Desert varnish: evidence for cyclic deposition of manganese
Abstract
WE have found evidence that desert-varnish coatings on rocks in the western US consist of micron-scale alternating dark and light layers that differ in manganese and iron content. We report here the first quantitative electron-microprobe analyses of desert varnish, that also show the chemical variations in these layers. In the field and laboratory we obtained new evidence that varnish covers a fresh substrate by nucleation of micron-sized patches that grow and coalesce.
- Publication:
-
Nature
- Pub Date:
- November 1978
- DOI:
- 10.1038/276489a0
- Bibcode:
- 1978Natur.276..489P