A regional structural model for gold mineralization in the southern part of the Archean Superior Province, United States / by P.K. Sims and W.C. Day.

Format:

Book

Government document

Author/Creator:

Sims, P. K. (Paul Kibler), 1918-2011, author.

Day, Warren C., author.

Contributor:

Geological Survey (U.S.), issuing body.

Series:

U.S. Geological Survey bulletin ; 1904-M.

Contributions to Precambrian geology of Lake Superior region ; ch. M.

U.S. Geological Survey bulletin ; 1904-M

Contributions to precambrian geology of Lake Superior Region ; ch. M

Language:

English

Subjects (All):

Gold ores--Michigan--Upper Peninsula.

Gold ores.

Gold ores--Minnesota.

Greenstone belts--Michigan--Upper Peninsula.

Greenstone belts.

Greenstone belts--Minnesota.

Geology, Stratigraphic--Archaean.

Geology, Stratigraphic.

Archaean Geologic Period.

Michigan--Upper Peninsula.

Minnesota.

Physical Description:

1 online resource (iii, 19 pages) : illustrations, maps.

Distribution:

[Washington, D.C.] : United States Government Printing Office

Place of Publication:

[Reston, Va.] : U.S. Department of the Interior, U.S. Geological Survey, 1992.

Summary:

The Canadian segment of the Archean Superior province is a major world source of lode gold. The gold deposits occur in or near regional transcurrent and oblique slip-shear deformation zones that comprise a conjugate set to a northwest- directed compression of the Superior province. These structures provided permeable pathways for the flow of large volumes of auriferous fluid derived from an external source. Historic gold production from the United States segment of the Superior province is modest, but the close similarity in the geologic environment of the United States and Canadian segments suggests that large gold deposits should be present in the U.S.A. An occurrence model largely based on known parameters of gold mineralization in Canada suggests that the greenstone-granite terranes of the Wawa and Wabigoon sub-provinces in the United States are favorable for important gold deposits. The model suggests that gold mineralization took place during or later than the transcurrent faulting and that it took place contemporaneously with emplacement of silica-undersaturated intrusions. The faulting occurred late in the igneous-tectonic history of the Superior province, about 2,690 Ma. Extensive, intense alteration comprising carbonitization, silicification, and sulfidization accompanied the gold mineralization. The relationships between alteration minerals and mineralized veins suggest a close temporal relationship between the alteration and gold mineralization processes. The proposed occurrence model for gold mineralization and the available data suggest that two broad regions of greenstone in the Archean Superior province in north-central United States are particularly favorable for gold deposits: (1) the Upper Peninsula of Michigan, and (2) northeastern Minnesota. The Ishpeming greenstone belt of the Wawa subprovince in Michigan contains the important Ropes deposit and several other known gold occurrences, and the Vermilion district (Wawa subprovince) in northeastern Minnesota contains highly anomalous gold in soils and minor known bedrock occurrences. Transcurrent faults in both areas should be favorable sites for gold mineralization

Notes:

Includes bibliographical references (pages 17-19).

Description based on print version record.

Electronic reproduction. [S.l.] : HathiTrust Digital Library, 2011.

Other Format:

Print version: Sims, P. K. (Paul Kibler), 1918-2011. Regional structural model for gold mineralization in the southern part of the Archean Superior Province, United States

OCLC:

937435770

Access Restriction:

Use copy Restrictions unspecified