|
|
Article: The occurrence of porcelaneous datolite in Michigan's Lake Superior Copper District: part 2: Southern Keweenaw, Houghton, and Ontonagon Counties, Michigan.
- Article from:
- Rocks & Minerals
- Article date:
- May 1, 2005
- Author:
CopyrightCOPYRIGHT 2005 Heldref Publications. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
|
Tenth in a series of articles on the mines and minerals of Michigan's Copper Country
Part 1 of this two-part article (Rosemeyer 2003a) discussed historical information, collecting history, and color and zoning in datolite nodules, along with datolite localities in northern Keweenaw County and Isle Royale National Park. Part 2 discusses collecting history and datolite localities associated with amygdaloidal copper lodes (see A Word to the Wise, this issue) that occurred in the Portage Lake Volcanics (PLV) in southern Keweenaw, Houghton, and Ontonagon counties.
GEOLOGY AND MINERALIZATION IN THE PLV
The PLV are 9,000-15,000 feet thick and are made ...