Author: Jeffrey K. GreenbergPublisher:
ISBN:
Category : Geology, Stratigraphic
Languages : en
Pages : 64
Book Description
Middle Proterozoic to Cambrian Rocks in Central Wisconsin
Author: Jeffrey K. GreenbergPublisher:
ISBN:
Category : Geology, Stratigraphic
Languages : en
Pages : 64
Book Description
Middle Proterozoic to Cambrian Rocks in Central Wisconsin Anorogenic Sedimentary and Igneous Activity
Author: J. K. GreenbergPublisher:
ISBN:
Category : Geology
Languages : en
Pages : 50
Book Description
Middle Proterozoic to Cambrian rifting, central North America
Author: Richard W. OjakangasPublisher: Geological Society of America
ISBN: 0813723124
Category : Science
Languages : en
Pages : 331
Book Description
Based on the Tenth International Basement Tectonics Conference held at the University of Minnesota-Duluth in August 1992, this volume contains 19 papers, 13 of which focus on the Middle Proterozoic Midcontinent Rift. An introductory essay discussing the Middle Proterozoic to Cambrian rifting in central North America is followed by contributions addressing topics including the Midcontinent Rift in Michigan and Minnesota, the Port Coldwell veins of northern Ontario, and petrography and sedimentation in the western Lake Superior region. The last five papers deal with the pre-Mount Simon basins of Ohio, the English Graben and the newly proposed East Continent Rift Complex, the Reelfoot Rift/Rough Creek Graben in the evolution of the Illinois Basin, and the A-type sheet granites in the Oklahoma Aulacogen of Cambrian age. Bandw illustrations. Annotation copyrighted by Book News, Inc., Portland, OR
New 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.
Weathering of Pre-Cambrian Rocks in Central Wisconsin
Author: Charles Sumner GwynnePublisher:
ISBN:
Category : Geology, Stratigraphic
Languages : en
Pages : 326
Book Description
Pleistocene Geology of Portage County, Wisconsin
Author: Lee ClaytonPublisher:
ISBN:
Category : Geology, Stratigraphic
Languages : en
Pages : 28
Book Description
U.S. Geological Survey Bulletin
Author: Basement and Basins of Eastern North America
Author: Ben A. Van der PluijmPublisher:
ISBN: 9780813723082
Category : Travel
Languages : en
Pages : 220
Book Description
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.