Eocene Tectonic Evolution of the Tetons-Absaroka Ranges, Wyoming

Wyoming2011_1What: 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

Geologic Background

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

  1. Finite strain study of a footwall fold in the Cambrian Flathead Sandstone (quartzite) overthrust by Archean gneisses (S. Tetons).
  2. Calcite twinning strain study of the footwall fold in lower Paleozoic carbonates overthrust by Archean gneisses (N. Tetons).
  3. Structural geology and geochemistry (XRF, detrital zircons) of vertical microbreccia “injectites” at White Mountain, Heart Mtn. detachment.
  4. Structural geology and geochemistry (XRF, detrital zircons) of vertical microbreccia “injectites” proximal to White Mountain, Heart Mtn. detachment.
  5. Structural geology and mapping of the rootless, folded S. Fork detachment (10 x 40 km; 2 students), with likely detrital zircon geochronology.

Wyoming2011_2

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.

Recommended Courses/Prerequisites

Mineralogy, Sedimentology, Structural geology

For More Information

Download the full project description PDF.

 

 

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