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Book Scientific Core Drilling in Central Minnesota

Download or read book Scientific Core Drilling in Central Minnesota written by David Leroy Southwick and published by . This book was released on 1986 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Scientific Core Drilling in North Central Minnesota

Download or read book Scientific Core Drilling in North Central Minnesota written by Sarah J. Mills and published by . This book was released on 1987 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Tectonic Imbrication and Foredeep Development in the Penokean Orogen East central Minnesota an Interpretation Based on Regional Geophysics and the Results of Test drilling

Download or read book Tectonic Imbrication and Foredeep Development in the Penokean Orogen East central Minnesota an Interpretation Based on Regional Geophysics and the Results of Test drilling written by David Leroy Southwick and published by . This book was released on 1991 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Report of Investigations Minnesota Geological Survey

Download or read book Report of Investigations Minnesota Geological Survey written by and published by . This book was released on 1963 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Scientific and Exploration Drilling in Northwestern Minnesota

Download or read book Scientific and Exploration Drilling in Northwestern Minnesota written by Mark A. Jirsa and published by . This book was released on 1993 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Great Lakes Tectonic Zone revisited

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.

Book Information Circular

Download or read book Information Circular written by and published by . This book was released on 1993 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book U S Geological Survey Bulletin

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:

Book Mineral Resource Assessment of the U S Portion of the International Falls 1 X 2 Quadrangle Northern Minnesota

Download or read book Mineral Resource Assessment of the U S Portion of the International Falls 1 X 2 Quadrangle Northern Minnesota written by T. L. Klein and published by . This book was released on 1997 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book U S Geological Survey Bulletin

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.

Book U S Geological Survey Professional Paper

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:

Book Report of Investigations

Download or read book Report of Investigations written by and published by . This book was released on 2005 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book U S Geological Survey Bulletin

Download or read book U S Geological Survey Bulletin written by Gene L. LaBerge and published by . This book was released on 1991 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: A reconnaissance study carried out in conjunction with regional geologic mapping.