Journal of Palaeogeography最新文献

{"title":"Palaeoweathering and palaeoclimate of the Lower Cretaceous upper Xiguayuan Formation in the Luanping Basin, North China: Implications for early Aptian global cooling","authors":"Long Sun ,&nbsp;Sheng-He Wu ,&nbsp;Da-Li Yue ,&nbsp;Si-Chong Jiang ,&nbsp;Wei Du ,&nbsp;Li-Jun Yang ,&nbsp;Zhen-Hua Xu ,&nbsp;Ke Zhang","doi":"10.1016/j.jop.2025.100295","DOIUrl":"10.1016/j.jop.2025.100295","url":null,"abstract":"<div><div>The Early Cretaceous greenhouse climate was interrupted by multiple intermittent cold snaps such as the Valanginian cold snap and late Aptian climate cooling events, but there is currently a lack of terrestrial palaeoweathering and palaeoclimate records for the early Aptian climate cooling event. The relationship between the regional climate of terrestrial lake basins and the global climate during the early Aptian is still unclear. The Luanping Basin, which is located in the northeastern North China Craton (NCC) and contains Lower Cretaceous sediments with a maximum thickness of ∼3200 m, is an ideal place for analysing the terrestrial weathering and climate. Sixteen mudstone samples were collected from the Lower Cretaceous upper Xiguayuan Formation in the Luanping Basin. The mineral compositions and major, trace and rare earth element contents of the mudstone samples were quantitatively determined via X-ray diffraction (XRD), X-ray fluorescence (XRF), and inductively coupled plasma‒mass spectrometry (ICP‒MS), respectively. Elemental geochemical analyses were carried out to determine palaeoweathering intensity, palaeoclimatic conditions, and their relationships with the global climate. The variation trends in multiple chemical weathering indices are reconstructed after the interference of nonweathering factors is eliminated, reflecting that the source area has experienced mainly weak to moderate weathering. After evaluating the influences of carbonate-sourced elements, we infer that the regional palaeoclimate is arid and cold on the basis of the Sr/Cu ratio, Rb/Sr ratio, C-value, land surface temperature (LST), and mean annual temperature (MAT). All chemical weathering indices and palaeoclimate proxies exhibit similar trends. Moreover, the cooling of palaeotemperatures could have been a response to the early Aptian global cold snap. The regional climate of the Luanping Basin is controlled mainly by global climate change, which provides terrestrial weathering and climate records for the early Aptian global cooling event.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"15 1","pages":"Article 100295"},"PeriodicalIF":2.0,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145322712","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":"Shaolinopteris gen. nov., a new fern rhizome genus with solenostele from the Jurassic of Northeast China and its palaeogeographic and taxonomic implications","authors":"Ning Tian ,&nbsp;Zi-Hui Sheng ,&nbsp;Fang-Yu Li ,&nbsp;Ning Lu ,&nbsp;Meng-Yu Chen ,&nbsp;Wen-Tao Liu","doi":"10.1016/j.jop.2025.100292","DOIUrl":"10.1016/j.jop.2025.100292","url":null,"abstract":"<div><div>China possesses an abundant fossil record of Mesozoic ferns, predominantly preserved as leaf compressions or impressions. In contrast, permineralized fern fossils revealing anatomical details are comparatively rare. Recently, a novel permineralized flora was discovered from the Middle Jurassic Xinmin Formation in Horqin Right Wing Middle Banner, Northeast China, yielding diverse permineralized plant remains. Here, we report a new permineralized fern rhizome genus <em>Shaolinopteris</em> gen. nov. from this flora. The new genus is anatomically characterized by a solenostele with exarch protoxylem, a homogeneous pith, a two-layered rhizome cortex, and “<em>Dennstaedtia</em>-type” adventitious roots featuring diarch protoxylems. Notably, the rhizome inner cortex comprises aerenchymatous columns. Anatomical analysis of <em>Shaolinopteris</em> indicates probable phylogenetic affiliation with the extant fern family Dennstaedtiaceae. Furthermore, a comprehensive revision of the fossil diversity and palaeogeographical distribution of Mesozoic solenostelic fern rhizomes is presented. This new specimen constitutes the first documented occurrence of Mesozoic solenostelic ferns in continental East Asia, providing critical evidence for reconstructing the palaeophytogeography of these taxa.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"15 1","pages":"Article 100292"},"PeriodicalIF":2.0,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223480","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":"Geochemical characteristics of the Upper Triassic Tanzhuang Formation in the Jiyuan sag, southern North China Block: Implications for the depositional environment and organic matter enrichment","authors":"Wei-Qing Liu ,&nbsp;Lu-Qi Chen ,&nbsp;Hua-Ying Song ,&nbsp;Yu Qiao ,&nbsp;Su-Ping Li ,&nbsp;Wei Wu ,&nbsp;Chang-Song Lin ,&nbsp;Jian-Xin Yao","doi":"10.1016/j.jop.2025.100290","DOIUrl":"10.1016/j.jop.2025.100290","url":null,"abstract":"<div><div>The organic-rich black oil shales of the Upper Triassic Tanzhuang Formation represent important source rocks within the southern North China Block. However, the mechanism of organic matter enrichment remains unclear. Additionally, the climate evolution and driving factors of the Late Triassic in the southern North China Block are still unknown. This study explores the paleoclimate, paleohydrology, paleoenvironment, and organic matter accumulation mechanism of the section containing the Tanzhuang Formation in the Jiyuan area, utilizing its geochemical characteristics as a basis for analysis. The oil shales in the Tanzhuang Formation can be categorized into two types: organic-rich shales (with total organic carbon (TOC) contents varying between 1.61 % and 4.17 %) and organic-lean shales (with TOC contents varying between 0.29 % and 1.44 %). The paleoclimatic indices, the chemical alteration index (CIA) and the C value, suggest that the organic-lean shales were deposited under warm and semihumid paleoclimatic conditions, whereas the organic-rich black shales formed under warm and humid climate conditions. The positive correlation between the Hg/Al ratios and C values suggests that volcanic activity was the cause of paleoclimatic changes, which may have been associated with global climatic events that occurred during the Late Triassic Carnian period. The oxidation–reduction indices, V, U, and Mo contents and the Mo–U correlation diagram indicate that dysoxic conditions prevailed in the Jiyuan Basin during the deposition of the oil shales in the Tanzhuang Formation. The primary productivity indices (e.g., Cu_EF and Zn_EF) suggest that higher primary productivity was observed during the deposition of the organic-rich shales. The positive correlations between the TOC contents and the Cu_EF and C values indicate that the enrichment of organic matter in the oil shales of the Tanzhuang Formation was influenced primarily by primary productivity and a warm and humid climate. The sedimentary model indicates that the elevated primary productivity may have originated from a warm and humid climate coupled with intense weathering caused by volcanic activity during the Late Triassic period, which formed a productivity model characterized by the accumulation of organic matter in the oil shales of the Tanzhuang Formation.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100290"},"PeriodicalIF":2.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145157624","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":"Devonian-Carboniferous paleosols and tectonics of northwest China","authors":"Xue-Lian Guo ,&nbsp;Gregory J. Retallack ,&nbsp;Shuang Dai","doi":"10.1016/j.jop.2025.100287","DOIUrl":"10.1016/j.jop.2025.100287","url":null,"abstract":"<div><div>Paleosols in the Late Devonian (Famennian) Shaliushui and Qianheishan formations near Pingchuan, in northeast Gansu, China, are characterized petrographically and chemically to reconstruct paleoenvironments early in the evolution of forests on Earth. The Devonian paleosols, analogous to Neogene paleosols in the Lesser Himalaya of India, formed within the outwash plain of an extremely high (5–8 km elevation) mountain range on the North Qilian Block resulting from continent–continent collision in North China. Such high paleoaltitude is evidenced by Devonian paleosols exhibiting unusually thick horizons of subsurface calcareous nodules, as evidence of inferred mean annual precipitation range of 107 ± 22 mm. These conditions are comparable to those observed in paleosols from India, where monsoonal seasonality is driven by extreme elevation differences. Depth to Bk (calcic horizon) corrected for burial compaction of the paleosols reveals semiarid mean annual precipitation (MAP) of 361 ± 147 mm, with some subhumid outliers of 563 ± 147 mm. Chemical composition of the paleosols is evidence of subhumid (MAP 572 ± 182 mm, but up to 936 ± 182 mm) and temperate climates (MAT 12.5 ± 4.4 °C, but up to 14.9 ± 4.4 °C). Such cool temperatures at low paleolatitude (5-20°) are additional evidence of high elevation of at least 1 km. The vegetation consisted of Devonian pteridophytic progymnosperms, evidenced by rare foliar spurs and common woody root traces.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100287"},"PeriodicalIF":2.0,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145157622","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":"Characteristics, genesis, and paleoenvironmental significances of oncolites in the lower Permian (Cisuralian) Balikelike Formation from the northwestern Tarim Basin, China","authors":"Guang Yang ,&nbsp;Zhen-Yu Wang ,&nbsp;Xing-Zhi Wang ,&nbsp;Yun-Feng Zhang","doi":"10.1016/j.jop.2025.100286","DOIUrl":"10.1016/j.jop.2025.100286","url":null,"abstract":"<div><div>The Permian marks a pivotal transition in Earth's evolutionary history, with oncolites offering insights into paleoenvironmental and evolutionary dynamics. This study documents the first occurrence of oncolites in the lower Permian (Sakmarian) Balikelike Formation in the Keping area, northwestern Tarim Basin, China. Integrated lithofacies analysis, geochemistry, and multi-scale observations reveal that the Balikelike Formation at the Subashi section comprises a complete third-order sequence, with two layers of oncolites developed in the highstand systems tract. These oncolites, predominantly developed on marl and interbedded with mudstone, exhibit elliptical, cap-shaped, hemispherical, and thin-plated morphologies. Fluorescence microscopy exhibits yellow-green fluorescence in dark laminae, while SEM identifies fossilized filamentous cyanobacteria. Geochemical data — Sr isotopes, weathering index values, and Sr/Ba ratios — suggest that oncolites develop in a warm, humid, and high-salinity environment with limited terrestrial input. The oncolite proliferation coincides with the initial magmatic phase of the Tarim Large Igneous Province, evidenced by negative carbon isotope excursions and the lower ⁸⁷Sr/⁸⁶Sr ratios compared to global seawater, signaling an interglacial warming phase. Volcanic activity likely curtailed the Asselian–Sakmarian glaciation in the Tarim Basin earlier than elsewhere, with carbon emissions, climate warming, and eutrophication, driving massive occurrence of oncolite.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100286"},"PeriodicalIF":2.0,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144925424","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":"New perspectives on the paleogeographic context of the Late Paleozoic Ice Age in Southwest Gondwana: U–Pb ages and sedimentary provenance data from the Paganzo Basin, Argentina","authors":"Julián D. Rolan ,&nbsp;Jonatan A. Arnol ,&nbsp;Francisco I. Lugo ,&nbsp;Norberto J. Uriz ,&nbsp;Andrea R. Bidone ,&nbsp;Carlos A. Cingolani ,&nbsp;Miguel A.S. Basei ,&nbsp;Maximiliano Naipauer","doi":"10.1016/j.jop.2025.100274","DOIUrl":"10.1016/j.jop.2025.100274","url":null,"abstract":"<div><div>This study presents the first detrital zircon U–Pb analysis alongside new petrographic data from the Jejenes Formation (Serpukhovian–Bashkirian), located on the southern margin of the Paganzo Basin, Argentina in Southwest Gondwana. The results were compared with previously published data from other synchronously deposited units to the north (Guandacol Formation) and northeast (Malanzán Formation). Notably, glacigenic deposits are present in both the Guandacol and Jejenes formations but absent in the Malanzán Formation. A sedimentary provenance analysis was conducted for the three units, highlighting similarities and differences among the depocenters, allowing for the reconstruction of the paleogeographic and topographic landscape of the Paganzo Basin during the Serpukhovian–Bashkirian time. The comparative analysis supports the idea of disconnection and isolation among the three depocenters with each unit recording predominantly proximal sources and the recycling of pre-Carboniferous substrate. Although certain similarities exist in the age distribution of the detrital zircon grains recorded for the Malanzán and Guandacol formations, this does not imply that the depocenters were connected or fed by the same source area. Instead, these successions were likely sourced from rocks with a similar geological history, resulting in comparable age distributions due to sediment recycling. Thus, the results support a conservative approach when estimating sedimentary provenance in ancient glacigenic deposits, emphasizing the need to evaluate local sediment sources. The absence of glacigenic deposits in the Malanzán Formation could be linked to a lower topography, linked to distinct tectonic histories in the Pie de Palo, Valle Fértil, and Chepes–Malanzán ranges, underscoring the role of tectonic inheritance in the distribution of glacial centers during the Late Paleozoic Ice Age.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100274"},"PeriodicalIF":2.0,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144914007","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":"Paleoenvironmental reconstruction and sequence biostratigraphy of Miocene transgressive–regressive sedimentary succession in the northern JDA, northern Malay Basin","authors":"Fatin Nur Adilah Md Idris ,&nbsp;Khairul Azlan Mustapha ,&nbsp;Fatin Izzati Mihnat ,&nbsp;Zainey Konjing","doi":"10.1016/j.jop.2025.100273","DOIUrl":"10.1016/j.jop.2025.100273","url":null,"abstract":"<div><div>The northern sector of the Malay Basin has long been underrepresented, leaving a gap in the understanding of its paleoenvironmental evolution. In addressing this gap, detailed biostratigraphic analysis based on palynology and foraminifera from two wells, i.e., Tj-1 and Tp-1, has been conducted to reconstruct the paleoenvironment during the Miocene age. The factors influencing their distribution were analyzed using a sequence biostratigraphic approach, complemented by environmental parameters such as grain size and organic matter content, supported by seismic and gamma ray logs. The findings reveal significant differences in the faunal distribution of the inner shelf and delta front between the two studied wells. The inner shelf in Tj-1 well is dominated by <em>Asterorotalia pulchella</em> and the accessory species <em>Pseudorotalia schroeteriana</em>. Whereas Tp-1 well, is dominated by <em>Pseudorotalia schroeteriana</em>, but <em>Asterorotalia pulchella</em> is absent. For delta front species, <em>Bigenerina</em> sp. and <em>Reophax</em> sp. are found throughout Tp-1 well. However, in Tj-1 well, the dominant assemblages are <em>Bigenerina</em> sp. and <em>Miliammina</em> sp. during Serravallian to Tortonian, and <em>Cavarotalia annectens</em> from Tortonian to Messinian. Furthermore, our study identifies a major transgressive–regressive (T–R) event during Langhian to Serravallian period, inferred from stratigraphic dating using the standard palynological zonation of Malay Basin (‘PR’ zone) with the age according to VIM (Vietnam–Indonesia–Malaysia) and SEA (Southeast Asia) cycles, which also highlights unconformities. This suggests that tectonic events have led to distinct fauna provinces within the Miocene biostratigraphic assemblages.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100273"},"PeriodicalIF":2.0,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739523","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 optical textures of pyrobitumen in nature and its geological significance: revealed from the Ediacaran pyrobitumen in the central Sichuan Basin, SW China","authors":"Lian-Qiang Zhu ,&nbsp;Ze-Zhang Song ,&nbsp;Bing Luo ,&nbsp;Guang-Di Liu ,&nbsp;Wen-Zhi Zhao ,&nbsp;Qian-Qian Feng ,&nbsp;Ben-Jian Zhang ,&nbsp;Gang Zhou ,&nbsp;Xing-Wang Tian ,&nbsp;Dai-Lin Yang ,&nbsp;Lu-Ya Wu ,&nbsp;Lin Ma ,&nbsp;Mikhail Spasennykh ,&nbsp;Yi-Shu Li","doi":"10.1016/j.jop.2025.100271","DOIUrl":"10.1016/j.jop.2025.100271","url":null,"abstract":"<div><div>Some natural pyrobitumens exhibit optical anisotropy similar to mesophase asphalt, potentially recording critical geological information. However, the significance of their distinctive optical textures remains understudied. Anisotropic pyrobitumen in the Ediacaran Dengying Formation (central Sichuan Basin, southwestern China) provides a key example. This study investigates controls on pyrobitumen optical texture evolution using petrography, scanning electron microscopy, and U–Pb dating. Then, it discusses the relationship between these textures and anomalous thermal events by analyzing their spatial distribution and their geological significance. Results reveal that anisotropic pyrobitumen in Dengying Formation formed from oil cracking caused by Late Permian hydrothermal activity. These pyrobitumen can be divided into two categories based on the optical textures: fibrous and mosaic, reflecting distinct internal physical structures. Fibrous pyrobitumen exhibits more ordered aromatic layers than the mosaic type. Temperature primarily controls optical textures by regulating polycondensation reactions and pyrobitumen viscosity. Although the Gaoshiti and Moxi areas share similar burial histories, Gaoshiti is dominated by highly evolved fibrous pyrobitumen, while Moxi contains predominantly low-evolved mosaic pyrobitumen. This disparity indicates formation of anisotropic pyrobitumen was unrelated to normal burial temperatures but to hydrothermal activity. This study demonstrates that anisotropic pyrobitumen cannot form below 240 °C, even over extended durations. Consequently, in situ anisotropic pyrobitumen in deep strata serves as an indicator of paleo-thermal anomalies, with varying textures acting as proxies for relative temperatures within these events. Under identical geological settings, fibrous pyrobitumen typically records higher temperatures than mosaic pyrobitumen.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100271"},"PeriodicalIF":0.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144695053","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":"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}