National mineral assessment tract SB40 (Sediment-hosted Au)

Tract SB40
Geographic region Southern Basin and Range
Tract area 18,700sq km
Deposit type Sediment-hosted Au
Deposit age Phanerozoic

Deposit model

Model code 26a
Model type descriptive
Title Descriptive model of carbonate-hosted Au-Ag
Authors Byron R. Berger


Confidence Number of
90% 0
50% 0
10% 0
5% 0
1% 1

P(none): 0.99

Estimators: DCox, Ludington


Explained by Dennis P. Cox
On the choice of deposit models
Although no sediment-hosted gold deposits are known, shales and carbonate rocks in sedimentary sequences thickened by thrust faulting are permissive conditions for undiscovered deposits of this type.
On the delineation of permissive tracts
Paleozoic sedimentary rocks that were folded and thrust faulted during Mesozoic or earlier orogenies constitute the permissive tract. There are no known deposits or prospects.
On the numerical estimates made
Because of the lack of known deposits and the fact that this area is a great distance from the well-recognized deposits in northern Nevada, the team made a low estimate. For the 90th, 50th, 10th, 5th, and 1st percentiles, we estimated 0, 0, 0, 0, 1 or more deposits consistent with the grade and tonnage model of Mosier and others (1992).
Mosier, D.L., Singer, D.A., Bagby, W.C., and Menzie, W. D., 1992, Grade and tonnage model of sediment-hosted Au, in Bliss, J.D., ed., Developments in deposit modeling: U.S. Geological Survey Bulletin 2004, p. 26-28.

Geographic coverage

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