Surface Geochemical Tools for Hydrocarbon Exploration and Structural Mapping in the Great Basin of Nevada and Utah
The innovative application of both organic and inorganic
surface geochemical tools has facilitated exploration and structural mapping in
the Great Basin. More specifically, the interrelationship of C1-C8 hydrocarbons
in soils is used
to predict “oil-prone” areas and the major and trace element
concentrations in soils map the spatial distribution of underlying hydrothermal
dolomites and faults. Soils over normal faults that bound oils typically have higher
concentrations of heavy hydrocarbons (>C5), carbon dioxide, carbon monoxide,
uranium, halogens, alkaline earth metals (i.e. Mg, Ca, and Sr)
and lower concentrations of transition metals (e.g. Fe, Mn,
Ni, etc.). Soils directly over the oil fields have unique multivariate
hydrocarbon ratios that distinguish them from barren unproductive areas. These
hydrocarbon ratios are
used
to predict oil
potential
in unknown areas. Case
studies from several areas of the Great Basin in Nevada and western Utah compiled
over a seven-year period will be presented to emphasize the
potential
of these
tools for both oil exploration and structural mapping in this extensional
geological environment.