青藏高原班公湖-怒江缝合带域岩石密度结构及意义  

Rock density structure in Bangong-Nujiang suture zone and its significance

作　　者：曹忠权 张智[2] 田小波[3] 

机构地区：[1]西藏地震局,拉萨850000 [2]吉林大学地球探测科学与技术学院,长春130026 [3]中国科学院地质与地球物理研究所,北京100029

出　　处：《地球物理学报》2007年第2期523-528,共6页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(40474034);国家基础研究"973计划"课题(2002CB412604)资助

摘　　要：班公湖-怒江缝合带分隔了青藏高原拉萨地块和羌塘地块，该带域岩样采集与分析对于该区地球物理资料深化解释、拉萨地块和羌塘地块拼贴碰撞过程的理解等均具有重要意义．1995年在措勤盆地中采集了3条剖面、从奥陶纪至第四系不同地质年代地层岩石标本共计2500块．通过岩石密度测试，获得了研究区不同地质年代岩石密度测量结果．结果表明，岩石由老到新密度变化范围为2．78—2．53g／cm^3；各相邻地质时代间岩石密度差基本上为0．10g/cm^3，白垩与侏罗、二叠与三叠之间岩石密度差最大为0．12—0．13g/cm^3．在措勤盆地内不同构造单元间岩石密度存在明显的纵横向非均一性．Bangong-Nujiang suture separates Lhasa and Qiangtang blocks in Qinghai-Tibet. The acquisition of rock samples and their analyses of physical properties in the area are very important both to the interpretation of deep geophysical data and to the understanding of convergence and collision between these two tectonic blocks. 2500 rock samples dated from Ordovician to Quaternary were acquired along 3 profiles in Coqen basin in 1995. After rock density indoor measurement, we obtained rock density dataset of these rock samples. The results demonstrate that their densities increase from Quaternary to Ordovician within the range of 2.78 - 2.53g/cm^2 and the density contrast between the neighboring rock ages is 0.10g/cm^3 in general, and reaches to the maximum of 0.12- 0.13g/cm^3 between Cretaceous and Jurassic, Permian and Triassic. The results also showed strong lateral heterogeneity of rock density between and in tectonic elements of the studied area.

关 键 词：班公湖-怒江缝合带 岩石密度 横向非均一性 

分 类 号：P584[天文地球—岩石学]