Discovery of Early Silurian graptolite fossils in the Qimantag Group in the western sector of the East Kunlun;

Graphic correlation of graptolite fauna near the Lower/Middle Ordovician boundary in South China

The Ordovician Dawan Formation of Yichang has been studied for a long time,but the graptolite succession of the formation is still poorly known,particularly due to the rare occurrences of graptolites.

Based on the analysis and study of poptolite fossil data from well Tazhong 29 in Tdrim Basin, it is considered that the geologic time of the graptolites is Middle Ordovician and early Late Oniovician,approximately corresponding to Caradoc in westem Europe.

Researches on characteristics of mineral rock association show that there is a great interdependency between gas oil enrichments and types of association.

The reservoir properties of favorable sandstones in strata are associated with the rock association and can be predicted within small areas.

The early middle Jurassic strata are outcropped in the Paducuo, Shuanghu area, Tibet, the rock association characteristics are different from Yanshiping Group, and correspond to the outcropped Sewa Formation in the Xiangcuo area, up to now, the upper of the strata is the richest ammonitic fossils in Bajocian stage, Jurassic in the northern part of Tibet.