A Quick Great Basin National Park Geology Day
Start at the Visitor Center with a short hike on the ¼-mile long Mountain View Nature trail to see the Pole Canyon Limestone, and pass by the natural entrance to Lehman Caves. Or, take a tour through the cave and walk through the bedrock and amongst beautiful calcite formations. Note here that standing on a limestone outcrop you are below the quartzite in elevation but still stand above it stratigraphically. These layers have been tilted so that, in places, the stratigraphy is confusing. The quartzite is below and older than the limestone.
From the visitor center parking lot, hop in the car and head towards Baker. Make a left turn onto the Wheeler Peak Scenic Drive (vehicles longer than 24 feet in length are not recommended on this road). White granite outcrops are visible to the west. Drive approximately 6 miles up the road to the Mather Overlook. Watch out for mule deer!
Mather Overlook. To the southwest, Wheeler Peak stands tall with the cliff face displaying the layers of the Prospect Mountain Quartzite. Glaciers carved the landscape below the peak and part of what is now the Lehman Creek drainage (the creek below you). The glacier probably stopped its advance at a point extending out from the Mather Overlook. Let your eyes follow the drainage down, and they will come to rest on the valley floor. The Snake Valley contained one of the southernmost arms of Lake Bonneville. The rock layers to the east-northeast are also Prospect Mountain Quartzite, as well as the large rocks sitting in the parking area. Take a close look at these rocks. Sedimentary structures, like cross-bedding of sand layers, are preserved in places. Get back into the car and continue up the drive approximately 3 more miles to the Wheeler Peak Overlook.
|Wheeler Peak Overlook. From here, you can look directly into the cirque, and view the large patch of ice at the base of the cliff walls. Freezing and thawing ice break rocks off of these walls, and frequently debris can be seen on top of the ice. Is this still a glacier? True glaciers move downhill under their own weight, but this movement is hard to observe when glaciers are moving very slowly or are melting back. The truth isn't clear, and unfortunately, not many people are scientifically observing it to find out.
Article written by: Kurt Danielson, 2000