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Journal Article
Journal: Geosphere
Published: 05 February 2018
Geosphere (2018) 14 (2): 835-860.
... history of this and related Paleozoic arc terranes of the western North American Cordillera. Mapping shows that the oldest YAC rocks consist of quartzofeldspathic paragneiss (meta-arkose) and quartzose calc-silicate paragneiss (metacalcareous siltstone) in gradational contact. Paragneisses are cut by syn...
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Journal Article
Journal: Geosphere
Published: 01 August 2016
Geosphere (2016) 12 (4): 1136-1153.
... metamorphic conditions consistent with transitional granulite facies (e.g., Dutrow et al., 1995 ; Metz, 2010 ; Dutrow et al., 2013 ). Most SMC paragneisses have been intensely and pervasively deformed by folding, thrusting, and dextral shearing and intruded by dikes and pods of Cretaceous and Eocene...
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Series: GSA Special Papers
Published: 01 May 2015
DOI: 10.1130/2015.2510(03)
... off along the NW-trending boundary with the Paleoproterozoic Svecofennian accretionary orogen. The main constituents of the Karelian-Belomorian region are: epicontinental sequences of greenstone belts (Kostomuksha, Khedozero-Bolsheozero, Gimoly-Sukkozero, Jalonvaara) and paragneiss belts (Hattu...
Series: GSA Memoirs
Published: 01 January 2014
DOI: 10.1130/2014.1211(14)
... noted between units. A few older 207 Pb/ 206 Pb ages obtained were ca. 2250 Ma and ca. 2800 Ma. Rocks of the eastern part of the transition zone include high-grade paragneisses that yielded numerous concordant 206 Pb/ 238 U ages between 103 and 123 Ma and between 200 and 255 Ma, and concordant 207 Pb...
Series: GSA Memoirs
Published: 01 September 2010
DOI: 10.1130/2010.1206(08)
... by a dominant D 2 migmatitic layering and are likely Taconic. U-Pb zircon crystallization ages of felsic orthogneiss and tonalite, syntectonic with respect to the formation of S 2 , and a biotite quartz diorite that crosscuts level 2 paragneiss are 437 ± 4 Ma, 434 ± 4 Ma, and 437 ± 4 Ma, respectively. Level...
Series: GSA Memoirs
Published: 01 September 2010
DOI: 10.1130/2010.1206(14)
... gneiss (1282 ± 7 Ma), dacitic gneiss (1254 ± 5 Ma), and dioritic gneiss (1248 ± 12 Ma) represent the southern continuation of eastern Laurentian margin arc activity. Supracrustal paragneisses, marble, and cogenetic metavolcanic rocks were deposited in a backarc basin inboard of the Losee arc. Ages...
... metasedimentary paragneiss. Geothermobarometric data from garnet amphibolite and granulite-facies metagabbro within the ophiolitic suite yielded pressure and temperature conditions of ~5–7 kb and ~650–750 °C. Geochemical data from samples of granulite, amphibolite, and leucotrondhjemite suggest a supra-subduction...
Series: GSA Special Papers
Published: 01 January 2007
DOI: 10.1130/2007.2423(19)
... U-Pb dating of detrital zircons separated from paragneiss of the Myrsini Crystalline Complex of eastern Crete yielded peaks in 207 Pb/ 206 Pb ages at 0.6, 0.8, 1.0, 2.0, and 2.5 Ga. A striking Mesoproterozoic age gap is present between 1.1 and 1.6 Ga. The new data are compatible with U-Pb...
Series: GSA Special Papers
Published: 01 January 2006
DOI: 10.1130/2006.2403(05)
...), the northern ultrahigh-pressure (UHP) zone (>2.8 GPa, 650–800 °C) dominated by paragneiss, and the northern UHP zone dominated by granitic gneiss. Exhumation was associated with retrograde amphibolite- to greenschist-facies metamorphism and oblique southeastward ductile extrusion within the subduction...
Journal Article
Published: 01 November 2001
Journal of the Geological Society (2001) 158 (6): 983-994.
... and the provenance of high-grade paragneisses in the Mid-German Crystalline Rise. These data furthermore allow us to assess the relative abundances of different crustal components in the source area from which the sediment was originally derived. The Variscan fold belt of Europe is highly complex, the product...
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Journal Article
Journal: Geology
Published: 01 December 1997
Geology (1997) 25 (12): 1103-1106.
Journal Article
Published: 01 April 1997
American Mineralogist (1997) 82 (3-4): 392-404.
...Ian Cartwright; Ian S. Buick; Simon L. Harley Abstract Mineralogically zoned, decimeter-diameter calc-silicate boudins enclosed within paragneisses from Little Italy Island, Rauer Group, east Antarctica underwent granulite-facies metamorphism ( P = 700–900 MPa, T = 840 ± 40 °C) followed by near...
Journal Article
Published: 01 May 1996
Canadian Journal of Earth Sciences (1996) 33 (5): 729-745.
.... S-wave velocities for selected samples range from 3.54 km/s (paragneiss) through 3.62 km/s (granitic gneiss) to 4.04 km/s (amphibolite). P-wave velocity anisotropy is weak in the granitic rocks (1.1% on average), but stronger in paragneisses and amphibolites from the region (5.2–5.9%). Comparison...
Journal Article
Published: 01 December 1995
The Canadian Mineralogist (1995) 33 (6): 1263-1284.
... fault zones. Field relationships, mineral textures, rock associations, and composites indicated that the mineral paragneiss is metasomatic in origin, and the result of hydrothermal fluids from the granitic plutons interacting with ultramafic rocks or detrital chromite derived from them. GeoRef...
Journal Article
Published: 01 December 1995
The Canadian Mineralogist (1995) 33 (6): 1255-1262.
Journal Article
Published: 01 November 1995
Canadian Journal of Earth Sciences (1995) 32 (11): 1899-1920.
.... These tectonic accidents separate the central parts of the Superior Province to the northwest from the Grenville Province to the southeast. The Archean age, high-grade polymetamorphic sequences of the Grenville Province consist of paragneisses and migmatitic quartzofeldspathic gneisses associated to coarse...
Journal Article
Published: 01 March 1995
Canadian Journal of Earth Sciences (1995) 32 (3): 281-291.
Journal Article
Published: 01 July 1994
Canadian Journal of Earth Sciences (1994) 31 (7): 1122-1133.
...Eriks M. Puris; Stephen M. Wickham Abstract Detailed oxygen-isotope profiles were measured across two very similar amphibolite-grade, paragneiss – mafic gneiss contacts located 2 km apart within the Kapuskasing structural zone. The first profile is asymmetrical about die contact. δ 18 O values...
Journal Article
Published: 01 June 1994
Canadian Journal of Earth Sciences (1994) 31 (6): 995-1001.
Journal Article
Published: 01 December 1992
Canadian Journal of Earth Sciences (1992) 29 (12): 2663-2676.
... shallow structural levels.Both groups of paragneisses also differ in some aspects of their bulk chemistry (notably CaO/K 2 O ratios) and their lithologic associations. The Meelpaeg metapelites are less calcic and relatively potassic (mean CaO/K 2 O = 0.32) compared with their counterparts in the PBGC...