National mineral assessment tract SB26 (Massive sulfide, kuroko)

Tract SB26
Geographic region Southern Basin and Range
Tract area 1,740sq km
Deposit type Massive sulfide, kuroko
Deposit age Proterozoic

Deposit model

Model code 28a
Model type descriptive
Title Descriptive model of Kuroko massive sulfide
Authors Donald A. Singer


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

P(none): 0.99

Estimators: Bartsch-Winkler, McLemore, Ludington, Wallace, Nash, Berger, Spanski


Explained by Steve Ludington and Miles Silberman
On the choice of deposit models
Metamorphosed Proterozoic volcanic rocks, especially felsic volcanic rocks in greenstone terranes often contain stratabound polymetallic massive sulfide deposits. The presence of kuroko deposits and prospects in other parts of New Mexico suggests they might occur in the Basin and Range province.
On the delineation of permissive tracts
The criteria for tract delineation include submarine island-arc volcanic host rocks of felsic composition and exhalative zones within the supracrustal sequence associated with the volcanic rocks (e.g., iron-formations or cherty zones) that provide evidence for submarine hydrothermal hot spring activity during volcanism. Greenstone belts make up a significant part of Proterozoic terranes in New Mexico; Robertson and others (1986) indicate areas where felsic and mafic rocks occur within Precambrian greenstone belts, thus defining the permissive tracts for kuroko massive sulfide deposits.
Important examples of this type of deposit
Significant deposits or prospects are not known in southwestern New Mexico.
On the numerical estimates made
The presence of several deposits and smaller prospects indicates that the mineralizing process took place in New Mexico. The permissive tract in the Basin and Range part of the State is, however, quite small, and there is little direct evidence for kuroko deposits. For the 90th, 50th, 10th, 5th, and 1st percentiles, the team estimated 0, 0, 0, 0, and 1 or more deposits consistent with the grade and tonnage model for kuroko massive sulfide deposits (Singer and Mosier, 1986).
Robertson, J.M., Fulp, M.S., and Daggett, M.D., III, 1986, Metallogenic map of volcanogenic massive sulfide deposit occurrences in New Mexico: U.S. Geological Survey Miscellaneous Field Studies Map MF-1853-A, scale 1:1,000,000.
Singer, D.A., and Mosier, D.L., 1986, Grade and tonnage model of kuroko massive sulfide, in Cox, D.P., and Singer, D.A., eds., Mineral deposit models: U.S. Geological Survey Bulletin 1693, p. 190-197.

Geographic coverage

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