A vocabulary of landscape — a landscape of words
1367 entries
exfoliate
To exfoliate is to shed in sheets. In geology, it describes rock that peels off in curved slabs parallel to its own surface, which is how granite domes get their shape: The rock formed under enormous pressure, and as the material above it was stripped away it expanded and cracked along curves, shedding shells like an onion. The same word covers the flaking of a rock face under repeated freezing and heating.
Etymology
The word is Latin for stripping the leaves off, from the ordinary Latin word for a leaf. That word is behind a whole shelf of English: foliage, folio, portfolio, and foil, which was originally a leaf of beaten metal. Geologists and dermatologists borrowed the same verb independently, which is why it now describes both a mountainside and a face scrub.
Notes
Exfoliation covers the process; this is the verb and its wider family. Half Dome, El Capitan, and Stone Mountain are all exfoliating, and the curved slabs that come off can be many feet thick. Rockfall from exfoliation sheets is a routine event in Yosemite and is often triggered by nothing more than a hot afternoon.