Some very ancientsediments were no longer recognizable, having been converted to igneous and metamorphic rocks in the course of mountain building.
在造山的过程中，一些非常古老的沉积物已被转化为火成岩和变质岩，已经无法辨认了。
2
However, if life once existed in surface environments, it is likely to have left behind a fossil record in ancientsediments now exposed at the surface.
然而，如果生命一旦在地表出现，他很有可能留下化石记录。这个记录可能是古沉积物形式保留在地表。
3
Biomarker has a wide application in the research of petroleum geology, such as different types of organics thermal evolution, ancientsediments' environment and so on.