Download or read book Proterozoic Baraboo Interval in Wisconsin written by Jeffrey K. Greenberg and published by . This book was released on 1986 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Wolf River Batholith and Baraboo Interval in Central Wisconsin written by and published by . This book was released on 1986 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Paleomagnetism of the Early Proterozoic Sioux Quartzite Southwestern Minnesota implications for Correlating Quartzites of the Baraboo Interval written by Val W. Chandler and published by . This book was released on 1993 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Paleomagnetic studies were conducted on the Early Proterozoic Sioux Quartzite, one of the so-called "Baraboo interval" red-bed sequences of the Lake Superior region. A total of 158 samples were collected from 17 sites scattered across four basins (Cottonwood County, New Ulm, northern Pipestone, and southern Pipestone) in southwestern Minnesota. Alternating-field and thermal demagnetization studies indicate that the magnetization is dominantly single component, and that the magnetic carrier is hematite. Hematite occurs both as a diagenetic mineral whose long paragenetic history began shortly after deposition and as veinlets that formed during a strain event possibly related to regional tilting. The magnetization is tentatively interpreted to have occurred before regional tilting, although a definitive fold test is difficult because dips are low. Measured paleomagnetic directions at both site and basin levels show good clustering, and the average directions obtained from each of the four basins are not significantly different at the 95 percent confidence level. The good clustering at all levels of sampling indicates that the Sioux Quartzite was magnetized either within a short time interval or during a period of subdued apparent polar wander. The structurally corrected paleomagnetic directions from the four basins yield a combined paleopole location at 1 01 ° W. and 16° N. (k=65, alpha 95=11 °). Dated paleopoles for Early Proterozoic rocks in North America and age dates of rocks interpreted to underlie the Sioux Quartzite imply that its age is 1,700-1,650 Ma. This interval corresponds in part with the age of 1,800-1,630 Ma of the Central Plains orogen, which lies some 200-300 kilometers south of the Sioux Quartzite out- crop. Quartzite may reflect a tectonic pulse related to the Central Plains orogen. Preliminary paleomagnetic data on Baraboo-interval quartzites from Wisconsin indicate that the Sioux paleopole cannot be distinguished at the 95 percent confidence level from that of the Barren Quartzite, but that it differs from that of the Baraboo Quartzite, which on the basis of existing apparent polar wander data could be as much as 100 million years older. The paleomagnetic data support previously raised cautions that some Baraboo interval quartz arenites may have been deposited in separate basins at significantly different times.
Download or read book Geology of the Baraboo Wisconsin Area written by Richard A. Davis Jr. and published by Geological Society of America. This book was released on 2016-08-10 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Primarily for students, this guidebook on, and road log to, the Baraboo, Wisconsin, area offers insight into a wide range of geologic features. Precambrian, Cambrian, and Quaternary times are represented in a range of lithologies, structures, stratigraphy, and geomorphology. This notable area lies at the boundary of the glacial and driftless regions of the Quaternary"--
Download or read book New Observations on the Age and Structure of Proterozoic Quartzites in Wisconsin written by Gene L. LaBerge and published by . This book was released on 1991 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book U S Geological Survey Bulletin written by Paul Kibler Sims and published by . This book was released on 1983 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Early Proterozoic Michigamme Formation of northern Michigan was deposited in the southeastern part of the Animikie basin. The formation conformably overlies the Goodrich Quartzite and comprises three widespread members a lower member of thin-bedded shale, siltstone, and sandstone; the Bijiki Iron-formation Member; and an upper member of tur- biditic graywacke, siltstone, and mudstone and a few local members. The Goodrich Quartzite is interpreted as having been deposited in a tidally influenced shallow marine environ- ment. The lower member of the Michigamme is interpreted as having been deposited in a tidally influenced environment, the iron-formation member as having been deposited below wave base in somewhat deeper water, and the upper member as having been deposited in still deeper water with turbidity currents being a major depositional mechanism. Several lines of evidence including paleocurrents, paleo- geographic setting, and neodymium isotopes suggest that the graywacke of the southern part of the outcrop area was derived from the south (Early Proterozoic Wisconsin magmatic terranes, Archean miniplates, and older Early Proterozoic sedimentary units formed on the continental margin), and that the graywacke in the northern area was derived from an Archean terrane to the north. The tectonic model that best fits the available data is a northward-migrating foreland basin.
Download or read book Precambrian Conterminous U S written by John C. Reed, Jr. and published by Geological Society of America. This book was released on 1993 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt: This wide-ranging discussion of Precambrian rocks includes contributions from a diverse array of authors actively engaged in investigations of various aspects of U.S. Precambrian geology. Summary discussions by the editors of the five major chapters place these contributions in a logical regional framework.
Download or read book U S Geological Survey Bulletin written by and published by . This book was released on 1983 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Early Proterozoic Geology of the Great Lakes Region written by L. Gordon Medaris and published by Geological Society of America. This book was released on 1983-01-01 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book North Central Section of the Geological Society of America written by Donald L. Biggs and published by Geological Society of America. This book was released on 1987 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geology of the Baraboo Wisconsin Area written by Richard A. Davis (Jr.) and published by . This book was released on 2016 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Primarily for students, this guidebook on, and road log to, the Baraboo, Wisconsin, area offers insight into a wide range of geologic features. Precambrian, Cambrian, and Quaternary times are represented in a range of lithologies, structures, stratigraphy, and geomorphology. This notable area lies at the boundary of the glacial and driftless regions of the Quaternary"--
Download or read book Archean and Early Proterozoic Tectonic History of the Wisconsin and Yellow River Areas Central Wisconsin written by Randall Steven Maass and published by . This book was released on 1990 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Middle Proterozoic to Cambrian Rocks in Central Wisconsin written by Jeffrey K. Greenberg and published by . This book was released on 1983 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Geological Survey Bulletin written by E. Neal Hinrichs and published by . This book was released on 1983 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modal, chemical, and isotopic data for the granitic rocks of the Tuolumne Meadows quadrangle.
Download or read book Geological Survey Professional Paper written by and published by . This book was released on 1984 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Geological Survey Circular written by and published by . This book was released on 1933 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Midcontinent Strategic and Critical Minerals Project written by Walden P. Pratt and published by . This book was released on 1995 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
