noun
geological time; geologic age
Technical term used in geology and earth sciences to refer to the vast timescale of Earth's history, divided into eons, eras, periods, etc.
地質年代で見ると、人類の歴史はほんの一瞬に過ぎない。
In geological time, human history is just a brief moment.
地質時代 is often used interchangeably with 地質年代, but 地質時代 can emphasize the chronological division (era/period) rather than the abstract concept of time scale.
Compound of 地質 (geological features/strata) and 年代 (age/era). The term is a direct translation of the Western geological concept.