gravel fraction是什么意思

用法例句

In the light of modern stratigraphic theories, the authors discuss the stratigraphic classification and tectonic evolution of Xinjiang basin,a Cretaceous terrestrial basin of Xinjiang River, Jiangxi Province,basing on the comprehensive information from the cyclicities of pebble contents, geochemical variations of elements in the sediments, and activities of magmas.

以现代地层学理论为指导,应用砾石成分的旋回变化、沉积物地球化学元素变化和岩浆活动类型变化的综合信息,论述了江西信江白垩纪陆相盆地的地层划分和中生代晚期的构造演化。