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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。
On the north side of the Yarlung Zangbo suture, there is a set of variegated glutenite conglomerates known as the Ciabulin Formation. Its predecessors often confused with the Tertiary Qiugu group, but also controversial about the ownership of its era. Because it may hold important information about the evolution of the Yarlung Zangbo suture zone, based on the study of remote sensing geology and field work, a typical section is selected. Three lithological segments can be established from bottom to top: Section and Tuen poor section, the depositional environment for the braided river - fan delta. Of particular importance is the gastropod-type fossil, Katosirasp, found in the silt-limestone sandwiched in the Tuen poor section. According to their age and regional geology, the era of the Ciabulin Group is classified as Early Middle Jurassic.