DOI: 10.1016/j.palaeo.2017.04.011
论文题名: Middle Eocene paleohydrology of the Dongying Depression in eastern China from sedimentological and geochemical signatures of lacustrine mudstone
作者: Ma Y. ; Fan M. ; Lu Y. ; Liu H. ; Hao Y. ; Xie Z. ; Peng L. ; Du X. ; Hu H.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2017
卷: 479 起始页码: 16
结束页码: 33
语种: 英语
英文关键词: Bohai Bay Basin
; Lithofacies
; Organic-rich mudstone
; Paleogene
; Paleolimnology
英文摘要: Previous understanding that stratigraphic variability in lacustrine sequences is primarily caused by depositional processes governed by regional tectonics and climatic change remains to be tested on microscopic scale. Here we study the upper fourth Member (Es4U) of the Eocene Shahejie Formation, the major source rock of the Dongying Depression, eastern China, in order to understand stratigraphic heterogeneity and tectonic and climate controls on depositional processes in lacustrine mudstone. Our study integrates core descriptions, microscopic observations, and studies of mineralogy, TOC and chemical weathering proxies of CIA* and Ln(Al2O3/Na2O) from two full-bore cores and correlation of gamma ray logs from six wells across the depression. We identified four major lithofacies, including the interbedded evaporite and mudstone deposited in a shallow salt lake; the silt-bearing clay-rich mudstone deposited in a pro delta environment within a shallow open lake; the laminated calcareous mudstone deposited in a deep, stratified meromictic lake with frequent earthquake activities; and the massive calcareous mudstone deposited in a shallow and oxygenated lake. The Es4U Member changed from the interbedded evaporite and mudstone-dominated lithofacies association to silt-bearing clay-rich mudstone-dominated lithofacies association, and then laminated calcareous mudstone-dominated lithofacies association, suggesting basin-wide changes in depositional processes, lake level, lake water chemistry, and paleohydrology. We suggest that these changes reflect balance between sediment and water supply and potential accommodation of the lake basin, which were governed by paleoclimate in the lake drainage and extensional tectonics. We infer that during the deposition of the Es4U Member, the lake basin evolved from an underfilled lake basin with salty lake water under arid climate to a shallow balanced-fill lake basin when climate became humid, then to a deep balanced-fill basin with stratified bottom lake water when climate became more humid and the basin was deepened by tectonic activity. This study demonstrates that climate and tectonics both control paleolimnological changes and depositional processes of lacustrine mudstone. © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/67816
Appears in Collections: 过去全球变化的重建
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作者单位: Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education, China University of Geosciences, Wuhan, China; Department of Earth and Environmental Sciences, University of Texas at Arlington, Arlington, TX, United States; College of Marine Science and Technology, China University of Geosciences, Wuhan, United States; Geoscience Research Institute, SINOPEC Shengli Oilfield CompanyShandong, China; School of Geosciences, Yangtze University, Wuhan, Hubei, China
Recommended Citation:
Ma Y.,Fan M.,Lu Y.,et al. Middle Eocene paleohydrology of the Dongying Depression in eastern China from sedimentological and geochemical signatures of lacustrine mudstone[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2017-01-01,479