Azoic

/eɪˈzoʊɪk/ adjective

Definition

Containing nitrogen or relating to azo compounds (molecules with two nitrogen atoms bonded together); also used in geology to describe the oldest rocks formed before life existed.

Etymology

From 'azo-' (nitrogen-nitrogen bonds) + Greek '-ic' (relating to). In geology, from Greek 'a-' (without) + 'zoic' (life), meaning lifeless—used for the Azoic eon before fossils appeared.

Kelly Says

Geologists used to call Earth's oldest rocks 'Azoic' because they found zero fossils in them, making it the ultimate dead zone of deep time—now we just call it the Hadean Eon.

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