Geochronometric and lead isotope data on samples from the Wallace 1 degree by 2 degrees Quadrangle, Montana and Idaho
Miscellaneous Field Studies Map
1354-G
By: R. F. Marvin, R. E. Zartman, J. D. Obradovich, and J. E. Harrison
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Abstract
Most of the bedrock in the Wallace quadrangle belongs to the Belt Supergroup, a thick (about 18,000 m) sequence of generally fine-grained clastic and carbonate rocks of Middle Proterozoic age. Regional metamorphism prior to Cambrian time prograded the Belt rocks to greenschist facies, and some metal-bearing veins were emplaced in fractures. The Belt rocks were intruded in Late Proterozoic time by basic dikes and sills.
Study Area
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Geochronometric and lead isotope data on samples from the Wallace 1 degree by 2 degrees Quadrangle, Montana and Idaho |
| Series title | Miscellaneous Field Studies Map |
| Series number | 1354 |
| Chapter | G |
| DOI | 10.3133/mf1354G |
| Year Published | 1984 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Description | 31.43 x 41.26 inches |
| Country | United States |
| State | Idaho, Montana |
| Scale | 250000 |