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Discerning biotic from abiotic carbonate cementations in Holocene beachrock: mineralogical and geochemical fingerprints for biosignatures 全新世滩岩中生物与非生物碳酸盐胶结的识别:生物特征的矿物学和地球化学指纹图谱
IF 2.7 2区 地球科学 Q2 GEOGRAPHY, PHYSICAL Pub Date : 2026-02-15 Epub Date: 2025-12-11 DOI: 10.1016/j.palaeo.2025.113454
Xi-yang Zhang , Ming-zhuang Wang , Qi Shi , Fei Tan , Guo-tao Zhang , Si-qi Chen , Hong-qiang Yang
Beachrock cementation, mediated by physicochemical and biological processes, plays a pivotal role in the rapid lithification of coastal sediments. Distinguishing between biotic and abiotic carbonate cements is critical for quantitatively reconstructing diagenetic pathways and accurately evaluating paleoenvironmental conditions. We analyzed Holocene beachrocks from Hainan and the Xisha Islands to compare their cement types. Beachrocks from Hainan are characterized by isopachous high-Mg calcite (HMC) rinds, HMC-rich peloidal fabrics, and blocky–drusy low-Mg calcite (LMC), whereas those from the Xisha Islands are dominated by acicular aragonite. HMC rinds composed of equilong fibrous crystals represent marine phreatic cements with minimal diagenetic alteration, whereas LMC forms through meteoric vadose processes, as indicated by red cathodoluminescent rings. Acicular aragonite nucleates within organic-rich micrite envelopes, with its rapid growth governed primarily by inorganic mechanisms. Peloidal fabrics exhibit distinct fluorescence patterns, dull cathodoluminescence, and elevated Mn/Fe ratios, consistent with their interpretation as microbially mediated precipitates formed during organic matter degradation under intermittently reducing conditions. Notably, peloidal fabrics and aragonite are enriched in bioactive metals (V, Fe, Zn, Pb) relative to coral Porites, consistent with active microbial metabolism. Unlike HMC rinds and acicular aragonite, peloidal fabrics display high total rare earth element (REE) contents, uniform REE distributions, LREE depletion (low LREE/HREE), negative Ce anomalies, positive La anomalies, Y/Ho ratios (∼45), and REE partitioning patterns closely matching modern seawater. These distinctive geochemical signatures establish peloidal fabrics as high-fidelity, high-resolution archives of paleo-seawater chemistry, providing a robust tool for deciphering ancient marine environments.
滩岩胶结作用是由物理化学和生物过程介导的,在海岸沉积物的快速岩化过程中起着关键作用。区分生物和非生物碳酸盐胶结物对于定量重建成岩路径和准确评价古环境条件至关重要。我们分析了海南和西沙群岛的全新世滩岩,比较了它们的胶结类型。海南滩岩以等径高镁方解石(HMC)表层、富HMC的似球粒状组构和块状低镁方解石(LMC)为主,西沙滩岩以针状文石为主。HMC环由等长纤维晶体组成,代表海洋潜水胶结物,成岩蚀变最小,而LMC则通过大气渗透过程形成,如红色阴极发光环所示。针状文石在富有机质泥晶包壳内成核,其快速生长主要受无机机制支配。Peloidal织物表现出明显的荧光模式、暗淡的阴极发光和升高的Mn/Fe比率,这与它们的解释一致,即在间歇性还原条件下有机物降解过程中形成的微生物介导的沉淀。值得注意的是,相对于珊瑚孔隙岩,peloidal fabric和文石富含生物活性金属(V, Fe, Zn, Pb),与活跃的微生物代谢一致。与HMC和针状文石不同,peloidal织物显示出高总稀土元素(REE)含量,均匀的REE分布,LREE枯竭(低LREE/HREE),负Ce异常,正La异常,Y/Ho比(~ 45),以及与现代海水密切匹配的REE分配模式。这些独特的地球化学特征使peloidal织物成为高保真度,高分辨率的古海水化学档案,为破译古代海洋环境提供了强大的工具。
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引用次数: 0
Multi-paleoclimatic proxies implicate climate shift from arid-to-humid in the Northeastern Arabian Sea teleconnected to ENSO events 多个古气候代用指标暗示了阿拉伯海东北部气候从干旱到湿润的变化与ENSO事件遥相关
IF 2.7 2区 地球科学 Q2 GEOGRAPHY, PHYSICAL Pub Date : 2026-02-15 Epub Date: 2025-12-11 DOI: 10.1016/j.palaeo.2025.113463
Sruthy Rose Baby , Mohan Kuppusamy , Busnur R Manjunatha , Jithin Jose , Pankaj Kumar , Saravanan Kothandaraman , Ravi Mishra
The Arabian Sea sediments have the records of significant temporal and spatial variations in response to the neotectonic changes, paleoclimatic and paleo-sea level fluctuations particularly from the Quaternary period. In this study area, environmental mineral magnetic parameters, diffuse reflectance spectroscopy (DRS), XRF (Fe/K, Ti/Al and Ca %) have been studied in an AMS radiocarbon dated core- SK240/473 from the coast off Saurashtra, south-western part of Gujarat State, north-western continental margin of India, to unravel paleoclimatic and paleoceanographic sedimentation and sea level changes over the past 15 ka BP. Currently, the rainfall of this region mainly occurs during the summer monsoon season. Based on results of multi-proxies measured in this core indicate that three major changes in the climate: phase- I before the Holocene thermal maximum (HTM), phase- II during the HTM, and phase- III after the HTM. The phase-I is mainly characterized by abundance of hematite over goethite with high carbonate content, but lower in total organic carbon (TOC) and chemical weathering index (CWI) suggesting arid climate of oxidizing environment of sediment deposition during the rapid sea level rise from 14.5 ka BP to 12.0 ka BP with a standstill sea level from 12 ka BP - 10 ka BP. In contrast, the phase-II marked by a transition from arid to humid condition of sediment deposition characterized by higher CWI, abundant TOC and goethite, but lower in hematite and carbonate concentrations reflecting humid climate of reducing environment of sediment deposition during the Holocene thermal maximum (HTM) from 10.00 ka BP to 5.50 ka BP. Interpretations made here are generally in good agreement with the deglacial to Holocene Sea level fluctuations curve proposed for the west coast of India. In Phase III, the χlf, χfd, and Chemical Index of Alteration (CIA) data from sediments deposited after the HTM largely suggest deposition in a humid environment, occasionally interrupted by arid episodes in the study region's hinterland. Such arid events linked to paleo-El Niño episodes recorded in the tropical eastern Pacific Ocean. This interpretation is further supported by the reason explained to the current rainfall variability in the hinterland of the study area. Overall, the data of the core studied reveal significant environmental, sea-level and monsoonal changes in the NE Arabian Sea since the deglacial period. The goethite/hematite (G/H) ratio, χlf and χfd profiles which is an indicator of humidity/aridity and coastal upwelling are different from the sea-level curve, suggesting that formers are better indicator of monsoon intensity that often regulated by the ENSO.
阿拉伯海沉积物对新构造变化、古气候和古海平面波动,特别是第四纪以来的变化具有显著的时空变化特征。本研究区对印度西北大陆边缘古吉拉特邦西南部Saurashtra海岸的一个AMS放射性碳定年岩心SK240/473进行了环境矿物磁性参数、漫反射光谱(DRS)和XRF (Fe/K、Ti/Al和Ca %)研究,揭示了过去15 ka BP的古气候和古海洋沉积和海平面变化。目前,该地区的降雨主要发生在夏季季风季节。基于该岩心的多指标测量结果表明,全新世热极大期前的第1阶段、热极大期中的第2阶段和热极大期后的第3阶段是气候变化的主要阶段。第一阶段主要表现为赤铁矿比针铁矿多,碳酸盐含量高,总有机碳(TOC)和化学风化指数(CWI)较低,表明海平面从14.5 ka BP快速上升到12.0 ka BP,海平面从12 ka BP到10 ka BP处于静止状态,处于干燥的氧化沉积环境。全新世热极大值(HTM)从10.00 ka BP降至5.50 ka BP,以CWI较高、TOC和针铁矿丰富、赤铁矿和碳酸盐含量较低为特征的ii期沉积条件由干旱向湿润过渡,反映了沉积环境的湿润气候。这里所做的解释通常与针对印度西海岸提出的从冰期到全新世的海平面波动曲线很好地吻合。在第三阶段,HTM之后沉积的沉积物的χf、χfd和化学蚀变指数(Chemical Index of蚀变,CIA)数据在很大程度上表明沉积在湿润环境中,偶尔会被研究区域腹地的干旱事件打断。这种干旱事件与热带东太平洋记录的古厄尔尼诺Niño事件有关。这一解释进一步得到了对研究区腹地当前降水变率的解释原因的支持。总体而言,所研究的岩心数据揭示了自冰期以来东北阿拉伯海的显著环境、海平面和季风变化。针铁矿/赤铁矿(G/H)比值、χf和χfd曲线与海平面曲线不同,表明针铁矿/赤铁矿(G/H)比、χf和χfd曲线更能反映季风强度,而季风强度通常由ENSO调节。
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引用次数: 0
Coupled tectonic-climatic-oceanographic dynamics drove the evolution of foraminiferal diversity in South China during the Middle to Late Mississippian 构造-气候-海洋耦合动力学驱动了密西西比中晚期华南有孔虫多样性的演化
IF 2.7 2区 地球科学 Q2 GEOGRAPHY, PHYSICAL Pub Date : 2026-02-15 Epub Date: 2025-12-24 DOI: 10.1016/j.palaeo.2025.113528
Chao Liu , Junjun Qi , Pedro Cózar , Ismael Coronado , Fei Li , Weiqing Liu , Meng Li , Ping Wang , Xin Li , Xia Hu , Song Jin
Understanding the interactions between biological evolution and other components of the Earth system, particularly tectonic, climatic, and environmental changes, has long been a central focus in Earth sciences. In this study, we present the first high-resolution foraminiferal species diversity curve spanning the late Visean to Serpukhovian from the Youjiang Basin of South China, integrated with multiple geochemical datasets, to elucidate the factors influencing foraminiferal diversification through robust correlations among sedimentological, biological, and geochemical records at a global scale. The widespread biodiversity crisis during the early late Visean (Aleksinian–Mikhailovian transition) is interpreted to have resulted from global oceanic bottom-water anoxia, coinciding with intensified continental silicate weathering and the onset of a major phase of Gondwanan glaciation. The uplift of the Hercynian orogenic belt, exposure of mantle-derived rocks at low latitudes, and the expansion of vascular plants during this interval are considered the primary driving mechanisms. Enhanced nutrients delivery to the oceans via terrestrial input elevated primary marine productivity and accelerated organic carbon export and burial, leading to excessive consumption of dissolved oxygen and other oxidants during organic matter degradation. Global foraminiferal radiation from the early late Visean to the earliest Serpukhovian is attributed to elevated dissolved oxygen concentrations and sufficient food availability, coupled with persistent carbonate supersaturation in contemporaneous upper ocean waters. The widespread loss of shallow shelf habitats, driven by the progression of the Hercynian orogeny and enhanced continental ice accumulation on Gondwana continent during the early to latest Serpukhovian, probably contributed to the observed foraminiferal diversity decline during this period. This study sheds new light on the interactions among various Earth systems during a period characterized by profound transformations in global paleogeography, climate, and oceanographic conditions.
了解生物进化与地球系统其他组成部分之间的相互作用,特别是构造、气候和环境变化,长期以来一直是地球科学的中心焦点。在此基础上,结合多组地球化学数据,首次建立了中国南方右江盆地晚Visean - Serpukhovian的高分辨率有孔虫物种多样性曲线,通过对全球范围内沉积学、生物学和地球化学记录的强相关性分析,阐明了影响有孔虫多样性的因素。在Visean早期晚期(Aleksinian-Mikhailovian过渡期),广泛的生物多样性危机被解释为全球海洋底水缺氧的结果,与大陆硅酸盐风化加剧和冈瓦纳冰川主要阶段的开始相吻合。海西造山带的隆升、低纬度幔源岩的暴露和维管植物的扩张被认为是主要的驱动机制。通过陆地输入向海洋输送的营养物质增加,提高了海洋初级生产力,加速了有机碳的输出和埋藏,导致有机物降解过程中溶解氧和其他氧化剂的过度消耗。从Visean晚期早期到Serpukhovian早期,全球有孔虫辐射归因于溶解氧浓度升高和充足的食物供应,以及同期上层海水中持续的碳酸盐过饱和。在Serpukhovian早期至晚期,海西期造山运动的推进和冈瓦纳大陆冰积累的增加导致了浅陆架栖息地的广泛丧失,这可能是该时期有孔虫多样性下降的原因。这项研究揭示了在全球古地理、气候和海洋条件发生深刻变化的时期,各种地球系统之间的相互作用。
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引用次数: 0
Deciphering Holocene monsoon dynamics in northeastern India using speleothem δ18O record and petrography 利用洞穴δ18O记录和岩石学解读印度东北部全新世季风动力学
IF 2.7 2区 地球科学 Q2 GEOGRAPHY, PHYSICAL Pub Date : 2026-02-15 Epub Date: 2025-12-22 DOI: 10.1016/j.palaeo.2025.113518
Yachna Verma , Anil K. Gupta , Prasanta Sanyal , Priyantan Gupta , Som Dutt , Pankaj Kumar , Abhijit Mukherjee
A high-resolution stalagmite δ18O record from Mawsmai Cave (MAW), spanning from ∼11,807 to 5622 calibrated years before present (cal yr BP), sheds light on the dynamics of the Indian Summer Monsoon (ISM). In the early Holocene (∼ 11,807–7700 cal yr BP) the decreased δ18O values suggest a period of intensified ISM, whereas in the middle Holocene (∼ 7700–5622 cal yr BP) the positive δ18O values demonstrate a weak ISM. Petrographic and mineralogical analyses suggest a correspondence between changes in stalagmite fabric and δ18O variability, implying a climatic control on stalagmite growth. The MAW record also depicts several multi-centennial scale ISM shifts that coincide with the Bond events 8, 7, 6, 5b, 5a, and 4, suggesting teleconnections between North Atlantic climate and ISM variability via changes in the Atlantic Meridional Overturning Circulation (AMOC). Spectral and continuous wavelet transform analyses of the MAW record reveal periodicities of ∼118 and ∼ 110 years, consistent with the centennial-scale Gleissberg solar cycles. These cyclicities indicate that solar variability in conjunction with coupled ocean–atmosphere dynamics, including the Pacific Decadal Oscillation (PDO) and the temperature gradient between the Tibetan Plateau and the Indian Ocean, played a dominant role in modulating ISM variability during the early to middle Holocene.
Mawsmai洞穴(MAW)的高分辨率石笋δ18O记录,跨度为距今约11,807至5622校准年(cal yr BP),揭示了印度夏季风(ISM)的动力学。在全新世早期(~ 11,807 ~ 7700 cal yr BP), δ18O值的下降表明了ISM的增强,而在全新世中期(~ 7700 ~ 5622 cal yr BP), δ18O值的上升表明ISM的减弱。岩石学和矿物学分析表明,石笋结构的变化与δ18O变率之间存在对应关系,表明气候控制了石笋的生长。MAW记录还描述了与Bond事件8、7、6、5b、5a和4相吻合的几次百年尺度ISM变化,表明北大西洋气候与ISM变率之间通过大西洋经向翻转环流(AMOC)的变化存在远相关。MAW记录的光谱和连续小波变换分析显示周期为~ 118年和~ 110年,与百年尺度的Gleissberg太阳周期一致。这些周期表明,在全新世早期至中期,太阳变率与太平洋年代际涛动(PDO)和青藏高原与印度洋之间的温度梯度等海洋-大气耦合动力学在调节ISM变率中起主导作用。
{"title":"Deciphering Holocene monsoon dynamics in northeastern India using speleothem δ18O record and petrography","authors":"Yachna Verma ,&nbsp;Anil K. Gupta ,&nbsp;Prasanta Sanyal ,&nbsp;Priyantan Gupta ,&nbsp;Som Dutt ,&nbsp;Pankaj Kumar ,&nbsp;Abhijit Mukherjee","doi":"10.1016/j.palaeo.2025.113518","DOIUrl":"10.1016/j.palaeo.2025.113518","url":null,"abstract":"<div><div>A high-resolution stalagmite δ<sup>18</sup>O record from Mawsmai Cave (MAW), spanning from ∼11,807 to 5622 calibrated years before present (cal yr BP), sheds light on the dynamics of the Indian Summer Monsoon (ISM). In the early Holocene (∼ 11,807–7700 cal yr BP) the decreased δ<sup>18</sup>O values suggest a period of intensified ISM, whereas in the middle Holocene (∼ 7700–5622 cal yr BP) the positive δ<sup>18</sup>O values demonstrate a weak ISM. Petrographic and mineralogical analyses suggest a correspondence between changes in stalagmite fabric and δ<sup>18</sup>O variability, implying a climatic control on stalagmite growth. The MAW record also depicts several multi-centennial scale ISM shifts that coincide with the Bond events 8, 7, 6, 5b, 5a, and 4, suggesting teleconnections between North Atlantic climate and ISM variability via changes in the Atlantic Meridional Overturning Circulation (AMOC). Spectral and continuous wavelet transform analyses of the MAW record reveal periodicities of ∼118 and ∼ 110 years, consistent with the centennial-scale Gleissberg solar cycles. These cyclicities indicate that solar variability in conjunction with coupled ocean–atmosphere dynamics, including the Pacific Decadal Oscillation (PDO) and the temperature gradient between the Tibetan Plateau and the Indian Ocean, played a dominant role in modulating ISM variability during the early to middle Holocene.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113518"},"PeriodicalIF":2.7,"publicationDate":"2026-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842086","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}
引用次数: 0
How volcanoes affect boreal mires: Climate-driven regional vegetation changes and stage-dependent responses to tephra fallout in Kamchatka during the Late Holocene 火山如何影响北方沼泽:晚全新世期间堪察加半岛气候驱动的区域植被变化和对火山灰沉降的阶段依赖反应
IF 2.7 2区 地球科学 Q2 GEOGRAPHY, PHYSICAL Pub Date : 2026-02-15 Epub Date: 2025-12-15 DOI: 10.1016/j.palaeo.2025.113501
Valerii E. Pimenov , Maria M. Pevzner , Natalia G. Mazei , Andrey N. Tsyganov , Ekaterina G. Ershova , Yuri A. Mazei
Studying vegetation dynamics in the regions with high volcanic activity is crucial for understanding ecosystem responses to environmental disturbances and predicting future ecological changes. However, the impacts of tephra deposition on vegetation at local and regional scales remain poorly quantified, limiting understanding of ecosystem resilience to volcanic disturbances. This study presents a high-resolution, multiproxy palaeobotanical record from the Kumroch peatland (Kamchatka, Eurasian Far East), integrating detailed tephrostratigraphy, radiocarbon ages, pollen, plant macrofossil, and loss on ignition data. The peat sequence spans the last ∼5 kyr, anchored by 28 recorded tephra layers. Birch forests (Betula ermanii) and alder shrublands (Alnus alnobetula subsp. fruticosa) dominated during the Middle and Late Holocene, with their proportions shifting in response to climate variations. These changes align in timing with the Late Holocene climate oscillations, primarily reflecting temperature fluctuations. Tephra fallout events had no persistent impact on regional vegetation and limited effects on the local vegetation. These findings demonstrate the resilience of boreal ecosystems to tephra deposition across volcanically active areas and underscore the importance of large-scale studies for understanding ashfall-related disturbances.
研究高火山活动区植被动态对于了解生态系统对环境扰动的响应和预测未来生态变化具有重要意义。然而,在局部和区域尺度上,火山沉积对植被的影响仍然缺乏量化,限制了对生态系统对火山扰动的恢复能力的理解。本文介绍了欧亚远东堪察加半岛Kumroch泥炭地的高分辨率、多代理古植物学记录,综合了详细的地层、放射性碳年龄、花粉、植物宏观化石和燃烧损失数据。泥炭层序列跨越最后~ 5 kyr,由28个记录的tephra层固定。白桦林(桦)和桤木灌丛(Alnus alnobetula subsp。在全新世中晚期占主导地位,其比例随气候变化而变化。这些变化在时间上与晚全新世气候振荡一致,主要反映温度波动。辐射尘事件对区域植被无持续性影响,对局地植被影响有限。这些发现证明了北方生态系统对火山活跃地区火山灰沉积的恢复能力,并强调了大规模研究对理解火山灰相关干扰的重要性。
{"title":"How volcanoes affect boreal mires: Climate-driven regional vegetation changes and stage-dependent responses to tephra fallout in Kamchatka during the Late Holocene","authors":"Valerii E. Pimenov ,&nbsp;Maria M. Pevzner ,&nbsp;Natalia G. Mazei ,&nbsp;Andrey N. Tsyganov ,&nbsp;Ekaterina G. Ershova ,&nbsp;Yuri A. Mazei","doi":"10.1016/j.palaeo.2025.113501","DOIUrl":"10.1016/j.palaeo.2025.113501","url":null,"abstract":"<div><div>Studying vegetation dynamics in the regions with high volcanic activity is crucial for understanding ecosystem responses to environmental disturbances and predicting future ecological changes. However, the impacts of tephra deposition on vegetation at local and regional scales remain poorly quantified, limiting understanding of ecosystem resilience to volcanic disturbances. This study presents a high-resolution, multiproxy palaeobotanical record from the Kumroch peatland (Kamchatka, Eurasian Far East), integrating detailed tephrostratigraphy, radiocarbon ages, pollen, plant macrofossil, and loss on ignition data. The peat sequence spans the last ∼5 kyr, anchored by 28 recorded tephra layers. Birch forests (<em>Betula ermanii</em>) and alder shrublands (<em>Alnus alnobetula</em> subsp. <em>fruticosa</em>) dominated during the Middle and Late Holocene, with their proportions shifting in response to climate variations. These changes align in timing with the Late Holocene climate oscillations, primarily reflecting temperature fluctuations. Tephra fallout events had no persistent impact on regional vegetation and limited effects on the local vegetation. These findings demonstrate the resilience of boreal ecosystems to tephra deposition across volcanically active areas and underscore the importance of large-scale studies for understanding ashfall-related disturbances.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113501"},"PeriodicalIF":2.7,"publicationDate":"2026-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799342","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}
引用次数: 0
Carbonate-associated sulfate isotope signatures in marine mollusk shells 海洋软体动物壳中碳酸盐伴生硫酸盐同位素特征
IF 2.7 2区 地球科学 Q2 GEOGRAPHY, PHYSICAL Pub Date : 2026-02-15 Epub Date: 2025-12-15 DOI: 10.1016/j.palaeo.2025.113503
Shanggui Gong , Yongbo Peng , Laurie C. Anderson , Annette Summers Engel , Huiming Bao
The oxygen and sulfur isotope compositions of carbonate-associated sulfate (CAS) in biogenic materials, such as mollusk shells, are valuable for inferring paleo-seawater sulfate isotope signatures. However, infaunal species may incorporate sulfate from sediment porewater or, in chemosymbiotic taxa, sulfate metabolized by endosymbiotic sulfur-oxidizing bacteria. To evaluate whether shell CAS primarily records seawater or an ecological niche signature, we measured the δ34S and δ18O of CAS from 24 modern and Holocene mollusk species spanning epifaunal, shallow infaunal, deep infaunal, and lucinid (chemosymbiotic) habitats across the northeastern Gulf of Mexico, Bahamas and Mexico. Results show substantial isotopic variability (δ34SCAS: 15.1–22.6 ‰; δ18OCAS: 8.5–14.3 ‰): 1) Epifaunal and lucinid δ34SCAS values cluster near seawater values, while shallow infauna exhibits the greatest variability (up to 7.5 ‰ range), and deep infauna consistently show lower δ34SCAS (17.1–19.9 ‰) than seawater. 2) All taxa exhibit δ18OCAS enrichment above seawater. The absence of 34S-enrichment in infauna suggests limited porewater sulfate incorporation. Epifaunal δ34SCAS values span a 2.6 ‰ range, with a minimum of 19.5 ‰, implying contributions from non-seawater sulfate, likely dietary sulfur or intracrystalline organic sulfate. Reduced δ34SCAS in deep infauna also supports these additional sulfate sources incorporation, as deep infauna increased reliance on deposit-feeding of deeper sediment organic matter characterized by decreasing δ34S value. For shallow infauna, their larger variability in δ34SCAS stems from diverse feeding strategies (filter- and deposit-feeding) and niche adaptations. Bulk CAS of shallow-water lucinid species archive limited 34S-depeted signal of endosymbiont-derived sulfate. CAS oxygen isotope is consistently enriched due to vital effects, with highly variable δ18OCAS value across all niches supporting multiple sulfate sources in shells. These findings demonstrate that mollusk shell CAS does not purely record seawater sulfate but incorporates ecological signatures, underscoring the importance of species-specific biology in CAS-based paleoenvironmental or symbiosis studies.
生物源材料(如软体动物壳)中碳酸盐伴生硫酸盐(CAS)的氧、硫同位素组成对推断古海水硫酸盐同位素特征具有重要价值。然而,动物物种可能从沉积物孔隙水中吸收硫酸盐,或者在化学共生分类群中,由内共生硫氧化细菌代谢的硫酸盐。为了评估贝壳CAS主要记录的是海水还是生态位特征,我们测量了墨西哥湾东北部、巴哈马和墨西哥的24种现代和全新世软体动物的CAS δ34S和δ18O,这些软体动物跨越了地表层、浅层、深层和lucinid(化学共生)栖息地。结果表明:1)浅层和lucinid的δ34SCAS值集中在海水附近,浅层动物δ34SCAS值变化最大(可达7.5‰),深层动物δ34SCAS值始终低于海水(17.1 ~ 19.9‰)。2)所有类群在海水以上均表现出δ18OCAS富集。动物体内不富集34s,说明孔隙水中硫酸盐的掺入有限。浅层δ34SCAS值在2.6‰范围内,最小值为19.5‰,表明非海水硫酸盐,可能是膳食硫或结晶内有机硫酸盐的贡献。深层动物δ34SCAS的减少也支持了这些额外的硫酸盐来源的结合,因为深层动物增加了对沉积物喂养的依赖,其特征是δ34S值降低。对于浅层动物,其δ34SCAS的较大变化源于不同的摄食策略(过滤器和沉积物摄食)和生态位适应。浅水lucinids物种档案的大量CAS限制了内共生衍生硫酸盐的34s信号。由于重要影响,CAS氧同位素持续富集,在所有生态位中δ18OCAS值变化很大,支持壳中多种硫酸盐来源。这些发现表明,软体动物壳CAS不仅记录了海水硫酸盐,而且包含了生态特征,强调了物种特异性生物学在基于CAS的古环境或共生研究中的重要性。
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引用次数: 0
Paleobiogeography of early to middle Paleozoic phytoplankton: A review and synthesis 早至中古生代浮游植物的古生物地理学综述与综合
IF 2.7 2区 地球科学 Q2 GEOGRAPHY, PHYSICAL Pub Date : 2026-02-15 Epub Date: 2025-11-08 DOI: 10.1016/j.palaeo.2025.113412
Eiver Gelan Manzano , Claude Monnet , David M. Kroeck , Stewart Molyneux , Hendrik Nowak , Paulina Nätscher , Thomas Servais
Phytoplankton form the foundation of marine food webs, and their fossil record provides key insights into ecosystem and climate evolution. We review the biogeography of Paleozoic phytoplankton based on data from the literature and new multivariate analyses of acritarch data that are georeferenced to paleolatitude and paleolongitude. Results show that acritarchs are rather cosmopolitan with wide geographic ranges, their distribution often differentiated into two broad latitudinal realms: a northern warm-water and a southern cold-water assemblage. Provincialism was most pronounced during the Ordovician and Devonian. The Ordovician provincial structure collapsed during the Hirnantian glaciation, resulting in a short-lived cosmopolitan phase that persisted into the early Silurian. Biogeographic differentiation re-emerged in the middle Silurian and was reorganized in the Devonian as plate movements closed ocean basins and enabled new intercontinental exchanges. Overall, climate change and plate tectonics appear to be the primary drivers of phytoplankton provincialism.
浮游植物构成了海洋食物网的基础,它们的化石记录为研究生态系统和气候演变提供了关键的见解。本文根据已有文献资料和对古纬度和古经度相关数据的多元分析,对古生代浮游植物的生物地理学进行了综述。结果表明,栖类具有较广的地理分布范围,它们的分布常常划分为两大纬向域:北部的暖水组合和南部的冷水组合。地方主义在奥陶纪和泥盆纪最为明显。奥陶纪的省域构造在希尔南田冰期崩塌,形成了一个持续到志留纪早期的短暂的世界性阶段。生物地理分化在志留纪中期再次出现,并在泥盆纪板块运动关闭海洋盆地并使新的洲际交流成为可能时进行了重组。总体而言,气候变化和板块构造似乎是浮游植物局部性的主要驱动因素。
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引用次数: 0
Taiwan's land-vertebrate suite: An assemblage forged by tectonism and sea-level shifts 台湾陆生脊椎动物群:由构造运动和海平面变化形成的组合
IF 2.7 2区 地球科学 Q2 GEOGRAPHY, PHYSICAL Pub Date : 2026-02-15 Epub Date: 2025-12-17 DOI: 10.1016/j.palaeo.2025.113502
Jason R. Ali , Uwe Fritz
Like many islands in continental-shelf settings, Taiwan has a rich land-vertebrate suite comprising mainly nonendemic taxa. Unusually, though, it also hosts a substantial fraction of endemic species, some the result of in situ diversification. Here, we disentangle the physical processes that have shaped the island's assemblage and document the roles they played. Taiwan is a high-elevation landmass on the edge of China's continental shelf, its emergence resulting from the ongoing collision between the Eurasian and Philippine Sea Plates, which started c. 5 Mya. For the first c. 4 Myr of the island's history colonizations involved over-water dispersal, hence relatively few establishment events. Significantly, the sizeable ecospace the incomers entered hosted a variety of niches (notably, greater than those in the areas they crossed from), and this spurred anagenesis and occasionally cladogenesis. Although the Pleistocene sea-level falls (starting c. 2.6 Mya) modified greatly and frequently the regional geography, only those occurring after 900 kya were sufficiently large (i.e., below −72/−75 m) to open up a succession of landbridges across the Taiwan Strait seabed to mainland Asia. Significantly, such episodes allowed taxa to enter Taiwan unimpeded, thereby accounting for the bulk of its lineages, most of which are nonendemic.
像许多大陆架上的岛屿一样,台湾有丰富的陆生脊椎动物群,主要由非地方性类群组成。然而,不同寻常的是,它还拥有相当一部分地方性物种,其中一些是原位多样化的结果。在这里,我们解开了塑造岛屿组合的物理过程,并记录了它们所扮演的角色。台湾是中国大陆架边缘的一块高海拔大陆,它的出现是由欧亚海板块和菲律宾海板块持续碰撞造成的,这种碰撞始于约5000万年前。在该岛历史的第一个c. 4世纪,殖民化涉及水上分散,因此相对较少的建立事件。值得注意的是,进入者所进入的相当大的生态空间承载了各种各样的生态位(值得注意的是,比他们所穿越的区域的生态位更大),这刺激了发育,偶尔也刺激了枝发生。虽然更新世海平面下降(始于2.6 Mya)极大且频繁地改变了区域地理,但只有发生在900 kya之后的海平面下降才足够大(即低于- 72/ - 75 m),从而在台湾海峡海底与亚洲大陆之间开辟了一系列陆桥。值得注意的是,这些事件使得分类群畅通无阻地进入台湾,从而占了其大部分谱系,其中大多数是非地方性的。
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引用次数: 0
Late Miocene tectonic reorganization and regional development of thrust faulting in the northeastern Tibetan Plateau 青藏高原东北部晚中新世构造重组与逆冲断裂区域发育
IF 2.7 2区 地球科学 Q2 GEOGRAPHY, PHYSICAL Pub Date : 2026-02-15 Epub Date: 2025-12-23 DOI: 10.1016/j.palaeo.2025.113522
Hao Xie , Caicai Liu , Dewen Zheng , Ying Wang , Jingxing Yu , Xudong Zhao , Zhuqi Zhang , Li Deng , Jiawei Zhang , Huiping Zhang
Constraining the initiation of intracontinental thrust faults is crucial for understanding deformation sequences that occurred during the growth of the Tibetan Plateau. This study investigates the activation timing of the nearly E–W-trending Qinghainan Shan and Gonghenan Shan thrust faults through integrated provenance analyses of Cenozoic sediments from the Chaka–Gonghe Basin, including sandstone petrography, heavy mineral assemblages, and detrital zircon U-Pb geochronology. Results reveal a pronounced provenance shift at ∼6–7 Ma, marked by a sharp increase in sediment derived from the adjacent Qinghainan Shan and Gonghenan Shan. This transition coincides with a decline in mineral maturity indices along with a change in the rotational trend, reflecting mountain uplift and constraining the initiation of these thrust faults to the late Miocene. Regionally, deformation propagated sequentially from WNW-trending strike-slip boundary faults to NNW-trending dextral strike-slip fault systems, and subsequently to intrablock thrusts. The late Miocene onset of these thrust faults represents a key kinematic step in strain partitioning, accommodating crustal shortening during the India–Asia convergence and facilitating the northeastward growth of the plateau. This progression from boundary faulting to distributed interior deformation supports a model of continuous, rather than rigid-block tectonic deformation during continental convergence.
控制陆内逆冲断层的起爆对于理解青藏高原发育过程中的变形序列至关重要。本文通过对察卡—共和盆地新生代沉积物源的综合分析,包括砂岩岩相学、重矿物组合、碎屑锆石U-Pb年代学等,探讨了近东西向的青海南山和公河南山逆冲断裂的活化时间。结果显示,在~ 6 ~ 7 Ma期间,物源发生了明显的转移,其特征是来自邻近的青海南山和公河南山的沉积物急剧增加。这一转变与矿物成熟度指数的下降和旋转趋势的变化相吻合,反映了山体隆升,将这些逆冲断层的起生限制在晚中新世。从区域上看,变形从西西向走滑边界断裂依次传播到北西向右走滑断裂系统,然后传播到块内逆冲构造。这些逆冲断层的晚中新世起生代表了应变划分的关键运动步骤,适应了印度-亚洲辐合期间地壳的缩短,促进了高原的东北生长。这种从边界断裂到分布的内部变形的进展支持了大陆收敛期间连续而非刚性块构造变形的模型。
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引用次数: 0
Sedimentary facies and invertebrate faunal exchange confirm humid conditions in the tropical eastern Atlantic during interglacial Marine Isotopic Stage (MIS) 11c 沉积相和无脊椎动物动物交换证实了间冰期海洋同位素阶段(MIS) 11c期间热带东大西洋的湿润条件
IF 2.7 2区 地球科学 Q2 GEOGRAPHY, PHYSICAL Pub Date : 2026-02-15 Epub Date: 2025-12-16 DOI: 10.1016/j.palaeo.2025.113505
Carlos S. Melo , José Madeira , Ricardo S. Ramalho , Ana C. Rebelo , Michael W. Rasser , Esther Martín-González , Alfred Uchman , Carlos Marques da Silva , Emílio Rolán , Luís Silva , Joseph A. Stewart , Laura F. Robinson , Deirdre D. Ryan , Alessio Rovere , Antje Voelker , Patrícia Madeira , Mário Cachão , Sérgio P. Ávila
The geological study of Marine Isotopic Stage (MIS) 11c (424–397 ka) is key to reconstructing the climatic and oceanographic conditions during one of the longest and the warmest interglacial in the last 1 million years. Moreover, interglacial MIS 11c is considered as an important analogue for our near future in times of climate change, under anthropogenic emissions scenarios, due to its similar orbital forcing configuration. Here we present the results of a comprehensive analysis of one of the most extensive Quaternary fossiliferous sedimentary successions in the Cabo Verde archipelago in the tropical northeastern Atlantic. The Nossa Senhora da Luz Bay (Santiago Island) is one of the few MIS 11 fossiliferous sites known in Macaronesia. The sedimentary succession records a set of transitions between fluvial and marine environments, and emersion and immersion events within a confined, highly protected bay environment. A thick layer of fine-branched rhodoliths in its upper part suggests ecological conditions that no longer exist in Cabo Verde. The presence of specimens of the intertidal clam Senilia senilis in life position ∼12 m above present-day mean sea level leads us to reinterpret the relative sea-level changes at Santiago Island and show that the uplift trend since MIS 11c is an order of magnitude lower (0.01 mm/yr) than previously calculated (0.10 to 0.14 mm/yr). The fossil assemblage includes representatives of five phyla, with molluscs being the most diverse and abundant. Despite the abundance of some bivalves (Saccostrea cuccullata, S. senilis, and Aequipecten opercularis), and gastropods (Thetystrombus latus and Thais nodosa), and some horizons showing the crustacean burrows Thalassinoides suevicus, the general biodiversity is low. The presence of S. cuccullata and S. senilis, both absent from present-day Cabo Verde archipelago, indicates a tropical, more humid climate in this region, during MIS 11c.
海洋同位素阶段(MIS) 11c (424-397 ka)的地质研究是重建近100万年来最长、最温暖的间冰期之一的气候和海洋条件的关键。此外,间冰期MIS 11c被认为是人类排放情景下不久的将来气候变化时期的重要模拟,因为它具有类似的轨道强迫配置。在这里,我们提出了对大西洋东北部热带佛得角群岛最广泛的第四纪化石沉积演替之一的综合分析结果。Nossa Senhora da Luz湾(圣地亚哥岛)是Macaronesia已知的少数MIS 11化石遗址之一。沉积演替记录了一系列河流环境与海洋环境之间的过渡,以及在一个封闭的、高度保护的海湾环境中发生的突出和浸没事件。它的上部有一层厚厚的细分枝的虹石,表明佛得角已不复存在的生态条件。在高于现今平均海平面约12米的生活位置发现了潮间带蚌Senilia senilis标本,这使我们重新解释了圣地亚哥岛的相对海平面变化,并表明自MIS 11c以来的上升趋势比先前计算的(0.10至0.14 mm/yr)低一个数量级(0.01 mm/yr)。化石组合包括五个门的代表,其中软体动物种类最多,数量最多。尽管一些双壳类(Saccostrea cuccullata、s.s senilis和Aequipecten opercularis)和腹足类(Thetystrombus latus和Thais nodosa)丰富,以及一些视野显示甲壳类动物洞穴,但总体生物多样性较低。现在佛得角群岛上都没有S. cuccullata和S. senilis的存在,这表明在MIS 11c期间,该地区属于热带,更潮湿的气候。
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Palaeogeography, Palaeoclimatology, Palaeoecology
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