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

Hydroclimatic evolution of the southwestern Tibetan Plateau since the last glacial maximum inferred from multi-proxy data in Lake Zabuye

IF 2.6 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-02-11 DOI: 10.1016/j.palaeo.2025.112809

Yuan Ling , Fangang Zeng , James Bendle , Jun Cheng , Long Zhang , Yong Wang , Lijun Tian

Hydroclimatic variations on the Tibetan Plateau since the Last Glacial Maximum (LGM) are still debated. Here, we reconstructed climatic and hydrological variability in the southwestern Tibetan Plateau since the LGM using climate proxies based on molecular distributions of n-alkanes, hydrogen (δD) and carbon (δ¹³C) isotopic compositions of terrestrial n-alkanes from sediments, and oxygen isotopic composition (δ¹⁸O) of authigenic carbonate at Lake Zabuye. The impact of climatic and environmental factors on these multiple proxies was discussed, and the TraCE-21 ka simulation was employed to facilitate a comprehensive model-data comparison. Our findings indicate that the δD of nC₃₁ alkane in this lake was primarily influenced by temperature from the LGM to early deglaciation period, shifting to a predominance of precipitation influence from the Heinrich event 1 (H1) to the Holocene period. In contrast, the carbonate δ¹⁸O was found to be primarily governed by evaporative processes. Through comprehensive analysis of all proxies, we suggest that Lake Zabuye was dominated by the mid-latitude westerlies with cold and moist conditions from the LGM to early deglaciation. The H1 and Younger Dryas events were characterized by low temperatures and reduced precipitation due to the influence of the moderately intensified westerlies. The Indian summer monsoon (ISM) intensified during the Bølling/Allerød period, and its strength was comparable to that of the westerlies, resulting in plentiful rainfall and high evaporation. The ISM was dominant during the Holocene, characterized by abundant rainfall and high evaporation.

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引用次数: 0

Dominance of coralline algae in the South China Sea: Insights into their responses to paleoceanographic events over the last 20 million years

IF 2.6 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-02-10 DOI: 10.1016/j.palaeo.2025.112805

Yinqiang Li , Kefu Yu , Lizeng Bian , Baoqing Hu , Zhiheng Liao , Shengmin Huang , Zhiguang Song , Weihua Liao

The evolution of Earth's climate is primarily reconstructed from deep-sea cores, while data from shallow-water carbonate successions play only a supplementary role. Furthermore, most available information originates from Western Europe, with limited data from the Middle East and almost none from the Americas and the Far East. While there has been significant discussion on the response of coralline algae to sea-level changes, their reactions to other paleoceanographic events and the long-term trends in their composition, abundance, and richness remain poorly understood. This study examines coralline algae in the carbonate rocks of Well CK2 in the northern South China Sea. A total of twelve genera, eight families, and three orders of coralline algae were identified in 666 petrologic thin sections. Coralline algal abundance was relatively high, between 10 and 4.28 Ma. In the early Miocene, coralline algal richness exhibited three distinct increases at 17.55 Ma, 17.45 Ma, and 17.44 Ma, corresponding to the Miocene Climate Optimum, likely as a response to global warming during this period. The distribution of Mesophyllum declined in response to a series of cooling events over the past 20 million years. Between 14.13 and 8.77 Ma, the concentration of Aethesolithon corresponded to a long-term sea-level fall, while its extinction indicated a rapid sea-level rise. At 6.71 Ma, the increasing abundance of Lithothamnion aligned with a rapid sea-level rise. A relative sea-level fall at 10 Ma was recorded by an increase in shallow-water coralline algae, which may be linked to regional uplift caused by the Dongsha movement. The algal distribution in the Xisha Islands reflects major geological and climatic events over the past 20 million years, underscoring the value of coralline algae as indicators of past climatic and environmental changes. These findings provide a new perspective on the late Cenozoic carbonate systems of the Far East.

{"title":"Dominance of coralline algae in the South China Sea: Insights into their responses to paleoceanographic events over the last 20 million years","authors":"Yinqiang Li , Kefu Yu , Lizeng Bian , Baoqing Hu , Zhiheng Liao , Shengmin Huang , Zhiguang Song , Weihua Liao","doi":"10.1016/j.palaeo.2025.112805","DOIUrl":"10.1016/j.palaeo.2025.112805","url":null,"abstract":"<div><div>The evolution of Earth's climate is primarily reconstructed from deep-sea cores, while data from shallow-water carbonate successions play only a supplementary role. Furthermore, most available information originates from Western Europe, with limited data from the Middle East and almost none from the Americas and the Far East. While there has been significant discussion on the response of coralline algae to sea-level changes, their reactions to other paleoceanographic events and the long-term trends in their composition, abundance, and richness remain poorly understood. This study examines coralline algae in the carbonate rocks of Well CK2 in the northern South China Sea. A total of twelve genera, eight families, and three orders of coralline algae were identified in 666 petrologic thin sections. Coralline algal abundance was relatively high, between 10 and 4.28 Ma. In the early Miocene, coralline algal richness exhibited three distinct increases at 17.55 Ma, 17.45 Ma, and 17.44 Ma, corresponding to the Miocene Climate Optimum, likely as a response to global warming during this period. The distribution of <em>Mesophyllum</em> declined in response to a series of cooling events over the past 20 million years. Between 14.13 and 8.77 Ma, the concentration of <em>Aethesolithon</em> corresponded to a long-term sea-level fall, while its extinction indicated a rapid sea-level rise. At 6.71 Ma, the increasing abundance of <em>Lithothamnion</em> aligned with a rapid sea-level rise. A relative sea-level fall at 10 Ma was recorded by an increase in shallow-water coralline algae, which may be linked to regional uplift caused by the Dongsha movement. The algal distribution in the Xisha Islands reflects major geological and climatic events over the past 20 million years, underscoring the value of coralline algae as indicators of past climatic and environmental changes. These findings provide a new perspective on the late Cenozoic carbonate systems of the Far East.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"663 ","pages":"Article 112805"},"PeriodicalIF":2.6,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387256","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

Late Miocene weakening of the South Asian Monsoon: Insights from the Siwalik of Nepal

IF 2.6 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-02-07 DOI: 10.1016/j.palaeo.2025.112789

Purushottam Adhikari , Gaurav Srivastava , Alexander Farnsworth , Harshita Bhatia , Sadanand , Sujata Poudel , Robert A. Spicer , Lalit K. Rai , Su Tao , Paul J. Valdes , Khum N. Paudayal

The South Asian Monsoon (SAM) is the strong summer monsoon within the Asian Monsoon System, driven by the thermal gradient between the warmer Asian landmass and the cooler Indian Ocean. High-resolution marine proxies indicate a decline in SAM strength after approximately 10 million years ago (Ma); however, terrestrial evidence has been limited. We present high-resolution and well-dated leaf assemblages from the Lower and Middle Siwalik of central Nepal, supported by paleoclimate modelling, which suggest a weakening of the SAM between 10.24 and 8.5 Ma. This decline is linked to a reduction in moisture supply, possibly due to a weakening of the Somali Jet. Our study highlights the potential of leaf physiognomy to reconstruct monsoon strength.

引用次数: 0

Huanan Ocean remained active from Neoproterozoic to Cambrian: Evidence from stratigraphic sequences and paleoocean-related remnants in South China

IF 2.6 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-02-07 DOI: 10.1016/j.palaeo.2025.112806

Weihong He , Elizabeth A. Weldon , Kexin Zhang , Jianjun Bu , Tianyu Zhao , Yadong Xu , Chen Wu , Yafei Huang , Guitang Pan

The timing of the assembly of the Yangtze Block with the Cathaysia Block has been disputed for a long time. Tectonics partly controlled deposition and stratigraphy, and consequently observable changes in the lithologic features and sequences provide insights into the evolution of the paleogeographic and tectonic settings. This study analyzes stratigraphic sequences from the Neoproterozoic (from ca. 820 Ma or late Tonian) to the Cambrian from six areas/sites across the Yangtze and Cathaysia blocks, three from each block. The contrasts in the depositional features and stratigraphic sequences reveal that the paleogeographic settings were different in the two blocks. The Yangtze Block evolved from a rift basin to a carbonate platform whereas deposition occurred in a pelagic to hemipelagic setting in Cathaysia in the late Tonian to the Cambrian. During the Cryogenian, sediments typical of a glacial setting were commonly recorded in the Yangtze Block but were absent in Cathaysia. In the upper Tonian to the Cryogenian tuffaceous sediments were occasionally discovered in the Yangtze Block, but in Cathaysia, igneous rocks (from acidic to intermediate, and basic or even ultrabasic) were commonly found. These contrasts indicate that the Yangtze and Cathaysia blocks were separate, and located far apart, leading to differences in the depositional and climate settings. Also, the difference in magmatism records suggests that the Yangtze Block was situated along a passive continental margin, whereas Cathaysia was in an active tectonic setting (subduction of paleoocean) in the Tethys Tectonic Domain.

The records of spatio-temporal distribution of paleoocean-related remnants further infer that at least two basins of the Huanan Ocean (= South China Ocean) could have been developed in the late Tonian to the early Paleozoic, the Jiang-Shao oceanic basin probably subducted eastward, and the Zhenghe-Dabu oceanic basin subducted westward.

{"title":"Huanan Ocean remained active from Neoproterozoic to Cambrian: Evidence from stratigraphic sequences and paleoocean-related remnants in South China","authors":"Weihong He , Elizabeth A. Weldon , Kexin Zhang , Jianjun Bu , Tianyu Zhao , Yadong Xu , Chen Wu , Yafei Huang , Guitang Pan","doi":"10.1016/j.palaeo.2025.112806","DOIUrl":"10.1016/j.palaeo.2025.112806","url":null,"abstract":"<div><div>The timing of the assembly of the Yangtze Block with the Cathaysia Block has been disputed for a long time. Tectonics partly controlled deposition and stratigraphy, and consequently observable changes in the lithologic features and sequences provide insights into the evolution of the paleogeographic and tectonic settings. This study analyzes stratigraphic sequences from the Neoproterozoic (from ca. 820 Ma or late Tonian) to the Cambrian from six areas/sites across the Yangtze and Cathaysia blocks, three from each block. The contrasts in the depositional features and stratigraphic sequences reveal that the paleogeographic settings were different in the two blocks. The Yangtze Block evolved from a rift basin to a carbonate platform whereas deposition occurred in a pelagic to hemipelagic setting in Cathaysia in the late Tonian to the Cambrian. During the Cryogenian, sediments typical of a glacial setting were commonly recorded in the Yangtze Block but were absent in Cathaysia. In the upper Tonian to the Cryogenian tuffaceous sediments were occasionally discovered in the Yangtze Block, but in Cathaysia, igneous rocks (from acidic to intermediate, and basic or even ultrabasic) were commonly found. These contrasts indicate that the Yangtze and Cathaysia blocks were separate, and located far apart, leading to differences in the depositional and climate settings. Also, the difference in magmatism records suggests that the Yangtze Block was situated along a passive continental margin, whereas Cathaysia was in an active tectonic setting (subduction of paleoocean) in the Tethys Tectonic Domain.</div><div>The records of spatio-temporal distribution of paleoocean-related remnants further infer that at least two basins of the Huanan Ocean (= South China Ocean) could have been developed in the late Tonian to the early Paleozoic, the Jiang-Shao oceanic basin probably subducted eastward, and the Zhenghe-Dabu oceanic basin subducted westward.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"664 ","pages":"Article 112806"},"PeriodicalIF":2.6,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420180","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

Sedimentary records of the southern Taiwan Strait since the late Pliocene and implications for sea-level and tectonic changes

IF 2.6 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-02-05 DOI: 10.1016/j.palaeo.2025.112797

Yifeng Zhang , Shaopeng Zheng , Huajian Yao , Yonghang Xu , Liang Yi , Dongyi Li , Youquan Ye , Shanhu Liu , Yonggu Zhang , Lei Xue

The Taiwan Strait, connecting the East China Sea to the north and the South China Sea to the south, lies adjacent to the tectonically active Zhe-Min Uplift and the Taiwan Orogenic belt; however, its sedimentary history, such as geochronology, depositional processes, and controlling factors, remains largely unclear. This report presents an integrated study on a 160-m long sediment core (ZK01) retrieved from the southern Taiwan Strait, in terms of magnetostratigraphy, luminescence dating, and sediment grain-size and color. Our findings indicate that the basal age of core ZK01 was ∼4 Ma, with the Quaternary boundary at a depth of 108 m, and the boundary between the lower and middle Pleistocene (0.77 Ma) at 19 m. Prior to 1.07 Ma, the sediment accumulation rate was relatively stable, ranging from 34.4 to 43.3 m/Ma, suggesting a consistent depositional environment. Between 1.07 and 0.77 Ma, the rate increased to 98 m/Ma, likely linked to regional tectonic activity and climate variability during the Mid-Pleistocene Transition (MPT). Constrained by these geochronological results, sediment grain-size and color indices (L*, a*, and b*) were strongly influenced by sea-level fluctuations during the Plio-Pleistocene epoch, while neritic deposits in the southern Taiwan Strait after the MPT were thinner than those in the Yellow and Bohai Seas, likely resulted from local tectonic uplift.

{"title":"Sedimentary records of the southern Taiwan Strait since the late Pliocene and implications for sea-level and tectonic changes","authors":"Yifeng Zhang , Shaopeng Zheng , Huajian Yao , Yonghang Xu , Liang Yi , Dongyi Li , Youquan Ye , Shanhu Liu , Yonggu Zhang , Lei Xue","doi":"10.1016/j.palaeo.2025.112797","DOIUrl":"10.1016/j.palaeo.2025.112797","url":null,"abstract":"<div><div>The Taiwan Strait, connecting the East China Sea to the north and the South China Sea to the south, lies adjacent to the tectonically active Zhe-Min Uplift and the Taiwan Orogenic belt; however, its sedimentary history, such as geochronology, depositional processes, and controlling factors, remains largely unclear. This report presents an integrated study on a 160-m long sediment core (ZK01) retrieved from the southern Taiwan Strait, in terms of magnetostratigraphy, luminescence dating, and sediment grain-size and color. Our findings indicate that the basal age of core ZK01 was ∼4 Ma, with the Quaternary boundary at a depth of 108 m, and the boundary between the lower and middle Pleistocene (0.77 Ma) at 19 m. Prior to 1.07 Ma, the sediment accumulation rate was relatively stable, ranging from 34.4 to 43.3 m/Ma, suggesting a consistent depositional environment. Between 1.07 and 0.77 Ma, the rate increased to 98 m/Ma, likely linked to regional tectonic activity and climate variability during the Mid-Pleistocene Transition (MPT). Constrained by these geochronological results, sediment grain-size and color indices (L*, a*, and b*) were strongly influenced by sea-level fluctuations during the Plio-Pleistocene epoch, while neritic deposits in the southern Taiwan Strait after the MPT were thinner than those in the Yellow and Bohai Seas, likely resulted from local tectonic uplift.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"663 ","pages":"Article 112797"},"PeriodicalIF":2.6,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378439","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

Palaeosols interbedded with overland flood deposits in a Holocene slope alluvium succession, Serra do Pasmar, Southeast Brazil: Implications for palaeoclimate evolution and anthropogenic influences

IF 2.6 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-02-05 DOI: 10.1016/j.palaeo.2025.112795

Giorgio Basilici , Juraj Janočko , Selma Simões de Castro , Paolo Lorenzoni , Paulo Roberto Oliveira da Silva , Áquila Ferreira Mesquita , Alexandre Ribeiro Cardoso , Alvaro Penteado Crósta , Carlos Roberto de Souza Filho , Dailto Silva , Daniele Cirillo , Taísa Rebuá Barroso , Adriana Mercedes Camejo Aviles , Frésia Soledad Ricardi Torres Branco

A Holocene sandy succession of Histosol, “lower interval deposits”, Spodosol and “upper interval deposits”, located at Serra do Espinhaço, SE Brazil, is interpreted as slope alluvium deposits, formed by unconfined water flows at the foot of hillslopes, near the sediment source area. This integrated study of macroscopic, micromorphological and geochemical features of this succession identifies the formative mechanisms that controlled the accumulation of the interbedded palaeosols and deposits.

The “lower interval deposits” and “upper interval deposits” represent the “construction” of a slope alluvium, i.e., the active sedimentation of material, previously weathered and stored on the adjacent bedrock areas, to form slope alluvium. The two palaeosols (Histosol - dated 8339–8049 cal yr BP; Spodosol – dated 1530–1404 cal yr BP) reflect the phase of “accumulation” and pedogenesis on the slope alluvium. The transition from the Histosol to “lower interval deposits” correlates with a sharp decrease of Araucaria forest likely driven by climate change. The transition from the Spodosol to “upper interval deposits” reflects anthropic fire-driven disruption of the original savannah vegetation. Dense vegetation cover promoted pedogenesis by sheltering deposits from erosion and enhancing intense weathering on the adjacent bedrock. Reductions in vegetation cover exposed weathered material on the bedrock, facilitating its erosion, transport and sedimentation on the slope alluvium.

Climatic or anthropogenic factors, which drove an increase and reduction in vegetation cover, appear to have been the primary variables controlling the development of slope alluvium successions in this Holocene inland cratonic area.

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引用次数: 0

Benthic foraminiferal Mg/Ca response across the Aptian-Albian Boundary Interval at DSDP Site 511 (Falkland Plateau)

IF 2.6 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-02-05 DOI: 10.1016/j.palaeo.2025.112769

Barbara Balestra , Brian Huber , Jonathan Chen , Gabriela A. Farfan , Kenneth G. MacLeod , Timothy Rose , Adina Paytan , Timothy Gooding

One of the largest extinctions among planktonic foraminifera occurred across the Aptian-Albian Boundary Interval (AABI), 113 million years ago. The cause of this extinction has not been determined and, paradoxically, no taxonomic turnover has been observed among other fossil groups living at the same time. The study presented here is based on core samples from Deep Sea Drilling Project (DSDP) Site 511 (Falkland Plateau), which yields the most complete record of the planktonic foraminiferal extinction record across the AABI. Stable oxygen and carbon isotopic ratios of carbonate in bulk samples both show a 2.5 ‰ negative excursion spanning ∼1 m.y. above and below the AABI. This research uses a multiproxy approach to investigate if there were significant changes in marine temperatures and/or shifts within the carbonate system that could explain the planktonic foraminiferal extinctions. New data include: 1) X-Ray diffraction analyses of surrounding sediments; 2) Mg/Ca analyses of the cross-sections of the test walls of different benthic foraminifera species in samples that span the AABI using in situ techniques; and 3) δ¹⁸O and δ¹³C on shell and spar, of monospecific separates of foraminiferal species analyzed for Mg/Ca. XRD results reveal that all samples are composed of similar mineral phases occurring in similar proportions. The Mg/Ca results show small changes across the interval suggesting a cooling trend. Finally, the new isotope analyses performed separately on the shell and spar show that the large negative excursion within the boundary interval seem more likely to represent post depositional diagenetic overprints than climatic signal.

{"title":"Benthic foraminiferal Mg/Ca response across the Aptian-Albian Boundary Interval at DSDP Site 511 (Falkland Plateau)","authors":"Barbara Balestra , Brian Huber , Jonathan Chen , Gabriela A. Farfan , Kenneth G. MacLeod , Timothy Rose , Adina Paytan , Timothy Gooding","doi":"10.1016/j.palaeo.2025.112769","DOIUrl":"10.1016/j.palaeo.2025.112769","url":null,"abstract":"<div><div>One of the largest extinctions among planktonic foraminifera occurred across the Aptian-Albian Boundary Interval (AABI), 113 million years ago. The cause of this extinction has not been determined and, paradoxically, no taxonomic turnover has been observed among other fossil groups living at the same time. The study presented here is based on core samples from Deep Sea Drilling Project (DSDP) Site 511 (Falkland Plateau), which yields the most complete record of the planktonic foraminiferal extinction record across the AABI. Stable oxygen and carbon isotopic ratios of carbonate in bulk samples both show a 2.5 ‰ negative excursion spanning ∼1 m.y. above and below the AABI. This research uses a multiproxy approach to investigate if there were significant changes in marine temperatures and/or shifts within the carbonate system that could explain the planktonic foraminiferal extinctions. New data include: 1) X-Ray diffraction analyses of surrounding sediments; 2) Mg/Ca analyses of the cross-sections of the test walls of different benthic foraminifera species in samples that span the AABI using in situ techniques; and 3) δ<sup>18</sup>O and δ<sup>13</sup>C on shell and spar, of monospecific separates of foraminiferal species analyzed for Mg/Ca. XRD results reveal that all samples are composed of similar mineral phases occurring in similar proportions. The Mg/Ca results show small changes across the interval suggesting a cooling trend. Finally, the new isotope analyses performed separately on the shell and spar show that the large negative excursion within the boundary interval seem more likely to represent post depositional diagenetic overprints than climatic signal.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"663 ","pages":"Article 112769"},"PeriodicalIF":2.6,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387310","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

Provenance of the Nantuo Formation in the Shennongjia region: Implications for the paleogeographic position of South China in Rodinia

IF 2.6 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-02-05 DOI: 10.1016/j.palaeo.2025.112793

Lisha Hu , Jie Yang , Yuansheng Du , Zuozhen Han , Chao Han , Wei Jin , Le Wan

The paleogeographic position and role of South China in the Rodinia supercontinent remain controversial. Sedimentary provenance analysis is an effective method for building linkages between continental fragments in supercontinent reconstructions. Systematic investigation of clastic sedimentary rocks in the Nantuo Formation—which preserve records of Rodinia's breakup—will advance our understanding of the paleogeographic evolution of South China during the Cryogenian. Here, we present new U-Pb ages and Hf isotopes of detrital zircons from the Cryogenian Nantuo Formation in the Shennongjia region along the northern margin of the Yangtze Block. Detrital zircons show three dominant age peaks at 820 Ma, 2100–1900 Ma, and 2750–2400 Ma, and one subordinate peak at 650 Ma. The youngest zircon groups yield a weighted average ²⁰⁶Pb/²³⁸U age of 649.8 ± 2.2 Ma, providing a maximum depositional age of ca. 650 Ma for the Nantuo Formation in the Shennongjia region. This age is consistent with the inferred age span (654–635 Ma) of the Nantuo Formation in other areas of South China. Based on the comprehensive analysis of new and published detrital zircon U-Pb ages and Hf isotope data, the clastic rocks of the Nantuo Formation in the Shennongjia region were mainly derived from the northern margin of the Yangtze Block. This result indicates that South China was located either on the periphery of or independent of Rodinia, rather than in its interior. Considering the Cathaysia Block of South China still received detritus from India during the Cryogenian, we suggest that the Yangtze Block was located off India and its combined Cathaysia Block was still linked with India during the Rodinia breakup.

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引用次数: 0

Historical inputs and biogeochemical transformations of dissolved organic matter since 1850 CE in a small plateau-lake, Southwest China

IF 2.6 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-02-04 DOI: 10.1016/j.palaeo.2025.112798

Shuaidong Li , Xiaolei Wang , Jinliang Liu , Yanhui Zhang , Robert G.M. Spencer , Anne M. Kellerman , Amy M. McKenna , Xiaohua Ma , Quanliang Jiang , Tao Huang , Hao Yang , Changchun Huang

Small lakes on the Yunnan-Kweichow Plateau of Southwest China are significant carbon sinks, and highly sensitive recorders of global climate change and human disturbance. However, the lack of robust sediment chronologies makes it challenging to unravel the dynamics of dissolved organic matter (DOM) accumulation in these sedimentary successions, and the driving mechanisms of change over historical timescales. In this paper, we constructed a robust chronology (1850–2019 CE) based on radioactive lead (²¹⁰Pb) for Xihu Lake, and used elemental analysis, optical spectroscopy, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and stable carbon isotopic measurements to evaluate long-term variations in the abundance, source and composition of sedimentary DOM. We found that DOM abundance increased after 2000 CE due to intensive socio-economic activities and climatic warming within the watershed. Stable carbon isotopic results are consistent with spectral parameters, suggesting the additional DOM abundance was mainly derived from annual input from autochthonous aquatic plants. These autochthonous sources shifted the DOM pool into saturated and S-containing aliphatic compound and protein-like fluorescence component, which had higher bio-lability and mineralization potential. After successive mineralization for hundreds of years, sedimentary DOM underwent a transition characterized by reduced bio-lability and increased persistence with time gradients. More oxygenated, aromatic and high-molecular-weight DOM fractions were preserved in deeper and older sediments, which became a key component of lake carbon sinks. Furthermore, massive diagenetic transformations resulted in an increasing tendency in diversity and richness of molecular assemblage. This work provides a comprehensive understanding of historical inputs, degradations and preservations of sedimentary DOM, and offers new insights into our understanding of DOM dynamics from a paleolimnological perspective.

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引用次数: 0

Solar modulation of hydroclimatic patterns in eastern China under influences of the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation

IF 2.6 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Palaeogeography, Palaeoclimatology, Palaeoecology

Pub Date : 2025-02-04 DOI: 10.1016/j.palaeo.2025.112796

Liang Zhang , Yang Liu , Mengxin Bai , Zhixin Hao

This study explores how solar activity modulates hydroclimatic patterns in eastern China (ECHPs) across different phases of the Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO), using the Community Earth System Model-Last Millennium Ensemble dataset and historical hydroclimate reconstructions. Under strong solar activity, positive phases of the AMO or PDO are associated with meridional dipole ECHPs, causing wet conditions in the southern Yangtze River and dry conditions in the north. This is driven by Eurasian-like teleconnection patterns and western Pacific anticyclonic anomalies, enhancing moisture transport to the southern Yangtze River. Negative AMO or PDO phases produce similar dipole ECHPs, with less pronounced effects in the southern Yangtze River, linked to positive phases of East Asia/Pacific-like teleconnection patterns and subtropical Pacific cyclonic anomalies. Under weak solar activity, positive PDO or negative AMO phases lead to reversed dipole ECHPs compared to those observed under strong solar forcing, with wet conditions in the northern Yangtze River and dry conditions in the south. Negative PDO or positive AMO phases result in meridional tripole ECHPs, with alternating dry-wet-dry conditions. All scenarios reveal changes in vertical moisture dynamics, with wind divergence and convergence patterns closely aligning with the observed ECHPs. The findings can improve predictive models for future hydroclimates and enhance adaptation strategies in East Asia.

{"title":"Solar modulation of hydroclimatic patterns in eastern China under influences of the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation","authors":"Liang Zhang , Yang Liu , Mengxin Bai , Zhixin Hao","doi":"10.1016/j.palaeo.2025.112796","DOIUrl":"10.1016/j.palaeo.2025.112796","url":null,"abstract":"<div><div>This study explores how solar activity modulates hydroclimatic patterns in eastern China (ECHPs) across different phases of the Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO), using the Community Earth System Model-Last Millennium Ensemble dataset and historical hydroclimate reconstructions. Under strong solar activity, positive phases of the AMO or PDO are associated with meridional dipole ECHPs, causing wet conditions in the southern Yangtze River and dry conditions in the north. This is driven by Eurasian-like teleconnection patterns and western Pacific anticyclonic anomalies, enhancing moisture transport to the southern Yangtze River. Negative AMO or PDO phases produce similar dipole ECHPs, with less pronounced effects in the southern Yangtze River, linked to positive phases of East Asia/Pacific-like teleconnection patterns and subtropical Pacific cyclonic anomalies. Under weak solar activity, positive PDO or negative AMO phases lead to reversed dipole ECHPs compared to those observed under strong solar forcing, with wet conditions in the northern Yangtze River and dry conditions in the south. Negative PDO or positive AMO phases result in meridional tripole ECHPs, with alternating dry-wet-dry conditions. All scenarios reveal changes in vertical moisture dynamics, with wind divergence and convergence patterns closely aligning with the observed ECHPs. The findings can improve predictive models for future hydroclimates and enhance adaptation strategies in East Asia.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"663 ","pages":"Article 112796"},"PeriodicalIF":2.6,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387255","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