Raft River EGS Project: A GIS-Centric Review of Geology

Abstract

The Raft River thermal anomaly is located on the northern margin of the Great Basin. This area has undergone numerous studies due its juxtaposition with the Raft River and Albion metamorphic core complexes, associated low-angle detachment faults, and the presence of the thermal anomaly. Miocene movement along the Raft River detachment displaced a large mass of Paleozoic and Mesozoic rock about 24 km to the east unroofing the shear zone and creating the Raft River Valley. The rocks in the Raft River detachment footwall/shear zone are Archean and Proterozoic in age and are overlain by late Miocene/Pliocene ash-flow tuff, tuffaceous sediments, rhyolite, and mixed Quaternary sediments. Work described here supports the DOE/U.S. Geothermal, Inc. supported Raft River EGS project which is aimed toward improving permeability in well RRG-9. A GIS data suite was developed from historical data and new data produced by this study to help underpin this project. The GIS includes well survey, lithologic, mineralogic, and geophysical data that were incorporated from disparate datasets ranging from scanned images to tabular data in spreadsheets. This data has been visualized and analyzed using GIS-based tools to help build a better understanding of the study area geology. This includes a possible structural explanation of ground water/geothermal fluid compartmentalization.