Palaeogeography, Palaeoclimatology, Palaeoecology最新文献_第7页

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

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub 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。

{"title":"Late Miocene tectonic reorganization and regional development of thrust faulting in the northeastern Tibetan Plateau","authors":"Hao Xie , Caicai Liu , Dewen Zheng , Ying Wang , Jingxing Yu , Xudong Zhao , Zhuqi Zhang , Li Deng , Jiawei Zhang , Huiping Zhang","doi":"10.1016/j.palaeo.2025.113522","DOIUrl":"10.1016/j.palaeo.2025.113522","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113522"},"PeriodicalIF":2.7,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842089","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

Factors affecting 87Sr/86Sr preservation in conodont apatite: An example from the Ordovician of Baltoscandia 影响牙形石磷灰石87Sr/86Sr保存的因素——以巴尔托斯坎迪亚奥陶系为例

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-12-22 DOI: 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/⁸⁶Sr_conodont – ⁸⁷Sr/⁸⁶Sr_seawater) 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.

尽管牙形刺经常被用作海水87Sr/86Sr的存档，但现有的成岩筛选工具对原生海水87Sr/86Sr保存的预测并不一致。在这里，我们试图分离影响海水87Sr/86Sr在牙形刺中保存的变量。我们在瑞典中部（Fjäcka, Kårgärde）和爱沙尼亚（Uuga Cliff， Viki钻孔）的中古纬度（30-45°S）碳酸盐岩地层中发现了新的中晚奥陶世（~ 470-450 Ma）牙形石87Sr/86Sr，牙形石蚀变指数（CAI）值较低，为1-1.5。Kårgärde和爱沙尼亚剖面的同期87Sr/86Sr测量值与全球海水偏移了~ +2 × 10−4，但保留了海水曲线的整体结构，表明存在轻微的成岩Sr交换。较泥质Fjäcka剖面的87Sr/86Sr测量显示广泛的蚀变，高放射性成因值比全球海水高~ 6 × 10−4，地层趋势偏离海水曲线。这可能是由于Fjäcka剖面的Kinnekulle k -膨润土和Fjäcka页岩单元对Sr的高放射性贡献所致。我们收集了1164个牙形石87Sr/86Sr测量值，跨度为485-250 Ma，并根据宿主岩石、样品制备、古纬度和CAI对测量值进行了分类。箱形图和相对于海水曲线（87Sr/ 86srconodon - 87Sr/ 86sr海水）的残差值Mann-Whitney U检验表明，古纬度和相关的沉积速率差异影响了海水87Sr/86Sr值在牙形刺中的保存。粘土矿物的相对丰度与中、低纬度沉积物中牙形刺的残值没有显著相关性。建议今后研究海水87Sr/86Sr记录时，采用牙形石磷灰石目标低纬、高沉积速率、CAI≤2的环境。

{"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":"2025-12-22","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}

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

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub 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 , Anil K. Gupta , Prasanta Sanyal , Priyantan Gupta , Som Dutt , Pankaj Kumar , 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":"2025-12-22","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

Corrigendum to “Orbital-scale palaeoclimate and palaeoceanographic evolution in the late Permian Western Hubei Trough, South China” [Palaeogeography, Palaeoclimatology, Palaeoecology (2025) 113466] “中国南方鄂西海槽晚二叠世轨道尺度古气候和古海洋演化”勘误表[古地理，古气候，古生态（2025）113466]

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-12-20 DOI: 10.1016/j.palaeo.2025.113507

Shuaicai Wu , Lei Chen , Wen Liu , Weiliang Kong , Min Xiong , Xiangyu Liu , Xiucheng Tan , Zuyou Zhang , Chongjie Liao

引用次数: 0

Reduction in the rate of exhumation of the Gangdese Mountains (Tibetan Plateau) through the Neogene and its implications for crustal shortening of the Himalaya

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-12-18 DOI: 10.1016/j.palaeo.2025.113514

Jie Wei, An Wang, Tianyi Shen, Ganyu Lyu, Haoruo Li, Guocan Wang

During the Neogene, the crustal deformation in the southern Tibetan Plateau propagated southward from the Gangdese Mountains to the Himalaya. This propagation provides a perspective for exploring Himalayan crustal shortening and topographic development through the tectonic history of the Gangdese Mountains. In this paper, we present new thermochronological data (16 apatite (UTh)/He, 25 apatite fission-track, and 23 zircon fission-track ages) from the southern Gangdese Mountains, which delineate a detailed history of attenuating rates of exhumation during the Neogene. Specifically, the southern margin of the Gangdese Mountains is characterized by a rapid exhumation (∼1.08 mm/yr) in the early Miocene, followed by a moderate rate of ∼0.27 mm/yr between 16 and 11 Ma, and subsequently a steady, lower exhumation rate of ∼0.18 mm/yr since 11–8 Ma. These progressively decreasing exhumation rates, interpreted as tectonically driven and coupled with the southward propagation of deformation in the Himalaya, correspond to an inverse correlation in partitioned shortening rates between the Himalaya and the Gangdese Mountains. This relationship enables a first-order estimation of Himalayan crustal shortening based on the tectonically determined exhumation rate in the Gangdese Mountains. Our data and analysis estimate total Neogene crustal shortening of ∼417–522 km across Himalaya, consistent with previous structural studies. Crustal thickening predicted by this shortening supports the interpretation that the modern crustal thickness and paleoelevation of the Himalaya were largely attained by the late Miocene.

这种传播为通过冈底斯山脉的构造史研究喜马拉雅地壳缩短和地形发育提供了新的视角。本文介绍了冈底斯山脉南部16个磷灰石(UTh)/He年龄、25个磷灰石裂变径迹年龄和23个锆石裂变径迹年龄的热年代学资料，详细描述了冈底斯山脉南部新近纪的出土衰减速率。具体而言，冈底斯山脉南缘在中新世早期具有快速的出土速度（~ 1.08 mm/yr），随后在16 ~ 11 Ma之间有中等的出土速度（~ 0.27 mm/yr），随后在11 ~ 8 Ma以来有稳定的较低的出土速度（~ 0.18 mm/yr）。这些逐渐减少的掘出率被解释为构造驱动，并与喜马拉雅地区的变形向南传播相结合，对应于喜马拉雅和冈底斯山脉之间的分区缩短率呈负相关。这一关系使我们能够根据冈底斯山脉构造确定的掘出速率对喜马拉雅地壳缩短进行一阶估计。我们的数据和分析估计整个喜马拉雅地区新近纪地壳总缩短约417-522公里，与之前的结构研究一致。这一缩短预测的地壳增厚支持了喜马拉雅现代地壳厚度和古海拔主要在晚中新世达到的解释。

{"title":"Reduction in the rate of exhumation of the Gangdese Mountains (Tibetan Plateau) through the Neogene and its implications for crustal shortening of the Himalaya","authors":"Jie Wei, An Wang, Tianyi Shen, Ganyu Lyu, Haoruo Li, Guocan Wang","doi":"10.1016/j.palaeo.2025.113514","DOIUrl":"10.1016/j.palaeo.2025.113514","url":null,"abstract":"<div><div>During the Neogene, the crustal deformation in the southern Tibetan Plateau propagated southward from the Gangdese Mountains to the Himalaya. This propagation provides a perspective for exploring Himalayan crustal shortening and topographic development through the tectonic history of the Gangdese Mountains. In this paper, we present new thermochronological data (16 apatite (U<img>Th)/He, 25 apatite fission-track, and 23 zircon fission-track ages) from the southern Gangdese Mountains, which delineate a detailed history of attenuating rates of exhumation during the Neogene. Specifically, the southern margin of the Gangdese Mountains is characterized by a rapid exhumation (∼1.08 mm/yr) in the early Miocene, followed by a moderate rate of ∼0.27 mm/yr between 16 and 11 Ma, and subsequently a steady, lower exhumation rate of ∼0.18 mm/yr since 11–8 Ma. These progressively decreasing exhumation rates, interpreted as tectonically driven and coupled with the southward propagation of deformation in the Himalaya, correspond to an inverse correlation in partitioned shortening rates between the Himalaya and the Gangdese Mountains. This relationship enables a first-order estimation of Himalayan crustal shortening based on the tectonically determined exhumation rate in the Gangdese Mountains. Our data and analysis estimate total Neogene crustal shortening of ∼417–522 km across Himalaya, consistent with previous structural studies. Crustal thickening predicted by this shortening supports the interpretation that the modern crustal thickness and paleoelevation of the Himalaya were largely attained by the late Miocene.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113514"},"PeriodicalIF":2.7,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799341","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

New insights into the Neogene sedimentary Formations of south-western India: Implications for provenance, palaeovegetation and depositional environment 印度西南部新近纪沉积地层的新认识：物源、古植被和沉积环境的意义

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-12-18 DOI: 10.1016/j.palaeo.2025.113499

K.V. Sarath , K. Sandeep , Alka Absur , Namitha Ajay , Poonam Verma , Yogesh P. Singh , A.K. Rafaz , V. Nandakumar , G. Indu , E. Shaji

The Warkalli Formation represents a key Neogene sedimentary archive along the south-western coast of India. This study examines the northern extension of the Formation exposed around Cheruvathur village, Kerala, integrating sedimentological, geochemical, and palynological data to reconstruct provenance, weathering conditions, palaeovegetation, and depositional environment. The succession is composed of arenaceous–argillaceous sediments capped by laterite and is classified into four facies associations: floodplain, active channel, lagoonal/lacustrine, and dune–beach transition facies, indicating major shifts in fluvial dynamics and changes in the coastline. Extremely high values of Chemical Index of Alteration and Fe-Al enrichment suggest intense tropical chemical weathering and derivation from nearby felsic to intermediate basement rocks, with minor mafic contributions. Pollen spectra dominated by pteridophyte spores and angiosperm pollen, along with fungal remains, indicate warm and humid climatic conditions with freshwater to coastal vegetation and episodic tidal influence. These observations collectively imply strong monsoonal forcing, short sediment transport, and fluctuating sea levels during the Mio-Pliocene. The study provides new insights into Neogene palaeoenvironmental evolution along the passive western margin of India and highlights the climatic sensitivity of tropical coastal depositional systems.

瓦尔卡利组代表了印度西南海岸一个重要的新近纪沉积档案。本研究考察了喀拉拉邦Cheruvathur村附近暴露的组北延伸，综合沉积学、地球化学和孢粉学数据，重建了物源、风化条件、古植被和沉积环境。该序列由红土覆盖的砂质-泥质沉积物组成，并划分为四个相组合：洪泛平原、活动水道、泻湖/湖泊和沙丘-海滩过渡相，表明河流动力学和海岸线的主要变化。异常高的蚀变化学指数和Fe-Al富集表明强烈的热带化学风化作用和从附近长英质到中间基岩的演化，基性贡献较小。以蕨类植物孢子和被子植物花粉为主的花粉谱，以及真菌残留物，表明气候条件温暖潮湿，淡水到沿海植被和潮汐的间歇性影响。这些观测结果共同暗示了在中新世-上新世期间强烈的季风强迫、短暂的沉积物输运和波动的海平面。该研究为研究印度被动西缘新近纪古环境演化提供了新的见解，并突出了热带海岸沉积体系的气候敏感性。

{"title":"New insights into the Neogene sedimentary Formations of south-western India: Implications for provenance, palaeovegetation and depositional environment","authors":"K.V. Sarath , K. Sandeep , Alka Absur , Namitha Ajay , Poonam Verma , Yogesh P. Singh , A.K. Rafaz , V. Nandakumar , G. Indu , E. Shaji","doi":"10.1016/j.palaeo.2025.113499","DOIUrl":"10.1016/j.palaeo.2025.113499","url":null,"abstract":"<div><div>The Warkalli Formation represents a key Neogene sedimentary archive along the south-western coast of India. This study examines the northern extension of the Formation exposed around Cheruvathur village, Kerala, integrating sedimentological, geochemical, and palynological data to reconstruct provenance, weathering conditions, palaeovegetation, and depositional environment. The succession is composed of arenaceous–argillaceous sediments capped by laterite and is classified into four facies associations: floodplain, active channel, lagoonal/lacustrine, and dune–beach transition facies, indicating major shifts in fluvial dynamics and changes in the coastline. Extremely high values of Chemical Index of Alteration and Fe-Al enrichment suggest intense tropical chemical weathering and derivation from nearby felsic to intermediate basement rocks, with minor mafic contributions. Pollen spectra dominated by pteridophyte spores and angiosperm pollen, along with fungal remains, indicate warm and humid climatic conditions with freshwater to coastal vegetation and episodic tidal influence. These observations collectively imply strong monsoonal forcing, short sediment transport, and fluctuating sea levels during the Mio-Pliocene. The study provides new insights into Neogene palaeoenvironmental evolution along the passive western margin of India and highlights the climatic sensitivity of tropical coastal depositional systems.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113499"},"PeriodicalIF":2.7,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842085","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

Mid-holocene environmental changes and glacial-isostatic uplift recorded in a coastal isolation basin on inexpressible Island, Ross Sea, Antarctica 南极罗斯海不可表达岛海岸隔离盆地中全新世环境变化与冰川均衡隆起记录

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-12-17 DOI: 10.1016/j.palaeo.2025.113516

Shuo Wang , Yuzhu Zhang , Ninglian Wang , Zhiheng Du , Yan Zhu , Peng Cheng , Yuda Chui

Antarctica's postglacial ice-free regions preserve sedimentary archives that are critical for reconstructing relative sea-level (RSL) changes and glacial-isostatic adjustment (GIA). This study presents a 37 cm sediment core from a coastal isolation basin (NYD Lake) on Inexpressible Island in Terra Nova Bay, Ross Sea. The basin's retaining sill is currently 1.1 m above mean sea level. The core spans the past ∼7400 calibrated years and captures a clear environmental transition from a tidal marine setting to a semi-enclosed lacustrine system. Three depositional units are identified: (1) a lower marine unit (below 18 cm; prior to ∼3500 cal yr BP) composed of coarse sand with high sulfur content, indicating strong tidal influence; (2) a transitional unit (18–7 cm) with mixed marine and freshwater signatures, reflecting gradual isolation; and (3) an upper lacustrine unit (above 7 cm; since ∼1700 cal yr BP), characterized by fine silt and organic geochemistry dominated by freshwater algal input but still subject to tidal or wave influence. C/N ratios and δ¹³C values indicate that the source of sedimentary organic matter shifted from a marine–terrestrial mixture to primarily freshwater algal origin after ∼1700 cal yr BP. This transition marks the isolation of the NYD Lake, coinciding with the sill emerging above sea level. Using the sill elevation and the timing of isolation, we estimate a crustal uplift rate of 0.65 ± 0.17 mm/yr. This record provides rare empirical constraints on Holocene RSL changes in the Terra Nova Bay and contributes to improving GIA models and understanding coastal evolution along the western Ross Sea margin.

南极洲冰期后无冰区保存着沉积档案，这些档案对于重建相对海平面（RSL）变化和冰川均衡调整（GIA）至关重要。本文研究了罗斯海特拉诺瓦湾不可表达岛（Inexpressible Island）海岸隔离盆地（NYD Lake）的37 cm沉积物岩心。目前，该盆地的挡土坝高出平均海平面1.1米。岩心跨越过去~ 7400校准年，捕捉了从潮汐海洋环境到半封闭湖泊系统的清晰环境转变。确定了3个沉积单元：(1)较低的海洋单元（低于18 cm；早于~ 3500 cal yr BP），由高含硫量的粗砂组成，表明潮汐的强烈影响；(2)过渡性单元（18-7厘米），具有海洋和淡水混合特征，反映出逐渐隔离；(3)上湖单元（7cm以上；自~ 1700 cal yr BP以来），特征为细粉砂和有机地球化学，以淡水藻类输入为主，但仍受潮汐或波浪影响。C/N比值和δ13C值表明，在~ 1700 cal yr BP之后，沉积有机质的来源从海陆生混合物转变为主要的淡水藻类来源。这种转变标志着纽约湖的孤立，与海平面以上的岩石相吻合。根据基台高程和隔离时间，我们估计地壳隆升速率为0.65±0.17 mm/yr。该记录为特拉诺瓦湾全新世RSL变化提供了罕见的经验约束，有助于改进GIA模型和理解罗斯海西部边缘的沿海演变。

{"title":"Mid-holocene environmental changes and glacial-isostatic uplift recorded in a coastal isolation basin on inexpressible Island, Ross Sea, Antarctica","authors":"Shuo Wang , Yuzhu Zhang , Ninglian Wang , Zhiheng Du , Yan Zhu , Peng Cheng , Yuda Chui","doi":"10.1016/j.palaeo.2025.113516","DOIUrl":"10.1016/j.palaeo.2025.113516","url":null,"abstract":"<div><div>Antarctica's postglacial ice-free regions preserve sedimentary archives that are critical for reconstructing relative sea-level (RSL) changes and glacial-isostatic adjustment (GIA). This study presents a 37 cm sediment core from a coastal isolation basin (NYD Lake) on Inexpressible Island in Terra Nova Bay, Ross Sea. The basin's retaining sill is currently 1.1 m above mean sea level. The core spans the past ∼7400 calibrated years and captures a clear environmental transition from a tidal marine setting to a semi-enclosed lacustrine system. Three depositional units are identified: (1) a lower marine unit (below 18 cm; prior to ∼3500 cal yr BP) composed of coarse sand with high sulfur content, indicating strong tidal influence; (2) a transitional unit (18–7 cm) with mixed marine and freshwater signatures, reflecting gradual isolation; and (3) an upper lacustrine unit (above 7 cm; since ∼1700 cal yr BP), characterized by fine silt and organic geochemistry dominated by freshwater algal input but still subject to tidal or wave influence. C/N ratios and δ<sup>13</sup>C values indicate that the source of sedimentary organic matter shifted from a marine–terrestrial mixture to primarily freshwater algal origin after ∼1700 cal yr BP. This transition marks the isolation of the NYD Lake, coinciding with the sill emerging above sea level. Using the sill elevation and the timing of isolation, we estimate a crustal uplift rate of 0.65 ± 0.17 mm/yr. This record provides rare empirical constraints on Holocene RSL changes in the Terra Nova Bay and contributes to improving GIA models and understanding coastal evolution along the western Ross Sea margin.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113516"},"PeriodicalIF":2.7,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842084","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

Dinoflagellate cyst and vegetational dynamics during the Early Jurassic (late Pliensbachian–early Toarcian) in Tibet

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-12-17 DOI: 10.1016/j.palaeo.2025.113500

Changjun Ji , Ahmed Mansour , Zhenhan Wu , James B. Riding , Yun Chen , Qian Wang

The late Pliensbachian–early Toarcian (Early Jurassic) marks a critical interval in Earth history, characterised by major palaeoclimatic, palaeoenvironmental, and palaeoceanographical perturbations. This study examines the Pliensbachian–Toarcian Quse Formation at the Qixiangcuo section in the Southern Qiangtang Basin (Tibet), using palynological analysis to investigate dinoflagellate cyst evolutionary patterns and vegetation dynamics prior to and during the Jenkyns Event. Palynological data showed a clear record of late Pliensbachian dinoflagellate cyst radiation, likely owing to cooler climatic and enhanced water mass circulation between the Arctic-Boreal and Tethyan realms. Prior to the Jenkyns Event, a dinoflagellate cyst acme is observed, possibly controlled by sea-level rise, increased seawater salinity, and well-ventilated conditions. During the Jenkyns Event, a blackout event of dinoflagellate cysts occurred in the Southern Qiangtang Basin, consistent with records from the central Tethys and Boreal regions, likely triggered by global warming and rising seawater temperatures. Pollen assemblages across the Pliensbachian-Toarcian transition are dominated by Cheirolepidiaceae conifers (Classopollis), compared to reduced cycadophytes, bennettites, and ginkgophytes, and sparse fern spores. This reflects a vegetation turnover towards xerophytic, drought-tolerant vegetation in arid lowland environments, likely linked to the initial phase of Karoo-Ferrar volcanism. During the Jenkyns Event, Cheirolepid coniferous pollen remained dominant before temporarily disappearing, indicating a demise of mixed wet mire-conifer communities and a shift towards drought-adapted flora. Similar patterns of deforestation and vegetation crisis are observed across the Tethys and Boreal realms, contemporaneous with the main phase of the Karoo-Ferrar volcanism and rising atmospheric CO₂. Regional comparisons of vegetation response across the Jenkyns Event reflect different magnitudes of predominance and recovery patterns in Cheirolepid conifers.

pliensbachia - Toarcian Early侏罗世是地球历史上一个以古气候、古环境和古海洋扰动为主要特征的关键时期。孢粉学数据显示了Pliensbachian晚期鞭毛藻囊辐射的清晰记录，可能是由于北极-北方和特提斯领域之间较冷的气候和增强的水团循环。在詹金斯事件之前，观察到甲藻囊肿顶点，可能由海平面上升，海水盐度增加和通风良好的条件控制。在詹金斯事件期间，在羌塘盆地南部发生了甲藻囊肿的停电事件，与特提斯中部和北方地区的记录一致，可能是由全球变暖和海水温度上升引发的。在pliensbachia - toarcian过渡时期，花粉组合以Cheirolepidiaceae针叶树（Classopollis）为主，相比之下，减少了苏铁植物、贝尼特植物和银杏植物，以及稀疏的蕨类孢子。这反映了干旱低地环境中植被向旱生耐旱植被的转变，可能与Karoo-Ferrar火山活动的初始阶段有关。在詹金斯事件期间，Cheirolepid针叶树花粉在暂时消失之前仍然占主导地位，这表明湿泥针叶树混合群落的消亡和向适应干旱的植物群的转变。在特提斯和北方地区也观察到类似的森林砍伐和植被危机模式，与Karoo-Ferrar火山活动的主要阶段和大气中二氧化碳的上升同时发生。在詹金斯事件中植被响应的区域比较反映了不同程度的优势和恢复模式。

{"title":"Dinoflagellate cyst and vegetational dynamics during the Early Jurassic (late Pliensbachian–early Toarcian) in Tibet","authors":"Changjun Ji , Ahmed Mansour , Zhenhan Wu , James B. Riding , Yun Chen , Qian Wang","doi":"10.1016/j.palaeo.2025.113500","DOIUrl":"10.1016/j.palaeo.2025.113500","url":null,"abstract":"<div><div>The late Pliensbachian–early Toarcian (Early Jurassic) marks a critical interval in Earth history, characterised by major palaeoclimatic, palaeoenvironmental, and palaeoceanographical perturbations. This study examines the Pliensbachian–Toarcian Quse Formation at the Qixiangcuo section in the Southern Qiangtang Basin (Tibet), using palynological analysis to investigate dinoflagellate cyst evolutionary patterns and vegetation dynamics prior to and during the Jenkyns Event. Palynological data showed a clear record of late Pliensbachian dinoflagellate cyst radiation, likely owing to cooler climatic and enhanced water mass circulation between the Arctic-Boreal and Tethyan realms. Prior to the Jenkyns Event, a dinoflagellate cyst acme is observed, possibly controlled by sea-level rise, increased seawater salinity, and well-ventilated conditions. During the Jenkyns Event, a blackout event of dinoflagellate cysts occurred in the Southern Qiangtang Basin, consistent with records from the central Tethys and Boreal regions, likely triggered by global warming and rising seawater temperatures. Pollen assemblages across the Pliensbachian-Toarcian transition are dominated by Cheirolepidiaceae conifers (<em>Classopollis</em>), compared to reduced cycadophytes, bennettites, and ginkgophytes, and sparse fern spores. This reflects a vegetation turnover towards xerophytic, drought-tolerant vegetation in arid lowland environments, likely linked to the initial phase of Karoo-Ferrar volcanism. During the Jenkyns Event, Cheirolepid coniferous pollen remained dominant before temporarily disappearing, indicating a demise of mixed wet mire-conifer communities and a shift towards drought-adapted flora. Similar patterns of deforestation and vegetation crisis are observed across the Tethys and Boreal realms, contemporaneous with the main phase of the Karoo-Ferrar volcanism and rising atmospheric CO<sub>2</sub>. Regional comparisons of vegetation response across the Jenkyns Event reflect different magnitudes of predominance and recovery patterns in Cheirolepid conifers.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113500"},"PeriodicalIF":2.7,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799354","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

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

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub 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。

{"title":"Taiwan's land-vertebrate suite: An assemblage forged by tectonism and sea-level shifts","authors":"Jason R. Ali , Uwe Fritz","doi":"10.1016/j.palaeo.2025.113502","DOIUrl":"10.1016/j.palaeo.2025.113502","url":null,"abstract":"<div><div>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 <em>c</em>. 5 Mya. For the first <em>c</em>. 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 <em>c</em>. 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.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113502"},"PeriodicalIF":2.7,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885191","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

Vegetation responses to the mid-Holocene abrupt climate events in the Forest-Steppe Ecotone in northern China 中国北方森林-草原交错带植被对中全新世气候突变事件的响应

IF 2.7 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-12-16 DOI: 10.1016/j.palaeo.2025.113506

Yao Zhang , Lili Niu , Qiaoyu Cui , Yi Lin , Zhiping Zhang , Jiaju Zhao , Xinwei Yan , Aifeng Zhou

Vegetation ecosystems in the East Asian monsoon margin in northern China are highly sensitive and ecologically vulnerable. Understanding long-term vegetation dynamics and their responses to abrupt climate events is critical for guiding ecological conservation and sustainable land-use planning. In this study, we reconstructed vegetation dynamics using a high-resolution pollen record from the Qixing peatland in the Saihanba region. Results indicated that climate was the primary driver of vegetation changes, while temperature and precipitation variations were asynchronous. The mid-Holocene was characterized by maximum precipitation; however, an abrupt cooling event between 7000 and 5500 cal yr BP triggered a rapid decline in deciduous broadleaf trees alongside a concurrent expansion of herbaceous vegetation, ultimately leading to steppe-dominated ecosystems. This transition was accompanied by reduced vegetation diversity and increased spatial heterogeneity. Subsequently, coniferous forests dominated by Pinus, as a major component of the secondary vegetation, became prevalent. However, a sudden shift to aridity around 5000 cal yr BP associated with the weakening of the East Asian summer monsoon prompted a rapid spread of herbs, along with a recovery in diversity and evenness. This study demonstrates that abrupt climate shifts caused forest retreat and grassland expansion once critical climatic thresholds were exceeded across the monsoon marginal zone. Given the current context of accelerated climate warming and increasingly frequent extreme climatic events, urgent protective measures are essential for these highly vulnerable ecosystems.

中国北方东亚季风边缘植被生态系统具有高度敏感性和生态脆弱性。了解植被长期动态及其对气候突变事件的响应对于指导生态保护和土地利用可持续规划具有重要意义。本文利用塞罕坝地区七星泥炭地的高分辨率花粉记录重建了植被动态。结果表明，气候是植被变化的主要驱动力，而温度和降水的变化是不同步的。中全新世以最大降水为特征；然而，在7000 - 5500 cal - yr BP之间的一次突然变冷事件引发了落叶阔叶树的迅速减少，同时草本植被的扩张，最终导致了草原为主的生态系统。这一转变伴随着植被多样性的减少和空间异质性的增加。随后，以松林为主的针叶林成为次生植被的主要组成部分。然而，在距今5000万年左右，东亚夏季风减弱导致了干旱的突然转变，促使草本植物迅速传播，多样性和均匀性也随之恢复。该研究表明，一旦超过季风边缘带的临界气候阈值，气候突变会导致森林退缩和草地扩张。在当前气候变暖加速和极端气候事件日益频繁的背景下，对这些高度脆弱的生态系统采取紧急保护措施至关重要。

{"title":"Vegetation responses to the mid-Holocene abrupt climate events in the Forest-Steppe Ecotone in northern China","authors":"Yao Zhang , Lili Niu , Qiaoyu Cui , Yi Lin , Zhiping Zhang , Jiaju Zhao , Xinwei Yan , Aifeng Zhou","doi":"10.1016/j.palaeo.2025.113506","DOIUrl":"10.1016/j.palaeo.2025.113506","url":null,"abstract":"<div><div>Vegetation ecosystems in the East Asian monsoon margin in northern China are highly sensitive and ecologically vulnerable. Understanding long-term vegetation dynamics and their responses to abrupt climate events is critical for guiding ecological conservation and sustainable land-use planning. In this study, we reconstructed vegetation dynamics using a high-resolution pollen record from the Qixing peatland in the Saihanba region. Results indicated that climate was the primary driver of vegetation changes, while temperature and precipitation variations were asynchronous. The mid-Holocene was characterized by maximum precipitation; however, an abrupt cooling event between 7000 and 5500 cal yr BP triggered a rapid decline in deciduous broadleaf trees alongside a concurrent expansion of herbaceous vegetation, ultimately leading to steppe-dominated ecosystems. This transition was accompanied by reduced vegetation diversity and increased spatial heterogeneity. Subsequently, coniferous forests dominated by <em>Pinus</em>, as a major component of the secondary vegetation, became prevalent. However, a sudden shift to aridity around 5000 cal yr BP associated with the weakening of the East Asian summer monsoon prompted a rapid spread of herbs, along with a recovery in diversity and evenness. This study demonstrates that abrupt climate shifts caused forest retreat and grassland expansion once critical climatic thresholds were exceeded across the monsoon marginal zone. Given the current context of accelerated climate warming and increasingly frequent extreme climatic events, urgent protective measures are essential for these highly vulnerable ecosystems.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113506"},"PeriodicalIF":2.7,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799344","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