从化石群及壳体同位素看古近纪东营湖湖水化学 |
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关键词:talassogenous fssils isotope water chemistry Paleogene Dongying depression |
基金项目:教育部高等学校骨干教师资助计划,教育部重大科学技术“中国新生代地形倒转及资源环境效应”项目 |
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Water Chemistry of the Paleogene Dongying Lake: Evidence from Fossil Assemblages and Shell Isotopes |
Water chemistry of the Paleogene Lake existent in Dongying depression of Shandong Province has been discussed by means of several new methods including talassogenous fossils, oxygen, carbon and strontium isotope of fossils. Foraminifera, calcareous nannofossils, dinoflagellates and acritarchs, fish and other groups of "marine type fossils" were discovered in Paleogene sediments from Dongying depression and were then used as the indicators of marine transgression. Comparing them with modern talassogenous fauna, the authors have reached the conclusion that these fossils are talassogenous in nature and lived in the saline lake rich in Na and Cl. Strontium isotopic analysis indicates that 87 Sr/ 86 Sr ratios of nannofossils from Eocene and Oligocene sediments are higher than those of sea water of the same periods, and are close to the 87 Sr/ 86 Sr ratios of modern river and lake water. These results imply that nannofossils lived in a paleolake rather than in seawater. Carbon and oxygen isotopic analysis also demonstrates that the Paleogene Dongying Lake was a hydrologically closed lake. Variations in paleosalinity have also been discussed based on the stratigraphic changes of δ 18 O and δ 13 C. |
LIU Chuan-lian,ZHAO Quan-hong,WANG Pin-xian.2002.Water Chemistry of the Paleogene Dongying Lake: Evidence from Fossil Assemblages and Shell Isotopes[J].Acta Geoscientica Sinica,23(3):237-242. |
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