Road Log to the Picket Pin Mountain, Chrome Mountain and Contact Mountain Areas
Route
Start point
Carter's Camp at the intersection of Montana Highway 419 and Montana Highway 420 (gravel road)
End point
Frog Pond Adit in saddle below Contact Mountain
Roads
Montana 420, U.S. Forest Service Road 142 (Picket Pin-Iron Mountain Road), other gravel roads
Total distance
31.08 miles
Geology
Summary
This road log describes the geologic features along the access roads for three additional traverses:
Guide to the Picket Pin Mountain Area,
Guide to the Chrome Mountain Area, and
A Traverse Through the Banded Series in the Contact Mountain Area. "This trip requires nearly 2 hours without stops. Beyond 12.5 miles, the road is rough and steep in places; a four-wheel-drive vehicle is recommended.
Key Lithologic Features
- tuff agglomerates of the Cretaceous Livingston Group
- glacial deposits
- anorthosites, cumulates, and mafic dikes in the Banded Series, Stillwater Complex
- Paleozoic limestone and dolomite
- unconformable contact (with paleoregolith) between Paleozoic limestone and Banded Series gabbros of the Stillwater Complex)
- Tertiary porphyritic dacite sill
Structures
- Horseman Thrust Fault
- Castle Creek Fault
Landforms
Other Features
Reference
Carlson, R.R., Page, N.J., and Czamanske, G.K., 1985, Road log to the Picket Pin Mountain, Chrome Mountain and Contact Mountain areas,
in Czamanske, G.K., and Zientek, M.L., eds.,
The Stillwater Complex, Montana: Geology and Guide : Montana Bureau of Mines and Geology Special Publication 92, p. 253-261.
Availability
Order from the Montana Bureau of Mines and Geology. Search for
this publication's record at the MBMG for ordering information.
