Weeks 4-6:
During the next segment of Field Camp we will work with Marli Miller to continue mapping near Dillon, Montana. During this time, we will complete three projects: a one-day project on glacial landforms and deposits on the east side of the Pioneer Range, a three day project mapping the mineralized contact of the Pioneer Batholith with Paleozoic rock, and a seven day project mapping complex structures of the Sevier Fold-Thrust Belt.
Glacial Landforms Project: We will map beautifully exposed Pinedale and pre-Pinedale moraines and ice-dam lake deposits at an elevation of 7000 feet in the Pioneer Range.
Intrusive Relations and Skarn Mineralization: This three day project will involve mapping deformed Paleozoic bedrock and its intrusive contact with the Cretaceous Pioneer Batholith. One emphasis of this project is the very well-developed mineralization along the contact.
Zone of skarn mineralization adjacent to Pioneer
Batholith
at Birch Creek.
----
Detailed Structural Analysis: This seven day project, at the "Block
Mountain Area" (see photos below), displays similar stratigraphy as at
Frying Pan. However, the structures at Block Mountain are far
more
complex, having formed during at least two distinct thrusting
episodes.
Our work here will therefore consist of detailed mapping of larger
structures,
and data collection of minor, related structures.
View of Block Mountain area from the air. Block
Mountain
itself (photo 2) is the mountain that looks like a block in the right
middle-ground.
The Block Mountain area displays a beautiful section
of Mesozoic sedimentary rocks which were folded and faulted during the
Sevier Orogeny.
Because of the clear stratigraphy and outstanding
bedrock
exposures in this area, we will be able to map some unusually
complicated
structures in great detail.
Hogbacks of Cretaceous Kootenai Fm. Block Mountain in
background.
Repetition of folded Triassic Dinwoody Fm. along
imbricate
thrust faults.
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Last updated 03 December 2004
University of Oregon Department of Geological Sciences