Yellowstone and Grand Teton National Parks and the Middle Rocky Mountains – Casper, Wyoming to Salt Lake City, Utah, July 20–30, 1989 Volme T328

Published by the American Geophysical Union as part of the Field Trip Guidebooks Series, Volume 328.

The route of Field Trip T-328 through Wyoming is shown on the tectonic map (Figure 1), and an abbreviated schedule is presented in Table 1.

This trip is designed to show participants the granite-cored Laramide (Late Cretaceous-earliest Eocene) mountain ranges in the middle Rocky Mountains, and their various stages of burial by Cenozoic deposits and subsequent Quaternary exhumation. Mountain-flank structures involving Precambrian, Paleozoic, and Mesozoic rocks, the classic Heart Mountain detachment fault complex, and the rootless overthrust mountain ranges of the Wyoming-Utah-Idaho thrust belt are traversed.

The Gas Hills, one of the largest "boom and bust" uranium open-pit mine areas in the United States is examined. Oil and gas fields are seen in two of the major intermontane basins (Wind River and Bighorn), and also in the overthrust belt that, in the last 15 years, has been found to be fabulously productive. The Absaroka volcanic field (Eocene) and the Late Cenozoic igneous, thermal, and seismic feature of Yellowstone National Park are traversed, as well as the related Hebgen earthquake and landslide phenomena created in 1959.