Palaeogeography, Palaeoclimatology, Palaeoecology最新文献

{"title":"Dental microwear and diet of the latest Miocene ape in southern China (Lufengpithecus lufengensis)","authors":"Yaobin Fan ,&nbsp;Christopher J. Bae ,&nbsp;Jianrong Liu ,&nbsp;Jiahui Ding ,&nbsp;Wei Liao ,&nbsp;Wei Wang ,&nbsp;Peter S. Ungar","doi":"10.1016/j.palaeo.2025.112869","DOIUrl":"10.1016/j.palaeo.2025.112869","url":null,"abstract":"<div><div><em>Lufengpithecus lufengensis</em> is the latest known Miocene ape in southern China, surviving into an interval of increasingly variable and seasonal conditions approaching the end of the epoch. Inferences of its dietary strategies may help us better understand its flexibility in light of these changing conditions. Previous studies, based solely on dental morphology, suggested that L. <em>lufengensis</em> likely consumed at least some tough foods, but actual evidence of food choice by the species has been lacking. Here, we report on a dental microwear texture analysis of L. <em>lufengensis</em> molars (<em>n</em> = 10) from the Shihuiba site in Yunnan Province, southwest China, dated to 6.9–6.2 Ma. Microwear texture complexity and anisotropy data were generated by white-light confocal profilometry and scale-sensitive fractal analysis and then compared with values for an extant baseline series of primate species with documented differences in diet. Our results indicate that L. <em>lufengensis</em> had a diet similar in central tendencies to tough food feeders, such as <em>Presbytis rubicunda,</em> but significantly different from hard-object feeders, such as <em>Cercocebus atys</em>. Further, <em>L. lufengensis</em> had dispersion of texture complexity values similar to those of extant folivores, but less than those of other primates. This, combined with inferred forested environments and arboreality, is consistent with a varied diet, including folivory, for L. <em>lufengensis.</em> This is consistent with previous assertions that thick enamel in this species was a functional adaptation for tough food rather than hard food consumption. A diet including leaves is seemingly consistent with the flexibility needed for L. <em>lufengensis</em> to respond to increasing seasonal food stress during the Late Miocene in southern China.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112869"},"PeriodicalIF":2.6,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620019","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":"High-resolution records of the mid-Homerian (Silurian) marine chemistry evolution and graptolite biodiversity across the Lundgreni Event reveal what nearly killed the graptolites","authors":"Jiří Frýda ,&nbsp;Barbora Frýdová","doi":"10.1016/j.palaeo.2025.112866","DOIUrl":"10.1016/j.palaeo.2025.112866","url":null,"abstract":"<div><div>The Silurian Period was characterized by repeated extinctions, carbon cycle fluctuations, and significant climatic shifts. Among the most notable events was the Homerian double-peaked carbon isotope excursion associated with the Mulde and Lundgreni extinctions, both linked to a period of global cooling. The Lundgreni Event was marked by a significant decline in graptolite diversity, while the Mulde Event was characterized by a reduction in conodont diversity. In this study, we present new data that characterize marine palaeoredox conditions in the Prague Basin, peri-Gondwanan terrane, based on high-resolution sampling of a section representing an offshore setting. Our data are derived from the Kosov section, which is known for the most detailed quantitative biostratigraphical record currently available from peri-Gondwana. High-resolution geochemical sampling of graptolite shales from the <em>Cyrtograptus lundgreni</em> Biozone to the <em>Colonograptus ludensis–gerhardi</em> Biozone, provides clear evidence of abrupt changes in marine palaeoredox conditions. The redox-sensitive trace metal data demonstrate that the stratigraphical interval corresponding to the upper <em>Cyrtograptus lundgreni</em> Biozone to the end of <em>Colonograptus praedeubeli-deubeli</em> Biozone represents a period of substantial oxygenation in offshore settings. A comparison of high-resolution chemostratigraphical and biostratigraphical records reveals that this increased oxygenation of offshore environments, which significantly reduced the habitable areas for graptolites, played a key role in the decline of graptolite biodiversity during the Lundgreni Event. This oxygenation correlates with a global sea-level drop, likely triggered by glaciation, and also with the Homerian double-peaked δ¹³C anomaly. In conclusion, the analysis of new high-resolution chemostratigraphical records across the Homerian Lundgreni Event, combined with a high-resolution quantitative graptolite biostratigraphical record from the same section, provides insights into the potential causes of this global marine ecosystem crisis and fills an important gap in our current global dataset for this interval of the Silurian.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"668 ","pages":"Article 112866"},"PeriodicalIF":2.6,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143685360","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":"Uppermost Permian to Lower Triassic conodont biostratigraphy and carbon isotope records from Southern Armenia","authors":"Chen Han ,&nbsp;Shunling Wu ,&nbsp;He Zhao ,&nbsp;Zhengyi Lyu ,&nbsp;Qiuyi Mei ,&nbsp;Laishi Zhao","doi":"10.1016/j.palaeo.2025.112870","DOIUrl":"10.1016/j.palaeo.2025.112870","url":null,"abstract":"<div><div>The Southern Armenia region is critical for studying biostratigraphy, chemostratigraphy, sedimentology, and environmental events during the Permian-Triassic transition. However, conodont data of previous studies are either outdated or lacking a detailed examination in terms of their classification and stratigraphic distribution, precluding a precise correlation of the strata and events with other Tethyan localities. This study presents an updated conodont taxonomy and biostratigraphy for the uppermost Permian to Lower Triassic from three sections in Southern Armenia. Eleven conodont zones are recognized in ascending order: the <em>Clarkina bachmanni</em>, <em>C. nodosa</em>, <em>C. yini</em>, <em>C. hauschkei</em>, <em>Hindeodus praeparvus</em>, <em>H. parvus</em>, <em>Isarcicella staeschei</em>, <em>Is. isarcica</em>, <em>H. postparvus</em>, <em>H. sosioensis</em>, and <em>Neospathodus dieneri</em> zones. These conodont zones, integrated with high-resolution carbonate carbon isotopic records, facilitate robust correlations between the Armenian sections and other well-studied Tethyan sections, particularly those in Iran and South China. The Permian-Triassic boundary is tentatively placed just above the basal microbialite unit of the Karabaglyar Formation, marked by the first occurrence of <em>Hindeodus parvus</em> and significant carbon isotope excursions. However, further studies are needed due to the limited preservation of conodonts within these microbialites. In the absence of index conodonts, the Induan-Olenekian boundary is inferred to lie just above a maximum regressive surface, marked by a distinct lithological change, and immediately below the P2 peak of the carbon isotope excursion in the Early Triassic.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112870"},"PeriodicalIF":2.6,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143593796","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":"Burial records of terrestrial organic carbon controlled by sea-level and monsoon variability in the Gulf of Thailand since the last deglaciation","authors":"Yazhi Bai ,&nbsp;Limin Hu ,&nbsp;Lina Jin ,&nbsp;Shuqing Qiao ,&nbsp;Yangshuo Zhang ,&nbsp;Bin Wu ,&nbsp;Dejiang Fan ,&nbsp;Shengfa Liu ,&nbsp;Gang Yang ,&nbsp;Jihua Liu ,&nbsp;Narumol Kornkanitnan ,&nbsp;Somkiat Khokiattiwong ,&nbsp;Xuefa Shi","doi":"10.1016/j.palaeo.2025.112863","DOIUrl":"10.1016/j.palaeo.2025.112863","url":null,"abstract":"<div><div>The sequestration of terrestrial organic carbon (OC_terr) exported from adjacent continent into marginal sea plays a critical role in the global carbon cycle over geological timescale. However, the processes controlling OC_terr burial in tropical coastal margins, particularly in response to sea-level and climatic changes, remain poorly understood. This study investigates millennial-scale OC_terr burial since the last deglaciation (∼14,640 years before present) in the Gulf of Thailand on the Sunda Shelf, Southeast Asia. By analyzing AMS¹⁴C, bulk organic carbon indicators (TOC/TN ratios, <em>δ</em>¹³C), and lipid biomarkers (e.g., <em>n</em>-alkanes), our results show that OC_terr dominated during last deglaciation (with meltwater pulses), coinciding with high OC_terr accumulation rates and a prevalence of herbaceous plants. Following the transgression phase, OC_terr sharply decreased to ∼20 % as sea level rose. The burial of OC_terr was modulated by high sedimentation rates, driven by rainfall associated with the East Asia Summer Monsoon, Indian Summer Monsoon, and Western Pacific warm Pool during the high sea-level stage. The evolution and burial of OC_terr in the northern Sunda Shelf since the last deglaciation have been primarily regulated by relative sea-level changes and monsoon variability. This study highlights the significance of sedimentary regime shift induced by sea-level fluctuation and monsoon dynamics in shaping OC_terr burial. It provides essential insights into the source-sink processes and paleo-environmental implications of millennial-scale sedimentary OC in tropical continental margins.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112863"},"PeriodicalIF":2.6,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579026","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 3700-year paleoenvironmental record from Jobos Bay, Puerto Rico: Applying multiple proxies to reconstruct late Holocene extreme events","authors":"Ethan J. Tiong ,&nbsp;Nicholas Culligan ,&nbsp;Kam-biu Liu ,&nbsp;Michael Martínez-Colón ,&nbsp;Thomas A. Bianchette","doi":"10.1016/j.palaeo.2025.112872","DOIUrl":"10.1016/j.palaeo.2025.112872","url":null,"abstract":"<div><div>Puerto Rico is prone to hurricanes capable of billions of dollars in property and infrastructure damage from heavy rainfall and severe storm surge flooding. Regional historical records are sparse, limiting an understanding of past hurricane trends to enact sensible risk assessment. Sedimentological reconstructions can determine hurricane activity on centennial to millennial timescales and help establish climatological mechanisms responsible for hyperactivity periods. Multi-proxy analysis was conducted on a 209 cm core (JOB 4) extracted from Jobos Bay National Estuarine Research Reserve (JBNERR) in Southern Puerto Rico, revealing a ∼ 3700-year record. Accordingly, a marine environment existed at the site from 3700 to 3230 cal yr BP. Mangroves dominated at 3230 cal yr BP, when the site transitioned to a backbarrier swamp. Six clastic deposits of varying thickness consisting of elevated carbonate content, low organic content, and large grain size are embedded in core JOB 4. A 35 cm thick deposit (∼3230 cal yr BP) with abundant shells, shell hash, and elevated marine element concentrations (Cl, Ca, Sr, Cl/Br values) is suggestive of significant tsunami run up. The other five sand deposits (2300, 1950, 1420, 1240 cal yr BP, and ∼ 2013 CE) contain elevated marine element concentrations (Cl, Ca, Sr, Cl/Br values) with low concentrations of terrestrial (Br, Ti, Fe, Fe/Sr) elements, indicative of hurricane-induced storm surge deposits, with minimal precipitation-induced terrestrial input. The hyperactive period of ∼2300–1200 cal yr BP at JBNERR is temporally similar to several regional paleohurricane records, occurring during a period of few El Niño events. Additionally, the JBNERR record contains evidence of infrequent hurricane activity during periods of both active and inactive ENSO. This paleohurricane record suggests that ENSO behavior might not be the most significant climatological determinant controlling the risk of hurricane landfalls for Puerto Rico.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112872"},"PeriodicalIF":2.6,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143611589","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 12,000-year dinoflagellate cyst record on the Vancouver Island margin, Canada: tracing past climatic, primary productivity and oceanographic conditions","authors":"Zhen Li ,&nbsp;Vera Pospelova ,&nbsp;Kenneth Neil Mertens ,&nbsp;Alice S. Chang ,&nbsp;Yongsheng Wu","doi":"10.1016/j.palaeo.2025.112876","DOIUrl":"10.1016/j.palaeo.2025.112876","url":null,"abstract":"<div><div>This is the first study to investigate dinoflagellate cyst records spanning the latest Pleistocene to the late Holocene on the Vancouver Island margin. We identified 14 autotrophic and 26 heterotrophic taxa, and defined four dinoflagellate cyst zones that were related to paleoclimatic and paleoceanographic conditions. Zone I (∼14–∼11.6 cal kyr BP) showed the lowest primary productivity (PP), indicated by the lowest total cyst concentrations and fluxes, with <em>Brigantedinium</em> spp. dominant in assemblages. This was likely due to cooler conditions associated with glacial meltwater input and weak coastal upwelling. Zone II (∼11.6–∼10.6 cal kyr BP) showed a slight increase in concentrations and fluxes of total cysts, a rapid increase in <em>Operculodinium centrocarpum</em> sensu Wall and Dale 1966 and the highest <em>Nematosphaeropsis labyrinthus</em> abundances. This zone was likely linked to reduced meltwater input and increased coastal upwelling, promoting primary productivity. Zone III (∼10.6–∼8.2 cal kyr BP) showed a rapid increase in PP, as demonstrated by maximum concentrations and fluxes of total cysts and autotrophic taxa abundances. This interval was interpreted as reflecting the strengthened California Undercurrent and increased upwelling, coinciding with the highest insolation intensity. High <em>Impagidinium</em> abundances during this time indicated more open ocean conditions. A sharp increase in <em>Operculodinium centrocarpum</em>–short processes during ∼9–8.2 cal kyr BP may be related to the 8.2 ka event and decelerated sea-level rise. Zone IV (∼8.2–∼2.3 cal kyr BP) suggested gentle fluctuations in PP, with overall declines of total cyst concentrations and fluxes, reaching the lowest at ∼8.0 cal kyr BP, followed by a slight increase at ∼6.5 cal kyr BP, and subsequent stabilization.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112876"},"PeriodicalIF":2.6,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143611590","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":"Drought reconstructions over the past 552 years based on minimum earlywood density in central Tianshan Mountains","authors":"Yifan Ma ,&nbsp;Huiming Song ,&nbsp;Yu Liu ,&nbsp;Quan Zhang ,&nbsp;Meng Ren ,&nbsp;Qiufang Cai ,&nbsp;Tongwen Zhang ,&nbsp;Kambiz Pourtahmasi ,&nbsp;Xiangyu Duan ,&nbsp;Pei Li","doi":"10.1016/j.palaeo.2025.112853","DOIUrl":"10.1016/j.palaeo.2025.112853","url":null,"abstract":"<div><div>Tree-ring minimum earlywood density (MND) is a parameter that has been relatively understudied in paleoclimate reconstructions, with only a limited number of studies conducted in drought-prone regions. In this study, various tree-ring density parameters were generated based on <em>Picea Schrenkiana</em> in the arid central Tianshan Mountains. We found that the MND chronology exhibited robust signals of drought, while maximum latewood density (MXD) showed significant responsiveness to drought variability rather than strong temperature signals typically observed in high latitude or high altitude regions. These distinct climate response patterns of tree-ring density data can be attributed to the prevailing arid climate at our study site. Based on these results, we reconstructed the drought history from 1464 to 2015 and identified a wetting trend from the 1920s until the present times. By integrating various hydroclimate reconstructions, we observed a wetting trend in both the western and central Tianshan Mountains but a drying trend in the eastern Tianshan Mountains. This study highlights the potential of tree-ring density as a tool for global climate reconstruction.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112853"},"PeriodicalIF":2.6,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143593797","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":"MIS 3 climate transitions revealed by high-resolution loess records from the eastern margin of the Tibetan Plateau","authors":"Xiaotong Wei ,&nbsp;Hanchao Jiang ,&nbsp;Youliang Bai ,&nbsp;Wei Shi ,&nbsp;Hongyan Xu ,&nbsp;Xiaolin Ma ,&nbsp;Ning Zhong ,&nbsp;Shenglin Li ,&nbsp;Qiuzhen Yin","doi":"10.1016/j.palaeo.2025.112874","DOIUrl":"10.1016/j.palaeo.2025.112874","url":null,"abstract":"<div><div>Humans evolved rapidly and significantly between 60 and 20 ka, placing unprecedented demands on detailed climate evolution during the marine isotope stage (MIS) 3 period. In this study, a high-resolution loess record from the eastern margin of the Tibetan Plateau revealed that the climate was optimal in 62–43.5 ka, relatively stable in 43.5–34 ka, and continuously cooled in 34–20 ka. Such a three-stage pattern can be well correlated with changes in the temperature and CO₂ content in Antarctica, climate evolution in Europe, and advances in the Laurentide Ice Sheet. The climate transition at 43.5 ka was closely related to the declining boreal summer insolation, CO₂ content, temperature, and sea level, whereas the climate transition at 34 ka corresponded to a decrease in the CO₂ concentration and development of polar ice sheets. These results are of great scientific significance because they provide insights into MIS 3 climate transitions and human migration.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112874"},"PeriodicalIF":2.6,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551487","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":"Multi-structural limestone-marl alternations from the Permian of northwestern Yangtze Craton: Petrogenesis and environmental-tectonic implications","authors":"Ying Xiong ,&nbsp;Kaibo Shi ,&nbsp;Bo Liu ,&nbsp;Tong Wang ,&nbsp;Sicong Luo ,&nbsp;Baobao Wang ,&nbsp;Xiucheng Tan ,&nbsp;Di Xiao","doi":"10.1016/j.palaeo.2025.112871","DOIUrl":"10.1016/j.palaeo.2025.112871","url":null,"abstract":"<div><div>Limestone-marl alternations (LMAs), a significant type of cyclothem, contain valuable information on paleoclimate and cyclostratigraphy. However, great controversies remain regarding the genesis of LMAs and their validity as environmental or tectonic archives. This study provides a typical example of LMAs from the Permian of northwestern Yangtze Craton, demonstrating a dynamic formation process closely related to environmental and tectonic changes. Integrated petrological, mineralogical, and geochemical data reveal that the LMAs exhibit multiple structures—bedded, nodular, and chaotic—reflecting the combined influence of depositional, diagenetic, and tectonic processes. During the depositional stage, high-frequency fluctuations in climate, terrigenous input, redox conditions and oceanic productivity led to the initial deposition of rhythmic limestone-marl beds. Concurrently, synsedimentary fault-associated slump deposits contributed to the transition from original bedded structure to disordered structures. Subsequently, differential diagenesis, mainly involving burial compaction and dissolution-cementation, further reinforced the mineralogical and structural differences between limestone and marl, ultimately resulting in the formation of multi-type LMAs. The results indicate that LMAs, especially those with well-bedded structure and good lateral continuity, can serve as effective environmental archive. They reflect subtle and frequent environmental variations in the northwestern Yangtze Craton during the icehouse-greenhouse transition period following the late Paleozoic ice age. The widespread chaotic limestone-marl structure, derived from synsedimentary fault-associated slump deposits in the lower Maokou Formation can be interpreted as associated with the pre-eruption uplift of the Emeishan mantle plume. This suggests that the Emeishan mantle plume activity predates the end of the Maokou stage as previously thought.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112871"},"PeriodicalIF":2.6,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551585","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":"Integrating sequence and carbon isotope stratigraphy in the lower Cambrian (Stage 3), Tarim Basin: Implications for stratigraphic correlation and environmental-biotic evolution","authors":"Bo Yang ,&nbsp;Daizhao Chen ,&nbsp;Mu Liu","doi":"10.1016/j.palaeo.2025.112881","DOIUrl":"10.1016/j.palaeo.2025.112881","url":null,"abstract":"<div><div>Carbon isotope stratigraphy is a strong tool for stratigraphic correlation and for understanding carbon cycling and biotic-environmental interactions. During the Cambrian Age 3 (ca. 521–514 Ma), metazoan (e.g, archaeocyathid, trilobite) diversification and subsequent first extinction (e.g., archaeocyaths) are marked with distinctive global carbon isotope excursions. However, correlating the carbon isotope records from the Xiaoerbulak (XBL) Formation (Stage 3) in the Tarim Basin with those from other regions has been challenged, hindering establishment of a reliable stratigraphic framework. To solve this dilemma, a sequence stratigraphic framework made of four and a half sequences was established for this formation, further revealing a long-term depositional hiatus in the platform interior. In this light, two continuous sections of deeper slope-basinal settings at Sugaitebulak (SG) and Kungaikuotan (KG) were selected for high-resolution δ¹³C_carb analysis. Three prominent negative (N1−N3) with two unnamed subordinate ones and two positive (P1, P2) excursions with an additional minor positive one were identified. Of these, N1 and N3 mark the base and top of XBL Formation, respectively. Combined with biostratigraphic constraints, the P1, P2, and N3 excursions correlate with the global Cambrian carbon isotope events CARE, MICE, and AECE, respectively. Notably, N2 and P2 perturbations were absent in the platform interior, confirming occurrence of the sedimentological hiatus. Coupled sequence and carbon isotope stratigraphic analysis reveals that the negative excursions are present in transgressive systems tracts, while the positive excursions in the highstand systems tracts dominated by metazoan-microbial buildups. This suggests that transgression-enhanced upwelling of ¹²C-rich, oxygen-depleted deep waters onto the shallow water regimesmay have caused negative δ¹³C_carb excursions and biotic declines, subsequently, the increased primary productivity and organic burialcould have drawn down the CO₂ levels in atmosphere/seawater, leading to the positive δ¹³C_carb excursion and eclogical amelioration, as seen in the HST successions.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112881"},"PeriodicalIF":2.6,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579024","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}