Early Proterozoic deformation in the western Superior province, Canadian Shield
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Research Article| December 01, 1990 Early Proterozoic deformation in the western Superior province, Canadian Shield D. C. KAMINENI; D. C. KAMINENI 1Atomic Energy of Canada Ltd., Pinawa, Manitoba, R0E 1L0, Canada Search for other works by this author on: GSW Google Scholar D. STONE; D. STONE 2Ontario Geological Survey, 77 Grenville Street, Toronto, Ontario, M7A 1W4, Canada Search for other works by this author on: GSW Google Scholar Z. E. PETERMAN Z. E. PETERMAN 3U.S. Geological Survey, Branch of Isotope Geology, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar Author and Article Information D. C. KAMINENI 1Atomic Energy of Canada Ltd., Pinawa, Manitoba, R0E 1L0, Canada D. STONE 2Ontario Geological Survey, 77 Grenville Street, Toronto, Ontario, M7A 1W4, Canada Z. E. PETERMAN 3U.S. Geological Survey, Branch of Isotope Geology, Denver, Colorado 80225 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1990) 102 (12): 1623–1634. https://doi.org/10.1130/0016-7606(1990)102<1623:EPDITW>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation D. C. KAMINENI, D. STONE, Z. E. PETERMAN; Early Proterozoic deformation in the western Superior province, Canadian Shield. GSA Bulletin 1990;; 102 (12): 1623–1634. doi: https://doi.org/10.1130/0016-7606(1990)102<1623:EPDITW>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 SocietyGSA Bulletin Search Advanced Search Abstract Late Archean granitic plutons (∼2700 to 2665 Ma; U-Pb zircon) of the Superior structural province are cut by a variety of brittle discontinuities, including joints, fractures, and faults, the latter of which show evidence of cataclasis and meter to tens of meters displacements. Fluid circulation, alteration of wall rocks, and neomineralization of epidote, actinolite, and chlorite occurred under greenschist facies conditions in these structures at the time of their formation. The Rb-Sr ages of host rocks are ∼2650 Ma, and the fracture-zone materials are 2300 Ma, indicating that most of this activity occurred long after Archean plutonism and was concentrated in Early Proterozoic time. The brittle structures formed in response to horizontal compression on a regional scale, possibly caused by tectonic processes at margins of the craton. The structures are seen as important clues to the tectonic evolution of the Superior province. 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.Keywords:
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This book and its companion, Early Proterozoic Geology of the Great Lakes Region ( Mem. 160 Geological Society of America, 1984), edited by L.G. Medaris, Jr., are the products of an International Proterozoic symposium held at the University of Wisconsin, Madison, May 18–21, 1981. This volume contains 23 papers that present the current thinking of experts on many aspects of Proterozoic evolution of the earth; it is divided into five broad categories: tectonics, magmatism and metamorphism, mineral resources, evolution of life and the atmosphere, and glaciation. The Proterozoic is a distinctive interval in the geologic history of the earth, encompssing the transition from Archean conditions to those of the Phanerozoic. By Early Proterozoic time, extensive stable continental plates existed, and deformation, deposition, and intrusion styles were comparable to those of today. Also, the amount of free oxygen in the atmosphere and hydrosphere continuously increased during the Proterozoic and eventually reached levels supportive of metazoan evolution.
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The paleo-middle Proterozoic strata are both best exposed in the eastern Liaoning and southern Jilin Provinces. However, their correlation is very difficult for different classification schemes used by the two provinces. By comparison of the magnesium marble of the Zhenzhumen Formation in rock association, tectonic sequence, REE geochimestry, chronostratigraphy and paleo-biology in both Ⅰand Ⅱareas, it is concluded that these marbles were formed in different geologic periods and different tectonic settings. The marbles in Ⅰarea were formed in middle Proterozoic while the marbles in Ⅱarea were formed in palaeo-Proterozoic. A new classification scheme is proposed for the palaeo-middle Proterozoic strata in southern Jilin Province by the present authors, in which the middle Proterozoic strata contain two formations:Dahongyu and Gaoyuzhuang Formations while the palaeo Proterozoic strata include Ji'an, Linjang, and Dalizi Groups.
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Abstract The Proterozoic assembly of Australia, the understanding of which is critical for reconstructing Proterozoic supercontinents, involved amalgamation of the West Australian (WAC), North Australian (NAC), and South Australian cratons (SAC). However, the basement between these Archean to early Proterozoic lithospheric blocks is mostly buried beneath younger basins; hence, its composition and age and the timing of Proterozoic assembly remain uncertain. In situ zircon U-Pb-O-Hf analyses of igneous rocks from drillholes that intersected basement beneath the northwestern Canning Basin reveal the presence of a substantial domain of juvenile Proterozoic lithosphere, the Percival Lakes province, between the WAC and NAC. Although isotopically distinct from the neighboring WAC and NAC, the Percival Lakes province is strikingly similar to other juvenile Proterozoic tectonic elements between the WAC, NAC, and SAC. Combining isotope and seismic data, we interpret the Percival Lakes province as part of an ~1700 × 400 km Proterozoic lithospheric domain that lacks evidence of Archean provenance but consists mainly of reworked remnants of Mesoproterozoic oceanic crust that survived WAC-NAC-SAC convergence. The apparent absence of Archean lithosphere between the cratons implies they never directly collided or that complete collision was prevented by impingement of three-dimensional promontories in the converging lithospheric blocks. Instead, the Percival Lakes province and other Proterozoic elements between the WAC, NAC, and SAC consist of oceanic lithosphere extracted from Earth's mantle in the Proterozoic. Our results imply that WAC-NAC convergence was younger than Columbia amalgamation at ca. 1.8 Ga and that Proterozoic Australia formed during the earliest phases of Rodinia assembly at ca. 1.3 Ga.
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Most of central Africa is underlain by Archaean terrains (mostly below a Phanerozoic cover), represented by high-grade gneissic complexes and by low-grade granite-greenstone belts. The lowermost Proterozoic is represented either by gneisses in mobile zones or low-grade supracrustals in forelands. The remaining Lower Proterozoic is made of low-grade supracrustal metasediments in mobile zones. Such zones developed thus almost immediately after the end-Archaean cratonization. The successive mobile zones appear to have developed in a centrifugal pattern during the Lower-Proterozoic. The mineral wealth is unevenly distributed. Only some greenstone belts have given an appreciable gold output, whereas the gneissic Archaean terrains have proven to be almost barren. Iron remains an important resource of the Archaean, as manganese is for the Lower Proterozoic. Uranium and some Cu, Co has been found in the Lower Proterozoic of respectively Gabon and Uganda.
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