Pub Date : 2026-03-15Epub Date: 2026-01-08DOI: 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。
{"title":"Late Holocene vegetation dynamics, fire regimes, and human impact in Southern Brazil: A multi-proxy palaeoecological record from the Matematico Lake","authors":"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","doi":"10.1016/j.palaeo.2026.113556","DOIUrl":"10.1016/j.palaeo.2026.113556","url":null,"abstract":"<div><div>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 (δ<sup>2</sup>H) from leaf-wax <em>n-</em>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 δ<sup>2</sup>H 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.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"686 ","pages":"Article 113556"},"PeriodicalIF":2.7,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981300","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}
Pub Date : 2026-03-15Epub Date: 2026-01-07DOI: 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).
{"title":"Chronological and climatic insights from Karst Cave Silt Sediment in Southwest China","authors":"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","doi":"10.1016/j.palaeo.2026.113543","DOIUrl":"10.1016/j.palaeo.2026.113543","url":null,"abstract":"<div><div>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 <sup>230</sup>Th dating, accelerator mass spectrometry radiocarbon (AMS<img><sup>14</sup>C) 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-<sup>14</sup>C 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).</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"686 ","pages":"Article 113543"},"PeriodicalIF":2.7,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981302","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}
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.
{"title":"Palaeoenvironmental reconstruction from Hulas Khera: Insights into mid-late Holocene hydroclimatic variability in the Central Ganga Plain","authors":"Arvind Tiwari , Binita Phartiyal , M.C. Manoj , Masud Kawsar , K. Prasanna , Rajveer Sharma , Pankaj Kumar , Anupam Sharma","doi":"10.1016/j.palaeo.2026.113551","DOIUrl":"10.1016/j.palaeo.2026.113551","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"686 ","pages":"Article 113551"},"PeriodicalIF":2.7,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981303","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}
Pub Date : 2026-03-15Epub Date: 2025-12-27DOI: 10.1016/j.palaeo.2025.113515
David A.T. Harper , Lucia Angiolini , Charles M. Henderson , Thomas Servais
The concept of the Global Boundary Stratotype Section and Point (GSSP) to define the bases of chronostratigraphic units, indicated by a spike in rock, has endured for over half a century. Each boundary is defined by a spike in a rock succession, coincident with available biological and or other markers and represents a unique point in time to serve as the standard (yardstick) against which other successions can be correlated. The GSSPs are geological standards, referred to as stratotypes and are key reference points in time. The methodology has brought precision and stability to the definition of geological time, providing a global language for Earth science and Earth scientists. It is the largest cooperative venture in the history of the Earth sciences. In recent years, some challenges to this practice have been voiced questioning the validity of the GSSP concept. It is thus opportune to address misconceptions and misunderstandings and clearly reiterate the necessity of this approach and its success.
{"title":"Stability and precision in chronostratigraphic definition: The Global Boundary Stratotype Section and Point (GSSP) is the solution","authors":"David A.T. Harper , Lucia Angiolini , Charles M. Henderson , Thomas Servais","doi":"10.1016/j.palaeo.2025.113515","DOIUrl":"10.1016/j.palaeo.2025.113515","url":null,"abstract":"<div><div>The concept of the Global Boundary Stratotype Section and Point (GSSP) to define the bases of chronostratigraphic units, indicated by a spike in rock, has endured for over half a century. Each boundary is defined by a spike in a rock succession, coincident with available biological and or other markers and represents a unique point in time to serve as the standard (yardstick) against which other successions can be correlated. The GSSPs are geological standards, referred to as stratotypes and are key reference points in time. The methodology has brought precision and stability to the definition of geological time, providing a global language for Earth science and Earth scientists. It is the largest cooperative venture in the history of the Earth sciences. In recent years, some challenges to this practice have been voiced questioning the validity of the GSSP concept. It is thus opportune to address misconceptions and misunderstandings and clearly reiterate the necessity of this approach and its success.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"686 ","pages":"Article 113515"},"PeriodicalIF":2.7,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981306","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}
Pub Date : 2026-03-15Epub Date: 2026-01-02DOI: 10.1016/j.palaeo.2025.113541
Dunfeng Xiang , Qigui Mao , Zhiyong Zhang , Songyan Liu , David Chew , Lin Wu , Nan Wang , Chao Guo , He Yang , Wenjiao Xiao
The Jurassic tectonic and geomorphic evolution of the Chinese West Tianshan (CWTS) remains controversial, with conflicting models proposing either regional peneplanation or a local topographic relief. We present the first integrated detrital apatite U-Pb geochronology and trace element geochemistry dataset from Jurassic strata in the Yili and Bayanbulak Basins, complemented by previously published detrital zircon U-Pb data, to constrain the Jurassic tectono-geomorphic evolution of the CWTS. Our results demonstrate that early Early Jurassic sediments in the northern Yili Basin were primarily sourced from the North Tianshan-northern Yili Block and central Yili Block, reflecting topographic barriers that restricted southern sediment input. By the late Early Jurassic, these barriers were eroded, enabling south-derived detritus (460–400 Ma) from the southern Yili-Central Tianshan to reach the northern Yili Basin, signaling diminished topographic relief. In contrast, the Bayanbulak Basin recorded consistent provenance from the southern Yili-Central Tianshan throughout the Jurassic, indicating sustained high topography in this domain. These findings reveal a two-stage Jurassic evolution in the Yili-Central Tianshan region: Early Jurassic uplift with proximal sedimentation likely driven by far-field stresses from the Qiangtang collision or Mongol-Okhotsk closure, followed by the late Early to Late Jurassic regional peneplanation, interrupted by a persistent relief in the southern Yili-Central Tianshan. The two-stage Jurassic tectono-geomorphological evolution of the Yili-Central Tianshan reveals a north-to-south, time-transgressive planation across the region, and demonstrates the critical influence of inherited Mesozoic structures on the present-day landscape.
{"title":"Two-stage Jurassic tectono-geomorphological evolution of the Yili-Central Tianshan: Insights into its role in shaping the Mesozoic-Cenozoic Landscape","authors":"Dunfeng Xiang , Qigui Mao , Zhiyong Zhang , Songyan Liu , David Chew , Lin Wu , Nan Wang , Chao Guo , He Yang , Wenjiao Xiao","doi":"10.1016/j.palaeo.2025.113541","DOIUrl":"10.1016/j.palaeo.2025.113541","url":null,"abstract":"<div><div>The Jurassic tectonic and geomorphic evolution of the Chinese West Tianshan (CWTS) remains controversial, with conflicting models proposing either regional peneplanation or a local topographic relief. We present the first integrated detrital apatite U-Pb geochronology and trace element geochemistry dataset from Jurassic strata in the Yili and Bayanbulak Basins, complemented by previously published detrital zircon U-Pb data, to constrain the Jurassic tectono-geomorphic evolution of the CWTS. Our results demonstrate that early Early Jurassic sediments in the northern Yili Basin were primarily sourced from the North Tianshan-northern Yili Block and central Yili Block, reflecting topographic barriers that restricted southern sediment input. By the late Early Jurassic, these barriers were eroded, enabling south-derived detritus (460–400 Ma) from the southern Yili-Central Tianshan to reach the northern Yili Basin, signaling diminished topographic relief. In contrast, the Bayanbulak Basin recorded consistent provenance from the southern Yili-Central Tianshan throughout the Jurassic, indicating sustained high topography in this domain. These findings reveal a two-stage Jurassic evolution in the Yili-Central Tianshan region: Early Jurassic uplift with proximal sedimentation likely driven by far-field stresses from the Qiangtang collision or Mongol-Okhotsk closure, followed by the late Early to Late Jurassic regional peneplanation, interrupted by a persistent relief in the southern Yili-Central Tianshan. The two-stage Jurassic tectono-geomorphological evolution of the Yili-Central Tianshan reveals a north-to-south, time-transgressive planation across the region, and demonstrates the critical influence of inherited Mesozoic structures on the present-day landscape.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"686 ","pages":"Article 113541"},"PeriodicalIF":2.7,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941352","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}
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.
{"title":"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","authors":"C.R. Blue , R.J. Diecchio , K.A. Eriksson , W.S. McClung","doi":"10.1016/j.palaeo.2026.113549","DOIUrl":"10.1016/j.palaeo.2026.113549","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"686 ","pages":"Article 113549"},"PeriodicalIF":2.7,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981305","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}
Pub Date : 2026-03-15Epub Date: 2026-01-14DOI: 10.1016/j.palaeo.2026.113568
Poonam Chahal , Rupa Ghosh , Debarati Nag , Anil Kumar , Yogesh Ray , Pradeep Srivastava
<div><div>The Himalaya and its foreland, a thrust fold belt, is one of the most geomorphically dynamic and populous regions on Earth. The tectonic forces and climate driven surface processes persistently shape the landscape of the region. The river systems draining through this mountain range actively respond to neotectonic deformation and climatic changes, recording the long-term history of mountain building and erosion. In this paper, we review the chronologically constrained fluvial archives such as river fills, strath terraces, and alluvial fans from the Indus, Ganga, Gandaki, and Brahmaputra systems. Together, these rivers capture the full range of climatic and tectonic conditions across the Himalaya. Building on these studies, we propose an integrated view of how climate and tectonics have jointly influenced the region’s landscape evolution.</div><div>Aggradation and incision in these rivers are controlled by the balance between sediment supply and stream power, which are linked to the changes in monsoon intensity and tectonic uplift. Chronological data reveal three main aggradational phases in the Indus (49–39, 30–20, and 13–5 ka) and Ganga (46–36, 29–23, and 16–8 ka), and two in the eastern Himalaya (32–22, and 18–8 ka), corresponding to glacial–interglacial transitions. Periods of climatic recovery from cold–dry to warm–humid conditions favored valley filling and fan formation, while strong monsoon phases triggered river incision and terrace development. Extreme monsoon-driven floods during 39-31ka and 13-5 ka left widespread sedimentary imprints across the mountain belt.</div><div>Fluvial archives across the Himalaya–Ganga Plain system shows a time-lagged response of 3–4 ka between incision in the mountains and in the foreland. The pattern reflects tight coupling between tectonic deformation and climate-driven erosion.</div><div>Neotectonic deformation in the NW Himalaya is expressed through active nature of south-vergent frontal thrusts and north-vergent backthrusts, forming a bivergent wedge. Rivers in this region record deformation in the form of strath terraces, which reflect alternating phases of uplift, incision, and stability, with incision rates ranging from ∼1 to 15 mm/yr with highest rates near the Himalayan Frontal Thrust. Spatial variations in the bedrock uplift and erosion reveal strong tectono-geomorphic coupling—rapid deformation at the frontal wedge, out-of-sequence uplift in the Lesser Himalaya, and active extensional faulting in the Tethyan sector. Together, these features demonstrate that the Himalaya is a critically tapered, asymmetric bivergent wedge, where both frontal thrusting and hinterland faulting actively shape uplift, erosion, and landscape evolution.</div><div>The Ganga foreland basin also remains tectonically active, influenced by Himalayan thrusting, reactivated basement faults, and flexural movements along the peripheral bulge. These forces have shaped its river systems, sedimentation, and characteristic
{"title":"Rivers of Himalaya: Response to climate and tectonic variables","authors":"Poonam Chahal , Rupa Ghosh , Debarati Nag , Anil Kumar , Yogesh Ray , Pradeep Srivastava","doi":"10.1016/j.palaeo.2026.113568","DOIUrl":"10.1016/j.palaeo.2026.113568","url":null,"abstract":"<div><div>The Himalaya and its foreland, a thrust fold belt, is one of the most geomorphically dynamic and populous regions on Earth. The tectonic forces and climate driven surface processes persistently shape the landscape of the region. The river systems draining through this mountain range actively respond to neotectonic deformation and climatic changes, recording the long-term history of mountain building and erosion. In this paper, we review the chronologically constrained fluvial archives such as river fills, strath terraces, and alluvial fans from the Indus, Ganga, Gandaki, and Brahmaputra systems. Together, these rivers capture the full range of climatic and tectonic conditions across the Himalaya. Building on these studies, we propose an integrated view of how climate and tectonics have jointly influenced the region’s landscape evolution.</div><div>Aggradation and incision in these rivers are controlled by the balance between sediment supply and stream power, which are linked to the changes in monsoon intensity and tectonic uplift. Chronological data reveal three main aggradational phases in the Indus (49–39, 30–20, and 13–5 ka) and Ganga (46–36, 29–23, and 16–8 ka), and two in the eastern Himalaya (32–22, and 18–8 ka), corresponding to glacial–interglacial transitions. Periods of climatic recovery from cold–dry to warm–humid conditions favored valley filling and fan formation, while strong monsoon phases triggered river incision and terrace development. Extreme monsoon-driven floods during 39-31ka and 13-5 ka left widespread sedimentary imprints across the mountain belt.</div><div>Fluvial archives across the Himalaya–Ganga Plain system shows a time-lagged response of 3–4 ka between incision in the mountains and in the foreland. The pattern reflects tight coupling between tectonic deformation and climate-driven erosion.</div><div>Neotectonic deformation in the NW Himalaya is expressed through active nature of south-vergent frontal thrusts and north-vergent backthrusts, forming a bivergent wedge. Rivers in this region record deformation in the form of strath terraces, which reflect alternating phases of uplift, incision, and stability, with incision rates ranging from ∼1 to 15 mm/yr with highest rates near the Himalayan Frontal Thrust. Spatial variations in the bedrock uplift and erosion reveal strong tectono-geomorphic coupling—rapid deformation at the frontal wedge, out-of-sequence uplift in the Lesser Himalaya, and active extensional faulting in the Tethyan sector. Together, these features demonstrate that the Himalaya is a critically tapered, asymmetric bivergent wedge, where both frontal thrusting and hinterland faulting actively shape uplift, erosion, and landscape evolution.</div><div>The Ganga foreland basin also remains tectonically active, influenced by Himalayan thrusting, reactivated basement faults, and flexural movements along the peripheral bulge. These forces have shaped its river systems, sedimentation, and characteristic","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"686 ","pages":"Article 113568"},"PeriodicalIF":2.7,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980561","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}
Pub Date : 2026-03-15Epub Date: 2026-01-16DOI: 10.1016/j.palaeo.2026.113565
Xiao-Hua Shao , Xiao-Hong Zhao , Peng-Fa Li , Kan Zhao , Xing-Gong Kong , Yong-Jin Wang , Hai Cheng
The 8.2 ka event represents a critical benchmark for understanding abrupt climate variability, yet prominent stalagmite records (DA and D4) from southwestern China display notable discrepancies, underscoring the need for new, precisely dated reconstructions to clarify regional monsoon responses. Here we present a high-resolution speleothem δ18O and δ13C record (SH) from Shuanghe Cave, southwestern China, with ∼2-year sampling resolution and a chronological uncertainty of ≤40 years, which captures detailed variability in the East Asian summer monsoon (EASM) during the 8.2 ka event. The SH δ18O record reveals a pronounced weak-monsoon signal with a characteristic double-plunging structure, terminating at 8070 ± 40 yr BP, consistent within dating uncertainties with Greenland ice cores and other high resolution monsoon stalagmite δ18O records. Simulated June–August wind anomalies from the TraCE model further corroborate a substantial reduction in EASM intensity during this interval. Moreover, the SH δ18O and δ13C records, together with other multi-proxy stalagmite data, indicate a largely synchronous hydroclimatic response from the northern to southern Chinese monsoon domain, characterized by a coherent shift toward drier conditions during the 8.2 ka event. When considered alongside Greenland ice-core evidence, these results highlight a strong North Atlantic–East Asian teleconnection, supporting the interpretation that abrupt North Atlantic cooling—caused by a slowdown of the Atlantic Meridional Overturning Circulation (AMOC)—shifted the Intertropical Convergence Zone (ITCZ) southward, thereby weakening the East Asian summer monsoon (EASM) and resulting in diminished rainfall across the Chinese monsoon domain.
{"title":"High-resolution stalagmite records from Southwest China reveal a North Atlantic link to the 8.2 ka event","authors":"Xiao-Hua Shao , Xiao-Hong Zhao , Peng-Fa Li , Kan Zhao , Xing-Gong Kong , Yong-Jin Wang , Hai Cheng","doi":"10.1016/j.palaeo.2026.113565","DOIUrl":"10.1016/j.palaeo.2026.113565","url":null,"abstract":"<div><div>The 8.2 ka event represents a critical benchmark for understanding abrupt climate variability, yet prominent stalagmite records (DA and D4) from southwestern China display notable discrepancies, underscoring the need for new, precisely dated reconstructions to clarify regional monsoon responses. Here we present a high-resolution speleothem δ<sup>18</sup>O and δ<sup>13</sup>C record (SH) from Shuanghe Cave, southwestern China, with ∼2-year sampling resolution and a chronological uncertainty of ≤40 years, which captures detailed variability in the East Asian summer monsoon (EASM) during the 8.2 ka event. The SH δ<sup>18</sup>O record reveals a pronounced weak-monsoon signal with a characteristic double-plunging structure, terminating at 8070 ± 40 yr BP, consistent within dating uncertainties with Greenland ice cores and other high resolution monsoon stalagmite δ<sup>18</sup>O records. Simulated June–August wind anomalies from the TraCE model further corroborate a substantial reduction in EASM intensity during this interval. Moreover, the SH δ<sup>18</sup>O and δ<sup>13</sup>C records, together with other multi-proxy stalagmite data, indicate a largely synchronous hydroclimatic response from the northern to southern Chinese monsoon domain, characterized by a coherent shift toward drier conditions during the 8.2 ka event. When considered alongside Greenland ice-core evidence, these results highlight a strong North Atlantic–East Asian teleconnection, supporting the interpretation that abrupt North Atlantic cooling—caused by a slowdown of the Atlantic Meridional Overturning Circulation (AMOC)—shifted the Intertropical Convergence Zone (ITCZ) southward, thereby weakening the East Asian summer monsoon (EASM) and resulting in diminished rainfall across the Chinese monsoon domain.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"686 ","pages":"Article 113565"},"PeriodicalIF":2.7,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038981","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}
Pub Date : 2026-03-01Epub Date: 2026-01-05DOI: 10.1016/j.palaeo.2026.113544
Feng Wang , Yunhai Li , Min Chen , Xuan Ding , Yunpeng Lin
This study systematically reconstructed the variations in the thermocline of the Arabian Sea over the past 55,000 years and its responsive relationships with global climate events through multi-proxy analyses (including planktonic foraminiferal assemblages, Mg/Ca temperature reconstruction, carbonate content, and fragment rate, etc.) of the CJ08–22 sediment core from the Arabian Basin in the northwestern Indian Ocean. During the MIS3 stage (40–29 ka), the thermocline depth exhibited significant fluctuations, with the sea surface-thermocline temperature difference (ΔT) varying synchronously with Dansgaard-Oeschger (DO) events. Enhanced Indian summer monsoons during warm periods led to weakened upwelling (decreased ΔT), whereas intensified winter monsoons during cold periods triggered strengthened upwelling (increased ΔT). During the MIS2 glacial maximum (29–14 ka), the thermocline shallowed with stably high ΔT, reflecting persistent upwelling driven by strong winter monsoons and deep-water acidification (minimum CaCO3 content). In the MIS1 Holocene (14 ka–), the thermocline deepened, with ΔT consistent with solar insolation. During the 8.2 ka event, the monsoon weakened in the short to medium term. After the establishment of the modern monsoon system, the upwelling intensified again. Principal component analysis of planktonic foraminifera reveals the antagonistic distribution between warm current species (such as Globigerinoides ruber) and upwelling species (such as Globigerina bulloides), suggesting the synergistic effect of the monsoon-driven Arabian Current and Ekman pumping. The thermocline variations in the Arabian Sea showed significant correlations with North Atlantic DO events, the Heinrich 1 event, and solar orbital forcing (20 ka precession cycle), indicating that high-latitude ice volume changes regulate low-latitude oceanic processes through atmospheric circulation (e.g., winter monsoons). This study provides new evidence for understanding the key role of the Arabian Sea in glacial-interglacial cycles, emphasizing that thermocline dynamics serve as a critical hub linking regional monsoon responses to global climate changes, which has implications for predicting the evolution of the Indian Ocean-monsoon system under future global warming.
{"title":"Dynamics of the Arabian Sea thermocline and monsoon-climate coupling mechanisms over the past 55,000 years: Multi-proxy paleoenvironmental reconstruction","authors":"Feng Wang , Yunhai Li , Min Chen , Xuan Ding , Yunpeng Lin","doi":"10.1016/j.palaeo.2026.113544","DOIUrl":"10.1016/j.palaeo.2026.113544","url":null,"abstract":"<div><div>This study systematically reconstructed the variations in the thermocline of the Arabian Sea over the past 55,000 years and its responsive relationships with global climate events through multi-proxy analyses (including planktonic foraminiferal assemblages, Mg/Ca temperature reconstruction, carbonate content, and fragment rate, etc.) of the CJ08–22 sediment core from the Arabian Basin in the northwestern Indian Ocean. During the MIS3 stage (40–29 ka), the thermocline depth exhibited significant fluctuations, with the sea surface-thermocline temperature difference (ΔT) varying synchronously with Dansgaard-Oeschger (D<img>O) events. Enhanced Indian summer monsoons during warm periods led to weakened upwelling (decreased ΔT), whereas intensified winter monsoons during cold periods triggered strengthened upwelling (increased ΔT). During the MIS2 glacial maximum (29–14 ka), the thermocline shallowed with stably high ΔT, reflecting persistent upwelling driven by strong winter monsoons and deep-water acidification (minimum CaCO<sub>3</sub> content). In the MIS1 Holocene (14 ka–), the thermocline deepened, with ΔT consistent with solar insolation. During the 8.2 ka event, the monsoon weakened in the short to medium term. After the establishment of the modern monsoon system, the upwelling intensified again. Principal component analysis of planktonic foraminifera reveals the antagonistic distribution between warm current species (such as <em>Globigerinoides ruber</em>) and upwelling species (such as <em>Globigerina bulloides</em>), suggesting the synergistic effect of the monsoon-driven Arabian Current and Ekman pumping. The thermocline variations in the Arabian Sea showed significant correlations with North Atlantic D<img>O events, the Heinrich 1 event, and solar orbital forcing (20 ka precession cycle), indicating that high-latitude ice volume changes regulate low-latitude oceanic processes through atmospheric circulation (e.g., winter monsoons). This study provides new evidence for understanding the key role of the Arabian Sea in glacial-interglacial cycles, emphasizing that thermocline dynamics serve as a critical hub linking regional monsoon responses to global climate changes, which has implications for predicting the evolution of the Indian Ocean-monsoon system under future global warming.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"685 ","pages":"Article 113544"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927943","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}
Pub Date : 2026-03-01Epub Date: 2025-12-22DOI: 10.1016/j.palaeo.2025.113524
Christopher T. Conwell , Matthew R. Saltzman , Anders Lindskog , Mats E. Eriksson , Elizabeth M. Griffith , Stephen A. Leslie , Cole T. Edwards , Olle Hints , Achim D. Herrmann
Despite frequent use of conodonts as an archive for seawater 87Sr/86Sr, available diagenetic screening tools are inconsistent predictors of primary seawater 87Sr/86Sr preservation. Here, we attempt to isolate variables affecting the preservation of seawater 87Sr/86Sr in conodonts. We present new Middle–Late Ordovician (∼470–450 Ma) conodont 87Sr/86Sr from mid-paleolatitude (30–45°S) carbonate successions from central Sweden (Fjäcka, Kårgärde) and Estonia (Uuga Cliff, Viki borehole) which have low Conodont Alteration Index (CAI) values of 1–1.5. Coeval 87Sr/86Sr measurements from Kårgärde and Estonian sections are offset from global seawater by ∼ +2 × 10−4 but preserve the overall structure of the seawater curve, suggesting minor diagenetic Sr exchange. 87Sr/86Sr measurements from the more argillaceous Fjäcka section show extensive alteration with highly radiogenic values as much as ∼6 × 10−4 greater than global seawater and a stratigraphic trend that diverges from the seawater curve. This may be explained by highly radiogenic Sr contribution from the Kinnekulle K-bentonite and Fjäcka shale units that occur at Fjäcka section.
We compiled 1164 conodont 87Sr/86Sr measurements spanning ∼485–250 Ma and categorized measurements by host rock, sample preparation, paleolatitude, and CAI. Boxplots and Mann-Whitney U testing of residual values relative to the seawater curve (87Sr/86Srconodont – 87Sr/86Srseawater) reveal that paleolatitude and associated differences in sedimentation rate affect preservation of seawater 87Sr/86Sr values in conodonts. The relative abundance of clay minerals did not significantly correlate with residual values for conodonts from mid- or low-latitude deposits. We recommend that future investigations of seawater 87Sr/86Sr records using conodont apatite target low-latitude settings with high sedimentation rate and CAI ≤ 2.
{"title":"Factors affecting 87Sr/86Sr preservation in conodont apatite: An example from the Ordovician of Baltoscandia","authors":"Christopher T. Conwell , Matthew R. Saltzman , Anders Lindskog , Mats E. Eriksson , Elizabeth M. Griffith , Stephen A. Leslie , Cole T. Edwards , Olle Hints , Achim D. Herrmann","doi":"10.1016/j.palaeo.2025.113524","DOIUrl":"10.1016/j.palaeo.2025.113524","url":null,"abstract":"<div><div>Despite frequent use of conodonts as an archive for seawater <sup>87</sup>Sr/<sup>86</sup>Sr, available diagenetic screening tools are inconsistent predictors of primary seawater <sup>87</sup>Sr/<sup>86</sup>Sr preservation. Here, we attempt to isolate variables affecting the preservation of seawater <sup>87</sup>Sr/<sup>86</sup>Sr in conodonts. We present new Middle–Late Ordovician (∼470–450 Ma) conodont <sup>87</sup>Sr/<sup>86</sup>Sr from mid-paleolatitude (30–45°S) carbonate successions from central Sweden (Fjäcka, Kårgärde) and Estonia (Uuga Cliff, Viki borehole) which have low Conodont Alteration Index (CAI) values of 1–1.5. Coeval <sup>87</sup>Sr/<sup>86</sup>Sr measurements from Kårgärde and Estonian sections are offset from global seawater by ∼ +2 × 10<sup>−4</sup> but preserve the overall structure of the seawater curve, suggesting minor diagenetic Sr exchange. <sup>87</sup>Sr/<sup>86</sup>Sr measurements from the more argillaceous Fjäcka section show extensive alteration with highly radiogenic values as much as ∼6 × 10<sup>−4</sup> greater than global seawater and a stratigraphic trend that diverges from the seawater curve. This may be explained by highly radiogenic Sr contribution from the Kinnekulle K-bentonite and Fjäcka shale units that occur at Fjäcka section.</div><div>We compiled 1164 conodont <sup>87</sup>Sr/<sup>86</sup>Sr measurements spanning ∼485–250 Ma and categorized measurements by host rock, sample preparation, paleolatitude, and CAI. Boxplots and Mann-Whitney U testing of residual values relative to the seawater curve (<sup>87</sup>Sr/<sup>86</sup>Sr<sub>conodont</sub> – <sup>87</sup>Sr/<sup>86</sup>Sr<sub>seawater</sub>) reveal that paleolatitude and associated differences in sedimentation rate affect preservation of seawater <sup>87</sup>Sr/<sup>86</sup>Sr values in conodonts. The relative abundance of clay minerals did not significantly correlate with residual values for conodonts from mid- or low-latitude deposits. We recommend that future investigations of seawater <sup>87</sup>Sr/<sup>86</sup>Sr records using conodont apatite target low-latitude settings with high sedimentation rate and CAI ≤ 2.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"685 ","pages":"Article 113524"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145872109","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}
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