摘要
大兴安岭中段林西组是重要的含烃源岩层位,烃源岩的形成与生烃母质生物活动和埋藏时的古气候、古构造、古环境息息相关。通过岩石地球化学分析可以恢复林西组沉积时期的气候与构造环境,利用Sr、Li、Ga含量、Sr/Ba值、U/Th值、δU及Sr/Cu值,从古盐度、氧化还原环境、古气候等方面分析了索伦地区林西组的沉积环境,认为林西组沉积时可能经历了中等—较强风化后的再沉积作用,总体为淡水—微咸水的氧化环境,气候温湿;Al_(2)O_(3)/(Al_(2)O_(3)+Fe_(2)O_(3))值、K_(2)O/Na_(2)O-SiO_(2)关系以及稀土元素特征表明:林西组形成于靠近大陆岛弧的活动大陆边缘,由早期弧后盆地的海陆过渡相半咸水环境向陆相的淡水环境演变,有利于有机质的富集和保存,是寻找烃源岩的有利层位。研究成果可为该区烃源岩勘查提供指导。
The Linxi Formation in central Greater Khingan Mountains is an important hydrocarbon source rocks strata.The formation of hydrocarbon source rocks is closely related to the paleoclimate,palaeostructure and palaeo-environment during the propagation and burial of hydrocarbon generation parent organisms.The climatic tectonic environment of Linxi Formation in sedimentary period can be restored through the geochemical analysis of rock data.Based on the Sr,Li and Ga content,the Sr/Ba ratio,the U/Th ratio and δU method,the Sr/Cu ratio,the authors in this paper have analyzed the sedimentary environment of Linxi Formation from the ancient salinity,re-dox environment,and the ancient climate.The results show that the Linxi Formation might be formed by resedimentation after middle-strong weathering.The oxidative deposition environment is freshwater-brackish water,and the paleoclimate is warm humid climate.The Al_(2)O_(3)/(Al_(2)O_(3)+Fe_(2)O_(3))and K_(2)O/Na_(2)O-SiO_(2) ratios,the content and parameters of rare earth elements were used to indicate the sedimentary environment of Linxi Formation.The results show that the Linxi Formation was formed in the active continental margin tectonic environment near the continental island arc,and the paleoenvironment evolved from the sea-land excessive brackish water to the continental freshwater environment in the early retroarc basin.The Linxi Formation is favorable for enrichment and preservation of organic matter,which is the beneficial horizon for hydrocarbon source rocks.This study can provide guidance for the esploration of hydrocarbon source roaks in this area.
作者
仲米山
吕东霖
王岐
张化南
敖光
吴子杰
杨运来
王艺龙
谭超
ZHONG Mishan;LV Donglin;WANG Qi;ZHANG Huanan;AO Guang;WU Zijie;YANG Yunlai;WANG Yilong;TAN Chao(College of Earth Sciences,Jilin University,Jilin Changchun 130061,China;Liaoning Provincial Institute of Geological Exploration Co.,Ltd,Liaoning Dalian 116100,China;Liaoning Provincial Geology and Mining Group Energy Geology Co.Ltd,Liaoning Shenyang 110013,China;Liaoning Geological and Mineral Survey Institute Co.Ltd,Liaoning Shenyang 110032,China;School of Geosciences,China University of Petroleum(East China),Shandong Qingdao 266580,China)
出处
《中国地质调查》
CAS
2022年第5期89-96,共8页
Geological Survey of China
基金
中国地质调查局“内蒙古1∶5万明水河林场等三幅区域地质矿产调查(编号:12120114013001)”项目资助。
关键词
索伦地区
林西组
地球化学特征
古气候
沉积环境
构造环境
Suolun area
Linxi Formation
geochemical characteristics
palaeoclimate
sedimentary environment
tectonic setting