This volume focuses on the geometry, kinematic development, and origin of regional segmentation structures within the basin and range province of Western North America. Contributions range from analysis of individiual structures to broad regional syntheses, including a map of basin and range structures and tilt domains. Several papers discuss the implications of regional segmentation structures in assessing seismic hazards, hydrocarbon and mineral resources, and ground-water supplies.

Accompanying CD-ROM titled: Supplementary materials to Miocene tectonics of the Lake Mead region, central basin and range.

This report (269 pages, 4 plates) presents hydrogeologic, groundwater-monitoring, and hydrochemical studies by the Utah Geological Survey (UGS) in Snake Valley, Tule Valley, and Fish Springs Flat in Millard and Juab Counties, west-central Utah. Data From the newly established UGS groundwater-monitoring network establish current baseline conditions, and will help quantify the effects of future variations in climate and groundwater pumping. New hydrochemical data show that groundwater quality is generally good, major-solute chemistry varies systematically from recharge to discharge areas, and suggest that most groundwater was recharged over one thousand years ago, implying low recharge rates and/or long or slow flow paths. Two aquifer tests yield estimates of transmissivity and storativity for the carbonate-rock and basin-fill aquifers. Variations in the potentiometric surface, hydrogeology, and hydrochemistry are consistent with the hypothesis of regional groundwater flow from Snake Valley northeast to Tule Valley and Fish Springs. Collectively, our work delineates groundwater levels, flow, and chemistry in Snake Valley and adjacent basins to a much greater degree than previously possible, and emphasizes the sensitivity of the groundwater system to possible increases in groundwater pumping.

The objective of this report is to summarize U.S. Department of Energy (DOE) supported studies in the Dixie Valley geothermal area and to relate the results of those studies to other, non-DOE-supported studies that have been done in the valley during the past 40 to 50 years. This compilation of past research includes new analysis resulting in a more in-depth understanding of the geothermal system in Dixie Valley. The focus is on the basin geology and structure, thermal regime, and geothermal system geochemistry. Reservoir studies are briefly discussed.