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Structural Mapping of Block Mountain and Trip to Glacier National Park

During the third segment of Field Camp, students will work with Marli Miller to continue mapping near Dillon, Montana, and take a four day field trip to Glacier National Park. The mapping project will highlight complex structures of the Sevier Fold-Thrust Belt, and the field trip will allow us to observe some classic (and spectacular!) structures and sedimentary rocks farther north.

The mapping project will consist of six days in the field at the “Block Mountain Area” (see photos below), which contains stratigraphy similar to that seen at Frying Pan. However, the structures at Block Mountain are far more complex, having formed during at least two distinct thrusting episodes. Our work there will consist mostly of detailed mapping of larger structures, and data collection of minor, related structures. The final project will include a geologic map, cross section, analysis of stereonets, and a written report.

The photo above shows a view of Block Mountain area from the air. Block Mountain itself 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.

This photo shows repetition of folded Triassic Dinwoody Fm. along imbricate thrust faults.