Discovery of silicified wood in the Middle Jurassic Gyari Formation in the southern Qiangtang depression, Tibet, China, and its significance.

Abstract: Recently silicified wood has been for the first time discovered in Middle Jurassic strata in southern Qiangtang, and its basic features are described. According to the features of the sporopollen assemblage, the strata is determined to be the Middle Jurassic Gyari Formation and the silicified wood is preliminarily designated as Araucarioxylon. The features of the sporopollen assemblage reflect that the Middle Jurassic climate was dry and hot in this area. According to this discovery, combined with the silicified wood discovered by previous researchers in Triassic strata, the authors present new ideas about the Middle Jurassic tectonic evolution and character of the Qiangtang basin.