These are also the telltales in distant layers of ejecta that the rock in question has come from an impact.
在年代久远的喷发物地层中有迹象表明此处的岩石产生于一次撞击。
2
The telltales are specific "lines" in the spectrum of infra-red light from the plume. These correspond to the frequencies of light given off when water molecules are energetically excited.