Dome-and-keel provinces formed during Paleoproterozoic orogenic collapse-core complexes, diapirs, or neither?: Examples from the Quadrilátero Ferrífero and the Penokean orogen

Abstract

Research Article| May 01, 1997 Dome-and-keel provinces formed during Paleoproterozoic orogenic collapse-core complexes, diapirs, or neither?: Examples from the Quadrilátero Ferrífero and the Penokean orogen Stephen Marshak; Stephen Marshak 1Department of Geology, University of Illinois, Urbana, Illinois 61801 Search for other works by this author on: GSW Google Scholar Douglas Tinkham; Douglas Tinkham 1Department of Geology, University of Illinois, Urbana, Illinois 61801 Search for other works by this author on: GSW Google Scholar Fernando Alkmim; Fernando Alkmim 2Departamento de Geologia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais 35.400, Brazil Search for other works by this author on: GSW Google Scholar Hannes Brueckner; Hannes Brueckner 3Department of Geology, Queens College, Flushing, New York 113674Lamont-Doherty Earth Observatory, Palisades, New York 10964 Search for other works by this author on: GSW Google Scholar Theodore Bornhorst Theodore Bornhorst 5Department of Geological Engineering, Geology and Geophysics, Michigan Technological University, Houghton, Michigan 49931 Search for other works by this author on: GSW Google Scholar Author and Article Information Stephen Marshak 1Department of Geology, University of Illinois, Urbana, Illinois 61801 Douglas Tinkham 1Department of Geology, University of Illinois, Urbana, Illinois 61801 Fernando Alkmim 2Departamento de Geologia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais 35.400, Brazil Hannes Brueckner 3Department of Geology, Queens College, Flushing, New York 113674Lamont-Doherty Earth Observatory, Palisades, New York 10964 Theodore Bornhorst 5Department of Geological Engineering, Geology and Geophysics, Michigan Technological University, Houghton, Michigan 49931 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1997) 25 (5): 415–418. https://doi.org/10.1130/0091-7613(1997)025<0415:DAKPFD>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Stephen Marshak, Douglas Tinkham, Fernando Alkmim, Hannes Brueckner, Theodore Bornhorst; Dome-and-keel provinces formed during Paleoproterozoic orogenic collapse-core complexes, diapirs, or neither?: Examples from the Quadrilátero Ferrífero and the Penokean orogen. Geology 1997;; 25 (5): 415–418. doi: https://doi.org/10.1130/0091-7613(1997)025<0415:DAKPFD>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Paleoproterozoic dome-and-keel provinces, in which troughs of deformed and metamorphosed Paleoproterozoic supracrustal rocks surround domes of Archean basement, continue to puzzle geologists. In current literature, some authors refer to the domes as diapirs (implying basement flowed vertically upward) and others consider them to be Cordilleran-type metamorphic core complexes (implying that the contact between basement and cover is an upwarped detachment). Geochronological studies suggest that dome emplacement occurred during extensional collapse of contractional orogens, seemingly supporting the core-complex analogy. However, structural analyses in the Quadrilátero Ferrífero (Brazil) and the Penokean orogen (Michigan) demonstrate that the domes resemble diapirs in shape and in terms of surface kinematics. The domes differ from diapirs, however, in that they did not flow penetratively within but were emplaced by movement along steeply dipping shear zones. We suggest that contrasts between dome-and-keel and core-complex provinces reflect contrasts between Paleoproterozoic and Phanerozoic crustal structure. Specifically, during the Paleoproterozoic, when crust was warmer and supracrustal assemblages denser, core-complex–like detachment faulting and associated plutonism resulted in juxtaposition of hot basement beneath a denser, tectonically thickened supracrustal layer. The resulting viscosity contrast and density inversion triggered vertical rise of diapir-shaped basement domes by slip on steep shear zones. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.