堆積岩(たいせきがん)

Composed of 堆積(たいせき) (accumulation; piling up) + 岩(がん) (rock). A standard term from earth science, used from elementary-school textbooks through university geology. Sedimentary rocks are particularly important in Japan because many geological formations — and most fossil sites — lie in sedimentary strata.

Common collocations

• 堆積岩(たいせきがん)の地層(ちそう): layers of sedimentary rock
• 堆積岩(たいせきがん)に含(ふく)まれる化石(かせき): fossils contained in sedimentary rock
• 堆積岩(たいせきがん)が形成(けいせい)される: sedimentary rock is formed
• 堆積岩(たいせきがん)の種類(しゅるい): types of sedimentary rock

Main types of sedimentary rock

• 砂岩(さがん): sandstone — formed from sand-sized grains
• 泥岩(でいがん): mudstone — formed from very fine mud particles
• 頁岩(けつがん): shale — a finely layered mudstone that splits into sheets
• 石灰岩(せっかいがん): limestone — formed from the calcium carbonate of shells and marine organisms
• 礫岩(れきがん): conglomerate — formed from rounded pebbles and rock fragments

Related words

• 火成岩(かせいがん): igneous rock — formed from cooled magma or lava
• 変成岩(へんせいがん): metamorphic rock — rock that has been transformed by heat and pressure
• 地層(ちそう): stratum; geological layer — the layered formation in which sedimentary rock typically appears
• 化石(かせき): fossil — the preserved remains or traces of ancient life
• 堆積(たいせき): sedimentation; accumulation

Usage

The three-way classification 火成岩(かせいがん) / 堆積岩(たいせきがん) / 変成岩(へんせいがん) is standard in Japanese science education and natural history museums. Students typically learn it in middle school.