| 从生物扰动构造看古近纪东营湖的湖水分层 |
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| 引用本文： | 刘传联,房殿勇,王慧中.从生物扰动构造看古近纪东营湖的湖水分层[J].现代地质,2002,16(1):59-63,T001. |
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| 作者姓名： | 刘传联 房殿勇 王慧中 |
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| 作者单位： | 同济大学,海洋地质系,教育部重点实验室,上海,200092 |
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| 基金项目： | 教育部重大科学技术项目“中国新生代地形倒转及其资源环境效应”，教育部高等学校骨干教师资助计划资助项目 |
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| 摘 要： | 生物扰动构造发育程度与湖水充氧条件及湖水分层有密切关系。通过对山东东营凹陷下第三系 5套油源岩的生物扰动构造进行分析 ,分别讨论了其沉积时期古湖泊水体的分层状况。富有机质纹层页岩中无生物扰动构造 ,生物扰动指数为 0 ,表明其沉积时为一稳定分层、底层水缺氧的古湖泊 ;钙质块状纹层泥岩中含显微生物扰动构造 ,主要分布在细粒方解石纹层中 ,生物扰动指数为 1,反映较稳定分层、缺氧但有短暂充氧的沉积环境 ;钙质纹层页岩中显微生物扰动构造可局部富集呈层 ,生物扰动指数为 1～ 2 ,反映当时古湖泊有季节性回水 ,含氧量呈季节性变化 ;红、灰条带状粉砂质泥岩肉眼即可观察到生物扰动构造 ,主要分布在红色层中 ,生物扰动指数为 2～ 3,反映为不分层、充氧的古湖泊环境 ;块状泥岩扰动最为强烈 ,生物扰动指数为 6 ,表明为不分层、充氧的沉积环境
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| 关 键 词： | 生物扰动构造 湖水分层 早第三纪 东营凹陷 |
| 文章编号： | 1000-8527(2002)01-0059-05 |
Stratification of the Paleogene Dongying Lake:evidences from bioturbation structures |
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| LIU Chuan-lian,FANG Dian-yong,WANG Hui-zhong.Stratification of the Paleogene Dongying Lake:evidences from bioturbation structures[J].Geoscience——Journal of Graduate School,China University of Geosciences,2002,16(1):59-63,T001. |
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| Authors: | LIU Chuan-lian FANG Dian-yong WANG Hui-zhong |
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| Abstract: | Stratification of the Paleogene Dongying Lake is discussed based on the bioturbation structures of lacustrine oil source rocks deposited in it. There is no bioturbation structure in organic rich laminated shales, and the bioturbation index (BI) is 0. This demonstrates that the paleolake is a permanent stable stratified anoxic lake. Discrete, isolated micro-bioturbation structures existed in calcareous laminated mudstones, and the original bedding are very slightly disturbed, so BI of these rocks is 1. This implies that the paleo-Dong-ying Lake was still a stable stratified anoxic lake in most of depositional periods, but mixing events might occurred in some times. Micro-bioturbation structures are generally isolated, but locally overlap in calcareous laminated shales,and BI of them are 1-2. The paleolake became to a seasonal overturn lake and oxygen level of it might change seasonally. Burrows are very common in red-gray banding silt-mudstones, especially in the red parts of them, and BI of them are 2-3.These rocks deposited in an episodic stratification lake. Bedding is nearly or totally homogenized by biturbation in massive mudstones, and BI of them is 6. This implies that these rocks deposited in a well-mixed, aerobic lake. |
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| Keywords: | bioturbation structure stratification Paleogene Dongying depression |
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