A GEOGRAPHIC INFORMATION SYSTEM FOR THE HUMBOLDT PEAK QUADRANGLE, EAST HUMBOLDT RANGE METAMORPHIC CORE COMPLEX, ELKO COUNTY, NEVADA

Analog format geologic mapping of the Humboldt Peak Quadrangle in Elko County, Nevada has been compiled and transformed into digital format using ArcGIS in order to produce a geographic information system synthesizing available data for this structurally complex region. The Humboldt Peak Quadrangle forms the central part of the East Humboldt Range metamorphic core complex, a polydeformed upper amphibolite grade terrain exhumed in the footwall of the Ruby Mountains-East Humboldt Range detachment fault system in Late Oligocene time. The map and associated cross-sections illustrate the dominant structural features of the region, the Late Cretaceous Winchell Lake recumbent fold-nappe and structurally deeper nappe sheets, and the overprinting Tertiary mylonitic shear zone. In addition, the GIS delineates the geometry of the Lizzies Basin migmatite complex which forms the structurally deepest part of the metamorphic core complex.

The presentation of this data in a geographic information system simplifies its manipulation and communication. The architecture of the GIS is built on a topographic base presented either as a digitized topographic contour map or a hillshade on the DEM. Overlying layers include the bedrock geology, metamorphic assemblages and PT determinations, radiometric age date localities, and structural orientation data including foliations, lineations, shear sense indicators, and fold hingelines and axial planes. Compilation of the orientation data in digital format facilitates domain analysis and data extraction for stereographic orientation analysis. Supplemental information includes a three-dimensional representation of the geology extruded on topography, the structural cross-sections, and remote sensing data. These tools will facilitate publication, dissemination, and future analysis of the data from the East Humboldt Range as well as providing a template for production of geographic information systems for adjacent areas. In addition, the flexibility of this approach allows for the accumulation of new data in the future.