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微量元素分析在判别沉积环境中的应用——以江汉盆地潜江组为例
石油实验地质
2007年 29卷 第3期
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Title
APPLICATION OF MICROELEMENTS ANALYSIS IN IDENTIFYING SEDIMENTARY ENVIRONMENT——TAKING QIANJIANG FORMATION IN THE JIANGHAN BASIN AS AN EXAMPLE
Authors
Liu Gang
Zhou Dongsheng
单位
中国地质科学院, 北京, 100037
2. 中国地质大学, 海洋学院, 北京, 100083
Organization
Chinese Academy of Geological Sciences, Beijing 100037, China
2. School of Marine Sciences, China University of Geosciences, Beijing 100083, China
摘要
湖泊沉积岩中的粘土矿物、泥岩和膏岩中的微量元素组成对沉积环境的水文变化很敏感,可以有效揭示湖平面的变化。封闭盐湖的沉积记录在垂向上以显著的岩性变化为特征,它们取决于河水补给与蒸发、沉淀和渗透之间的平衡作用,并导致湖平面的相应变化和湖岸线的频繁迁移。文中选取江汉盆地潜江组中对沉积环境反映最为敏感的硼(B)、锶(Sr)、钡(Ba)、钛(Ti)、铁(Fe)、磷(P)、锰(Mn)等微量元素指标,分析其在不同层序、不同体系域的变化特征,并讨论其环境意义。沉积岩中B含量一般比岩浆岩高,在页岩中其含量可达135×10-6,砂岩中较低,一般为(1~40)×10-6。Sr元素在咸水中含量一般为0.8‰~1‰,在淡水中的含量一般为0.1‰~0.3‰。
Abstract
The compositions of microelements in clay minerals,mud rock and gypsum in lake sediments are very sensitive to the change of sedimentary environment.It may reveal lake-level change.The lithology change of sediment in saline lake in vertical is distinct,this change is controled by the balance in supply,evaporation and sediment of the river,which lead to the change of lake level.The paper mainly introduces using microelements,B,S,Ba,Ti,Fe,P,Mn etc.,in the Qianjiang Sag of the Jianghan Basin as an indication for sedimentary environment change to analyse the characteristics of change in different sequence and different systems tract,and discusses paleoclimate and sedimentary environment in different sequence.The content of B in sedimentary rock is more then in igneous rock commonly.The content of B is 135×10-6 in shale and(1~40)×10-6 in sand rock.The content of Sr is 0.8‰~1‰ in saline lake and 0.1‰~0.3‰ in freshwater.
关键词:
微量元素;
盐湖;
古气候;
沉积环境;
潜江组;
潜江凹陷;
江汉盆地;
Keywords:
microelements;
saline lake;
paleoclimate;
sedimentary environment;
Qianjiang Formation;
the Qianjiang Sag;
the Jianghan Basin;
DOI
https://doi.org/10.11781/sysydz200703307