Author: David Leroy SouthwickPublisher:
ISBN:
Category : Geology
Languages : en
Pages : 40
Book Description
Tectonic Imbrication and Foredeep Development in the Penokean Orogen, East-central Minnesota
Author: David Leroy SouthwickPublisher:
ISBN:
Category : Geology
Languages : en
Pages : 40
Book Description
Tectonic Imbrication and Foredeep Development in the Penokean Orogen, East-central Minnesota
Author: David Leroy SouthwickPublisher:
ISBN:
Category : Geology, Stratigraphic
Languages : en
Pages : 27
Book Description
U.S. Geological Survey Bulletin
Author: Gene L. LaBergePublisher:
ISBN:
Category : Faults (Geology)
Languages : en
Pages : 344
Book Description
A reconnaissance study carried out in conjunction with regional geologic mapping.
U.S. Geological Survey Bulletin
Author: New Publications of the U.S. Geological Survey
Author: New Publications of the Geological Survey
Author: Geological Survey (U.S.)Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 746
Book Description
Great Lakes Tectonic Zone in Marquette Area, Michigan
Author: Paul Kibler SimsPublisher:
ISBN:
Category : Faults (Geology)
Languages : en
Pages : 28
Book Description
Great Lakes Rocks
Author: Stephen E. KeslerPublisher: University of Michigan Regional
ISBN: 0472053809
Category : Science
Languages : en
Pages : 369
Book Description
A much-needed exploration of Great Lakes geology
Nature and Style of Deformation in the Foreland of the Early Proterozoic Penokean Orogen, Northern Michigan
Author: J. S. KlasnerPublisher:
ISBN:
Category : Geology
Languages : en
Pages : 32
Book Description
Evidence for Early Proterozoic north-verging folding and thrusting in the continental foreland of the Penokean orogen is present in two widely separated areas in northern Michigan. In the eastern part of the exposed orogen, asymmetric to over-turned folds in the Early Proterozoic Michigamme Formation suggest an initial (D1) phase of possibly north verging thin-skinned deformation. A second phase (D2 ) is characterized by a more thick skinned deformation consisting of northward thrusting of Archean gneiss and overlying Early Proterozoic quartzite along ductile thrust faults. Crosscutting shear zones indicate a third phase (D3 ) of deformation involving east- northeast thrusting of Archean gneiss. Thick-skinned deformation D2 and D3 phases include spaced fracture cleavage, kink folds, and lineations in D1, foliation surfaces. Near the west end of the exposed orogen in Michigan, bedding-cleavage relationships in the Early Proterozoic Tyler Formation also indicate northward tectonic transport. These structures, which are interpreted as D1 lie along the north edge of the Archean Puritan batholith and associated Archean greenstone. The north-verging structures in the northern Michigan segment of the Penokean orogen were formed approximately 1,850 Ma during collision of the Wisconsin magmatic terranes with the continental foreland of Michigan, Wisconsin, and Minnesota.
Precambrian Crustal Blocks in Minnesota
Author: S. R. HemmingPublisher:
ISBN:
Category : Geology
Languages : en
Pages : 24
Book Description
Sm-Nd survey of Precambrian granitic and metasedimentary rocks collected from several geophysically defined blocks in central Minnesota confirms the presence of some fundamental geologic boundaries previously mapped on the basis of structure. The Malmo discontinuity an Early Proterozoic structure separates the Archean Minnesota River Valley ter- ranes from an Early Proterozoic (Penokean magmatic) terrane and the McGrath Gneiss dome of east-central Minnesota North of this boundary, the Penokean fold-and-thrust belt can be divided into fault-bounded terranes that were assembled during the Penokean orogeny. Each terrane within the study area has distinct crust formation ages.