From neighboring property
The Property is located in the western Harquahala Mountains in the Basin and Range Province of southwestern United States. The Basin and Range Province is a Cenozoic-age terrane, 350 to 900 km wide, that extends from southern Canada to southern Mexico and occupies much of the western United States. The Province is characterized by widespread, voluminous, Cenozoic magmatism and highly variable east-west extension of 10 to 300%. Magmatism and extension appear to have been localized in numerous north-trending corridors, starting as early as 50 Ma in northeastern Nevada and leading to the formation of hundreds of individual basin and range pairs separated by normal faults with major offsets. The Harquahala Mountains is one of these ranges and is bordered on the north and south by broad alluvial basins. Basin and Range extension has also created detachment, normal, and oblique faults in the Property area.
Tertiary-age Basin and Range extension in the region was preceded by the Laramide and Sevier Orogenies. The Laramide Orogeny was a continental-scale compressional tectonic event resulting from generally northeast-directed subduction of the Farallon (Pacific) Plate beneath the North American Plate during the period 97 to 35 Ma, that resulted in widespread metamorphism, magmatism, folding, and thrust faulting throughout western North American. It was also a major metallogenic event, creating the large porphyry copper deposits of the western U.S., Mexico, and Canada, as well as the orogenic gold deposits in California, the Canadian Cordillera, and western Mexico.
The Property is located within the Mojave-Sonora Gold Belt, a trend that includes 17 mines and deposits with more than 34 million contained ounces of gold (Figure 7.1). Gold deposits in the belt are dominantly orogenic- type and many are related to shallow-dipping thrust faults that formed as a result of Laramide compression. The orogenic gold deposits formed from gold-bearing metamorphic fluids generated by compression and dewatering of subducted oceanic sediments migrating up major fluid pathways to depositional sites beneath or within thrust faults. Age dates in the region, combined with structure, mineralogy, alteration, anomalous trace elements, and geophysical results indicate that gold mineralization within the Property is likely orogenic and of Laramide age.
The Property is located in the eastern end of the east-trending Maria Fold and Thrust Belt that is 25 to 35 km wide and is characterized by south-vergent, large-scale folds, thrust faults, and metamorphism (Spencer and Reynolds, 1990; Richard, et al., 1990; Salem, 2009; Figure 7.2). The east trend of the Maria Fold and Thrust Belt is anomalous within the northwest-trending Mojave-Sonora Gold Belt as well as within the north-trending structures of the Cordilleran Orogen to the north. North-south compression in the Maria Fold and Thrust Belt, between 97 to 67 Ma (Salem, 2009), has been correlated with syntectonic deposition of the upper McCoy Mountains Formation of Cretaceous age (116 to 84 Ma; Barth et al., 2004), located within and to the south of the Maria Fold and Thrust Belt. The McCoy Mountains Formation is the prospective host rock for gold mineralization within the Property.
The Maria Fold and Thrust Belt in the Property area includes as many as eight stacked thrust plates and thrust faults that record several phases of Late Cretaceous, Laramide and Sevier-aged crustal shortening. The thrust faults interleave a wide range of rocks, including Proterozoic metamorphic rocks, Paleozoic sedimentary rocks, Jurassic volcanics and intrusives, Cretaceous intrusive and sedimentary rocks, and Tertiary volcanics and sediments. Figures 7.3 and 7.4 show the principal thrust faults and tectonic plates in the Property area, Figure 7.5 shows the regional geology, and Table 7.1 shows the stratigraphy of the Property region.
Magmatism in the region includes Late Cretaceous-age plutons ranging in age from about 79 to 54 Ma (Richard et al, 1990; Richard et al, 1998; Salem, 2009). Laramide compression and magmatism was followed by uplift, erosion, and Basin and Range extension beginning around 25 Ma, that resulted in northwest-trending high- angle normal and strike-slip oblique faults, and large-displacement detachment faults (Reynolds and Spencer, 1985; Richard et al, 1990).
