Geochemical and palynological records of rapid climatic change from the early to late Aptian: evidence from the Jiaolai Basin, eastern China

作者：X. X. Wang, Xiangyu Zhang, W. X. Wang, Shoujun Li, Min Qin · 发表于：Figshare · 年份：2022 · DOI：10.6084/m9.figshare.19172550 · 研究领域：Geology and Paleoclimatology Research、Geological and Geophysical Studies、Isotope Analysis in Ecology

The Laiyang Group in the Jiaolai Basin, eastern China, contains Lower Cretaceous continental river and lake deposits that provide a complete record of the evolution of the paleoclimate in the Laiyang area from the early to late Aptian. This study used novel chemical weathering indices and palynological data for Lower Cretaceous mudstone in the Laiyang Group coupled with existing geochemical data, clay mineralogy and plant fossil record to reconstruct the geochemical weathering conditions and paleoclimatic evolution of the Jiaolai Basin over this period. Four distinctive episodes of paleoclimatic change were identified, with one linked to an extremely dry–hot climatic event correlated with the Oceanic Anoxia Event (OAE)1a. During Stage 1, strong chemical weathering was correlated with a relatively warm–humid climate during the early Aptian but the intensity of chemical weathering tended to decrease with an increasingly dry and hot climate. In contrast, Stage 2 was characterised by stable conditions with weak chemical weathering and an extremely dry, hot climate during the early and middle Aptian. The presence of organic-rich black shale and the associated distribution of organic carbon isotope values verified that the extremely dry–hot climate during this stage was related to OAE 1a. Stage 3 was a transitional period extending through the middle and late Aptian during which the climate became relatively warm and humid, triggering increases in chemical weathering. Finally, Stag...