A Geoscience Digital Image Library

TitleMylonite, Los Angeles County, California
DescriptionMylonites form as a result of dyanmic metamorphism. They may be breccia-like, or streaked or banded. Mylonites result from grinding, granulation, pulverization and shearing during faulting. This sample is a jumble of rock and mineral fragments (up to 3 mm across) in a fine grained matrix. The fragments include mostly quartz and plagioclase with lesser amounts of biotite, hornblende and sphene. The matrix includes the same minerals, especially biotite, which accounts for the overall brownish color. The exact provenance of this sample is unknown.
LocationUSA ▹ California ▹ Los Angeles County. Near Los Angeles.
PhotographerNessa Eull. 2001-05-22.
CollectionWard’s University Rock Collection #179.
Key wordsmylonite, California
Tech details1.07 MB. Hand specimen. Fujifilm FinePix S1Pro digital camera; 60mm AF Nikon micro lens.
GeoDIL number512