四川盆地西南中二叠统白云岩的地球化学特征及其成因  

Origin and Geochemical Characteristics of Dolomites in the Middle Permian Formation,SW Sichuan Basin,China

作　　者：韩晓涛[1,2] 鲍征宇[1,3] 谢淑云[1,3] 

机构地区：[1]中国地质大学地球科学学院,湖北武汉430074 [2]辽宁省地质矿产研究院,辽宁沈阳110032 [3]中国地质大学地质过程与矿产资源国家重点实验室,湖北武汉430074

出　　处：《地球科学（中国地质大学学报）》2016年第1期167-176,共10页Earth Science-Journal of China University of Geosciences

基　　金：国家重大专项(No.2011ZX05005-002);国家"973计划"项目(No.2012CB214802)

摘　　要：白云岩储层是碳酸盐岩油气领域的研究热点.在分析白云岩优质储层孔—洞—缝演化过程中,白云岩成因是重要的研究内容.以四川盆地西南间断出露的中二叠统栖霞组地层为研究对象,采用岩相学、X粉晶衍射及地球化学方法,讨论白云岩成因.白云岩野外发育于断裂破碎带周围,透镜状产出,多呈斑马纹状构造.显微镜下白云石鉴定为鞍状白云石.此外,白云岩具有较高的白云石有序度,地球化学特征则表现为明显偏负的氧同位素值和高锶同位素值.综合地质资料分析,白云岩为构造热液白云岩化成因.The dolomite reservoir play＇s an important role in the research of carbonate oil and gas reservoirs. The origin of dolo- mite is an integral component in analyzing the evolution of pore-cave-fracture system in high-quality dolomite reservoirs. The dolomites of Middle Permian Qixia Formation, SW Sichuan basin were studied in this paper by the method of petrology and geochemical analyses aiming at the discovery of the origin of dolomites. The dolomites are mainly controlled by fault zones, associated with zebra fabric. The dolomite fabrics exhibit non-planar saddle crystals and strongly undulose extinctions. In addition, the high degree of order is found in hydrothermal dolomites. The geochemical characteristics of saddle dolomites show noticeable negative δ^18 OPDU and an enrichment of strontium isotopes. In the end, the dolomites have been proved to be the product of structurally controlled hydrothermal dolomitization on the basis of comprehensive geologic research.

关 键 词：川西南 中二叠统 栖霞组 热液白云岩 地球化学 

分 类 号：P59[天文地球—地球化学]