Guide to the Picket Pin Mountain Area
Route
Start point
30m beyond Gallatin National Forest boundary along Picket Pin-Iron Mountain Road
End point
unnamed outcrop on NW side of Picket Pin Mountain
Roads (and Trails)
U.S. Forest Service Road 140 (Picket Pin-Iron Mountain Road)
Total distance
unknown
Geology
Summary
This traverse through part of the Banded series provides relatively easy access to the upper half of the exposed part of the Stillwater Complex. The percentage of outcrops is high, and even in areas of soil or tundra cover, the float appears to be sufficiently immobile and concentrated to give an accurate picture of the underlying bedrock geology....The traverse begins in the Middle gabbro zone and terminates where Paleozoic limestone unconformably overlies the Upper anorthosite zone. Above the Middle anorthosite zone, it follows the Picket Pin section described by McCallum and others (1980) and Raedeke (1982b)....An optional traverse through some lithologically complex and intriguing rocks in the Upper anorthosite zone north of the Castle Creek fault is also described. Total traverse time, including the drive from Carter's Camp and return, is 8-10 hours. Elevations range from 9,300 to 10,000 feet.
Key Lithologic Features
- cumulate rocks (gabbros and anorthosites) of the Banded Series
- mafic pegmatoids in the Banded Series
Structures
Landforms
Other Features
Reference
Carlson, R.R., and Zientek, M.L., 1985, Guide to the Picket Pin Mountain Area,
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. 262-276.
Availability
Order from the Montana Bureau of Mines and Geology. Search for
this publication's record at the MBMG for ordering information.
