LS07 - Lake Superior

Marine carbonaceous strata of the Mesoproterozoic Nonesuch Formation overlying Mesoproterozoic continental clastic rocks of the Copper Harbor Formation, Midcontinent Rift
Tract ID 003rfCu3003
Country United States of America
Commodity Cu
Study area name United States National Assessment, revised
Deposit type sediment-hosted stratabound copper
Grade-tonnage model Sediment-hosted stratabound copper—Reduced facies-nonbrecciated
Geologic age
Geologic feature age Mesoproterozoic
Identified Cu resources 9,435,100metric tons

Results of the assessment

Assessment date 1998
Estimators Bill Cannon, Suzanne Nicholson, and Laurel Woodruff
Assessment depth 1km
Quantitative assessment Yes

Estimated number of deposits

Number of deposits Confidence level
2 90%
5 50%
10 10%
10 5%
10 1%
Mean estimated deposits 5.5 ±3 (54%)
Probability of mean 0.35
Probability of no copper 0.04

Estimated deposit density

(sq km)
Deposit density
per 100,000 sq km
2 7.5 123,147 0.6

Mean estimated tonnage

Copper 18,000,000

Undiscovered copper resource

Confidence level 95% 90% 50% 10% 5%
Tonnage 76,000 590,000 10,000,000 47,000,000 67,000,000

Economic analysis

Bibliographic references

General U.S. Geological Survey National Mineral Resource Assessment Team (2002)
U.S. Geological Survey National Mineral Resource Assessment Team, 2002, Assessment of undiscovered deposits of gold, silver, copper, lead, and zinc in the United States: U.S. Geological Survey Open-File Report 02–198, CD-ROM. Also available at

Deposits and prospects associated with this tract

Name Type State Country Details
White Pine deposit Michigan United States Details
Presque Isle deposit Michigan United States Details