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greenschist

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Journal Article
Journal: Geology
Published: 15 November 2023
Geology (2024) 52 (1): 67–71.
... across the greenschist- to amphibolite-facies transition. However, hypozonal orogenic gold deposits represent an enigma in this context. Some of these apparently formed in higher-grade metamorphic rocks when temperatures were beyond the wet solidus of quartz-feldspar–bearing rocks; it is therefore...
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Journal Article
Journal: GSA Bulletin
Published: 30 October 2023
GSA Bulletin (2024) 136 (5-6): 2596–2615.
... between 1900 Ma and 1850 Ma. The Karrat Group and magmatic arc rocks underwent metamorphism ca. 1830–1800 Ma during the collisional phase of the Rinkian orogeny. The metamorphic grade of the Karrat Group increases from greenschist facies in the south to granulite facies in the north, where it is marked...
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Journal Article
Journal: GSA Bulletin
Published: 24 February 2022
GSA Bulletin (2022) 134 (11-12): 2723–2744.
... of 400–650 °C, which suggests amphibolite to greenschist facies conditions. In addition, it is extremely likely that the mylonites experienced late-stage, lower temperature deformation as demonstrated by the sporadic bulging recrystallization, the quartz basal <a> slip system, and the two-feldspar...
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Journal Article
Published: 01 February 2022
Italian Journal of Geosciences (2022) 141 (1): 104–119.
... Calcaire. In the norther part of the Rif, the Sebtide complex cropping out at the core of the Beni Mezala antiform suffered maximum paleo-temperatures derived from Raman parameters typical of greenschists facies, whereas in the flanks of the antiform the gap in temperatures between Lower Paleozoic...
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Journal Article
Journal: Economic Geology
Published: 01 December 2021
Economic Geology (2021) 116 (8): 1981–2009.
... to understand the genesis of these deposit types. Results suggest that the iron oxide-apatite deposits were emplaced in an intracontinental back-arc basin, and they formed precrustal shortening under shallow crustal conditions. Subsequent east-west crustal shortening under greenschist facies metamorphism...
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Series: GSA Field Guide
Published: 18 May 2020
DOI: 10.1130/2020.0059(05)
EISBN: 9780813756592
... largely lack sodic amphibole, however, and range from lawsonite-albite facies to low greenschist facies with actinolite + epidote ( Bebout and Fogel, 1992 ; Bebout et al., 1993 ; Grove and Bebout, 1995 ). It is uncertain whether these differences reflect a transitional decrease of metamorphic grade...
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Series: Special Publications of the Society of Economic Geologists
Published: 01 January 2020
DOI: 10.5382/SP.23.02
EISBN: 9781629496429
... metamorphosed at peak greenschist to lower amphibolite facies conditions at ~2660 to 2658 Ma, during D 2 compressive deformation, and are cut by a variety of postvolcanic intrusions ranging from ~2695 to 2640 Ma. The Canadian Malartic deposit encompasses several past underground operations and is currently...
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Journal Article
Published: 01 August 2019
American Mineralogist (2019) 104 (8): 1197–1212.
...An-Ping Chen; Jian-Jun Yang; Da-Lai Zhong; Yong-Hong SHI; Jing-Bo Liu Abstract Epidote spherulites are identified in a greenschist facies metavolcanic breccia enclosing a body of coesite-bearing eclogite at Ganghe in the Dabie ultrahigh-pressure metamorphic belt, east-central China. The epidote...
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Journal Article
Journal: Lithosphere
Publisher: GSW
Published: 12 December 2018
Lithosphere (2019) 11 (1): 44–58.
... Ma. Subsequent underplating of the Darrington Phyllite occurred at ∼7 kbar and ∼320 °C prior to ca. 148 Ma until at least ca. 142 Ma. Blueschist-facies conditions and exhumation to ∼5 kbar occurred between ca. 140 and 136 Ma during later accretion and deformation of Shuksan greenschist-blueschist...
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Journal Article
Published: 10 May 2018
Geological Magazine (2019) 156 (6): 1003–1026.
... in eastern Crete (Greece). Based on these data, the Uppermost Unit in the study area can be subdivided (from bottom to top) into the Arvi Unit, Theodorii Greenschist and Asterousia Crystalline Complex (ACC)-type rocks. The ACC-type rocks have been affected by polyphase deformation (D 1 –D 3...
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Journal Article
Published: 11 September 2017
Russ. Geol. Geophys. (2017) 58 (9): 1070–1079.
... with an impurity of meteoric water prevailed in the fluid system. We propose a model for the gold deposit formation, which takes into account the generation of a mineral-forming fluid at the progressive stage of greenschist dynamometamorphism of the host rocks and the formation of gold mineralization...
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Journal Article
Published: 07 March 2017
Journal of the Geological Society (2017) 174 (4): 741–758.
..., blueschists; grey dots, greenschists; white dots: micaschists). Geological units after Clark et al . (1975) . ( b ) Conceptual geological sketch showing the general structural architecture of the Asalem metamorphic complex (not to scale; location of structures and units is only indicative). Below are shown...
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Journal Article
Published: 01 March 2017
South African Journal of Geology (2017) 120 (1): 63–76.
... associated with volcanogenic massive sulfides (VMS). The juvenile subduction-related origin of the Shield rocks and the pervasiveness of shearing and greenschist-to-amphibolite facies metamorphism associated with late Neoproterozoic orogeny are geologic features highly favorable for the development...
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Journal Article
Published: 01 December 2016
European Journal of Mineralogy (2016) 28 (6): 1059–1078.
... of a Cretaceous accretionary prism. The metabasic rocks occur as blueschists and greenschists, whereas the metasedimentary rocks are former greywackes s.l ., or psammopelites, and can now be characterized as phyllites. Eight characteristic mineral assemblages can be defined within the metabasic sample suite...
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Journal Article
Journal: Economic Geology
Published: 01 September 2016
Economic Geology (2016) 111 (6): 1411–1438.
... bodies in duplex structures, the passive thickening of orebodies due to folding, and remobilization of base metal sulfides within syndeformational shear zones ( Castroviejo et al., 2011 ). Archean VMS deposits in the Abitibi subprovince of Canada are affected by regional greenschist metamorphism...
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Journal Article
Published: 13 May 2016
Canadian Journal of Earth Sciences (2016) 53 (11): 1336–1371.
...–trondhjemite–granodiorite (TTG) gneisses, suggesting that the Târtoq greenstone belt represents a relict fragment of Mesoarchean supra-subduction zone oceanic crust. In this study, we present new field, and major and trace element data for metamorphosed gabbros (meta-gabbro), mafic volcanic rocks (greenschist...
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Series: GSA Special Papers
Published: 01 December 2015
DOI: 10.1130/2015.2513(08)
... the Northern Sierra terrane, Calaveras Complex, Feather River ultramafic belt, phyllite-greenschist belt, mélanges, and Foothills terrane. Important changes occur in all belts across the Placerville–Highway 50 corridor, which may separate a major culmination to the south from a structural depression...
Journal Article
Published: 20 November 2015
The Canadian Mineralogist (2015) 53 (3): 379–400.
...Ben J. Cave; Aleksandr S. Stepanov; Dave Craw; Ross R. Large; Jacqueline A. Halpin; Jay Thompson Abstract Detrital rutile is observed in trace amounts in the sub-greenschist facies, graywacke, and argillite lithologies of the Torlesse Terrane-derived Otago Schist, New Zealand. Trace element...
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Journal Article
Published: 01 December 2011
European Journal of Mineralogy (2011) 23 (6): 883–893.
... groups (basalt-dolerite-metadolerite, greenschist-contact metabasite-amphibolite, blueschist, hornfels, “white stone”, ultramafic rocks and intermediate volcanic rocks) could be distinguished. Moreover, different rock types were recognized within each group ( e.g ., greenschist-contact metabasite...
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Journal Article
Published: 01 December 2011
Russ. Geol. Geophys. (2011) 52 (12): 1662–1671.
... ). In this work we consider the geochemical features of the terrigenous deposits of the first two units of the Oka Group. The Rb-Sr geochronological study of the Oka Group rocks showed that they underwent high-pressure metamorphism (829 ± 23 Ma) and superposed greenschist metamorphism (624 ± 52 Ma...
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