Paleozoic stratigraphy and kinematics of the Roberts Mountains allochthon in the Independence Mountains, northern Nevada


New biostratigraphic, stratigraphic, and structural data from deformed lower
Paleozoic sedimentary units of the Roberts Mountains allochthon (RMA), Independence
Mountains, Nevada, have enabled the identification of stratigraphic units within
the allochthon that range in age from Late Cambrian through Late Devonian. The
McAfee thrust fault emplaced a relatively thick (>200 m) sheet of Ordovician Valmy
quartzite (locally termed the McAfee Quartzite) on complexly deformed units of the
RMA (locally termed the Snow Canyon Formation) comprised of the Vinini Formation,
Elder Sandstone, and Slaven Chert. The rocks were affected by multiple phases
of deformation during and after the Devonian-Mississippian Antler orogeny, including:
emplacement of the Roberts Mountains allochthon with south-vergent folding
and faulting of the upper and lower plate rocks to the Roberts Mountains thrust; emplacement
of Upper Mississippian (324 Ma) basalt dikes that cross-cut the upper
(allochthonous) and lower (para-autochthonous) plate rocks and south-vergent folds;
emplacement of the McAfee Quartzite; and upright north-trending folding after the
deposition of Antler overlap rocks. Recognition of this history is required to determine
the internal structure and thickness of the allochthon and location of high-angle
structures within it that, respectively, may conceal and localize Carlin-type gold
deposits in underlying carbonate rocks.

SKU: 2010-56 Category:

Additional information


Primary Author

Christopher Holm-Denoma






Deposit Type



Geologic Era