Abstract Title: Earthscope as a tool for understanding crustal mass transfer 
processes in the Great Basin

Abstract Author(s): Arehart, Greg (University of Nevada, Reno) - Gustafson, Lew 
(Independent Consultant)  

Abstract: The search for resources is multidisciplinary and requires a 
4-dimensional understanding of both regional and local geology, including 
aspects of structure, stratigraphy, geochemistry, geophysics, and 
geochronology. The Great Basin hosts a wide variety of resources, including 
major gold production, major porphyry metal deposits, and significant numbers 
of geothermal systems. Resource companies and academic and government 
investigations have all generated an understanding of the shallow environment, 
but major questions remain about deep crustal controls on resource formation. 
Earthscope provides the impetus and opportunity for integration of the 
available data from this variety of sources, along with an exciting opportunity 
to design experiments that will shed light on resource-forming processes at a 
regional scale. Three of the most important resource-related problems are 
outlined here. 1. Carlin-type gold deposits have an enigmatic relationship to 
Eocene igneous activity in the Great Basin, and form in apparent NNW linear 
arrays. A better understanding of large-scale earth structure and processes 
during the development of the Great Basin is necessary to help elucidate the 
origin of these deposits, as well as to understand why they are unique to the 
region. 2. An east-west alignment of Eocene porphyry copper deposits, including 
Bingham Canyon, crosses the Carlin trend in NE Nevada, but does not fit the 
predominant tectonic model for porphyry deposit formation elsewhere in the 
world. Generally contemporaneous with the possibly more shallow-seated Carlin 
deposits, they are more closely linked to magma generation and to a different 
set of structural controls. Earthscope could provide clues as to how the 
tectonic regime influenced the formation of these large metal deposits. 3. The 
Great Basin also hosts a very large number of metal-bearing active geothermal 
systems, a source of electrical energy and analogues for the paleogeothermal 
systems which formed gold deposits. How can the dynamic structural controls, 
deep magmatic activity and fluid movement, and heat flow which drive these 
systems be imaged by Earthscope?