Western U.S. and Sonoran Desert Jurassic Arc

U.S. and Mexican parts of a composite island-continental margin arc that formed during subduction of the Farallon Plate beneath western North America
Tract ID 003pCu9006x
Country Mexico-United States of America
Commodity Cu
Study area name Mexico and US revised
Tectonic setting mixed
Deposit type porphyry copper
Grade-tonnage model General porphyry copper model (Singer and others, 2008)
Geologic age
Geologic feature age Triassic through Jurassic
Generalized age Mesozoic
Oldest rocks age 251Ma
Youngest rocks age 145.5Ma
Age range 105.5Ma
Identified Cu resources 11,000,000metric tons
Mean Cu (t/sq km) 278t/sq km
Map scales used 250K, 500K

Results of the assessment

Assessment date 2010
Estimators Steve Ludington, Jane Hammarstrom, Gilpin Robinson, and 1996 Team
Assessment depth 1km
Quantitative assessment Yes

Estimated number of deposits

Number of deposits Confidence level
1 90%
4 50%
14 10%
14 5%
14 1%
Mean estimated deposits 6.03 ±4.82 (0.8%)
Probability of mean 0.29
Probability of no copper 0.06

Estimated deposit density

Known
deposits
Total
deposits
Area
(sq km)
Deposit density
per 100,000 sq km
6 12.03 255,630 5

Mean estimated tonnage

Copper 23,000,000
Molybdenum 590,000
Gold 600
Silver 7,400
Ore 4,600

Undiscovered copper resource

Confidence level 90% 50% 10% 5%
Tonnage 460,000 11,000,000 55,000,000 84,000,000

Economic analysis

Fraser country California
Fraser type 0.95%
Fraser high 0.05%
Typical cost 1%
High cost 0%
Infrastructure setting Typical
Comments on depth default
Expected depth distribution
0 - 250m 0.25
250m - 500m 0.25
500m - 1km 0.5
Economically recoverable resources
Copper 15,000,000t
Molybdenum 290,000t
Gold 320t
Silver 4,500t
Probability no econ recoverable 0.15
Econ NPV 4,300x $1M
Exp dollars 15.01x $1M/100,000 sq km
Exp value class Medium

Bibliographic references

General Hammarstrom and others (2010) and U.S. Geological Survey National Mineral Resource Assessment Team (2002)
Economic Robinson and Menzie (2012)

Deposits and prospects associated with this tract

Name Type State Country Development Details
Yerington deposit Nevada United States Occurrence Details
Afterthought prospect Nevada United States Occurrence Details
Ann Mason deposit Nevada United States Prospect Details
Bear-Lagomarsino deposit Nevada United States Occurrence Details
Bisbee deposit Arizona United States Past Producer Details
Buckskin prospect Nevada United States Past Producer Details
Contact deposit Nevada United States Past Producer Details
Delcer Buttes prospect Nevada United States Occurrence Details
MacArthur deposit Nevada United States Occurrence Details
Royston prospect Nevada United States Occurrence Details