BH250-101
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Subject
Description
The Alta Stock, located in Alta, Utah, is a well-known granodioritic intrusion notable for its role in regional Mesozoic magmatism, contact metamorphism, and hydrothermal skarn mineralization.
Geochemically, the stock ranges from intermediate to felsic composition (see table below). It intrudes Mississippian–Pennsylvanian carbonate and clastic sedimentary rocks, producing a prominent contact metamorphic aureole. Metamorphic assemblages within this aureole include periclase, pure forsteritic olivine, tremolite, talc, diopside, wollastonite, ludwigite, vesuvianite, and recrystallized calcite and dolomite. These assemblages reflect both high-temperature metamorphism and skarn-type alteration, especially in carbonate-rich units exposed to metal-bearing hydrothermal fluids. Hornfels facies also developed in surrounding sedimentary rocks.
Additionally, the Alta Stock is spatially associated with mineralization in the Little Cottonwood mining district, hosting or occurring near historic silver-lead-zinc veins.
Coverage
Nearby Geographic Features: Alta Stock
GPS Coordinates: 40°34'53.31"N, 111°36'58.20"W