Download or read book Archean and Proterozoic Geology of the Lake Superior Region U S A 1993 written by Geological Survey (U.S.) and published by . This book was released on 1996 with total page 134 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 Geology and Tectonics of the Lake Superior Basin written by Richard John Wold and published by Geological Society of America. This book was released on 1982-01-01 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Archean and Early Proterozoic Tectonic Framework of North Central United States and Adjacent Canada written by Paul Kibler Sims and published by . This book was released on 1995 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings and Abstracts for the Annual Institute on Lake Superior Geology written by and published by . This book was released on 1990 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 U S Geological Survey Bulletin written by Paul Kibler Sims and published by . This book was released on 1983 with total page 272 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 Earth s Oldest Rocks written by Martin J. Van Kranendonk and published by Elsevier. This book was released on 2007-10-26 with total page 1331 pages. Available in PDF, EPUB and Kindle. Book excerpt: Earth’s Oldest Rocks provides a comprehensive overview of all aspects of early Earth, from planetary accretion through to development of protocratons with depleted lithospheric keels by c. 3.2 Ga, in a series of papers written by over 50 of the world's leading experts. The book is divided into two chapters on early Earth history, ten chapters on the geology of specific cratons, and two chapters on early Earth analogues and the tectonic framework of early Earth. Individual contributions address topics that range from planetary accretion, a review of Earth meteorites, significance and composition of Hadean protocrust, composition of Archaean mantle and deep crust, all aspects of the geology of Paleoarchean cratons, composition of Archean oceans and hydrothermal environments, evidence and geological settings of early life, early Earth analogues from Venus and New Zealand, and a tectonic framework for early Earth. * Contains comprehensive reviews of areas of ancient lithosphere on Earth, of planetary accretion processes, and of meteorites* Focuses on specific aspects of early Earth, including oldest putative life forms, evidence of the composition of the ancient atmosphere-hydrosphere, and the oldest evidence for subduction-accretion* Presents an overview of geological processes and model of the tectonic framework on early Earth
Download or read book Correlation of Precambrian Rocks of the Lake Superior Region United States written by G. B. Morey and published by . This book was released on 1988 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lithology, distribution, correlation, and isotope ages of exposed Precambrian rocks in the Lake Superior region of the north-central United States.
Download or read book U S Geological Survey Professional Paper written by and published by . This book was released on 1984 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Great Lakes Tectonic Zone revisited written by Paul Kibler Sime and published by . This book was released on 1993 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Great Lakes tectonic zone (GLTZ) is a Late Archean crustal boundary (paleosuture) at least 1,200 kilometers long that juxtaposes a Late Archean greenstone-granite terrane (Wawa subprovince of Superior province) on the north and an Early to Late Archean gneiss terrane (Minnesota River Valley subprovince) on the south. Recent mapping of an exposed seg- ment in the Marquette, Michigan, area provides new data on the vergence of the structure. These data necessitate reexami- nation of the COCORP seismic-reflection profiling in central Minnesota, which has been the principal basis for past views on the vergence of the GLTZ. In the Marquette area, the GLTZ is a northwest-striking mylonite zone about 2.3 kilometers wide that is superposed on previously deformed rocks of both Archean terranes. Shear zone walls strike N. 55°-60° W., and foliation in mylonite within the GLTZ strikes (average) N. 70° W. and dips 75° SW. A stretching lineation plunges 42° in a S. 43° E. direction. Hinges of tight to open (sheath?) folds of both Z- and S-symmetries plunge parallel to the lineation. The attitude of the lineation (line of tectonic transport and X finite strain axis), together with asymmetric kinematic indicators, indicates that collision at this locality was oblique; the collision resulted in dextral- thrust shear along the boundary, northwestward vergence, and overriding of the greenstone-granite terrane by the gneiss terrane. In contrast, the seismic-reflection profiling in central Minnesota has been interpreted by several investigators to indicate that the GLTZ is a shallowly north dipping (=30°) structure, which implies southward vergence on a north-dipping subduction zone. We suggest, alternatively, that the shallow- dipping reflectors in the seismic profiles indicate lithologic contacts related to recumbent and gently inclined folds (D1), perhaps enhanced by ductile deformation zones, and that the Morris fault is indeed the GLTZ. The Morris fault strikes about N. 70° E., dips steeply southeastward, is transparent in seismic profiles, appears to be narrow, and coincides with the inferred position of the GLTZ as shown on earlier maps. The oblique collision along northwest-trending segments of the GLTZ would be expected to produce dextral transpression across a large region north of the GLTZ, and may have produced an early nappe-forming event (D1) as well as younger upright folds (D2), and as a later, more brittle event, the numerous dextral faults and conjugate sinistral faults that are widespread in the Wawa and adjacent subprovinces.
Download or read book New Publications of the U S Geological Survey written by Geological Survey (U.S.) and published by . This book was released on 1994 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Publications of the U S Geological Survey written by and published by . This book was released on 1996 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Middle Proterozoic to Cambrian rifting central North America written by Richard W. Ojakangas and published by Geological Society of America. This book was released on 1997-01-01 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Download or read book Gneiss Domes in Orogeny written by Donna Whitney and published by Geological Society of America. This book was released on 2004-01-01 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1996 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt:
