Paleoweathering and paleoenvironmental change recorded in lacustrine sediments of the early to middle Eocene in Fushun Basin, Northeast China
Paleoweathering and paleoenvironmental change recorded in lacustrine sediments of the early to middle Eocene in Fushun Basin, Northeast China
复制标题
抚顺盆地早至中期始新世湖泊沉积物记录的古风化与古环境变化
DOI：
10.1002/2016gc006573
复制
发表时间：
2017-01-01
影响因子：
3.5
通讯作者：
Cui, Linlin
中科院分区：
文献类型：
--
作者：
Chen, Zuoling;Ding, Zhongli;Cui, Linlin
解读大陆硅酸盐风化、全球气候和大气CO2浓度之间的长期相互作用有助于理解新生代气候变化的机制，并评估未来气候和环境对人为碳排放的响应。始新世，其特征是早期始新世气候最佳（EECO）和随后的全球变冷，代表了一个理想的测试案例。本文通过对抚顺盆地始新世湖相沉积物的地球化学分析，探讨了区域气候对全球气候变化的响应。化学蚀变指数（CIA）和斜长石蚀变指数（PIA）一致地显示出逐渐的、长期的减小，表明抚顺盆地始新世期间气候经历了从温暖潮湿到相对寒冷干旱的转变。这一气候变化趋势与全球气候变冷和CO2浓度降低的趋势基本一致，表明区域气候变化与全球气候变化在地质时间尺度上有着密切的联系。此外，极端硅酸盐风化和湖泊生产力高，反映了相对积极的湖相有机质的C-13值与EECO。这种一致性可能表明，增强的大陆风化和湖泊生产力已成为降低整个EECO大气CO2的有效汇。总的来说，我们新的地球化学数据为始新世期间大陆硅酸盐风化、气候和全球碳循环之间的长期密切耦合提供了支持证据。
Deciphering the long-term interaction among continental silicate weathering, global climate, and atmospheric CO2 concentrations is helpful in understanding the mechanisms of the Cenozoic climate change and accessing the future climatic and environmental response to anthropogenic carbon emissions. The Eocene, which is characterized by the Early Eocene Climatic Optimum (EECO) and the following global cooling, represents an ideal test case. Here we generate geochemical data of the Eocene lacustrine sediments from the Fushun Basin, northeast China, to explore the regional climatic response to the global climate change. The chemical index of alteration (CIA) and plagioclase index of alteration (PIA) consistently show a gradual, long-term decrease, indicating a climatic transition from warm and humid to relatively cold and arid during the Eocene in the Fushun Basin. This climatic trend is broadly coincident with the global cooling and decreasing CO2 concentration, implying that the regional climate is closely correlated with the global climate change over geological time scales. Additionally, the extreme silicate weathering and high lake productivity as reflected by relatively positive C-13 values of lacustrine organic matter are associated with the EECO. This consistency may demonstrate that enhanced continental weathering and lake productivity had served as effective sinks to lower atmospheric CO2 across the EECO. Collectively, our new geochemical data add supporting evidence for a long-term, close coupling among continental silicate weathering, climate, and global carbon cycle during the Eocene.