Eocene Tectonic Evolution of the Tetons-Absaroka Ranges, Wyoming
What: Structural geology of Laramide and Heart Mountain detachment deformation
When: mid-July to mid-August
Where: Northwest Wyoming (Cody and Jackson)
Who: John Craddock (Macalester College) and Dave Malone (Illinois State University) plus 6 students
Northwest Wyoming is a unique field location where the overlap, in space and time, between the Sevier thin-skin (Cretaceous-late Paleocene) and Laramide (late Cretaceous-Eocene) thick-skin orogens can be observed. Contemporaneous with these orogens is the collapse of the Eocene Sunlight volcano, forming the world’s largest debris avalanche and low-angle normal fault detachment, the Heart Mountain detachment. The S. Fork detachment chaos is part of the Heart Mountain system southwest of Cody.
Potential Student Projects
- Finite strain study of a footwall fold in the Cambrian Flathead Sandstone (quartzite) overthrust by Archean gneisses (S. Tetons).
- Calcite twinning strain study of the footwall fold in lower Paleozoic carbonates overthrust by Archean gneisses (N. Tetons).
- Structural geology and geochemistry (XRF, detrital zircons) of vertical microbreccia “injectites” at White Mountain, Heart Mtn. detachment.
- Structural geology and geochemistry (XRF, detrital zircons) of vertical microbreccia “injectites” proximal to White Mountain, Heart Mtn. detachment.
- Structural geology and mapping of the rootless, folded S. Fork detachment (10 x 40 km; 2 students), with likely detrital zircon geochronology.
Logistics/Special Field Conditions
We will be camping and in the field most of the month with backpacking required for the 2 projects in the Tetons. The daily hiking can be strenuous and involves lots of topography.
Mineralogy, Sedimentology, Structural geology
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