Structural and Stratigraphic Controls on the Geothermal System Near Paisley, Oregon

Abstract

Geothermal resources in southeast Oregon are predominantly similar to those further to the south in Nevada and can be classified as Basin and Range geothermal systems. Work done on the geothermal system near Paisley, Oregon exemplifies the relationship between regional and local structure as it controls thermal fluid movement. Neogene tectonism has produced the Basin and Range and the Brothers Fault Zone. Paisley, Oregon lies at a unique location where these individual tectonic provinces coalesce to produce an extremely high geothermal resource potential. Thermal upwelling and production in the Paisley Geothermal System is controlled by the Paisley Hills Fault where it lies in a structural transfer zone evidenced by overlapping en echelon geometry with the Winter Ridge Fault. This structural setting has produced the necessary permeability to allow for the concentrated flow of thermal fluids.