. The stacking patterns of the lowstand and highstand systems tracts reveal the interplay of progradational and aggradational parasequence signatures of siltstones and sandstone lithologies. The paleodepositional sedimentary packages of the BG-1 well are recognised from the Inner-Neritic to Bathyal environment. The sequence stratigraphic integration of lithofacies and foraminifera assemblages in this study has created a model of the distribution of the elements in the hydrocarbon system of the offshore Eastern Dahomey basin. Therefore, this study will underscore the critical role of sequence biostratigraphy in enhancing the accuracy and efficiency of exploration and development efforts in the hydrocarbon industry. [ABSTRACT FROM AUTHOR]

The controlling factors of organic-rich shale accumulation is essential for the exploration and development of shale oil and gas resources. The sedimentary environment plays a vital role in the formation of organic-rich sediments in lacustrine facies. This article unravels the mineralogy, geochemistry, and paleoenvironmental evolution during the deposition of the Paleogene Shahejie Formation (Es3 L). It discusses the effects of paleoclimate, paleosalinity, paleoredox conditions, paleowater depth, and paleoproductivity on organic matter (OM) enrichment. Finally, the OM enrichment model was established. The results show that the mineralogical compositions are mainly composed of calcite (avg. 40.13%), quartz (avg. 21.64%) and clay minerals (avg. 24.07%), accompanied by dolomite (avg. 7.07%), feldspar (avg. 6.36%) and pyrite (avg. 2.95%). The Es3 L shale has a high abundance of OM, with total organic carbon (TOC) ranging from 1.07% to 5.12%. The organic matter type is mainly composed of type I-II1 kerogen, which is generally considered a good-quality source rock. The source of OM is a mixture of lower bacteria, algae, and plants. During the early sedimentary period, the paleoclimate was dry and cold, with high salinity, intense reducibility, and relatively low productivity. During the late sedimentary period, the climate became warmer and more humid. As a result, the salinity decreased to a level that was suitable for biological reproduction, and productivity increased gradually due to the input of terrigenous plants. Paleosalinity and paleoclimate determined the environment of the sedimentary period, in addition, paleoproductivity and paleoredox condition indicated the formation and preservation conditions of OM. The warm and humid climate, brackish water, suitable reduction conditions and high productivity are the favorable conditions for the generation and preservation of organic matter. The research results may have implications for the genetic mechanisms of organic matter accumulation. They will provide theoretical and technical insights into the exploration and development of shale oil. [ABSTRACT FROM AUTHOR]

The sedimentary sequence of the Ninama Basin is associated with the latest phase of the continental Deccan volcanism of the Indian peninsula. It occurs as inter-, intratrappeans with a 39-m thick sequence comprising Sukhbhadar Formation and Ninama Limestone. The investigation aims to reconstruct its depositional setting based on the lithofacies and inorganic geochemistry to understand the influence of paleosalinity, paleoredox, paleodepth, provenance and paleoclimate on the sedimentation pattern. It is characterized by clastic and chemically formed rocks, including shale, mudstone, siltstone, sandstone and limestone. Facies analysis has revealed seven lithofacies, amongst which four are clastic facies, shale (SH), calcareous shale (CSH), silty mudstone (SM) and lithic greywacke (LGW), and three are carbonate facies, namely, grey-black limestone (GBL), cherty limestone (CL) and marlite (ML). Using geochemical analysis of major oxides and trace elements, ratios of Ca/(Ca+Fe), Sr/Ba, V/(V+Ni), V/Cr, Fe/(Ca+Mg), Ti/Al, Na/K, K/(Fe+Mg), CIA-K and MAP were determined and used to interpret and note the changes in the depositional system. The combined results of the lithofacies and geochemistry indicate that the deposition occurred in three phases. Phase 1 is characterized by high energy conditions in the shallow to moderate depth brackish-saline lake with oxic to dysoxic conditions; Phase 2 is characterized by anoxic deep fresh to the brackish water basin; and Phase 3 is characterized by semiarid conditions, saline, anoxic waters, high evaporation leading to shallowing of the lake, and low to moderate terrestrial input. This lacustrine basin in the paleotopographic low of the Deccan Volcanic Province is characterized by distinct lithology governed by various depositional parameters. A composite depositional model is constructed for the Ninama Basin, reflecting three phases of evolution that are dominantly controlled by the paleoenvironment. Research highlights: The present study focuses on lithofacies and inorganic geochemical analysis of Ninama paleolake sediments, Saurashtra intertrappeans, to interpret their paleosalinity, paleoredox, water depth, provenance, detrital influx, and paleoclimate. Phase 1 deposition was initiated in paleotopographic low of Deccan Traps, in an oxic–dysoxic, high-energy turbulent brackish water environment, in humid conditions. Phase 2 characterizes fine-grained clastic facies deposited in anoxic, fresh-brackish, deep lake waters in humid conditions. Phase 3 marks the shallowing, evident by carbonate facies with low-moderate terrestrial input deposited in saline and anoxic paleolake in semiarid conditions with high evaporation and low-moderate precipitation. The Deccan Traps have influenced the paleolake intertrappean sequence. [ABSTRACT FROM AUTHOR]

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

A multidisciplinary approach allowed the reconstruction of the shallow, highly complex Neogene lacustrine-type sedimentological interplay between the peri-Pannonian (sub)basin subsidence and its seafloor topography. The current study further discusses the mechanism of localized uplift and subsidence by analyzing depositional cycles of middle Miocene sediments drilled in a northwestern or shallower Toplica Basin depocenter (borehole BL4, depth up to 630 m; Central Serbia). Supported by recent constraints on a deeper basinal section of eastern and western subbasin depocenters, the composite study of the segmented Toplica Basin involved geological, sedimentological, mineralogical, inorganic, and organic geochemical analysis, as well as constraints on interchanging geodynamic drivers. The data were extracted from thirty-one selected samples from four sedimentary lithomembers: A, B, C, and D. The architecture of these deposits reflects an intricate pattern influenced by complex lake bottom and subsurface geology (dis)connecting the two depocenters. The investigated Neogene deposition, as a whole, was dominantly controlled by a lithospheric-scale extensional graben system (involving the Jastrebac core complex-type tectonic exhumation) developed on top of the underlying Serbo-Macedonian basement unit. The crustal extension allowed rapid material inflow from other exposed sequences of the juvenile basin, including the abutting surface exposures. During the initial stretching and basin subsidence stage, sediment inflow towards the eastern Toplica depocenter was hindered. The influx of surface-eroded material was interrupted by a natural "obstacle". In turn, such a configuration facilitated voluminous material transport into the western depocenter of the basin, thereby controlling the deposition of lithomembers A and B. After the deposition of lithomember B ceased, the "barrier", or likely intrabasinal structural high, contributed to a reversal of the former westward-directed transport. In that manner, the vertical movements of the structural high enabled material transfer typical for the eastern basin segment, consequently prompting a sedimentary development of the lithomembers C and D. In this context, mineralogical and geochemical differences between the sequences are used as tracers of depositional changes affected by tectonic events. Sequences of sand and gravel layers of upper lithomembers C and D pointed out that alluvial processes strongly influenced their depositional cycle. On the other hand, a more pronounced presence of sulfide minerals (pyrite concretions) in lithomembers A and B correlated with a calm and anoxic paleoenvironment. The elevated trend of mixed terrigenous and/or microbiologically reworked organic matter (higher carbon/nitrogen (C/N) ratio and terrigenous/aquatic (TAR) ratio, the lower sum of steroids/sum of hopanoids (S/H)) ratio, deposited under anoxic–dysoxic freshwater lacustrine conditions (higher pristane/phytane (Pr/Ph) ratio, absence of squalane (i -C 30) and β-carotane), is observed towards a shallower section of the borehole (lithomembers C and D). [ABSTRACT FROM AUTHOR]

I was thrilled to receive a Lifetime Achievement Medal at the 15th International Paleolimnology Symposium (IPS) in Bariloche, Argentina (2022). I will use this opportunity to tell the story of how I stumbled into the field of paleolimnology, a discipline I had not heard of until I entered graduate school. In retrospect, I feel extremely lucky to have been able to spend the last five decades addressing interesting paleoclimate/paleoenvironment questions. Furthermore, my research and teaching have taken me to many biologically fascinating and culturally intriguing places around the world. I will also use this forum to express my gratitude to the many mentors, colleagues, students, friends, and acquaintances with whom I have collaborated throughout my career. Whatever success I have enjoyed, I attribute to my good fortune in having been able to work with numerous talented and hard-working fellow scientists. [ABSTRACT FROM AUTHOR]

Recent geomorphological, paleoenvironmental, and chronological evidence allows for a reconstruction of the coasts of southwest Iberia during the firstmillennium BCE that accords with descriptions of the region offered by authors of antiquity, most notably the description by the fourth-century CE Roman writer R. F. Avienus in his poem Ora Maritima. This poem contains information that appears to date from the sixth century BCE regarding, for instance, the pre-Roman polity of Tartessos. The reliability of this work as a historical source has been questioned for decades. Critics argue that the information is pertinent to our understanding of the literary, rather than historiographical, context of the Late Roman Empire. However, philological as well as historical analyses reveal no clear cause to doubt the documentary value of the Ora Maritima. Furthermore, geomorphological research makes it possible to identify most place-names in the poem; for example, the city embraced by the river Tartessos, apparently the political and trade center of the realm, may likely have stood on the present-day spit of La Algaida, which was an isle in the first millennium BCE. While this hypothesis has been advanced elsewhere, this article offers an entirely new set of evidences to support it. [ABSTRACT FROM AUTHOR]

Introduction: What were the effects of paleoanthropogenic activities on the physicochemical properties and degree of the development of soil? To search for this answer, we can not only understand the different types of ancient human activities but also explore the intensity and characteristics of the activities. Methods: In this study, soil samples from different soil layers and two profiles in the Yangshao Village cultural site in Henan Province were collected. Their physicochemical properties and the sporophyte phyllosilicates they contain were analyzed and compared. Results: We found that the paleoanthropogenic activities started in the relatively low-lying area, in which the slash-and-burn activities resulted in the soil being filled with intrusions such as charcoal debris and ceramic shards. At the same time, the coarse-grained matter was affected by the plowing activities and mostly decomposed into fine particles, and the content of clay particles reached an extreme value. The total nitrogen, phosphorus, and calcium carbonate content exceeded the average value of the natural profile, indicating that ancient humans had used human and animal feces to a certain extent to restore the fertility of arable land. Discussion: Overall, ancient human activities hindered the development of the soil, especially the ground created due to habitation activities. From the type and content of clay minerals, it could be seen that the soil in this layer has been transported from other places, has a high content of clay particles, and has experienced fire baking. It was assumed that the ground was used to cover the grain or bury the garbage and lay with clay in order to achieve the effect of sealing. As a result, the soil voids and structure had been damaged to some extent, which prevented the downward leaching or precipitation of soil particles and minerals to a certain extent, thus affecting soil development. [ABSTRACT FROM AUTHOR]

Why and how organismal lineages radiate is commonly studied through either assessing abiotic factors (biogeography, geomorphological processes, and climate) or biotic factors (traits and interactions). Despite increasing awareness that both abiotic and biotic processes may have important joint effects on diversification dynamics, few attempts have been made to quantify the relative importance and timing of these factors, and their potentially interlinked direct and indirect effects, on lineage diversification. We here combine assessments of historical biogeography, geomorphology, climatic niche, vegetative, and floral trait evolution to test whether these factors jointly, or in isolation, explain diversification dynamics of a Neotropical plant clade (Merianieae, Melastomataceae). After estimating ancestral areas and the changes in niche and trait disparity over time, we employ Phylogenetic Path Analyses as a synthesis tool to test eleven hypotheses on the individual direct and indirect effects of these factors on diversification rates. We find strongest support for interlinked effects of colonization of the uplifting Andes during the mid-Miocene and rapid abiotic climatic niche evolution in explaining a burst in diversification rate in Merianieae. Within Andean habitats, later increases in floral disparity allowed for the exploitation of wider pollination niches (i.e. shifts from bee to vertebrate pollinators), but did not affect diversification rates. Our approach of including both vegetative and floral trait evolution, rare in assessments of plant diversification in general, highlights that the evolution of woody habit and larger flowers preceded the colonization of the Andes, but was likely critical in enabling the rapid radiation in montane environments. Overall, and in concert with the idea that ecological opportunity is a key element of evolutionary radiations, our results suggest that a combination of rapid niche evolution and trait shifts was critical for the exploitation of newly available niche space in the Andes in the mid-Miocene. Further, our results emphasize the importance of incorporating both abiotic and biotic factors into the same analytical framework if we aim to quantify the relative and interlinked effects of these processes on diversification. [ABSTRACT FROM AUTHOR]

The eastern Junggar Basin in Xinjiang harbors abundant coal resources within the Middle Jurassic Xishanyao Formation. However, the formation environment associated with these coal-bearing strata remains unclear. Geochemical characteristics serve as crucial geological indicators of the sedimentary period. Therefore, it is imperative to explore the geochemical attributes and sedimentary context of the coal-rich layers within the Middle Jurassic Xishanyao Formation in the Zhundong region to enhance the prospects of coal extraction and utilization. The elemental compositions, both major and trace, of the Xishanyao Formation were analyzed through X-ray fluorescence spectrometry (XRF) and inductively coupled plasma mass spectrometry (ICP-MS). A comprehensive analysis was conducted on the sediment provenance, tectonic background, and depositional environment of the coal-bearing strata in the Xishanyao Formation. Moreover, through the utilization of a range of discrimination indices, including Sr/Cu, B/Ga, Sr/Ba, V/Cr, Ni/Co, and δCe, the paleo-depositional setting of the coal-containing layers was reconstructed. The findings suggest that the primary source rocks of the coal-bearing beds in the Xishanyao Formation consist of continental tholeiites, with the predominant material composition in the source region being felsic volcanic rocks originating from the upper crust. The tectonic backdrop of the source region is marked by a continental island arc environment. During the sedimentation period of the Xishanyao Formation, the depositional environment was characterized by a freshwater oxidizing setting. Additionally, it experienced a transition from arid-hot to humid-hot before returning to arid-hot conditions. [ABSTRACT FROM AUTHOR]

Lake sediment records are of great importance for understanding the evolution of watershed environments. Various studies have been carried out to determine the depositional ages of lake sediments and to examine their physical, chemical, and biological characteristics. The aim is to construct the historical vegetation, environment, and climate patterns in Chinese lake watersheds. In this review, we obtained relevant studies on lake sediment records by searching the key word 'age-depth' from the following databases: Web of Science and the China National Knowledge Infrastructure (CNKI, the largest Chinese academic database). We analyzed the literature based on its type (published in a Chinese/English journal or as a Master's/PhD thesis), period of publication, journal (if published in a journal), key authors, study area, dating scale, and main aims. The results suggest that the lakes in the plateau regions are the most popular research topic, typically covering 100–200 years (short-term) and 500–30,000 years (long-term). The literature focuses on a wide range of topics, from past environmental evolution in watersheds to lake ecology, and it provides a solid foundation for a better understanding of the regional climate change and the preservation of lake environments and ecosystems. In the future, the resulting data obtained from environmental reconstructions with lake sediments will need to be integrated with emerging information processing technologies (e.g., artificial intelligence and meta-analysis) to disentangle the complex interplay between the Earth's surface processes and global climate change; furthermore, strengthening interdisciplinary collaboration will deepen our comprehension of the man-land relationship and promote the sustainable management of lake ecosystems in the context of global climate change. [ABSTRACT FROM AUTHOR]

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Purposes: This research focuses on the characterization of phosphate ore, its solid effluents, and nearby contaminated soils in the southwest Tunisia (Gafsa-Metlaoui Basin). It aims also at evaluating the vertical distribution and abundance of critical rare earth elements (REE) in the different materials and their ecological and environmental risks. Materials and methods: The sampled materials went through physical, chemical, and mineralogical characterization which involved XRF, XPS, XRD, and ICP-MS analyses. The REE anomalies and the environmental and ecological indices were calculated. Results and discussions: Results show relatively high concentrations of nine rare REEs, following the sequence La > Ce > Nd > Y > Gd > Eu > Sm > Yb > Tb and trace metal elements (TME) such as Cd, Cr, Mn, Zn, Co, Fe, Sr, Cu, Ni, Pb, Ba that surpass, in some cases, international standards. The vertical distribution of the studied elements within a sediment, tailings, and soil profiles (beyond 20 cm of depth) indicates their likely in-depth migration. TME- and REE-bearing phosphate samples reflect mostly oxic conditions in the southern area with high positive Eu anomalies signifying possible mixing of sources. The environmental assessment indicate no contamination and a moderate enrichment of REEs, except for Eu, which displays significant contamination and extreme enrichment. Whereas, a deficiency of Y has been detected in most of the studied samples except for sludge sample which was also found significantly enriched with REE. Conclusions: There are fundamental similarities between the different studied samples with high carbonate mineral concentrations. Statistical analysis confirmed the spectroscopic fingerprints demonstrating that the different materials share a similar composition. All of these similarities are most likely linked to the impact of mining activities on sediments and soils. Overall, our findings highlight the global effect of ore processing in determining the geochemical and the mineralogical characteristics of the surrounding environments of mines. [ABSTRACT FROM AUTHOR]

The Baraichari Shale Formation, which is equivalent to the Boka Bil Formation, is well exposed within the Neogene sequence of the Sitapahar Anticline in the Chittagong-Tripura Fold Belt, Bengal Basin, Bangladesh. Regardless of its importance in hydrocarbon accumulation, a comprehensive facies analysis is essential to understand and explain the heterogeneity within different depositional architectural elements. The purpose of this work is to delineate the lithofacies characteristics, depositional environment heterogeneities and propose a generic depositional model for the Middle to Late Miocene shallow marine sediments of the formation. The sedimentary facies were investigated at three outcrops along the Kaptai–Chandraghona road cut sections of the Sitapahar anticline. The formation is composed of dark to bluish-gray shale, silty shale, yellowish brown siltstone, and gray to yellowish brown fine-to medium-grained sandstone. Eight distinct sedimentary facies have been identified and were categorized into three facies associations: subtidal or estuarine, mixed flats with tidal creeks, and tidal mud flats. The subtidal facies, predominant in the middle member, consists of fine to medium-grained ripple cross-stratified sandstone-siltstone, herringbone cross-stratified sandstone, and trough cross-stratified sandstone, indicating sub-tidal channel deposition. Mixed flats with tidal creeks exhibit heterolithic facies, suggesting energy level changes in intertidal to sub-tidal zones influenced by tidal currents. Tidal mud flats are predominantly laminated shale/mudstone and lenticular laminated sandstone-siltstone, reflecting deposition during tide transitions in the intertidal zone. Fining upward cycles within the formation indicate progressive progradation or changes in inner tidal flats conditions during regressive periods. These depositional settings serve as analogs for equivalent subsurface reservoirs and contribute to the construction of reservoir models with greater accuracy.

This paper examines the interplay of environmental change and human demographic shifts among late Pleistocene and Holocene populations in the hyper-arid context of the Central Namib Gravel plains, Western Namibia. This paper applies a structural equation modeling (SEM) approach to arid-zone hunter-gatherer mobility patterns and settlement systems based on variability among ethnographically and historically observed groups. It then applies this model in examining issues related to the Middle-to-Later Stone Age transition at the sites of Erb Tanks and the Mirabib rock shelter. This model suggests that, among modern arid-zone foragers, population density is by far the strongest factor influencing mobility and settlement systems, with higher population densities favoring longer residential site usages and shorter residential moves within smaller territories. In contrast, environmental variables having to do with annual rainfall, rainfall seasonality, and effective temperature affect mobility and settlement systems in ambiguous and statistically insignificant ways. This paper closes by arguing that regional-scale population increases signaled by various features of Later Stone Age archaeological patterning led to local population expansions in the Central Namib Desert, and that this in turn caused a range of recognizable cultural shifts that were strongly linked with adaptations to aridity.