TOPOGRAPHIC LINEAMENTS AND EXPRESSION OF FRACTURE ARRAYS IN THE EDELMAN AND NORTH PAINT ROCK CREEK LINEAMENTS, BIGHORN MOUNTAINS, WYOMING

摘要

The Bighorn Mountains of north central Wyoming are a basement-cored arch formed during the Laramide Orogeny. Working in association with the Bighorn Arch Seismic Experiment (www.bighorns.org), the Bighorns Keck project seeks to, develop a better understanding of the structures active within crystalline basement and sedimentary cover rocks during the formation of the arch. Little is known of the origin of the brittle structures within the crystalline rocks at the core of the arch, and distinguishing Laramide-re-lated features from older features is not an easy task. Large-scale linear topographic features are prominent throughout the core of the Bighorn Arch (Hoppin, 1974). This study focuses upon two specific lineaments, the drainages of Edelman Creek and North Paint Rock Creek in the central Bighorn Mountains. I combine detailed field measurements and geographic information systems (GlS)-based topographic lineament-analysis in an attempt to understand the relationship between outcrop-scale brittle fractures in the crystalline basement and regional-scale lineaments in the Bighorn Mountains, and advance the understanding of the manner of deformation of the crystalline basement formation of the Laramide arch.