A Geology Meme

From Reporting on a Revolution Blog:  The Geology Haiku Meme

Suvratk's is:

deep in a bioreef
a Permian story
calcite dripstones tell

Rules: Three lines and a max of seventeen syllables. Use of kigo, which is the traditional reference to a season, may be substituted by a reference to a geological period. The use of kireji, which is a word that serves to give structural support to the verse is not widely practiced in English haiku, so you may give that a pass.

Here's Mine:

Welded tuff

Bands of pink and tan rock

Ash compacted from volcano

~~~~~~~~~
Neat