Regional low-grade polygenetic metamorphism and inversion in the northern part of the eastern belt, northern Sierra Nevada, California
Bevins RE and Robinson D. 1995. Regional low-grade polygenetic metamorphism and inversion in the northern part of the eastern belt, northern Sierra Nevada, California. Pages 29-50. In Bevins RE and Robinson D. Low grade metamorphism of mafic rocks. Geological Society of America. Boulder, CO
The Eastern belt of the Sierra Nevadas is bordered to the west by the Feather River peridotite belt, and to the east by the Sierra Nevada batholith. Rocks of this Eastern belt have undergone low-grade polygenetic metamorphism at greenschist and subgreenschist facies levels. The earliest metamorphic event was of the Barrovian type, and occurred prior to accumulation of the first volcanic arc rocks (probably in Devonian time) and resulting in epizonal crystallinities of illite in pelitic rocks of the Shoo Fly Complex. Decreasing in grade from west to east, the metamorphic alteration affected younger arc rocks. From textural and chemographic evidence, at least three discrete metamorphic events appear to have affected the various arc volcanic rocks: a pretectonic prehnite-pumpellyite facies burial event, a syntectonic pumpellyite-actinolite facies event coincident with development of the Nevadan foliation, and a posttectonic static event, possibly due to loading effects related to thrusting, also in the pumpellyite-actinolite facies. Rocks found east of the area were affected by contact metamorphism as a result of emplacement of the Sierra Nevada batholith granitoids, which overprinted effects of the earlier regional metamorphic episodes.
- Type
- Book Chapter
- Authors
- Bevins, Richard; Robinson, Douglas
- Units
- LAVO
- Keywords
- Geomorphology, Metamorphism, Physical Sciences, Shoo Fly Complex, Sierra Nevadas