Bedrock geologic map of the southern part of the Diorite and Champion 7 1/2 minute quadrangles, Marquette County, Michigan

This map illustrates the bedrock geology of part of the Marquette iron range in the Diorite and Champion 7 ½-minute quadrangles. The area includes part of the Marquette trough, a synclinorium containing rocks of the Marquette Range Supergroup (Precambrian X) and older Precambrian W basement gneiss. Among the Precambrian X rocks is the economically important banded iron-formation, and the oldest rocks of the Precambrian W gneiss consist of a mafic-ultramafic volcanic-intrusive complex that contains gold deposits.