noun
sedimentary layer; sedimentary stratum
Geological term for a layer of sediment deposited over time.
この地域の堆積層から化石が発見された。
Fossils were discovered in the sedimentary layers of this region.
堆積岩 refers to sedimentary rock, the solid rock formed from consolidated sediment, while 堆積層 refers to the layer or stratum itself.
Compound of 堆積 (たいせき, 'accumulation, sedimentation') and 層 (そう, 'layer, stratum').