Home

About

Advanced Search

Browse by Discipline

Scientific Societies

E-print Alerts

Add E-prints

E-print Network
FAQHELPSITE MAPCONTACT US


  Advanced Search  

 
Paper No. 63-3 Presentation Time: 8:50 AM-9:05 AM THE LINK BETWEEN BEDDED BARITE AND CARLIN-TYPE GOLD
 

Summary: Paper No. 63-3 Presentation Time: 8:50 AM-9:05 AM THE LINK BETWEEN
BEDDED BARITE AND CARLIN-TYPE GOLD
DEPOSITS IN NEVADA AREHART, Greg B., Geological Sciences, Univ of
Nevada, Reno, Geological Sciences, MS-172, University of Nevada, Reno, Reno, NV 89557,
arehart@unr.edu and MUNTEAN, John, Placer Dome Exploration, 240 S. Rock Blvd., Suite
117, Reno, NV 89509
Carlin-type gold deposits are found in several localities around the world, however, the deposits
of substantial size are all concentrated in western North America, and within a very restricted
area in northeastern Nevada. This occurrence suggests a convergence of events is required to
generate large deposits of this type. Spatially overlapping with Carlin-type deposits, which are
dominantly of Eocene age, are bedded barite deposits of Paleozoic age. In addition, some
Paleozoic rock units in this region contain abundant organic matter. We propose that the bedded
barite and organic matter are important in the development of bisulfide-bearing fluids capable of
transporting unusually high concentrations of gold. As hydrothermal circulation cells developed
in conjunction with Eocene extensional tectonism and/or magmatism, sedimentary barite was
reduced thermochemically to bisulfide by the associated organic matter. The abundance of
sulfate resulted in a very bisulfide-enriched fluid, capable of transporting gold large distances
through the crust to within a few kilometers of the surface before depositing gold. The
characteristic high Au:Ag observed in Carlin-type deposits resulted from the extreme
enrichments (relative to most hydrothermal fluids) in bisulfide, perhaps as high as 1 molar H2S.

  

Source: Arehart, Greg B. - Department of Geological Sciences, Mackay School of Mines, University of Nevada, Reno

 

Collections: Geosciences