地层 dìcéng stratum Origin Definitions Defs Strokes Stroke Words Sentences Sents 地层学 dìcéngxué stratigraphy The branch of geology concerned with the study of rock layers and layering.地层下陷 dìcéngxiàxiàn land subsidence The sinking or settling of the ground surface caused by the movement of the earth's crust or the over-extraction of groundwater.