Fracture pattern study, Bull Canyon, Montrose and San Miguel counties, Colorado

Abstract

A study was made of the joint patterns in four different formations exposed in Bull Canyon, and of favorable and unfavorable ground in the upper ore-bearing sandstone unit of the Salt Wash member of the Jurassic Morrison formation, from which about two-thirds of the uranium production in Bull Canyon has come. Two major joint sites sets were found in all formations, forming a conjugate system, striking N 50-60° W and N 30-40° E. Most prominent are the northwestward joints, which are approximately parallel to the adjacent Paradox Valley and Gypsum Valley anticlines.