Objectives:The Upper Cretaceous Zongzhuo Farmation in southern Xizang(Tibet) is located on the south side of the Yarlung Zangbo suture zone. Academics believe that it should belong to sedimentary mélange,and has always been attracting the attention of the scholars both at home and abroad. Until now, geologists have usually been studying configuration, material sources of the rock block, in order to study formation mechanism but neglected the “matrix”. Therefore, the rock thin section and detratal zircon from the Zongzhuo Formation in Bailang area had been collected to analyze the formation timing and provenance by author. Methods:The cathodoluminescence technique and the detratal zircon UPb ages were used to determine the provenance of the “matrix” from the Zongzhuo Farmation.The cathodoluminescence image of sandstone sample and the detratal zircon UPb analysis were carried by State key laboratory of continental dynamics at Northweatern University. Results: he ages of the detrital zircons are nearly all between 422～2867Ma（43.5%） and 71～205Ma（52.2%）. Conclusions:The rock debris of the sandstones in the “matrix” are mainly intermediate—acid volcanic rock; Quartz should come from ancient sedimentary rock, because they have no light by cathodoluminescence; Most of the detrital zircons that belong to magmatic zircons look like circle after transportation and abrasion; The comprehensive evaluation showed that the deposition time of the Zongzhuo Formation is limited to Maastrichtian because the youngest UPb age was 71±2Ma; the provenance were from the volcanic—magma arc belts of Gangdisi and the northern margin of the Indian Continent.