摘要
华北新元古界青白口系下马岭组是我国华北地区从元古界到下古生界海相沉积有机质相对富集的沉积层段,其有机质含量最高达16%以上。对下马岭组富有机质层段的常量元素、微量元素和有机质含量的系统分析表明:该组富有机质泥质岩的SiO2含量明显高于贫有机质的泥质岩,且SiO2含量与TOC成正相关关系、与TiO2(指示陆源物质加入)的含量成反比关系,Si/(Si+Al+Fe)值与TOC具正相关关系;同时,在富有机质层段中与海底热水流体活动有关的P、Cu、Zn、Co、Ni、V等元素明显富集,Ba/Sr值远远大于1。认为下马岭组富有机质层段沉积时可能存在海底热水活动;海底热水活动一方面可能为生物的繁衍提供了大量的N、P、K、SiO2等营养物质,另一方面可能为生物的繁荣茂盛提供了能量,从而造成海底热水流体活动区沉积层段中有机质明显富集。
Xiamaling Formation of Qingbaikou System of later Proterozoic in North China is relatively more abundant in organic matter in marine sedimentary stratigraphies from Proterozoic to later Paleozoic in North China area. The content of organic matter is beyond 16% at most. The analyzing result of main elements, trace elements and organic matter content of Xiamaling Formation shows that the content of SiO_2 is apparently higher in organic matter rich mud rock than organic poor mud rock, the content of SiO_2 has a positive correlation with TOC content, and has a negative correlation with TiO_2 content (indicator of land matter input). The ratio of Si/(Si+Al+Fe) has a positive correlation with TOC content, too. In organic matter rich stratigraphy, there is apparently higher element content of P, Cu, Zn, Co, Ni, V which are related to thermal fluid activity in ocean floor, and the ratio of Ba/Sr is far more than 1. These characteristics indicate that during the organic matter rich stratigraphy of Xiamaling Formation was depositing, there is thermal fluid activity in ocean floor at the same time. The activity of thermal fluid can provide organism a lot of nutrition, such as N, P, K, SiO_2 and so on, it also can provide much energy for organism to grow. As a result, it leads to apparently better accumulation of organic matter in depositional stratigraphy of thermal fluid active area in ocean floor.
出处
《天然气地球科学》
EI
CAS
CSCD
2004年第2期110-114,共5页
Natural Gas Geoscience
关键词
地球化学特征
元素分布
有机质含量
海底热水流体
华北新元古界
Xiamaling Formation
Characteristic of element distribution
Organic matter content
Thermal fluid activity in ocean floor.
