Colorado Plateau 2005

Previous | Next | Index

Reduction spots in the Bright Angel shale. The red color of the shale is due to oxidized iron (hematite). The center of each spot contains a small amount of carbonaceous material, causing a spherical volume with iron in the reduced state. Such spots are often used in geologic strain analysis.

All images copyright © 2016 F.W. Vollmer and may not be used without permission.