Journal of Palaeogeography最新文献

{"title":"Plio–Pleistocene water cooling in the southeastern Pacific Ocean: Insights from paleoecology, marine sedimentary facies analysis, and Sr isotope stratigraphy at Coquimbo (∼30°S), Chile","authors":"Diego Partarrieu ,&nbsp;Luisa Pinto ,&nbsp;Constanza García ,&nbsp;Saleta de los Arcos ,&nbsp;Melissa González ,&nbsp;Gabriela Solís-Pichardo ,&nbsp;Gerardo Arrieta-García ,&nbsp;Teodoro Hernández-Treviño ,&nbsp;Peter Schaaf ,&nbsp;Francisco Fonseca ,&nbsp;F. Amaro Mourgues ,&nbsp;Pablo Oyanadel-Urbina ,&nbsp;Martín Chávez-Hoffmeister ,&nbsp;Jorge D. Carrillo-Briceño ,&nbsp;Valentina Flores-Aqueveque ,&nbsp;Patricio Zambrano-Lobos ,&nbsp;Cristina Ortega ,&nbsp;Marcelo M. Rivadeneira","doi":"10.1016/j.jop.2025.100269","DOIUrl":"10.1016/j.jop.2025.100269","url":null,"abstract":"<div><div>Understanding the oceanographic and environmental changes experienced on the South American Pacific coast during the Plio–Pleistocene transition and the influence of these variations on the evolution of marine ecosystems is particularly interesting to assess the effects of current global climate projections. We present a stratigraphic model of the marine sedimentary successions exposed in Coquimbo (∼30°S), northern Chile, supported by 22 numerical ages from the last 6 Ma obtained through ⁸⁷Sr/⁸⁶Sr dating of fossil mollusk shells. This stratigraphic model, and paleoecological and sedimentary facies analyses allow us to interpret the paleoenvironmental evolution and depositional dynamics in the basin. The marine successions accumulated in four sedimentation episodes: the first two on the shoreface during Messinian–Zanclean (∼6–5.10 Ma) and Zanclean–Piacenzian (∼4.23–3 Ma) ages, whereas the last two occurred mainly on the foreshore during middle Calabrian (∼1.15 Ma) and late Calabrian–Chibanian (∼0.83–0.25 Ma). The most significant taxonomic changes are observed in the transition between the Pliocene and Pleistocene deposits (∼3–1.15 Ma), reflecting the shift from faunal associations typical of warm-temperate waters to others of cool-temperate water preferences. The faunal turnover identified in this study correlates well with two climatic transition pulses out of three previously recognized in the southeastern Pacific Ocean for the Plio–Pleistocene: one during the Piacenzian–Gelasian (3–2.4 Ma), marked by a decrease in water temperature and an expansion of upwelling zones in the Humboldt Current System; and the other during the Gelasian–Calabrian (2–1.5 Ma), which has been linked to the establishment of the current El Niño Southern Oscillation (ENSO) climate system.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100269"},"PeriodicalIF":2.0,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144771381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lithofacies division and intelligent identification of the lacustrine mixed rocks in the Upper Xiaganchaigou Formation in Yingxi area of the Qaidam Basin, northwestern China","authors":"Yong-Shu Zhang ,&nbsp;Jia-Lin Fu ,&nbsp;Kun-Yu Wu ,&nbsp;Wu-Rong Wang ,&nbsp;Ying-Hai Jiang ,&nbsp;Shu-Qi Zhang ,&nbsp;Jian Li ,&nbsp;Han Wang ,&nbsp;Li-Ben Deng ,&nbsp;Zi-Mo Xu ,&nbsp;Na Zhang ,&nbsp;Cheng-Zao Jia ,&nbsp;Da-Li Yue","doi":"10.1016/j.jop.2025.100270","DOIUrl":"10.1016/j.jop.2025.100270","url":null,"abstract":"<div><div>The Lower Ganchaigou Formation in the Yingxi area of the Qaidam Basin is a typical lacustrine mixed rock reservoir in western China. It is characterized by strong interlayer heterogeneity, development of diverse lithofacies types, and complex response features in logging curves. These complexities make lithofacies identification of the Ganchaigou Formation particularly challenging for non-coring wells, demanding a more efficient and accurate approach. Based on lithology and structural patterns, a lithofacies classification scheme was established. Three intelligent logging identification methods based on improved long short-term memory (LSTM) networks were constructed for lithofacies identification. The accuracy of these methods was evaluated, and the most suitable intelligent logging identification method for the reservoir lithofacies in the Yingxi area was selected. In the Upper Xiaganchaigou Formation (E₃² section) of the Yingxi area, a total of eight lithofacies types were identified: laminated lime-dolostone, stratified lime-dolostone, laminated dolostone-lime, stratified dolostone-lime, laminated lime-dolomitic shale, massive mudstone, sandstone, and gypsum. The overall recognition accuracies of the LSTM, Bi-LSTM, and Attention-based Bi-LSTM intelligent identification models are 81%, 85%, and 87%, respectively. The overall recognition accuracies of the three intelligent algorithms are relatively high, with the Attention-based Bi-LSTM model achieving the highest accuracy. This model demonstrates superior applicability for intelligent lithofacies identification in lacustrine mixed rock reservoirs, particularly those dominated by carbonates in the Yingxi area. It effectively interprets the lithofacies types of non-coring wells in the study area and provides a valuable reference for interpreting lithofacies logs in similar depositional environments.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100270"},"PeriodicalIF":0.0,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144694897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sedimentary facies architecture and terminal fan systems of the lower Palaeogene Shahejie formation in Bonan Sag, Bohai Bay Basin, China: implications for hydrocarbon exploration","authors":"Arthur Paterne Mioumnde ,&nbsp;Li-Qiang Zhang ,&nbsp;Yi-Ming Yan ,&nbsp;Lauben Twinomujuni ,&nbsp;Hong-Wei Ran ,&nbsp;Victor Sedziafa ,&nbsp;Kevin Zebaze Djuka ,&nbsp;Moise Bessong ,&nbsp;Emmanuel Melaine Kouame","doi":"10.1016/j.jop.2025.100268","DOIUrl":"10.1016/j.jop.2025.100268","url":null,"abstract":"<div><div>In the search for oil reservoirs within the lower fourth member of the Paleogene Shahejie Formation (Es4x), understanding the depositional model is crucial, particularly in the Bonan Sag of the Bohai Bay Basin. Previous studies have provided limited perspectives on the depositional mechanisms in complex geological settings characterized by tectonic orogeny, volcanic activity, and metamorphism. This research seeks to address this knowledge gap by focusing on sedimentary deposits formed by the terminal fan system, diverging from the more commonly studied fan delta models. This study aims to clarify the depositional environment and mechanisms of the Es4x Member by identifying and characterizing the sedimentary facies and exploring how provenance influences the distribution of sandstone reservoirs in this heterogeneous formation. Data from more than 20 wells and over 500 m of cores revealed 15 lithofacies types, which were grouped into five facies associations (FA1--FA5) and used to describe the depositional architecture. These subfacies are categorized into feeder, distributary, and basal zones, with proximal, medial, and distal subfacies. Lithological analysis identified the dominant rock types as lithic arkose, feldspathic litharenite, and litharenite. The results show that the medial subfacies dominates the Bonan Sag during the deposition of the Es4x Member, occasionally extending towards the basinal zone through sporadic diffuse flood channels. This depositional mechanism reflects ephemeral water stretches influenced by varying weather conditions. Volcanic clasts distributed beyond the terminal fan system further illustrate the influence of volcanic activity on depositional processes. This study provides key findings on the sedimentary mechanisms in the Es4x Member, offering important information regarding deep reservoirs in tectonically active areas, particularly the challenges of predicting oil reservoirs in thin versus thick red beds.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100268"},"PeriodicalIF":2.0,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145157621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Paleocene syncollisional deposits in Renbu, southern Tibet, China: New insights into the foredeep–wedge evolution of the Himalayan foreland","authors":"Zhen Wei ,&nbsp;Xiang-Hui Li ,&nbsp;Min-Jia Sun ,&nbsp;Xiao-Long Fan ,&nbsp;Jing-Yu Wang","doi":"10.1016/j.jop.2025.100263","DOIUrl":"10.1016/j.jop.2025.100263","url":null,"abstract":"<div><div>Understanding turbidites and olistostromes in the foredeep depozone is critical for deciphering foreland–orogenic wedge interactions. Despite the abundance of syncollisional deposits in the central Himalaya, current research lacks analysis of their depositional models in this context. Our study focuses on the Renbu Unit, a recently discovered Paleocene syncollisional deposits in Renbu, assessing its lithological composition, sedimentary environment, and provenance. The lower part of the Renbu Unit is characterized by fine-grained turbiditic sandstones, showcasing maximum depositional ages of ∼80 Ma. Contrarily, the upper part, composed of coarse-grained turbiditic sandstones, presents a maximum depositional age of ∼64 Ma. The sandstones sources vary from the recycled Xigaze forearc basin in the lower unit to the Gangdese arc in the upper unit. Hence, the lower Renbu Unit could equate to the Jiachala Formation, and the upper Renbu Unit could correspond to its eroded counterpart whose zircon geochronology fits the biostratigraphic data of the Jiachala Formation. This leads to a new depositional model suggesting near-contemporaneous deposition of the Zongzhuo mélange, Jiachala Formation, and the Renbu Unit in the foredeep, demonstrating events like the orogenic front's collapse and gravity flow deposition.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100263"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144657097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Astronomically-paced lake-level changes on halite deposition during the Paleogene in the Huanggang Basin, East China","authors":"Cui-Yu Song ,&nbsp;Da-Wei Lü ,&nbsp;Wen-Tao Chen ,&nbsp;Munira Raji ,&nbsp;Bin Yang ,&nbsp;Zhen-Guo Ning ,&nbsp;Lu-Lu Tang ,&nbsp;Zhi-Hui Zhang","doi":"10.1016/j.jop.2024.12.008","DOIUrl":"10.1016/j.jop.2024.12.008","url":null,"abstract":"<div><div>The formation of halite in continental basins is intimately linked to lake-level changes. Current research has revealed the connection between lake-level variations and astronomical forcing on a million-year scale. Other studies have also highlighted the influence of orbitally-induced climate cycles on halite deposition. However, our understanding of the impact of astronomically-paced lake-level changes on halite formation remains constrained. The Paleogene Dawenkou Formation in the Huanggang Basin of East China provides a continuous salt-bearing sedimentary record to investigate the lake-level changes in halite deposition. Lake-level fluctuations reconstructed by sedimentary noise modeling for the Middle and Upper members of the Dawenkou Formation indicate that the lake-level variations in the Huanggang Basin were linked to astronomical forcing with periods of ∼2.4 Myr, ∼1.2 Myr and/or ∼100 kyr. Our results suggest that astronomical forcing, as a driver of lake-level variations, may have had an impact on halite deposition during the Paleogene. In the initial stage of halite formation within the Middle Member of the Dawenkou Formation, reduced heat and moisture transport during the ∼1.2 Myr obliquity minima resulted in low lake levels in mid-to-high latitudes. The prolonged droughts caused by the low amplitude of ∼2.4 Myr eccentricity created conditions more favorable for the development of thicker layers of halite. Subsequently, in the next halite-forming stage, a larger amplitude of ∼2.4 Myr eccentricity led to a more humid climate. Warm/dry winters and cool summers paced by the ∼100 kyr orbital eccentricity minima resulted in enhanced evaporation, relatively lower lake levels, and thinner halite deposition. Nevertheless, the possible transgressions may have contributed to complicated phase relationship between the lake-level change cycles and orbital cycles. This study offers an opportunity to delve deeper into the mechanism of halite deposition by objectively reconstructing lake levels using sedimentary noise modeling.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100250"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144720963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Systematic palaeontology and biostratigraphy of early Oligocene larger benthic foraminifera, offshore, southern Iran (Asmari Formation)","authors":"Mohsen Yazdi-Moghadam ,&nbsp;Mehdi Sarfi ,&nbsp;Mehrdad Naghusi ,&nbsp;Mohammad Sharifi ,&nbsp;Reza Aharipour ,&nbsp;Houshang Khairy","doi":"10.1016/j.jop.2024.08.013","DOIUrl":"10.1016/j.jop.2024.08.013","url":null,"abstract":"<div><div>The biostratigraphic aspects of the lower Oligocene carbonates of the Asmari Formation, offshore, southern Iran were analyzed, providing a high-resolution dating based on recovered larger benthic foraminifera. As a part of the Tethyan Seaway, the Asmari Formation is located between the Western and Eastern Tethys Oceans. The fauna is dominated by both hyaline perforated and porcelaneous forms, including <em>Nummulites fichteli</em>, <em>Operculina complanata</em>, <em>Eulepidina formosoides</em>, <em>Austrotrillina paucialveolata</em>, and <em>Peneroplis thomasi</em>. Data from the Asmari Formation show a high similarity to occurrences from the Western Tethys. The co-existence of <em>Nummulites fichteli</em> and <em>Eulepidina formosoides</em> indicates SBZ 22A Subzone referring to a short time span restricted to late Rupelian.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100252"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cyclic gravity flow deposits constrained by alternating dry/wet climates in a middle‒late Eocene saline lake, Jianghan Basin, Hubei Province, China","authors":"Tao-Yuan Ge ,&nbsp;Xiang-Xin Kong ,&nbsp;Zai-Xing Jiang ,&nbsp;Shi-Qiang Wu ,&nbsp;Mathieu Schuster ,&nbsp;Guilherme Bozetti","doi":"10.1016/j.jop.2025.100257","DOIUrl":"10.1016/j.jop.2025.100257","url":null,"abstract":"<div><div>Lacustrine sediments serve as valuable archives of extreme events and past environmental changes. However, the formation mechanisms and distribution patterns of gravity flow deposits in inland hypersaline lakes under climatic controls remain underexplored. In the Eocene Jianghan Basin, rhythmic strata influenced by climatic cycles provide a unique opportunity to investigate the relationship between gravity flow deposits and paleoclimate. According to core descriptions, thin section analysis, logging data, and grain size analysis, seven lithofacies and four lithofacies associations related to gravity flow deposits were identified. Frequent turbidity flows, primarily flood-induced gravity flows, are widely distributed in the saline lake. Proximal gravity flow deposits are characterized by thick, massive sandstones with minimal mud debris, occasionally featuring deformed lamination and scoured bases. Distal gravity flow deposits comprise clast-bearing massive sandstones, planar laminated sandstones, and graded siltstones. Paleoclimate analysis, based on trace elements and rock salt thickness, reveals a strong linkage between gravity flow deposits and climatic cycles. Correlations were established by systematically identifying short-term base-level cycles, which were subsequently grouped into medium-term base-level cycles through stacking pattern analysis. Short-term base-level changes, corresponding to stable climatic cycles, are marked by rhythmic salt layers. In contrast, medium-term base-level cycles, controlled by orbital periods, govern the deposition of gravity flow deposits. Under arid climatic conditions, reduced vegetation coverage and pronounced temperature variations lead to intensified erosion and increased suspended particle concentration. The deposition of sandstone layers is more substantial, and the frequency of turbidity flows is significantly higher under arid climatic conditions compared to humid climatic conditions. This research highlights how climatic cycles influence gravity flow deposits in hypersaline lake environments.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100257"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fossil evidence and ecological niche modelling reveal trait evolution and biogeography of the Ilex cornuta lineage","authors":"Xue-Yan Li ,&nbsp;Gi-Soo Nam ,&nbsp;Shu-Feng Li ,&nbsp;Anna Averyanova ,&nbsp;Yi Yang ,&nbsp;Ma-Byong Yoon ,&nbsp;Lin-Bo Jia","doi":"10.1016/j.jop.2025.02.003","DOIUrl":"10.1016/j.jop.2025.02.003","url":null,"abstract":"<div><div>Naturally occurring in the subtropical regions of China to Korea, Chinese Holly (<em>Ilex cornuta</em> Lindl. &amp; Paxton, Aquifoliaceae), is widely cultivated as an ornamental plant. However, the origins of the phenotypical diversity of the species as well as its geographical history remain elusive. Here we report 50 exceptionally well-preserved fossil leaves of the <em>I</em>. <em>cornuta</em> lineage from the middle Miocene of South Korea. These fossils showcase delicate details, encompassing both adaxial and abaxial surfaces, as well as primary to quinternary venation patterns. The varied leaf morphologies, ranging from three to seven spines, demonstrate that these leaf morphologies of <em>I. cornuta</em> were established by the middle Miocene. Furthermore, fossil discoveries from the middle and late Miocene of Korea and China, coupled with the enduring presence of highly suitable habitats in Asia since the late Paleogene, suggest a longstanding persistence of the <em>I. cornuta</em> lineage in this region. The identification of closely related fossils from the Miocene to Pliocene of Europe implies potential floristic interchange between the continents, facilitated by the regression of the Turgai Strait in the Paleogene. This is consistent with the broad suitable habitat of the lineage, which once spanned Europe and Asia from the late Eocene to early Oligocene. Our study provides an example for integrating fossil records with ecological niche modelling to elucidate the biogeographical history of plants.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100251"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrocarbon signatures as a tool for unraveling the stratigraphic problem for Upper Cretaceous–Paleogene sediments from Internal Dinarides, Serbia","authors":"Ivana Jovanić ,&nbsp;Aleksandra Šajnović ,&nbsp;Bojan Glavaš-Trbić ,&nbsp;Sanja Stojadinović ,&nbsp;Nikola Burazer ,&nbsp;Branimir Jovančićević","doi":"10.1016/j.jop.2025.100260","DOIUrl":"10.1016/j.jop.2025.100260","url":null,"abstract":"<div><div>Inorganic and organic geochemical analyses, assisted by micropaleontological investigations, were performed on the Paskovac sediments to differentiate the Cretaceous and Paleogene deposits in Internal Dinarides region. Owning to the presence of fossil assemblages in the in Upper Cretaceous sediments and their scarcity in the Paleogene siliciclastic sediments, the entire Paskovac area was fundamentally incorrectly classified as the Campanian–Maastrichtian. Besides, the Paskovac sedimentary sequence was formed as a consequence of the uppermost Cretaceous–Paleogene tectonic shortening of the Dinarides, during which the Maastrichtian sediments were re-deposited within the Paleogene sequence from the underlying Maastrichtian sediments. Therefore, this study employed thin-section microscopy, atomic absorption spectrometry (AAS), and gas chromatography–mass spectrometry (GC–MS) techniques to closely inspect 27 samples from the Paskovac drillhole. The results revealed a clear division of the samples into two groups based on their geochemical similarities. One group marked as Paleogene clastic sediments characterizes the highest content of terrigenous elements, namely SiO₂ (49.49 %–62.22 %), Al₂O₃ (16.18 %–21.75 %), Fe₂O₃ (3.41 %–6.67 %), TiO₂ (0.63 %–0.80 %), along with sulfur content (2.33 %–2.80 %). The organic matter is rich in odd long-chain <em>n</em>-alkanes, C₂₉ regular sterane (&gt;60 %), benzohopanes, retene, cadalene, and benzo[<em>b</em>]naphthofurans, suggesting predominately terrestrial biomass deposited under suboxic–oxic conditions. Another group, represented by carbonates (CaO up to 51.02 %), contains Maastrichtian assemblages (e.g., <em>Siderolites calcitrapoides</em>), indicating shallow-marine depositional settings. Short-chain even <em>n</em>-alkanes, branched alkanes (e.g., 5,5-diethylalkanes), and C₂₇ regular sterane suggest the presence of biodegraded mixed algal/microbial biomass.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100260"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unravelling the Pleistocene climatic evolution in the Siwaliks: implications for hominin settlement in the upper Soan Valley, Pakistan","authors":"Nadir Fawad ,&nbsp;Dai-Du Fan ,&nbsp;Tai-Xun Liu ,&nbsp;Muhammad Kamran ,&nbsp;Qazi Adnan Ahmed","doi":"10.1016/j.jop.2025.100262","DOIUrl":"10.1016/j.jop.2025.100262","url":null,"abstract":"<div><div>Since the early Pleistocene, climatic variability has profoundly influenced population dynamics, including the migration of hominins into and out of Africa. In South Asia, Quaternary sediments, particularly those found in the Siwaliks, provide a valuable record of climatic changes relevant to hominin habitation. While the upper Soan Valley in Pakistan has been extensively studied for evidence of hominin to modern human activities, the associated environmental and climatic changes remain underexplored. This study aims to elucidate the climatic evolution of the Quaternary sediments in the Riwat area, with the primary objective of reconstructing the environmental conditions that facilitated long-term hominin settlement and survival. To address this knowledge gap, we analyzed the geochemistry and clay mineralogy of 46 sediment samples utilizing spectroscopy and X-ray diffractometry (XRD), focusing on the Plio-Quaternary period. Our findings reveal three distinct climatic stages. The first stage (Stage I), was characterized by cold conditions during the Pliocene, and was further divided into semi-arid to semi-humid substages based on C-values. This was followed by a cold to humid climatic stage (Stage II) during the early to middle Pleistocene, marked by moderate to high chemical weathering, which was also categorized into semi-arid to semi-humid substages. Within Stage II, a warm and humid phase was inferred during the early to middle Pleistocene, culminating in the coldest and most arid conditions of Stage III during the late Pleistocene to Holocene. The climatic changes observed are indicative of the uplift of the Himalayan-Tibetan Plateau and the influence of the southwestern monsoon on the Indian subcontinent. Moderate to intense monsoonal activity characterized the early to middle Pleistocene, creating conditions conducive to early hominin settlement and adaptation due to the availability of resources. Conversely, environmental conditions during periods of weakened monsoons exhibited an arid climate from the late Pleistocene to Holocene (corresponding to MIS 1-4 in oceanic records). This study enhances our understanding of hominin-climate interactions and has implications for the role of climate in shaping diverse hominin habitation patterns, both globally (out of Africa) and regionally (South Asian) contexts.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100262"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}