沉积与特提斯地质2018，Vol.38Issue(2)：45-54,10.
西藏南羌塘坳陷昂达尔错地区侏罗系布曲组碳酸盐岩阴极发光特征与成岩阶段划分
Cathodoluminescence features and diagenetic stage division of the carbonate rocks in Buqu Formation of Jurassic, Southern Qiangtang Depression,Tibet
摘要
Abstract
Based on petrographic characteristics and cathodoluminescence analysis, combined with the corresponding Fe-,Mn-,the Sr and oxygen isotope data,this article studies the cathodoluminescence features and diagenetic stage division in Buqu Formation of Jurassic carbonate rocks in Angdaercuo area of Southern Qiangtang Depression,Tibet. The results show that:(1 )Carbonate rocks of Buqu Formation generally have dull cathodoluminescence,which results from lower Fe and Mn contents,indicating the limited influence of non-marine fluid during post-sedimentation and the diagenesis of the carbonates should have been governed by the marine fluid. (2)Different types of rocks with the increase of the strength of diagenesis,the content of Mn elements increased gradually,the content of Sr elements decreased gradually,the oxygen isotope values generally show the evolution characteristics of high negative direction migration,the corresponding cathodoluminescence intensity is gradually enhanced. (3 )The mud-microcrystalline dolomite has the strongest cathodoluminescence and the highest Mn content. It may be related to the weakly reducing environment near the surface during dolomization. Evaporation pump and permeate reflux may be the main mechanism of the dolomization of these rocks. The crystalline dolomite has weak cathodoluminescence and low Mn content. The pore fluid may be far away from atmospheric freshwater, and the homogenization temperature of the inclusion shows that the dolomitization occurs in a deep-buried environment. (4)The Buqu Formation carbonate rock experienced a contemporaneous-penecontemporaneous stage of seawater diagenetic environment→Early diagenetic stage of near-surface -shallow burial diagenesis weak reduction environment→Middle-deep diagenetic stage of mid-deep burial of deep-cycle water and high-salinity formation water environment → Late-Cretaceous-Paleogene early tectonic thermal events hydrothermal reform stage → The exodiagenesis stage.关键词
阴极发光/成岩阶段/碳酸盐岩/布曲组/南羌塘坳陷Key words
cathodoluminescence/diagenetic stage/carbonate rocks/Buqu Formation/Southern Qiangtang Depression分类
天文与地球科学引用本文复制引用
孙伟,陈明,万友利,谢尚克,陈浩..西藏南羌塘坳陷昂达尔错地区侏罗系布曲组碳酸盐岩阴极发光特征与成岩阶段划分[J].沉积与特提斯地质,2018,38(2):45-54,10.基金项目
羌塘盆地金星湖-隆鄂尼地区油气资源战略调查(DD20160159). （DD20160159）
