quality gravel是什么意思

用法例句

Zircons from one granitic gravel sample of the metaconglomerate were chosen for SHRIMP U-Pb dating,and an age of(2632± 18)Ma is interpreted as the formation age of the granitic rocks of gravel,which suggests that at least part of gravels in the metaconglomerate were of tectonic origin.

对其中变质砾岩中的一花岗质砾石进行了锆石SHRIMP定年,(2632±18)Ma年龄为砾石所代表的花岗质岩石的形成时代,表明雁翎关变质砾岩中至少部分砾石为构造成因。