noun
asphalt rock; bituminous rock
Technical term in geology and civil engineering for natural rock impregnated with asphalt or bitumen.
この地域では瀝青岩が産出される。
Asphalt rock is mined in this region.
アスファルト is the common word for asphalt as a paving material, while 瀝青岩 refers specifically to the natural rock containing bitumen.
Compound of 瀝青 (bitumen, asphalt) and 岩 (rock). The exact historical derivation is uncertain; the spelling is conventionally associated with the meaning.