2011年6月，第17卷，第2期，220-230页 June2011,Vol.17，No.2，p.220230
高校地质学报
Geological Journal of China Universities
西藏仁布地区上三叠统复理石物源分析徐文礼，李祥辉，王尹2，曾庆高3，孙勇，尼玛次仁3 1.成都理工大学沉积地质研究院，成都610059；2.南京大学地球科学系，南京210093；
3.西藏自治区地质调查院一分院，堆龙德庆850000
摘要：运用砂岩碎屑组分、古水流、微量和稀土元素方法对西藏南部仁布地区上三叠统朗杰学群和涅如组的物源进行了分析。碎屑组分和地球化学研究结果显示，盆地中的碎屑物源主要来自再旋回造山带，部分来自造山之前的混合区，少数源于大陆基底，且物源区蕴含有造山前的大陆边缘岛弧过程；物源区母岩主要为沉积再旋回和后太古代再旋回沉积物：古水流测量分析表明，朗杰学群和涅如组的物源可能均来自北边，但前者物源偏于东北方向，后者物源偏于西北方向，且前者较后者离物源区相对较近，符合现今二者地层的分布特征。这些认识为研究区上三叠统复理石可能来自北部甚至拉萨地块的观点提供了新的支持。
关键词：物源分析；碎屑成分；岩石地球化学；古水流；上三叠统；仁布；西藏南部
中图分类号：P315.61
文献标识码：A
文章编号：1006-7493（2011)02-022011
Provenance Analysis of the Upper Triassic Flysch in Renbu Area,
SouthernTibet
XU Wen-lit, LI Xiang-hui?,WANG Yin',ZENG Qing-gao",SUN Yong',NIMA Ciren
1. Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu 610059, China; 2. School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, China;
3. Tibetan Geological Survey, Duilongdeqing 850000, China;
Abstract: The sandstone clastic composition, paleocurent, trace element and rare earth clement are combined to analyze the provenance of the Upper Triassic Langjiexue Group and the Nieru Formation in Renbu area, southem Tibet, Results of the clastic composition and geochemistry indicate that most of the clastic imaterials were derived from the recycled orogenic belt; Some of them were from the mixed area before the orogeny; Few was from the continental basement and recorded continental margin are process prior to the orogeny. It is verified that parent rocks came from the recycled sediments of the orogen and post-Archean. Paleocurrent measurement shows that the Langjiexue Group and the Nieru Formation were probably sourced from the North. The former was from the northeast, but the latter was from the northwest. The latter is closer to the source region than the former. These are consistent with the present distribution of strata. These results suggest that the upper Triassic flysch were probably sourced from the north or even the Lhasa Block.
Key words: provenance analysis, clastic composition, geochemistry, paleocurrent, upper Triassic flysch, Renbu, southern Tibet
Author: Xu Wenli, Ph.D candidate.E-mail: xuwenli5@163.com 收稿日期：201009-21：修回日期：2010-11-09
基金项目：国家自然科学基金项目（41072075）资助
作者简介：徐文礼，男，1982年生，博士研究生，沉积地质学；E-mail；xuwenli5@163.com