羌塘盆地东部中侏罗统陆源碎屑与碳酸盐混合沉积成岩特征  

Characteristics of Mixed Sedimentations and Diagenesis of Terrigenous Clastic Rock and Carbonate:The Middle Jurassic in the East Qiangtang Basin,Tibet,China

作　　者：马伯永[1] 王根厚[2] 李尚林[3] 徐红燕[1] 

机构地区：[1]中国地质调查局,北京100037 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]中国地质调查局西安地质调查中心,西安710054

出　　处：《吉林大学学报（地球科学版）》2015年第5期1310-1321,共12页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(40172014);中国地质调查局区域地质调查项目(I46C004003)

摘　　要：近年来,混合沉积显示的沉积环境和油气地质意义越来越受到学界的重视。羌塘盆地是目前国内油气勘探最重要的战略选区之一,具有良好的油气勘探远景。研究区侏罗系广泛发育陆源碎屑与碳酸盐的混合沉积。综合前人研究成果、区域地质资料和室内样品分析,笔者对研究区广泛分布混合沉积的岩石学特征、沉积环境、成岩作用进行了详细地研究。研究发现:区内中侏罗统混合沉积表现为混积岩、混积层系两种形式;对岩性、层系及组合特征进行观察发现,它们主要形成于滨岸、碳酸盐岩缓坡、潮坪沉积环境,把混合沉积划分为4个三级地层层序,提高了地层划分的精度,建立了研究区中侏罗世雀莫错期、布曲期、夏里期的岩相古地理格局;混积岩中最显著的成岩作用类型有压实-压溶、胶结、破裂和溶蚀作用,其中以破裂作用、溶蚀作用最为发育,有利于形成优质储层,可为沉积储层预测及研究区的石油普查评价提供重要参考。Abtracts：Geological researchers have paid more and more attention to the mixed siliciclastic carbonate sediments and its geological significance of oil and gas.Qiangtang basin is one of the most important strategic selection for oil and gas exploration.The mixed siliciclastic carbonate sediments are extensively developed in the eastern part of Qiangtang basin.Combined the regional geological data and indoor sample analysis with the previous researches,we study the characteristics of the mixed sediments,their sedimentary environment,and their diagenesis.The results show that the research area is characterized by interactive sediments of terrigenous clast and carbonate on the microscopic level,so called＂mixed rock＂,and by interbedded rocks of terrigenous clastic rock,carbonate rock or mixed rock in macro.These lithoface types are mainly formed in a sedimentary environment of shore,carbonate ramp,or tidal flat-lagoon.It can be divided into four three-level sequences,which remarkably improves the precision of stratigraphic classification.The lithofacies palaeogeography of Quemocuo,Buqu and Xiali age are established.The diagenesis types of the mixed rocks are cementation,compaction,pressure solution,fragmentation,and dissolution.The pressure solution,fragmentation and dissolution are more common than others,which are conducive to form a mixed rock reservoir.This research can provide valuable information for petroleum and natural gas exploration.

关 键 词：碳酸盐岩 陆源碎屑岩 混合沉积 成岩作用 油气 中侏罗统 羌塘盆地 

分 类 号：P618.13[天文地球—矿床学]