primary rocks
Geological term for rocks that have not undergone significant alteration since their original formation; often contrasted with secondary or metamorphic rocks.
The primary rocks in this area were formed about 200 million years ago.
Metamorphic rocks, which have been altered by heat and pressure, unlike 原成岩石 which are unaltered primary rocks.
Igneous rocks formed from cooled magma; a type of primary rock, but 原成岩石 is a broader term encompassing all unaltered original rocks.
Compound of 原成 (primary formation) and 岩石 (rock). The exact historical derivation is uncertain; the term is used in geological contexts.