Journal of Palaeogeography最新文献

{"title":"Cyclostratigraphy of the Middle Jurassic Aalenian Sha-1 member lacustrine record in central Sichuan Basin, southwestern China","authors":"Xiao-Fei Feng ,&nbsp;Xiao-Ming Zhao ,&nbsp;Massine Bouchakour ,&nbsp;Xi Zhang ,&nbsp;Jia-Wang Ge ,&nbsp;Yue-Li Liang ,&nbsp;Chang-Cheng Yang","doi":"10.1016/j.jop.2025.03.001","DOIUrl":"10.1016/j.jop.2025.03.001","url":null,"abstract":"<div><div>Cyclostratigraphic studies enable to reconstruct the geological timescales of many marine formations. However, these investigations are still lacking a precise astronomical tuning in lacustrine environments, particularly in the Middle Jurassic, due to the paucity of biological traces and the lack of data. In this study, detailed spectral analyses of natural gamma ray (GR) logging data were conducted on the lacustrine Sha-1 member from two wells in the Sichuan Basin, southwestern China. Core data samples were calibrated to test the lithological changes for proceeding with cyclostratigraphic analysis with more confidence. The spectral analysis and evolutionary spectral analysis of the GR logs reveal that the wavelength ratios of the stratigraphic cycles are ∼20:5:2:1, being consistent with the period ratios of astronomical cycles (long eccentricity, short eccentricity, obliquity, and precession). Correlation coefficient (COCO) analyses were applied to quantitatively measure the fitting of the witnessed sedimentary cycles to astronomical periods and provide a possible sedimentation rate range. The results show that astronomical time scale of the studied interval comprises 58.4–60.6 m cycles, representing the 405 kyr eccentricity cycles, and 14.9–16.6 m cycles, representing the ∼100 kyr eccentricity cycles. This study reveals a ∼2.43 Myr duration for the Sha-1 member. Sedimentary noise modeling reveals that long-term million-year period (1.2 Myr) astronomical forcing may have been a significant driver of lake-level changes in the Sichuan Basin. Moreover, high-frequency (405 kyr scale) lake-level variations associated with the mid-term base-level cycles (4th-order sequences) were linked to climato-eustatic changes. This study suggests comparison between parameters of cyclostratigraphic records and sequence stratigraphic base-level cycles in lacustrine sediments. The stratigraphic surfaces of mid-term base-level cycles correspond to minima ∼405 kyr-long eccentricity cycle curve and high values of DYNOT (dynamic noise after orbital tuning). Integrating cyclostratigraphy with the base-level cycles is, therefore, a vital approach for defining the short-term oscillations of lake-level, and proved to be a useful tool for characterizing thin-bedded lacustrine reservoirs.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 452-475"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869731","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 species of larger benthic foraminifera from the Maastrichtian deposits of the southern margin of the Neotethys (Zagros Foreland Basin)","authors":"Hossein Ghanbarloo ,&nbsp;Amrollah Safari ,&nbsp;Muhittin Görmüş","doi":"10.1016/j.jop.2024.10.003","DOIUrl":"10.1016/j.jop.2024.10.003","url":null,"abstract":"<div><div>The investigation mainly focuses on larger benthic foraminifera, <em>Canalispina</em>, <em>Siderolites</em>, <em>Loftusia</em>, and <em>Omphalocyclus</em> from the Maastrichtian deposits (Tarbur Formation) in the Zagros Foreland Basin. The four new species: <em>Canalispina zagrosia</em> sp. nov., <em>Siderolites persica</em> sp. nov., <em>Loftusia tarburica</em> sp. nov., and <em>Omphalocyclus tarburensis</em> sp. nov., and four other index species: <em>Siderolites calcitrapoides</em>, <em>Omphalocyclus cideensis</em>, <em>O. macroporus</em>, and <em>Loftusia baykali</em> were identified. <em>L. harrisoni</em> is thought to be ancestor of <em>L. minor</em>, <em>L. arabica</em>, <em>L. matsumarui</em>, <em>L. tarburica</em> sp. nov., <em>L. occidentalis</em>, <em>L. coxi</em>, <em>L. baykali</em>, <em>L. kahtaensis</em> and <em>L. oktayi</em> during the early, middle and late Maastrichtian, while <em>L. persica</em> and <em>L. elongata</em> evolved into <em>L. arabica</em> in the middle Maastrichtian. <em>L. turcica</em> and <em>L. morgani</em> are close forms of <em>L. elongata</em> in the middle and late Maastrichtian, and <em>L. anatolica</em> and <em>L. morgani</em> are the predominant forms in the late Maastrichtian. The wall structures of <em>Loftusia</em> species are more complex in the late Maastrichtian than in early Maastrichtian forms due to evolutionary trends. <em>Loftusia</em> species with numerous whorls were predominant in the middle Maastrichtian. In contrast to this, the species with low whorl numbers during the early and late Maastrichtian were dominant. Detailed studies on <em>Omphalocyclus</em> species indicate that (1) the genus <em>Omphalocyclus</em> migrated from the middle part of the Tethys to other Tethyan areas during the late Campanian, and (2) the diversity of <em>Omphalocyclus</em> species of eastern Tethys (North African part) was higher than in other areas.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 535-558"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869264","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":"Dinoflagellate cyst and nannofossil imprints in the middle Eocene Kirthar transgressive strata from the western Garo Hills, South Shillong Plateau, India","authors":"Ashish Kumar Mishra ,&nbsp;Prem Raj Uddandam ,&nbsp;Stuti Saxena ,&nbsp;Abha Singh","doi":"10.1016/j.jop.2025.01.005","DOIUrl":"10.1016/j.jop.2025.01.005","url":null,"abstract":"<div><div>One of the global characteristic features of the Eocene is the extensive development of carbonate platforms in various regions of Tethys. Paleogene sequences of the Shillong Plateau from west to east are exposed in the steep Garo, Khasi and Jaintia hills. In the Khasi and Jaintia hills, Paleogene successions are represented by alternating carbonates and siliciclastics and provide datable micropaleontological fossils, whereas in the Garo Hills, which is in the south-western part of the Shillong Plateau, the Paleogene succession is mainly represented by siliciclastics and fewer carbonates. As the carbonates in this area are mostly marly, the recovery of carbonate microfossils is difficult. Accurate age assignment is important to correlate the sedimentary successions of the Khasi, Jaintia and Garo hills, which are mostly time transgressive and different lithologies were deposited at the same time. A detailed palynological investigation of 65 samples from the 25-m-thick sedimentary succession of the Siju Formation, Western Garo Hills, has yielded well-preserved and diverse organic-walled dinoflagellate cysts and calcareous nannofossils. Dinoflagellate cysts (<em>Heteraulacacysta porosa, H. leptalea</em>) and nannofossils (<em>Discoaster barbadiensis</em>, <em>D. saipanensis</em>, <em>Reticulofenestra bisecta</em>, <em>R. erbae</em>, and <em>R. reticulata</em>) indicate a middle Eocene age (Bartonian) for the studied section. The synthesis of nannofossils and dinocysts with records from India and Australia reveals a major late Bartonian transgression in the Indo-Pacific known as the ‘Kirthar transgression’.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 559-578"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869265","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":"Origin and evolution of large-scale sublacustrine fans in a lacustrine rift basin: a case study from the Liaozhong Depression (Bohai Bay Basin, E China)","authors":"Bang-Ning Xu,&nbsp;Hao Liu,&nbsp;Jie Xu","doi":"10.1016/j.jop.2025.02.001","DOIUrl":"10.1016/j.jop.2025.02.001","url":null,"abstract":"<div><div>Large-scale sublacustrine fans developed in lacustrine rift basins in China received extensive attention due to their significant implications in both sedimentological studies and petroleum exploration. Taking Member 3 of the Dongying Formation in the central-southern Liaozhong Depression, Liaodong Bay, Bohai Bay Basin as a case study, we conducted a systematic investigation into the depositional characteristics, sedimentary processes, and controlling factors governing the development of large-scale lacustrine fans through integrated analysis of seismic profiles, core samples, and well logging data. The research results indicated that three braid deltas developed in the transgressive systems tract of Member 3 of the Dongying Formation in the western slope belt of the study area. In contrast, the large-scale sublacustrine fan developed in the lake basin environment on the east side of the braid delta system. The sublacustrine fan is primarily composed of grey sandstone and mudstone, with deformed structures and coarse debris. Based on sedimentary characteristics, it can be categorized into two main types: turbidity currents and sandy debris flows. The development of large-scale sublacustrine fans is primarily influenced by four key factors: tectonic activity, paleogeomorphology, sediment supply, and lake-level fluctuations. During the deposition of the Dongying Formation, strike-slip and extension processes created multiple uplifts and depressions in the Liaodong Bay, including the Liaoxi Depression, the Liaoxi Uplift, and the Liaozhong Depression. The Liaoxi Uplift and the Yanshan Fold Belt to the west of the Liaodong Bay are the main sediment sources for the formation of multiple braid deltas on the western slope of the Liaozhong Depression, which in turn provided sediments for the sublacustrine fans. In addition, the sedimentary slope break located between the delta front and the prodelta controls the development and distribution of sublacustrine fans. The rising lake-level during the transgressive systems tract led to frequent fluctuations in water levels, establishing optimal water depth and hydrodynamic conditions conducive to the development of sublacustrine fans. The sublacustrine fan in the lacustrine rift basin was influenced by various factors, with multiple provenance supplies being one of the crucial factors for the development of large-scale sublacustrine fans. This favorable geological setting provided optimal conditions for the development of high-quality reservoirs and facilitated the exploration of substantial hydrocarbon accumulation. This research will serve as a reference for other similar lake basins worldwide.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 431-451"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869007","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":"Integrated sedimentological, ichnological, taphonomic, and low-order sequence-stratigraphic insights into the Oligocene shoal deposits: The Coral Limestone Member, Kutch Basin, India","authors":"Kanchan Prasad,&nbsp;Sudipta Dasgupta,&nbsp;Renzo D'souza","doi":"10.1016/j.jop.2024.11.006","DOIUrl":"10.1016/j.jop.2024.11.006","url":null,"abstract":"<div><div>Integrating the ichnologic, taphonomic, and sedimentologic data enhances the accuracy of palaeoenvironmental interpretations. The integrated analysis of the Chattian-age Coral Limestone Member within the Maniyara Fort Formation in Kutch Basin focuses on understanding the palaeogeographic architecture of microfacies association and the influencing factors determining the same on a typical Late Oligocene carbonate ramp. Through distinct petrographic examination, six distinct microfacies representing outer ramp (MF1 and MF2), middle ramp (MF3, MF4, and MF5), and inner ramp (MF6) depositional settings were identified. The Member, characterised primarily by multiple carbonate coquina intervals, was further classified based on taphonomical and ichnological characteristics. Four taphofacies (TF1, TF2, TF3, and TF4) and five ichnofabrics were identified. The outer ramp exhibits massive-appearing intensely to completely bioturbated (BI 5–6) marly mudstone–wackestone lithofacies with erosional contacts. The middle ramp displays oligotrophic conditions characterised by swaley cross-stratified bioclastic packstone–rudstone beds showing an upward intensifying moderate to intense bioturbation (BI 3–5). The storm-influenced inner ramp features the crudely swaley cross-stratified rudstone shell beds and patchy coral reefs with intense bioturbation (BI 5). Intermittent non-depositional and bioerosional short-duration episodes were observed at the top of skeletal concentrations. The integrated findings mentioned above exhibit coherence and offer valuable insights into the development of carbonate ramps. Our study offers insight into the aggrading and prograding shoal deposits within the carbonate ramp settings of a Chattian tropical sea. It highlights the complex interaction of environmental factors during this period within a high-resolution sequence-stratigraphic framework, extending up to the 5th-order, reported for the first time. This study deepens our comprehension of Oligocene carbonate buildups on a global scale — a research that has received lesser recognition compared to Eocene or Miocene carbonates.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 579-602"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869266","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":"Giant paleo-landslides in the upper reaches of the Yellow River: Spatio–temporal distribution, and possible controlling factors","authors":"Yi-Qi Ji ,&nbsp;Sheng-Rui Su ,&nbsp;Alessandro Simoni ,&nbsp;Qiang-Bing Huang","doi":"10.1016/j.jop.2024.12.006","DOIUrl":"10.1016/j.jop.2024.12.006","url":null,"abstract":"<div><div>A large number of giant paleo-landslides were found in the section from Lagan Gorge to Liujia Gorge, which is located in the upper reaches of the Yellow River. This area is located in the transition zone between the Qinghai–Tibet Plateau and the Loess Plateau with a semi-arid climate. The occurrence of lacustrine deposits suggests that some of the giant landslides ever blocked the river and landslide-dammed lakes have occurred in this area. The chronology of the giant landslide in the upper Yellow River was obtained and analyzed by optically stimulated luminescence (OSL) dating and established a chronological framework combining previous data. From the perspective of space, there are five major landslide clusters in the upper Yellow River. They are mainly located in the canyons at the junction of the Yellow River valley, and the center of every basins, which are inextricably linked to the unique sedimentary and tectonic environments of each basin. From the perspective of time, giant landslides also tend to occur during interglacial or glacial-to-interglacial transitions. Paleoseismicity and precipitation appear to be coupled and have competing relationships in their contribution to the formation of giant landslides.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 391-412"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868997","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":"Mass organic matter accumulation induced by rapid redox variations in lakes: Evidence from the Miaoxi area, Bohai Bay Basin, China","authors":"Peng Sun ,&nbsp;Hai-Feng Yang ,&nbsp;Fei-Long Wang ,&nbsp;Jun-Pei Yue ,&nbsp;Yan-Fei Gao ,&nbsp;You-Jun Tang","doi":"10.1016/j.jop.2024.11.004","DOIUrl":"10.1016/j.jop.2024.11.004","url":null,"abstract":"<div><div>The Member 4 of the Paleogene Shahejie Formation (Es4) in the Bohai Bay Basin is interspersed with a set of high-quality source rocks typified as intercalation of red and black mudstones. A large amount of petroleum (crude oil) originates from these source rocks. The Paleocene–Eocene Thermal Maximum (PETM) event occurred during the deposition of Es4 in the Bohai Bay Basin, and the organic matter enrichment model under this event is worth further investigation due to its relationship with and influence on petroleum accumulations. Well LK25-A, as the first oil exploration well drilled into the Es4 in Miaoxi area, serves as a valuable case to study organic matter accumulation. In this study, we integrate total organic carbon (TOC), Rock–Eval pyrolysis, microscopic observation, vitrinite reflectance (VRo), elemental analysis, and gas chromatography–mass spectrometry (GC–MS) to evaluate the hydrocarbon generation potential, organic matter types, thermal maturity, and sedimentary environment of the Es4 in Miaoxi area. The analysis of maceral and rock pyrolysis data reveals that Type I and Type II organic matter make up the majority of Paleogene mudstones in this region. The TOC and rock pyrolysis data show that mudstones in this area have high organic matter abundance and oil-generation potential. The measured vitrinite reflectance distribution of mudstone samples, which ranges from 0.3% to 0.74%, demonstrates that the Paleogene strata are at the immature to mature stage, and the samples from this area contain a sizable amount of bituminite and mineral-bituminous groundmass. The analysis of biomarkers in the mudstone samples indicates that most of the mudstones in this area are in lacustrine and brackish-hypersaline lacustrine environment under a reducing condition, and some of the red mudstones in the Es4 are formed under a suboxic condition. Based on the size and morphology of the pyrite framboid, the redox conditions of the water mass during deposition or diagenesis are further analyzed. The ratio of the size of framboid pyrite (D) to the size of its micrograins (d) suggests that the Es4 black mudstone developed in an anoxic sulfuretted water environment. Both the inorganic and organic geochemical indexes show that the Paleogene paleoclimate has a great influence on the source rocks of Es4 in this area. The distribution of red–black strata in the area is the result of the combined action of the water redox state and the climatic variation during the PETM event. The development models of organic-rich source rocks from the Es3 and Es4 in this area have been created in light of potential connections between rapid redox variation and the PETM event during the Paleogene. These models may offer a theoretical guidance for petroleum exploration in Miaoxi area of Bohai Bay Basin and other contemporaneous continental basins around the world.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 1","pages":"Pages 291-313"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metallogenic model of sandstone-hosted copper deposits: a case study from the Paleogene in Jiashi area, northwestern China","authors":"Long-Qing Shi ,&nbsp;Xing-Yue Qu ,&nbsp;Carlos Zavala ,&nbsp;Yang Li","doi":"10.1016/j.jop.2024.11.001","DOIUrl":"10.1016/j.jop.2024.11.001","url":null,"abstract":"<div><div>Sandstone-hosted copper deposits, a type of Sediment-Hosted Stratiform Copper (SSC) deposits, are widely distributed globally. While economically viable deposits of SSC are relatively scarce, they account for approximately 30 % of the world's total discovered copper resources. However, there is still a lack of comprehensive and in-depth research into the depositional and metallogenic models of these deposits. The Jiashi area of the Tarim Basin in northwestern China, known for its economically significant Paleogene SSC deposit, lacks in-depth studies on metallogenic processes. To address this, field profile observations were conducted to analyze the sedimentary evolution, sequence stratigraphy, and tectonism of the Paleogene strata in the Jiashi area. Combined with elemental geochemical analysis of samples, the provenance of sediment, and the source of metallogenic materials, a robust metallogenic model was established. The results reveal the influence of provenance for the origin of Paleogene copper-rich strata. Sedimentary evolution played a crucial role in controlling the distribution of copper and sulfur elements, as well as the spatial arrangement of metallogenic beds. Additionally, nappe movement potentially generated faults, allowing upward movement of basin fluids, which played a crucial role in the formation of copper deposits within sandstone-hosted systems. Thus, this study offers a comprehensive analysis of the metallogenic processes involved in sandstone-hosted copper deposits, thereby contributing significant insights to the broader research on SSC deposits worldwide.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 1","pages":"Pages 105-125"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Facilitation of microbialite development by continental weathering in the Cambrian Zhangxia Formation, southern North China Block","authors":"Wen-Tao Yang ,&nbsp;Jia-Qi Zhu ,&nbsp;Min Wang ,&nbsp;Chao Liu ,&nbsp;Yong-An Qi","doi":"10.1016/j.jop.2024.11.002","DOIUrl":"10.1016/j.jop.2024.11.002","url":null,"abstract":"<div><div>We report geochemical data for carbonate rocks from the Cambrian Zhangxia Formation, southern North China Block, including trace-element contents and C, O, and Sr isotopic compositions, to determine the controls on the development of microbialites in this formation. The sedimentary environment of the Zhangxia Formation evolved from carbonate-slope through platform-margin-reef to ooid-shoal, and then to open-platform settings, corresponding to the development of micrites, microbialites, and oolitic limestones. Geochemical data show that δ¹³C values decrease upwards through the Zhangxia Formation, from 0.99‰ to −1.59‰, whereas δ¹⁸O values increase from −9.91‰ to −7.10‰. Total rare earth element (REE) contents decrease upwards through the stratigraphy, and the contents of Th and Sc show a similar trend. ⁸⁷Sr/⁸⁶Sr ratios reach a maximum of 0.710544 in the horizons of microbialite development, Member 2 of the Zhangxia Formation, above which the ratios are uniform, with a mean value of 0.709251. Combining these geochemical data with the inferred sedimentary evolution, the Zhangxia Formation is interpreted to have formed in a depositional environment that changed from transgression to regression. Continental weathering played a crucial role in promoting the input of terrigenous materials, which in turn favored the development of microbialites during the early stage of deposition of the Zhangxia Formation.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 1","pages":"Pages 172-185"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Palaeodrainages of the Sunda Shelf detailed in new maps","authors":"Shawn Cheng ,&nbsp;Mohd Azahari Faidi","doi":"10.1016/j.jop.2024.10.001","DOIUrl":"10.1016/j.jop.2024.10.001","url":null,"abstract":"<div><div>The Sunda Shelf is a prime biodiversity hotspot where some of the planet's most endemic species can be found. Much of the diversity in this important bioregion has been shaped by sea-level fluctuations that took place during the Pleistocene. Using depth contours obtained from the General Bathymetric Chart of the Oceans Grid 2023, we provide high-resolution reconstruction of land areas and palaeo-drainages on the Sunda Shelf at the 50, 75, 100, and 120 m isobaths, as well as palaeo-catchments at the 120 m isobath, in order to elucidate the history of this region. The maps presented here aim to reconstruct the connection between palaeo-rivers in the Sunda Shelf and contemporary rivers and identify possible dispersal routes and barriers for the floras and faunas/biotas associated with riverine systems found here.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 1","pages":"Pages 186-202"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}