Sulfide-mineral zoning in the basal nonesuch shale, Northern Michigan

Economic Geology
By:  and 



A zone, 1 to 50 feet thick, at the base of the Nonesuch Shale, is relatively rich in copper, chiefly as chalcocite. Pyrite is the characteristic sulfide mineral of the overlying 400 to 600 feet of the formation. The boundary of the cupriferous zone with the pyrite zone regionally transgresses both stratigraphic layering and fades gradations indicative of ancient environmental boundaries. The top of the cupriferous zone is marked by the upward sequence, chalcocite-bornite-chalcopyrite-pyrite, and by the cadmium sulfide, greenockite. The sulfide zoning does not appear to be syngenetic. The regional configuration of the cupriferous zone suggests, instead, that the copper was introduced after deposition of the entire 50-foot sequence of strata. The area in which the top of the cupriferous zone is stratigraphically highest is related spatially, and probably genetically, to a zone of wedging in the underlying Copper Harbor Conglomerate. 

Study Area

Publication type Article
Publication Subtype Journal Article
Title Sulfide-mineral zoning in the basal nonesuch shale, Northern Michigan
Series title Economic Geology
DOI 10.2113/gsecongeo.61.7.1171
Volume 61
Issue 7
Year Published 1966
Language English
Publisher Society of Economic Geologists
Description 20 p.
First page 171
Last page 1190
Country United States
State Michigan
Other Geospatial Northern Michigan
Google Analytic Metrics Metrics page
Additional publication details