CONTRIBUTIONS TO THE SIERRA NEVADA DIGITAL EARTH SCIENCE ATLAS: CARBONATE ROCKS AND METALLOGENIC BELTS

As part of the project on the Sierra Nevada Digital Earth Science Atlas, we are presenting two datasets on the mineral resources of the Sierra Nevada: carbonate rocks and metallogenic belts. Best known for its substantial historical gold production, the region also hosts a diverse suite of mineral deposits. “Carbonate rocks” are defined as limestone, dolomite, and metamorphic equivalents. These important industrial minerals are typically found in discontinuous beds or lenses in the Foothills Metamorphic Belt (FMB) and roof pendants throughout the central and southern Sierra Nevada. This dataset represents locations of economically significant carbonate deposits described in the California Division of Mines and Geology Bulletin 194 and includes unpublished historical geochemical data.

“Metallogenic belts” are defined as areas that contain or are favorable for a group of genetically related, significant mineral deposit types. This dataset builds upon previous mineral deposit syntheses using updated mineral deposit models and geologic mapping to refine the extent of metallogenic belts in the Sierra Nevada. Significant mineral deposits were described and classified based on deposit type, age, host lithology and structure. Eight major metallogenic belts were delineated: (1) Late Paleozoic to Jurassic podiform Cr deposits hosted in fault-bounded ophiolite slices within the FMB; (2) Late Triassic to mid-Cretaceous W skarn and vein deposits at or near the contact between calc-alkaline plutons and carbonate-bearing metasedimentary pendants; (3) Jurassic volcanogenic massive sulfide deposits of the Foothills Cu-Zn Belt hosted in metavolcanic sequences of the FMB; (4) Mid-Jurassic(?) polymetallic replacement deposits (Ag-Pb-Zn) in folded and faulted Paleozoic-Mesozoic carbonate formations in the White-Inyo Mountains; (5) Late Jurassic to early Cretaceous orogenic Au-quartz veins, including the Mother Lode gold belt; (6) Oligocene to Pliocene epithermal Au-Ag vein deposits in the eastern Sierra Nevada and Walker Lane transition; (7) Tertiary deposition of Au (+/- PGE) gravels in large east-west trending paleovalleys created by erosion and drainage of a topographic high to the east; (8) Quaternary deposition of Au (+/- PGE) placers in rivers and floodplains presently draining the Sierra Nevada.