The fluvial action was the main geological agen in Jurrassic and the sandy fluvial sediments, which were more than 2000m thick, were developed in the suitable tectonic condition.

• 侏罗纪时期,河流作用是最主要的地质营力,在适宜的构造条件下,发育了2000多米厚砂质河流沉积。