塔里木盆地石炭-二叠纪异常热演化及其对深部构造-岩浆活动的指示  

Carboniferous-Permian abnormal thermal evolution of the Tarim basin and its implication for deep structure and magmatic activity

作　　者：李佳蔚[1,2] 李忠[1] 邱楠生[3] 左银辉[4] 于靖波[1] 刘嘉庆[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]中国科学院大学,北京100049 [3]中国石油大学(北京)盆地与油藏研究中心,北京102249 [4]成都理工大学能源学院,成都610059

出　　处：《地球物理学报》2016年第9期3318-3329,共12页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(41372120);国家自然科学基金项目(41302084)资助;国家重大专项课题(2011ZX05008-003);国家杰出青年基金项目(41125010)

摘　　要：本文分析了塔里木盆地大量实测镜质体反射率（Ro）数据,显示盆地西北部石炭系与二叠系之间Ro值演化不连续,记录了石炭-二叠纪间发生的构造-热事件,是地层抬升剥蚀和高温热事件共同作用的结果.热史模拟得出盆地在石炭纪末地温梯度开始升高,至-300 Ma达到峰值,分布在4.8-5.6℃/100m之间,早二叠世迅速降低,随后进入缓慢稳定降低阶段.区域上高温热效应空间分布与塔里木大火成岩省的分布范围存在较好的相关性,但早于大规模玄武岩喷发的时间（290—288Ma）,且后者热效应范围有限.因此推断这种高温异常是大规模的深部岩浆活动,即深部岩浆房相对长时间热烘烤的结果.该研究结果为塔里木盆地热演化机制及相关热效应提供了新的线索.Measured vitrinite reflectance（Ro）data reveal a discontinuous evolution between the Carboniferous and the Permian which resulted from tectonic uplift and erosion and thermal events in the northwestern Tarim basin.Roevolution records a tectono-thermal event during the PermoCarboniferous.The simulated thermal history suggests that geothermal gradients began to increase from the end of Carboniferous and reached a peak of 4.8-5.6 ℃/100 mat about 300 Ma.Geothermal gradients decreased from the Early Permian.The influenced area of the thermal event is consistent with the distribution of large igneous provinces in Tarim basin while the thermalevent significantly affected geotemperature of Tarim basin before major eruption of basalt with limited heating effects during 290—288 Ma.Therefore the abnormal high temperature gradients should be caused by deep igneous activity.This result sheds a light on thermal evolution genesis of the Tarim basin.

关 键 词：塔里木盆地 镜质体反射率 古地温梯度 异常热事件 

分 类 号：P314[天文地球—固体地球物理学]