The Mesozoic Sporopollen Assemblage in the Sichuan Basin and Its Significance to Paleovegetation and Paleoclimate

The 70 mudrock samples have been collected from the Mesozoic continental strata in the Sichuan basin,but only more than 20 samples from the Upper Triassic Xujiahe Formation,Middle Jurassic Xintiangou Formation and Shaximiao Formation yield abundant sporopollen,23 genus and 81 species among which are firstly discovered.Up to now,146 genus and 341 species have been discovered in the Upper Triassic Xujiaohe Formation to the Cretaceous Guankou Formation in the Sichuan basin.The study shows that the plant genus and amount went on decrease,and suggests that climate in Sichuan basin changed from warm and humid in the Late Triassic to hot and arid in the Cretaceous.