The subscript O and W identify the unweathered and weathered states.
下标O和W分别表示属于未风化和已风化的状态.
Chemical weathering was beginning to attack the unweathered bedrock.
化学侵蚀作用开始攻击还未侵蚀的岩床.
Brightrays such as these are produced as impacts excavate and eject relatively unweathered subsurface material.
这些放射状陨石坑产生于天体撞击溅出的地下物质,绵延在遍布陨石坑的水星表面数百公里.