Palaeogeography, Palaeoclimatology, Palaeoecology最新文献

{"title":"Middle to late Miocene cooling and drying in the northern Tibetan Plateau based on evidence from plant-insect interactions","authors":"Cui Wang ,&nbsp;Yusheng (Chris) Liu ,&nbsp;Natalia Maslova ,&nbsp;Hui Jia ,&nbsp;Qijia Li ,&nbsp;Cheng Quan","doi":"10.1016/j.palaeo.2024.112496","DOIUrl":"10.1016/j.palaeo.2024.112496","url":null,"abstract":"<div><div>The Qaidam Basin in the northern Tibetan Plateau is currently arid, but may have had a semi-humid to semi-arid climate in Miocene times, as suggested by pollen and isotopic data; however, the lack of macroscopic fossils hinders more precise paleoclimatic calibration. In this paper, we report fossil leaves with insect damage from a late Miocene layer (HT-5) in the Huaitoutala section dated ∼11.4 Ma, and compare them with records from a middle Miocene layer (HT-1) dated ∼12.7 Ma. Results show that damage diversity dropped from 36 types in HT-1 to 24 types in HT-5, suggesting a fall in mean annual temperature. Damage frequency decreased from 70 % in HT-1 to 32 % in HT-5, pointing to a drop in the coldest month temperature. Moreover, a slight fall in the diversity of mining damage, from 5 types in HT-1 to 4 types in HT-5, suggests a shift towards a slightly more arid climate from the middle to late Miocene. The flora from HT-5 is composed mainly of Betulaceae, <em>Populus</em>, <em>Ulmus</em>, and shrubs. Based on the distribution of these taxa in modern vegetation, the climate was probably semi-humid, not entirely arid during the late Miocene. These results are corroborated by fossil mammal data from the same section. Therefore, despite a cooling and drying trend from the middle to late Miocene, the climate of the Qaidam Basin was not as extremely arid as today.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112496"},"PeriodicalIF":2.6,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tracing the Neoproterozoic Marinoan Snowball Earth thaw from deep sea to coastal waters","authors":"Jingxuan Zhang ,&nbsp;Zhichao Yang ,&nbsp;Gang Wang ,&nbsp;Kun Zhao ,&nbsp;Shengxian Zhu ,&nbsp;Lei Zhang ,&nbsp;Xianguo Lang","doi":"10.1016/j.palaeo.2024.112503","DOIUrl":"10.1016/j.palaeo.2024.112503","url":null,"abstract":"<div><div>The deglaciation of the Neoproterozoic Snowball Earth occurred over a few thousands to several tens of thousands of years. This short interval was characterized by a rapid increase in global sea level, resulting in an abrupt deposition of the post-glacial cap carbonates overlying the glacial deposits. However, the transition from glacial diamictites to cap carbonates in different depositional environments displayed considerable variability, indicating a more complex deglacial process than previously thought. To elucidate the end of the Snowball Earth, a comprehensive facies analysis was performed on the Cryogenian Nantuo Formation (the Marinoan glacial deposits) in the Nanhua Basin, South China. The analysis revealed that the Nantuo Formation encompasses a spectrum of facies associations, including subglacial, proximal glaciomarine, distal glaciomarine, and non-glacial marine facies, with obvious differences observed in the deglacial sequences between deep and shallow marine environments. In the deep-water environments, which was the deglacial deposits underwent a transition from massive diamictite to turbidite sequences, succeeded by the deposition of fine-grained sandstone to siltstones, and finally capped by the deposition of cap carbonates. In contrast, the shallow-water environments showed a progression from sheared diamictites to massive diamictite, which then evolved into cap carbonates. These observed differences highlight the spatial heterogeneity inherent in the deglaciation process, with the deep-water facies deglaciating before the shallow-water facies, implying a sequential retreat of the ice sheet towards the terrestrial domain. The findings support the hypothesis that the Neoproterozoic Snowball Earth deglaciation was a progressive event, beginning offshore and gradually extending onshore, which induced changes in depositional patterns and ocean alkalinity.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112503"},"PeriodicalIF":2.6,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sedimentary evolution of the Holocene subaqueous Changjiang Delta, with an emphasis on contributions of the two major Rivers, the Changjiang and Yellow Rivers","authors":"Taoyu Xu ,&nbsp;Xiaohui Liu ,&nbsp;Xisheng Fang ,&nbsp;Aimei Zhu ,&nbsp;Lianhua He ,&nbsp;Hongmin Wang ,&nbsp;Jinxia Chen ,&nbsp;Zhifang Xiong ,&nbsp;Yanguang Liu ,&nbsp;Xuefa Shi","doi":"10.1016/j.palaeo.2024.112501","DOIUrl":"10.1016/j.palaeo.2024.112501","url":null,"abstract":"<div><p>Subaqueous deltas of large rivers are important repositories of historical environmental changes, and understanding the evolution of deltas is essential for extracting paleoenvironmental data. This study focuses on investigating the evolution of the Holocene subaqueous Changjiang Delta using a long core CJK11 (72.2 m long). The uppermost Holocene mud layer (36.7 m thick) is divided into three units with varying accumulation rates. Through the analysis of source-discriminating proxies, such as clay mineral composition, geochemical trace elements, and strontium isotope ratios (⁸⁷Sr/⁸⁶Sr), it is determined that a significant proportion of sediments were derived from the Yellow River (peaking at 36.6 % and averaging 18.4 %), in addition to the predominant sediments from the Changjiang River. By integrating these results with core isochronous correlations and geological contexts, this study establishes the evolution pattern of the modern subaqueous Changjiang Delta, characterized by three distinct stages. During the initial stage (10–5 ka), the study area shifted to neritic environments far from the Changjiang Estuary and experienced slow accumulation due to limited input from the Changjiang and Yellow River-derived sediments. In the middle period (5–3 ka), the study area was situated in neritic environments near the Changjiang Estuary and experienced a sedimentary hiatus due to the absence of contributions from both rivers under cold and arid climatic conditions. High accumulation rates observed locally during the earlier periods may have been influenced by marine hydrodynamic reworking and redeposition processes. In the recent period (3–0 ka), the study area transitioned to prodelta environments, with spatially and temporally varying contributions from the two rivers due to coastal changes resulting from rapid delta progradation. The sedimentary evolution of the subaqueous Changjiang Delta was primarily controlled by climate fluctuations, which may encompass specific factors such as delta progradation, Yellow River channel shifts, and coastal current processes.</p></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112501"},"PeriodicalIF":2.6,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142239110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Bajocian event of global coral reef growth: Record from northern Switzerland","authors":"Arnaud Ruchat ,&nbsp;Bernard Lathuilière ,&nbsp;Stephan Wohlwend ,&nbsp;Gaudenz Deplazes ,&nbsp;Gregor P. Eberli ,&nbsp;Susanne Feist-Burkhardt ,&nbsp;Elias Samankassou","doi":"10.1016/j.palaeo.2024.112504","DOIUrl":"10.1016/j.palaeo.2024.112504","url":null,"abstract":"<div><div>Following the extinction event at the Triassic – Jurassic boundary and during the Pliensbachian – Toarcian events, coral reef builders were severely affected, and the number of reef domains during the early Middle Jurassic was at an all-time low. However, new and updated data seem to show that corals were more widespread than previously thought, particularly during the Bajocian (170–168 Ma), but biostratigraphic markers are lacking to constrain the precise timing of reef evolution of this interval. A recently discovered 40 m-thick carbonate unit in northern Switzerland, on the northern Tethys margin, documents this rapid growth. Two cores from this unit display a reef with a high number of specimen but a low coral diversity, dated as Bajocian, which likely grew at a considerable water depth (upper limit of the mesophotic zone or 20–30 m). Additionally, it developed on top of clay mineral-rich accumulation characterised by low relief. Twelve different coral genera were identified, with a strong predominance of <em>Periseris, Isastrea, Thamnasteria</em> and <em>Dendraraea</em>. In the absence of other biostratigraphic markers, palynomorphs were used to provide accurate dating, which shows that palynology is a powerful tool for dating reef deposits. The results show reef growth during the early Bajocian, in the Sauzei and Humphriesianum ammonite zones, based on the palynological data, yielding similar ages to other Bajocian reef localities in the Eastern Paris Basin in France and Luxembourg dated simultaneously. These results indicate that the Middle Jurassic and more specifically the last two ammonite zones of the early Bajocian were periods suitable for coral reef builders, and that global regrowth of coral reefs occurred more rapidly than expected. A new Bajocian reef distribution is presented, showing no reefs at latitudes below 15°. This distribution pattern is probably due to the fact that water temperature was too elevated (&gt; 25 °C) towards the equator for corals, which prevented reef growth. This would tend to favour a scenario in which the global climate, in particular temperature, is a determining factor for coral reef growth.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112504"},"PeriodicalIF":2.6,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0031018224004930/pdfft?md5=ed9392fad730a489eeb5eae05d418b38&pid=1-s2.0-S0031018224004930-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Carbonate δ13C chemostratigraphy of the Hunjiang Group in North China and a tentative stratigraphic framework for the Meso-Neoproterozoic transition","authors":"Junyao Kang ,&nbsp;Qing Tang ,&nbsp;Benjamin C. Gill ,&nbsp;Rachel Reid ,&nbsp;Wentao Zheng ,&nbsp;Shuhai Xiao","doi":"10.1016/j.palaeo.2024.112505","DOIUrl":"10.1016/j.palaeo.2024.112505","url":null,"abstract":"<div><div>A robust stratigraphic framework for the Meso-Neoproterozoic transition is necessary for a better understanding of evolutionary and environmental changes during this critical geological time interval. Given the limited availability of radiometric and biostratigraphic data from late Mesoproterozoic to early Neoproterozoic strata, chemostratigraphic correlations have been used to build this framework. To contribute to Proterozoic chemostratigraphy, here we report new carbonate carbon isotope data from the Hunjiang Group in the Baishan area of Jilin Province in North China. The carbon isotope data (average 3.00 ‰ ± 1.15 ‰, 1 SD), together with existing detrital zircon constraints and microfossils, confirm a late Mesoproterozoic to early Neoproterozoic age of the Hunjiang Group. Using the dynamic time warping algorithm, we then constructed a global chemostratigraphic framework for the Meso-Neoproterozoic transition based on δ¹³C_carb data from the North China, São Francisco, and Congo cratons. This exercise confirms the generally narrow range of δ¹³C_carb fluctuations in the late Mesoproterozoic but also substantiates a negative δ¹³C_carb excursion of notable magnitude (∼9 ‰) and of potential global extent at ca. 1 Ga. This negative excursion, known as the Majiatun excursion, likely marks the Meso-Neoproterozoic transition and the onset of the dynamic carbon cycle in the Neoproterozoic Era.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112505"},"PeriodicalIF":2.6,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The evolution and relationship of the Yellow Sea warm current and the Yellow Sea Cold Water Mass since the Mid-Holocene and possible ENSO influences","authors":"Zhong Pi ,&nbsp;Fengming Chang ,&nbsp;Qingyun Nan ,&nbsp;Yikun Cui ,&nbsp;Qinghe Liu ,&nbsp;Jingjing Zhang ,&nbsp;Hongliang Li ,&nbsp;Jianfang Chen ,&nbsp;Tiegang Li","doi":"10.1016/j.palaeo.2024.112494","DOIUrl":"10.1016/j.palaeo.2024.112494","url":null,"abstract":"<div><p>The Yellow Sea Warm Current (YSWC) and Yellow Sea Cold Water Mass (YSCWM) are crucial components of Yellow Sea oceanic dynamics. Investigating their historical relationships since the mid-Holocene, as demonstrated by modern observations, is highly important. We reconstructed their evolution using 37 surface sediment samples and core Z1 from the Yellow Sea. Basic end-member analysis of core sediment grain sizes revealed that end-member two had a dominant peak at 12 μm, indicating the evolution of the YSWC. The analysis of the structure of benthic foraminiferal communities in surface sediments indicated that the combination of <em>Ammonia ketienziensis</em>, <em>Hanzawaia nipponica</em>, and <em>Astrononion italicum</em> serves as a reliable indicator of the evolution of the YSCWM. By integrating sedimentological and micro-palaeontological evidence with published organic geochemical findings, we elucidated high-resolution evolutionary records of the YSWC and YSCWM since the mid-Holocene. Our findings indicate that the YSWC underwent rapid intensification with significant fluctuations during ∼6.0–3.9 ka. It then decreased to modern levels between ∼3.9 ka and ∼1.9 ka, remaining relatively stable during ∼1.9–0.0 ka, with enhancements noted at ∼1.4 ka and ∼0.3 ka. The YSCWM evolved synchronously with the YSWC after ∼6.0 ka, weakened and then strengthened during ∼6.0–1.9 ka, and maintained relative stability during ∼1.9–0.0 ka, with decreases observed at ∼1.4 ka and ∼0.3 ka. The YSWC and YSCWM exhibited opposite changes, similar to modern oceanographic patterns, except for synchronous variations during ∼4.0–3.9 ka, when the YSCWM was formally established. The decoupling of the YSCWM and the YSWC during ∼4.0–3.9 ka and the significant enhancements of the YSCWM at ∼2.5 ka and ∼2.0 ka when the YSWC slightly weakened are associated with the substantial influence of the ENSO climate phenomena on the coastal regions of East Asia from ∼4.0 ka to ∼1.9 ka. We propose that the YSCWM is more sensitive to ENSO, potentially making it more suitable for reconstructing the palaeoceanography and palaeoclimatology of the Yellow Sea.</p></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112494"},"PeriodicalIF":2.6,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quaternary provenance changes in the loess deposits of the western Chinese Loess Plateau: Insights from U-Pb age spectra of detrital zircon","authors":"Yanning Niu ,&nbsp;Lin Qi ,&nbsp;Yansong Qiao","doi":"10.1016/j.palaeo.2024.112498","DOIUrl":"10.1016/j.palaeo.2024.112498","url":null,"abstract":"<div><p>The western region of the Chinese Loess Plateau (CLP) on the western side of the Liupan Mountains connects the Tibetan Plateau with the deserts of the northern arid zones. This region is key for understanding of the coupled relationship between tectonic uplift and surface processes (erosion and climate) on the Tibetan Plateau; however, the variation of Quaternary wind-dust sources in the region remains uncertain, confounding analysis. In this paper, we conduct a source tracing investigation using detrital zircon U-Pb dating of 12 loess layers from the Huining aeolian sedimentary sequence of the western CLP, reconstruct the history of provenance changes during the Quaternary Period, and further explore driving mechanisms. Results show that aeolian dust from the western CLP is mainly from the northeastern margin of the Tibetan Plateau (NTP). At 1.8–1.66 Ma, the main source region was the NTP, which corresponds to the Episode C uplift event of the Tibetan Plateau. The dominant source area transitioned to the Gobi Altay Mountains (GAMs) around 1.5–1.4 Ma. This shift suggests that the tectonic uplift of the Tibetan Plateau had entered a period of stasis following the conclusion of Episode C, leading to increased transport of detrital material from the GAMs by the East Asian Winter Monsoon. After 1.24 Ma, the dominant source region abruptly changed from the GAMs to the NTP and lasted until 0.04 Ma. The topographic fluctuations caused by the Kunhuang Movement appears to have been the main reason for the sudden source change. Based on our results and evidence from previous studies, the source changes that occurred during the Quaternary Period were in response to a combination of tectonic events and climate change. Comparison of zircon age spectra between the eastern and western CLP further support the idea that the Plateau Winter Monsoon was the main transport system for aeolian dust in the western CLP.</p></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112498"},"PeriodicalIF":2.6,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142168542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Global correlation of the Guadalupian–Lopingian transition and associated events using a quantitative conodont-based biostratigraphic scheme","authors":"Shu-han Zhang ,&nbsp;Dong-xun Yuan ,&nbsp;Shu-zhong Shen","doi":"10.1016/j.palaeo.2024.112502","DOIUrl":"10.1016/j.palaeo.2024.112502","url":null,"abstract":"<div><p>The Guadalupian–Lopingian boundary (GLB) interval contains global-scale changes in biota and environment. The establishment of a uniform time scale and a robust system of global correlation are critical in order to unravel the tempo of these events. Conodonts are key biostratigraphic tools; however, major discrepancies exist in conodont taxonomy and correlation in this interval. In this paper, we compile conodont data from 17 well-studied sections in South China, Japan, Oman and North America, comprising 206 occurrences and 100 species, based on previous publications and our own revisions, to test the reproducibility and correlation value of formerly established interval zones. The Unitary Association method (UAM), a quantitative stratigraphic method for the construction of biozones, is applied to construct a robust conodont biozonation for the GLB. Eleven unitary associations (UAs) and eight unitary association zones (UAZs) are recognized to establish biozones and the GLB was constrained within the UAZ5. According to the reproducibility of these UAZs, the correlation of the Lopingian is generally better than the Guadalupian. Apparent contradictions revealed by the UAZs suggest that biostratigraphic and/or taxonomic issues are present within the <em>Clarkina liangshanensis</em>, <em>C. leveni</em>, <em>C. transcaucasica</em> interval zones. The interval between UAZ4 and UAZ5 records the conodont turnover event from <em>Jinogondolella</em> to <em>Clarkina</em> in the paleoequatorial region. Our results suggest that the UAZs are more reliable for correlation. By contrast, some taxonomic and phylogenetic issues are present in the interval zones based on the conodont succession around the GLB. Although at a coarser stratigraphic resolution, removing all the contradictions enables UAZs to better correlate global sections compared with interval zones. The newly established UAZs indicate that the previously reported isotope excursions around the GLB in different regions may be temporally inconsistent.</p></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112502"},"PeriodicalIF":2.6,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatiotemporal evolution of the early Permian multi-source-to-sink system in the northwestern margin of the North China Block: Implications for the paleogeographic reconstruction along the southern margin of the Paleo-Asian Ocean","authors":"Zhiwei Wang ,&nbsp;Lei Liu ,&nbsp;Jianling Hu ,&nbsp;Dan Li ,&nbsp;Hongde Chen ,&nbsp;Shuyue Zhu ,&nbsp;Chenggong Zhang ,&nbsp;Junxing Zhao","doi":"10.1016/j.palaeo.2024.112500","DOIUrl":"10.1016/j.palaeo.2024.112500","url":null,"abstract":"<div><p>The northwestern margin of the North China Block, situated at the intersection of multiple tectonic units, presents a complex geological setting that challenges paleogeographic reconstructions. The subduction and closure of the Paleo-Asian Ocean have further complicated the understanding of sediment provenance during the Early Permian. In this study, we integrated sedimentological, geochemical, and U<img>Pb dating methods to delineate the Early Permian source-to-sink systems along the northwestern margin of the North China Block. The identification of four key source-to-sink systems—the Alxa, Langshan, Serteng–Wula, and Jining–Daqing—reveals a pronounced east–west provenance differentiation, indicative of the regional tectonic and sedimentary responses to subduction of the Paleo-Asian Ocean.</p><p>During the Shanxi Formation deposition, the western regions were dominated by the Inner Mongolian continental island arc as a principal sediment source, fostering distal meandering river deltas. Conversely, the eastern regions were predominantly influenced by the North China Block basement, leading to the deposition of proximal, shallow meandering river deltas. As the Shihezi Formation deposition ensued, the western source-to-sink systems continued to receive sediments from the uplifted Inner Mongolian Arc, transitioning to distal braided river deltas amidst an orogenic setting. Meanwhile, the eastern systems, particularly Jining–Daqing, showed increased contributions from the North China Block basement, forming mixed-source, shallow braided river deltas.</p><p>This research provides a refined understanding of the spatiotemporal evolution of source-to-sink systems and their responses to the tectonic setting, offering valuable insights into the paleogeographic evolution along the southern margin of the Paleo-Asian Ocean.</p></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112500"},"PeriodicalIF":2.6,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142239111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Middle Ordovician paleoenvironmental evolution of the western Laurentian carbonate platform: Evidence for persistent oxygenation of the shallow ocean and implications for biodiversification","authors":"Charles W. Diamond ,&nbsp;Matthew R. Saltzman ,&nbsp;Timothy W. Lyons ,&nbsp;Cole T. Edwards","doi":"10.1016/j.palaeo.2024.112499","DOIUrl":"10.1016/j.palaeo.2024.112499","url":null,"abstract":"<div><p>The Great Ordovician Biodiversification Event (GOBE) encompasses a series of rapid and sustained diversification pulses unparalleled in Earth history. Despite the uniqueness and magnitude of the GOBE, a singular driving force for this critical interval has not been identified. Multiple hypotheses have been presented, some pairing the GOBE as cause and effect with extrinsic factors such as changing global temperatures, ocean chemistry, or paleogeography, while others have pointed to factors intrinsic to biology itself, such as the proliferation of skeletonization, predator-prey escalation, or the development of complex tiered seafloor communities. Sufficient data are not available at present to ascertain what combination of these factors was the key to generating the GOBE.</p><p>Here, we present new paired carbon and sulfur isotope data (δ¹³C_carb, δ¹³C_org, and δ³⁴S_CAS), along with iodine concentration data from a Darriwilian carbonate sequence exposed at Meiklejohn Peak in southwestern Nevada, USA. Within a detailed lithologic and biostratigraphic framework, these new data provide a robust correlation to chemostratigraphic zonation established in Baltica and eastern Laurentia along with insights into the evolution of Middle Ordovician biogeochemical cycling. Carbon isotope data indicate a slight (2 ‰) increase in the fractionation between carbonate carbon and organic matter (Δ¹³C) during the onset of the middle Darriwilian carbon isotope excursion (MDICE), and new carbonate-associated sulfate (CAS) sulfur isotope data are consistent with a decrease in global pyrite burial during this time. Both of these observations support previous work arguing for a synchronous increase in the [O₂] of the global oceans. New iodine concentration data from Meiklejohn Peak also suggest a progressive and sustained increase in the [O₂] of regional waters throughout the Darriwilian during a period of relative sea-level highstand. This expansion of stable and well‑oxygenated ecospace could have laid the foundation for rapid diversification during one of the largest pulses of the GOBE.</p></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112499"},"PeriodicalIF":2.6,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142171771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}