Palaeogeography, Palaeoclimatology, Palaeoecology最新文献_第4页

Quantitative histological analysis of dental variability in Anchitherium: insights into growth dynamics and dental development 牙变异性的定量组织学分析：对生长动力学和牙齿发育的见解

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-12 DOI: 10.1016/j.palaeo.2026.113557

Teresa Calderón , Andrea Cuccu , Jorge Morales , Beatriz Azanza , Daniel DeMiguel

The correlation between enamel microstructure and life history has allowed researchers to gather important information on the dental growth and development of both extant and fossil taxa. The approach has been especially developed on primates but also applied to ungulates. Among them, equids have received particular attention, since the enamel microstructure has been examined in several species of hipparionines and Equus. However, this aspect has been completely unexplored in more basal equid taxa. In this work, we analyse the dental microstructure of upper and lower dental elements and calculate for the first time the dental parameters of Anchitherium, a three-toed equid that inhabited the Palaearctic region from the Early to Late Miocene. Results revealed significantly higher secretion rates in the first lower molar and similar extension rates in all the dental elements analysed. In addition, the study of both upper and lower elements in this work seems to indicate that the method of analysing only the lower dentition, as employed in many studies, may not provide the complete framework to make inferences (at least in Anchitherium) and hence, should be taken with caution. Comparing Anchitherium enamel parameters with more derived members of the family Equidae has allowed us to observe a clear correlation between enamel secretion rate and hypsodonty index, which increases over time, coinciding with the acquisition of hypsodont teeth. In parallel, a trend towards a faster pace of growth was identified over time, which could be related to the Miocene environmental changes. The present work deepens our understanding of equid dental development and the evolution of this iconic group of ungulates.

牙釉质微观结构与生命史之间的相关性使研究人员能够收集有关现存和化石分类群牙齿生长和发育的重要信息。这种方法是专门针对灵长类动物开发的，但也适用于有蹄类动物。其中，马科动物受到了特别的关注，因为在几种马科动物和马的牙釉质微观结构中进行了研究。然而，这方面在更基础的马科动物分类群中还完全没有被探索过。本文分析了上齿和下齿的显微结构，并首次计算了生活在早中新世至晚中新世古北地区的三趾马科动物Anchitherium的牙齿参数。结果显示，第一下磨牙的分泌率明显较高，所有牙元的伸展率相似。此外，这项工作中对上、下两个元素的研究似乎表明，许多研究中采用的仅分析下牙列的方法可能无法提供完整的框架来进行推断（至少在古齿目中是这样），因此，应该谨慎对待。将Anchitherium牙釉质参数与Equidae家族的更多衍生成员进行比较，使我们能够观察到牙釉质分泌率与下齿指数之间的明确相关性，该指数随着时间的推移而增加，与下齿的获得一致。与此同时，随着时间的推移，人们发现了一种更快增长的趋势，这可能与中新世的环境变化有关。目前的工作加深了我们对马科动物牙齿发育和进化的理解。

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引用次数: 0

Miocene evolution of the Humboldt Current 洪堡流中新世的演化

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-12 DOI: 10.1016/j.palaeo.2026.113558

John A. Barron , Thomas J. DeVries , Jason J. Coenen

Diatom records from the East Pisco Basin (EPB) of southern Peru and offshore Ocean Drilling Program (ODP) Hole 682 A reveal stepwise increases in the primary productivity of the Humboldt Current during the middle and late Miocene. Although diatoms are present back through the late middle Eocene, successively enhanced diatom production occurs during the Miocene in four steps. The first step between 14.2 and 13.8 Ma marks the onset of diatom deposition in the Pisco-0 sequence. A second step at ∼12.9 Ma coincides with a major drop in global sea level during which diatom deposition ceased in the EPB but continued in ODP 682 A as well as in Chile, Ecuador, and Colombia. Beginning at 10.4 to 10.0 Ma, a major increase in diatom sedimentation rates in both the EPB and in ODP 682 A signals an abrupt intensification of the Humboldt Current productivity, which may be related to the closure of the Central American Seaway to deeper water circulation. A fourth step coincides with the transgressive deposition of the diatom-rich Pisco-2 sequence at 8.4 Ma and is enhanced by the onset of the global Late Miocene Biogenic Bloom (8.0–4.5 Ma). Between 7 and 6 Ma, common subtropical diatoms in ODP 682 A contrast with high diatom deposition rates in the EPB, suggesting variable El Niño-La Niña conditions. During this time, fossil vegetation evidence from southern Peru supports the presence of seasonal periods of enhanced rainfall typical of El Niño conditions. The Miocene trend of increasing sea mammal diversity in the EPB parallels these steps, further supporting stepwise enhancement of primary productivity in the Humboldt Current during the Miocene.

来自秘鲁南部东皮斯科盆地（EPB）和ODP 682 A孔的硅藻记录揭示了中新世中晚期洪堡流初级生产力的逐步增加。虽然硅藻早在始新世中晚期就已存在，但中新世硅藻生产先后经历了四个阶段。14.2 ~ 13.8 Ma之间的第一步标志着Pisco-0层序硅藻沉积的开始。第二步发生在~ 12.9 Ma，与全球海平面大幅下降相吻合，在此期间，EPB的硅藻沉积停止，但ODP 682 A以及智利、厄瓜多尔和哥伦比亚的硅藻沉积仍在继续。从10.4至10.0 Ma开始，EPB和ODP 682 a的硅藻沉积速率的显著增加标志着洪堡流生产力的突然增强，这可能与中美洲海道向更深水循环关闭有关。第四阶段与8.4 Ma富硅藻的Pisco-2层序的海侵沉积相吻合，并因全球晚中新世生物爆发（8.0-4.5 Ma）的开始而加强。在7 ~ 6 Ma之间，ODP 682 A中常见的亚热带硅藻与EPB中高硅藻沉积率形成对比，表明El Niño-La Niña条件变化。在此期间，来自秘鲁南部的化石植被证据支持厄尔尼诺Niño典型条件下季节性降雨增加的存在。中新世EPB海洋哺乳动物多样性增加的趋势与这些步骤相似，进一步支持中新世洪堡海流初级生产力的逐步增强。

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引用次数: 0

The variations of the North African monsoon precipitation over the past 200 years 近200年来北非季风降水的变化

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-10 DOI: 10.1016/j.palaeo.2026.113554

Sainan Liu , Ru Huang , S.-Y. Simon Wang , Chenxi Xu

The North African monsoon (NAFM) is a critical component of regional climate systems, sustaining livelihoods while shaping ecological and socio-economic conditions. However, its long-term variability and drivers remain insufficiently constrained. Here we present a two-century reconstruction (1801–1994) of NAFM precipitation based on humidity index from western North Africa and tree-ring records from the Ethiopian highlands. The reconstruction reveals two prolonged periods of reduced precipitation, leading to extreme droughts in 1820–1837 and 1954–1983, followed by a partial recovery after the 1980s that has not returned to pre-1954 levels. The longest period of decreased precipitation in mid-20th century was driven jointly by the negative phase of the Atlantic Multidecadal Oscillation (AMO) and remoted regulation of multi-ocean basin teleconnections. Across all periods, AMO exerts the dominant influence on NAFM precipitation variability by modulating ITCZ migration, and it further regulates the covariation between the North African and South Asian monsoons.

北非季风（NAFM）是区域气候系统的一个重要组成部分，在塑造生态和社会经济条件的同时维持生计。然而，其长期可变性和驱动因素仍然没有得到充分约束。本文基于北非西部的湿度指数和埃塞俄比亚高原的树木年轮记录，重建了两个世纪（1801-1994）的NAFM降水。重建结果显示，有两个较长的降水减少期，导致了1820-1837年和1954-1983年的极端干旱，随后在20世纪80年代之后出现了部分恢复，但没有恢复到1954年之前的水平。20世纪中期最长的降水减少周期是由大西洋多年代际涛动（AMO）负相和多洋盆遥相关的远程调节共同驱动的。在所有时期，AMO通过调节ITCZ迁移对NAFM降水变率产生主导影响，并进一步调节北非和南亚季风之间的共变。

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引用次数: 0

Recurrent catastrophic outburst floods in the Yarlung Tsangpo Gorge system: Chronology, magnitude, and climatic drivers 雅鲁藏布江流域周期性特大溃决洪水：年代学、震级和气候驱动因素

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-09 DOI: 10.1016/j.palaeo.2026.113553

Jiantao Xie , Na Yang , Jingran Zhang , Mengying He , Chaogang Zheng , Zhigang Zhang , Xinggong Kong , Zhijun Zhao , Xilin Cao

Catastrophic outburst floods from natural-dam failures are among Earth's most powerful landscape-sculpting agents, yet their long-term frequency and relationship with orbital-scale climate cycles remain poorly constrained. The Yarlung Tsangpo River in the eastern Himalaya provides an unparalleled setting to resolve this, but research has largely focused on Holocene events. Here, we extend this record into the deep past, presenting a comprehensive geomorphological and geochronological reconstruction of outburst floods extending back to ∼259 ka. We identify at least six distinct, high-magnitude outburst flood episodes based on field evidence of giant bars. Hydraulic modeling shows these events had colossal peak discharges ranging from 0.2 to 2.1 × 10⁶ m³/s. Robust single-grain post-infrared infrared stimulated luminescence (pIRIR) dating establishes a chronology securely linked to distinct clusters: an early series associated with Marine Isotope Stage (MIS) 8 and its termination (∼259 ka, <242 ka, and ∼ 232 ka), followed by major events at ∼115 ka (MIS 5d), ∼18 ka (MIS 2), and ∼ 11 ka (Latest Pleistocene). Crucially, the stratigraphic tight coupling of flood deposits with immediately overlying paleosols provides physical evidence that these catastrophic failures were synchronous with rapid climatic transitions. This confirms a systematic causal mechanism: the advance of valley glaciers during cold stages (e.g., MIS 8, MIS 6, MIS 2) repeatedly dammed the river at the Gyaca Gorge, with catastrophic failure triggered during subsequent periods of climatic amelioration. Our findings reveal that glacial-interglacial climate cyclicity has exerted a first-order control on the pacing of the most extreme geomorphic events, fundamentally shaping the long-term landscape evolution of the world's highest mountain range.

自然大坝溃坝造成的灾难性突发洪水是地球上最强大的景观塑造因素之一，但它们的长期发生频率及其与轨道尺度气候周期的关系仍然缺乏约束。喜马拉雅东部的雅鲁藏布江提供了一个无与伦比的环境来解决这个问题，但研究主要集中在全新世事件上。在这里，我们将这一记录扩展到深过去，提出了一个全面的地貌和地质年代学重建溃坝，可追溯到~ 259 ka。我们根据巨大沙洲的现场证据确定了至少六个不同的、高震级的溃决洪水事件。水力模拟表明，这些事件具有巨大的峰值流量，范围为0.2至2.1 × 106 m3/s。强大的单粒红外后红外激发发光（pIRIR）测年建立了一个与不同集群安全相关的年表：与海洋同位素阶段（MIS） 8及其终止（~ 259 ka, <；242 ka和~ 232 ka）相关的早期系列，随后是在~ 115 ka (MIS 5d), ~ 18 ka （MIS 2）和~ 11 ka（最新更新世）发生的重大事件。至关重要的是，洪水沉积物与直接覆盖的古土壤的地层紧密耦合提供了物理证据，表明这些灾难性的破坏与快速的气候转变是同步的。这证实了一个系统的因果机制：在寒冷阶段（例如，MIS 8, MIS 6, MIS 2），山谷冰川的推进在Gyaca峡谷反复阻塞河流，并在随后的气候改善时期引发灾难性的破坏。我们的研究结果表明，冰期-间冰期气候循环对最极端地貌事件的速度起着一级控制作用，从根本上塑造了世界最高山脉的长期景观演变。

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引用次数: 0

Palaeoenvironmental reconstruction from Hulas Khera: Insights into mid-late Holocene hydroclimatic variability in the Central Ganga Plain Hulas Khera的古环境重建：对恒河平原中部全新世中晚期水文气候变化的认识

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-09 DOI: 10.1016/j.palaeo.2026.113551

Arvind Tiwari , Binita Phartiyal , M.C. Manoj , Masud Kawsar , K. Prasanna , Rajveer Sharma , Pankaj Kumar , Anupam Sharma

This study from Hulas Khera, in the Central Ganga Plain, reconstructs past climatic conditions and lake-level fluctuations since ∼6350 calibrated years BP. It integrates sediment textural analysis, mineral magnetism, elemental composition, and AMS radiocarbon dating. Variations in detrital input reflect catchment erosion associated with shifts in rainfall patterns, indicating precipitation as the primary driver of magnetic property changes. The C-M diagram indicates floodplain deposition, driven by suspension settling. Grain-size end-members EM1 and EM2 (mean sizes: 8.9 and 53 μm) in the fine to coarse silt domain are associated with surface runoff during periods of heightened seasonal precipitation, corresponding to intensified Indian Summer Monsoon activity around 5400 to 4600, 4000, 3300, 2000, and 800 cal yrs. BP. In contrast, EM3 and EM4 (mean sizes: 92 and 160 μm), within fine sand domain, are prominent during intervals of extended drought and monsoon minima around ∼6300–5400, ∼4300, ∼3600, ∼2800–2200, ∼1800–900, and ∼ 600–300 cal yrs. BP, coinciding with regional dry phases recorded in the Kanwar Lake record from the Central Ganga Plain, and reduced upwelling record of the Arabian Sea. Abrupt shifts in Indian Summer Monsoon (ISM) strength recorded correspond to known monsoon minima during the Little Ice Age and the Dark Age Cold Period, highlighting the sensitivity of regional hydrodynamics to mid- to late-Holocene monsoonal variability.

这项研究来自恒河平原中部的Hulas Khera，重建了自~ 6350校准年BP以来的过去气候条件和湖泊水位波动。它集成了沉积物的结构分析，矿物磁性，元素组成，和AMS放射性碳定年。碎屑输入的变化反映了与降雨模式变化相关的流域侵蚀，表明降水是磁性变化的主要驱动因素。C-M图显示了由悬浮沉降驱动的洪泛平原沉积。细至粗粉土区粒度端元EM1和EM2（平均粒径8.9 μm和53 μm）与季节性降水增加期间的地表径流有关，对应于5400至4600、4000、3300、2000和800 cal年左右印度夏季风活动的加剧。英国石油公司。相比之下，EM3和EM4（平均尺寸：92 μm和160 μm）在细沙域内，在约6300-5400、约4300、约3600、约2800-2200、约1800-900和约600-300 cal年左右的延长干旱和季风极小期期间表现突出。BP，与恒河平原中部坎瓦尔湖记录的区域干期一致，与阿拉伯海上升流减少记录一致。记录到的印度夏季风（ISM）强度突变与已知的小冰期和黑暗寒期季风极小值相对应，突出了区域水动力学对全新世中后期季风变化的敏感性。

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引用次数: 0

Extraprovincial cold-water marine mollusks: Evidence bearing on ocean circulation patterns off northwestern Peru during the Late Pliocene and Pleistocene 外省冷水海洋软体动物：晚上新世和更新世期间秘鲁西北部海洋环流模式的证据

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-08 DOI: 10.1016/j.palaeo.2025.113540

Thomas J. DeVries

Northwestern Peru at the latitudes of ∼4°30′S to ∼6°30′S straddles the boundary between the Panamic and Peruvian molluscan faunal provinces. At the same latitudes currents of the cold-water eastern boundary Humboldt Current System blend with warmer-water Pacific equatorial currents and countercurrents. On the coastal plain facing those currents, Pliocene and Pleistocene mollusks are abundantly preserved in the Taime Formation and Mancora, Talara, and Lobitos tablazos in sediments characteristic of nearshore, shoreface, and lagoonal environments. During the late Early Pleistocene, the number of cool-water “Peruvian” species in molluscan assemblages in those sediments abruptly declined and the number of warm-water “Panamic” species substantially increased to a level seen in modern assemblages from the same region. A case is made that the shift from a cool-water to warm-water fauna can be related to (1) a changing configuration of the coastline of northwestern Peru due to Early Pleistocene uplift of the coastal plain that forced cold-water currents to veer westward farther south than they once had, and/or (2) a warming of the Ecuador-Peru Coastal Current, the consequence of interactions between its source of water, the Equatorial Undercurrent, and the Galápagos Islands. To ascertain whether the faunal change in northwestern Peru occurred during the Mid-Pleistocene Transition (∼1 Ma) and is related to the onset of higher amplitude glacial-interglacial eustatic sea-level fluctuations and/or related to the blocking at ∼1.6 Ma of the Equatorial Undercurrent by the Galápagos Islands, will require new approaches to dating fossil mollusks from the Taime Formation and tablazos.

秘鲁西北部在纬度为~ 4°30′s至~ 6°30′s的地方跨越了Panamic和秘鲁软体动物区系省之间的边界。在同一纬度，东部边界的冷水洪堡流系统与温暖的太平洋赤道流和逆流混合在一起。在面对这些洋流的沿海平原上，泰姆组和Mancora、Talara和Lobitos tablazos的近岸、滨面和泻湖环境的沉积物中大量保存着上新世和更新世的软体动物。在早更新世晚期，这些沉积物中软体动物组合中冷水“秘鲁”物种的数量突然减少，而温水“泛海”物种的数量大幅增加，达到同一地区现代组合的水平。从冷水动物群到温水动物群的转变可能与以下因素有关：(1)由于沿海平原的早更新世隆起导致秘鲁西北部海岸线的变化，迫使冷水流向西转向比以前更南，和/或(2)厄瓜多尔-秘鲁海岸流的变暖，这是其水源、赤道潜流和Galápagos群岛之间相互作用的结果。为了确定秘鲁西北部的动物区系变化是否发生在中更新世过渡时期（~ 1 Ma），是否与更高幅度的冰期-间冰期海平面上升波动的开始有关，以及/或与Galápagos群岛在~ 1.6 Ma阻断赤道潜流有关，将需要采用新的方法来确定泰米组和tablazos的软体动物化石的年代。

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引用次数: 0

Late Holocene vegetation dynamics, fire regimes, and human impact in Southern Brazil: A multi-proxy palaeoecological record from the Matematico Lake 巴西南部晚全新世植被动态、火情和人类影响：来自Matematico湖的多代古生态记录

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-08 DOI: 10.1016/j.palaeo.2026.113556

Antonia Lena Reinhardt , Philip Riris , Barnabas Harris , Deepak Kumar Jha , Gisele Leite de Lima Primam , Soraia Girardi Bauermann , Kasun Gayantha , Rachel Rudd , Patrick Roberts , Hermann Behling

The long-term interactions between forest and grassland in Southern Brazil remain poorly understood, despite the region's ecological importance and the ongoing debate about natural versus anthropogenic drivers of landscape dynamics. In this study we present a multi-proxy palaeoecological study of the Matematico sediment core from the Southern Brazilian highlands, with the aim of disentangling the roles of climate and human activity in shaping late Holocene Araucaria Forest and Campos (grassland) dynamics. We combined pollen, non-pollen palynomorphs (NPPs), charcoal, and compound-specific hydrogen isotopes (δ²H) from leaf-wax n-alkanes, making this the first study in Southern Brazil to integrate these proxies within a single core. Between ∼3.500 and 2.100 cal yr BP (calibrated years before present), the landscape was dominated by Campos under relatively dry conditions, with low fire activity and limited forest cover. Subsequent Araucaria Forest expansion happened in two phases, which were identified at ∼1700 and ∼ 500 cal yr BP. Both phases correspond with shifts to more negative δ²H values, indicating a forest expansion due to wetter climatic conditions. However, the earlier wet phase, corresponding to the wettest interval of the last 8000 years in Southern Brazil, did not trigger lasting forest establishment, suggesting that climate alone was insufficient to drive large-scale forest expansion. Meanwhile, the later expansion at ∼500 cal yr BP a coincides with increased charcoal influx and archaeological evidence of intensived occurrence of Southern Jê groups of the Taquara/Itararé Tradition, suggesting potential human influence in this latter expansion. This integrated multi-proxy approach provides new insights into the ecological and cultural legacies of the today's threatened Araucaria Forest–Campos mosaic.

尽管该地区具有重要的生态意义，并且关于景观动态的自然驱动因素与人为驱动因素的争论正在进行，但对巴西南部森林和草地之间的长期相互作用仍知之甚少。在这项研究中，我们对巴西南部高地的Matematico沉积物岩心进行了多代古生态研究，目的是解开气候和人类活动在塑造晚全新世Araucaria森林和Campos（草地）动态中的作用。我们将花粉、非花粉孢粉形态（NPPs）、木炭和来自叶蜡正烷烃的化合物特异性氢同位素（δ2H）结合起来，使这项研究成为巴西南部第一个将这些指标整合到单个岩心中的研究。在~ 3.500 ~ 2.100 cal yr BP之间（距今校准年），在相对干燥的条件下，景观以坎波斯为主，火灾活动低，森林覆盖有限。随后的原生林扩张分为两个阶段，分别发生在~ 1700和~ 500 cal - yr BP。这两个阶段都与δ2H值的负变化相对应，表明由于气候条件湿润，森林扩张。然而，较早的湿润期（与巴西南部过去8000年来最湿润的间隔相对应）并没有引发持久的森林形成，这表明仅靠气候不足以推动大规模的森林扩张。与此同时，在约500 calyr BP a的后期扩张与木炭流入的增加和Taquara/ itarar传统的南方Jê群体密集出现的考古证据相吻合，表明人类在后期扩张中可能受到影响。这种综合的多代理方法为今天受到威胁的阿劳卡利亚森林-坎波斯马赛克的生态和文化遗产提供了新的见解。

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引用次数: 0

A mid-Cretaceous (late Albian–early Turonian) stable isotope record from southern Tibet – Pristine or diagenetically altered? 藏南中白垩世（阿尔白垩世晚期-吐鲁番世早期）稳定同位素记录——原始还是成岩蚀变？

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-07 DOI: 10.1016/j.palaeo.2026.113552

Meiling Han , Gang Li , Alexander Wheeler , Ulrich Heimhofer , Jörg Mutterlose

The late Albian to early Turonian interval was characterized by a pronounced greenhouse climate, marked by major perturbations of the global carbon cycle and the development of several Oceanic Anoxic Events (OAEs). These events are recognized by the widespread deposition of organic-rich black shales, typically associated with distinctive carbon isotope excursions (CIEs). While high-resolution carbon isotope records of the late Albian OAE (OAE 1d, ∼103 to 99.5 Ma) are well-documented in the western Tethys and North Atlantic, detailed studies across this event from the eastern Tethys remain limited. Here, we present new data from the Qiangdong section (Gamba area, southern Tibet), including stable carbon and oxygen isotope curves, mineralogy, Rock-Eval pyrolysis and palynofacies analysis. Our continuous δ¹³C_carb record provides detailed geochemical documentation for the upper Albian to lower Turonian, enabling robust chemostratigraphic correlation with global OAE 1d records. Negative δ¹⁸O_carb values (as low as −11.9‰) and mineralogical evidence (dominated by illite, > 50%) indicate strong diagenetic overprint. Both T_max values (432–560 °C) and highly degraded, dark-colored palynomorphs suggest that the sedimentary sequence of the Qiangdong section has undergone significant thermal alteration, with organic matter reaching mature to overmature stages. This is further supported by the dominance of Watznaueria barnesiae, consistent with previous findings indicative of significant diagenetic overprint. While the δ¹³C_carb record robustly captures the OAE 1d excursion, the characteristic CIE associated with the late Cenomanian to early Turonian OAE 2 is not well expressed. This attenuation is likely due to diagenetic overprinting and decrease in carbonate content, which may have altered or obscured primary palaeoenvironmental signals in the upper part of the Qiangdong section.

晚阿尔比世至早Turonian期以温室气候显著为特征，其标志是全球碳循环的重大扰动和几次海洋缺氧事件（oae）的发展。富有机质黑色页岩的广泛沉积可以识别这些事件，通常与独特的碳同位素漂移（CIEs）有关。虽然在特提斯西部和北大西洋有关于晚Albian OAE （OAE 1d, ~ 103 ~ 99.5 Ma）的高分辨率碳同位素记录，但从特提斯东部对这一事件的详细研究仍然有限。本文介绍了藏南甘巴羌东剖面的新资料，包括稳定碳氧同位素曲线、矿物学、岩石热解和孢粉相分析。我们的连续δ13Ccarb记录为上阿尔比统至下Turonian统提供了详细的地球化学记录，并与全球OAE 1d记录进行了强有力的化学地层对比。负δ18Ocarb值（低至- 11.9‰）和矿物学证据（以伊利石为主，占50%）显示出强烈的成岩覆印作用。Tmax值（432 ~ 560℃）和高度退化、颜色较深的岩相均表明强东剖面的沉积层序发生了明显的热蚀变，有机质达到成熟至过成熟阶段。巴氏瓦氏菌的优势进一步支持了这一点，与先前的研究结果一致，表明了显著的成岩叠印。虽然δ13Ccarb记录有力地反映了OAE的1d偏移，但与晚Cenomanian -早Turonian OAE 2相关的特征CIE并没有很好地表达。这种衰减可能是由于成岩叠印作用和碳酸盐含量的降低，改变或掩盖了强东剖面上部的原始古环境信号。

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引用次数: 0

Chronological and climatic insights from Karst Cave Silt Sediment in Southwest China 中国西南喀斯特溶洞泥沙沉积物年代学和气候学研究

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-07 DOI: 10.1016/j.palaeo.2026.113543

Yuan-Yuan Mu , Qing-Duo Wang , Chang-Sheng Wang , Tian-Zhou Zhang , Shao-Qin Ma , Jing-Ming Yang , Hai-Cheng , Wen-Jun Sun , Jun-Yun Li , Yan-Min Dong , Lu-Peng Yu , Ting-Yong Li

Cave silt sediment (CSS) holds significant potential for reconstructing climate and environmental changes. However, its application has long been limited by the difficulty of establishing a reliable chronology. In this study, we used ²³⁰Th dating, accelerator mass spectrometry radiocarbon (AMS¹⁴C) dating, and single-grain quartz optically stimulated luminescence (OSL) dating methods on the CSS collected from a karst cave in Southwest China (SW-C), aiming to assess the applicability of OSL dating in such sediments. The OSL and AMS-¹⁴C dating results are consistent within analytical uncertainties, indicating that the OSL method can establish a reliable chronology for CSS. Through integrated analyses of sedimentation rate, grain size, and geochemical elements, we found that CSS can serve as a valuable archive for paleoenvironmental reconstruction. Finally, by combining archaeological evidence with other data, we reveal the impact of hydroclimatic changes and human activities on the regional environment since the late Holocene. From 4000 to 1500 yr BP, climate change played a dominant role, with wetter periods fostering agricultural expansion and cultural prosperity. Since 1500 yr BP, human activities have become one of the primary drivers of environmental transformations. Regional hydroclimatic variability has been jointly controlled by both external and internal forcing factors, including Total Solar Irradiance (TSI), meridional migration of the Intertropical Convergence Zone (ITCZ), and fluctuations in the El Niño-Southern Oscillation (ENSO).

洞穴淤泥沉积物（CSS）具有重建气候和环境变化的巨大潜力。然而，由于难以建立可靠的年表，它的应用长期受到限制。本文采用230Th定年法、加速器质谱放射性碳（AMS14C）定年法和单粒石英光激发光（OSL）定年法对西南某溶洞沉积物进行测年，以评价OSL定年法在该类沉积物中的适用性。OSL和AMS-14C测年结果在分析不确定度范围内是一致的，表明OSL方法可以建立可靠的CSS年表。通过对沉积速率、粒度和地球化学元素的综合分析，我们发现CSS可以作为古环境重建的宝贵档案。最后，结合考古证据和其他资料，揭示了晚全新世以来水文气候变化和人类活动对区域环境的影响。从4000年到1500年，气候变化起了主导作用，湿润时期促进了农业扩张和文化繁荣。自1500年前以来，人类活动已成为环境变化的主要驱动力之一。区域水文气候变率受内外强迫因素共同控制，包括太阳总辐照度（TSI）、热带辐合带（ITCZ）经向迁移和El Niño-Southern涛动（ENSO）波动。

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引用次数: 0

Paleogeography and sequence stratigraphic architecture of the upper Ordovician Juniata Formation, central Appalachians: The interplay of tectonics and eustacy prior to the onset of the Hirnantian glaciation 阿巴拉契亚中部上奥陶统朱尼亚塔组古地理与层序地层构造：希尔南天冰期开始前构造与海平面的相互作用

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2026-01-07 DOI: 10.1016/j.palaeo.2026.113549

C.R. Blue , R.J. Diecchio , K.A. Eriksson , W.S. McClung

Upper Ordovician (Katian) strata of the Central Appalachians provide an opportunity to study the effects of both tectonics and eustasy on siliciclastic sedimentation within a foreland-basin setting. The Juniata Formation consists of interbedded red sandstone, siltstone, and shale that were deposited as part of an extensive siliciclastic basin-fill that resulted from the Taconic Orogeny. This study attempts to resolve some of the questions regarding tectonic and eustatic influences on sedimentation by (1) examining the stratigraphic architecture of the Juniata Formation, and (2) reconstructing the paleogeographic environment of the Juniata Formation. Fifteen lithofacies are grouped into four facies associations (A–D), interpreted as deposited in a tidal-flat setting deepening down paleoslope through shoreface to marine offshore environments. Isopach and paleocurrent data suggest the shoreline was oriented NE–SW and siliciclastic sediment was dispersed west and southwest across the basin. Tectonics controlled the 2nd-order basin-fill patterns that vary along the strike of the basin. Eustatic changes are expressed in two 3rd-order sequences and in Milankovitch-forced cycles/parasequences of Facies Associations A, C and D. The Juniata Formation was deposited prior to the influence of high-amplitude eustatic sea-level fluctuation during the Hirnantian glaciation.

阿巴拉契亚中部的上奥陶统（卡田）地层为研究前陆-盆地背景下构造和沉积对硅屑沉积的影响提供了一个机会。朱尼亚塔组由互层红色砂岩、粉砂岩和页岩组成，它们是由塔尼克造山运动形成的广泛的硅屑盆地填充物的一部分。本研究试图通过(1)研究朱尼亚塔组的地层构型，(2)重建朱尼亚塔组的古地理环境，来解决有关构造和隆起对沉积影响的一些问题。15个岩相被划分为4个相组（a - d），被解释为沉积在潮滩环境中，沿着古斜坡向下延伸，穿过海岸到海洋近海环境。等厚层和古海流资料表明，岸线为NE-SW向，硅屑沉积分布在盆地西部和西南方向。构造控制了沿盆地走向变化的二级盆地充填模式。海平面升降变化表现在两个三级层序和A、C、d相组合的milankovitch强迫旋回/准层序中。朱尼亚塔组沉积于hirntian冰期海平面高振幅上升波动影响之前。

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引用次数: 0