西藏日喀则地区恰布林组地层学研究

雅鲁藏布江缝合带北侧发育一套杂色砂砾岩系，被称为恰布林组。前人经常将它与第三纪秋乌组相混，对其时代归属也颇多争议。由于它可能保存着雅鲁藏布江缝合带演化的重要信息，因此，在遥感地质研究和野外工作基础上，选择了典型剖面，实测结果由下至上可建立三个岩性段：江庆则段、德日段和屯穷段，其沉积环境为辫状河－扇三角洲。尤为重要的是，屯穷段所夹粉砂质灰岩中发现腹足类化石Ｋａｔｏｓｉｒａｓｐ．，根据其时代并结合区域地质将恰布林组时代归为早中侏罗世。

STRATIGRAPHIC RESEARCH ON GIABULIN FORMATION IN THE XIGAZE REGION, XIZANG(TIBET)

A suit of mottled sandstone and conglomerate developed along the north of the Yarlung Zangbo River suture zone, which was named Giabulin Formation. Predecessors used to confuse it with the Tertiary Qiuwu Formation and to debate its era. Because it may contain the important im formation about the evolution of the Yarlung Zangbo River suture zone, we select and measure the typical cross section based on the remote geology and field investigation. Three lithological members are founded in Giabulin Formation from down to upper: Jiangqingze member, Deri member and Dunqiong member. The sedimentary environment is a braided river-fan delta. The most important breakthrough is that gasteropod fossils Katosira sp. is discovered among the silty limestone intercalation in Dunqiong member. The era of Qiabulin Formation belongs to the Early-Middle Jurassic according to the era of fossils and the regional geology.