古新世-始新世极热事件期间的浊积岩沉积对气候变化和天文旋回的响应  

RESPONSE OF TURBIDITE DEPOSITION TO CLIMATE CHANGE AND ASTRONOMICAL FORCING DURING THE PALEOCENE-EOCENE THERMAL MAXIMUM

作　　者：金思敏 David B.KEMP 张仲石 黄春菊 刘晴 JIN Simin;David B.KEMP;ZHANG Zhongshi;HUANG Chunju;LIU Qing(Department of Atmospheric Science,School of Environmental Studies,China University of Geosciences(Wuhan),Wuhan 430074,Hubei;State Key Laboratory for Biogeology and Environmental Geology,School of Earth Sciences,China University of Geosciences(Wuhan),Hubei Key Laboratory of Critical Zone Evolution,Wuhan 430074,Hubei)

机构地区：[1]中国地质大学(武汉)环境学院大气科学系,湖北武汉430074 [2]中国地质大学(武汉)地球科学学院,生物地质与环境地质国家重点实验室,关键带演化湖北省重点实验室,湖北武汉430074

出　　处：《第四纪研究》2024年第5期1225-1234,共10页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:42125502、42272033、42230208和41888101);中国博士后科学基金项目(批准号:GZC20232476)共同资助。

摘　　要：浊流是地表最重要的沉积物运移过程之一,主导了沉积物从大陆架到深海的输送。通过研究深时极热事件期间浊流的分布规律,可为类比推测未来全球变暖背景下浊流活动的变化趋势提供重要参考。前期研究发现,古新世-始新世极热事件(PETM)期间,英国东部北海盆地的高频浊积砂岩沉积受到了气候变化的影响。本研究进一步对西班牙Basque盆地Zumaia剖面古新统-始新统458层浊积岩(深度范围为-19.76~37.12 m)进行了时间序列分析,发现浊积岩沉积存在着显著的405 ka长偏心率周期信号。通过总结古新统-始新统浊积岩记录对天文旋回的响应,发现仅在英国北海盆地和西班牙Basque盆地识别出了天文旋回信号,且这两个点位的地理位置与模拟结果显示的年平均降水对轨道参数变化的敏感区相吻合。此外,本研究还讨论了PETM期间不同沉积环境中浊积岩沉积记录对海平面变化和全球升温的响应。Turbidity currents are one of the most important sediment transport processes on the Earth's surface,and the key means by which sediment is moved from continental shelves to the deep ocean.By studying the distribution patterns of turbidite event beds deposited during hyperthermal events,important insights can potentially be gained about how turbidity currents,and marine sediment fluxes generally,behave under global warming scenarios.In a previous study,we found evidence for high-frequency precession-modulated turbidite deposition in the North Sea Basin during the Paleocene-Eocene Thermal Maximum(PETM).In this study,we conducted further time series analysis on Paleocene-Eocene turbidites from the Zumaia section(43°18'4.5″N,2°15'31.2″W)in the Basque Basin,Spain.Based on published age models,we converted the 458 beds in turbidite sequence at Zumaia section(from-19.76 m to 37.12 m in depth)from the depth domain to the time domain via linear interpolation.Three independent methods of spectral analysis(circular spectral analysis,Schuster spectrum,and multi-taper method)of the age-constrained turbidite sequence indicate that there is a ca.400 ka cycle in turbidite recurrence time.Considering potential errors in the chronological anchors and depth-time conversion processes,we suggest that the turbidites(and hence sediment flux)responded to 405 ka long eccentricity climate forcing.Analysis of other PETM turbidite records failed to find clear evidence of astronomical cycles.As such,among the available Paleocene-Eocene turbidite records,astronomical forcing signals can be robustly identified only in the North Sea Basin and the Basque Basin.The locations of these records appear to coincide with areas that were likely sensitive to orbital parameter variations based on analysis of simulated annual mean precipitation from climate modeling.This supports the inference that enhanced precipitation,represented by some turbidite deposits during this greenhouse climate period,responded to astronomical cycles.However,it also impl

关 键 词：古新世-始新世极热事件 天文旋回 浊积岩 偏心率 岁差 

分 类 号：P534.612[天文地球—古生物学与地层学] P539.2[天文地球—地质学] P512.2