Author: Allen Roys OstranderPublisher:
ISBN:
Category :
Languages : en
Pages : 76
Book Description
Geology and Structure of Hamilton Mounds, Adams County, Wisconsin
Author: Allen Roys OstranderNew Observations on the Age and Structure of Proterozoic Quartzites in Wisconsin
Author: Gene L. LaBergePublisher:
ISBN:
Category : Geology, Stratigraphic
Languages : en
Pages : 28
Book Description
Proterozoic quartzite is exposed at several isolated localities within an area of nearly 13,000 square kilometers in Wisconsin. Although early workers proposed that the quartzite is of two different ages, more recent workers have suggested that the various quartzite bodies are correlative, and that their protoliths were deposited between 1,760 and 1,630 Ma. Structural and stratigraphic studies of the quartzite deposits together with new age data indicate that the quartzite is at least of two distinct ages. Quartzite at McCaslin and Thunder Mountains, in northeastern Wisconsin, is older than 1,812 Ma, as indicated indirectly by a dated intrusion, and quartzite boulders in conglomerates in central Wisconsin are at least as old as the rhyolite country rock (=1,840 Ma). Deformed quartzite at Hamilton Mounds, in south-central Wisconsin, is intruded by undeformed granite that is 1,764 Ma. The ages of many other quartzite bodies, however, cannot be tightly constrained at present. Quartzite exposed in central and southern Wisconsin, south of the Eau Pleine shear zone, is interpreted as remnants of a passive margin sequence that was deposited on an Archean microcontinent (Marshfield terrane) and subsequently deformed in a major south-verging fold-thrust system during collision between the microcontinent and oceanic-arc rocks of the Pembine-Wausau terrane. The occurrence of quartzite-bearing conglomerates in the 1,860 Ma volcanic rocks of the Marshfield terrane suggests that the allochthonous quartzite bodies are 1,860 Ma or older. Collision occurred at about 1,840 Ma, and marked the end of the Penokean orogeny.
North-Central Section of the Geological Society of America
Author: Donald L. BiggsPublisher: Geological Society of America
ISBN: 0813754038
Category : Science
Languages : en
Pages : 460
Book Description
U.S. Geological Survey Bulletin
Author: Gene L. LaBergePublisher:
ISBN:
Category : Faults (Geology)
Languages : en
Pages : 346
Book Description
A reconnaissance study carried out in conjunction with regional geologic mapping.
U.S. Geological Survey Bulletin
Author: Middle Proterozoic to Cambrian Rocks in Central Wisconsin
Author: Jeffrey K. GreenbergPublisher:
ISBN:
Category : Geology, Stratigraphic
Languages : en
Pages : 64
Book Description
The History of Geology and Geophysics at the University of Wisconsin-Madison, 1848-1980
Author: Sturges W. BaileyPublisher:
ISBN:
Category : Geology
Languages : en
Pages : 188
Book Description
Geoscience Wisconsin
Author: Proceedings and Abstracts for the ... Annual Institute on Lake Superior Geology
Author: Centennial Field Guide
Author: Geological Society of AmericaPublisher: Boulder, Colo. : Geological Society of America
ISBN:
Category : Canada
Languages : en
Pages : 480
Book Description