The purpose of this project is to expose you to the mapping of faults, Paleozoic bedrock and syntectonic growth strata associated with a classic Laramide uplift. You are given two field days and one drafting day to complete a geologic map and two cross sections of a portion of the Steerhead Ranch, roughly ten miles west of Buffalo, Wyoming. The area consists of Archean igneous and metamorphic basement rocks nonconformably overlain by Paleozoic (Cambrian-Pennsylvanian) cratonic sedimentary rocks. Both Archean and Paleozoic rocks were deformed during the Laramide Orogeny and numerous faults of various orientations and slip sense occur within the area. The principal structure of the area is the Clear Creek Thrust, one of the major range-bounding faults that carries the Bighorn Mountains above it. A thick succession of syntectonic Tertiary gravel occurs within both the hanging wall and footwall of the fault.
When constructing your map and cross sections, be mindful of what we know about the regional structural geology. The map area is largely a hanging-wall anticline developed above a basement fault and any subsidiary faults and folds should have geometries similar to those documented in similar structures. Tear faults and extensional faults both exist in this mapping area.
Follow the Guidelines for Map and Cross Section construction when preparing your project. The map, explanation and both cross sections should be constructed on the paper provided. You are free to design the layout of these items any way you like, but they all must fit on the same sheet of paper.
When mapping in the field or drawing your cross sections, observe the following guidelines: