Delineation of isograds in siliceous dolomitic marbles along the Sharbot Lake – Frontenac terrane boundary of the Grenville Province, southeastern Ontario

This study presents details of the mineralogy and petrology of siliceous, dolomitic marbles of the Sharbot Lake domain along the Frontenac terrane boundary in the Grenville Province of southeastern Ontario. The location of four mineral isograds in the marble and the related univariant reactions were identified in the Almonte – Carleton Place area. Delineation of the isograds is based on detailed mapping, petrographic analysis of coexisting mineral assemblages, and a polybaric T–XCO2 diagram calculated using thermobarometric data from associated gneissic rocks, where T is temperature and X is fluid composition. The T–X section is based on a field gradient of 32 °C/km. The isograds correspond to the first appearance of tremolite (5 dolomite + 8 quartz + H2O = tremolite + 3 calcite + 7 CO2), diopside (tremolite + 3 calcite + 2 quartz = 5 diopside + 3 CO2 + H2O), diopside + dolomite (tremolite + 3 calcite = dolomite + 4 diopside + H2O + CO2), and forsterite (diopside + 3 dolomite = 2 forsterite + 4 calcite + 5 CO2). Mineral assemblages above and below each isograd are described and relevant examples are shown. Results of this study are consistent with a mixed volatile fluid of a uniform composition during mid- to upper amphibolite-facies metamorphism.

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Pressure, temperature and fluid composition during amphibolite facies metamorphism of graphitic metapelites, Howard Ridge, British Columbia

Journal of Metamorphic Geology ◽

10.1111/j.1525-1314.1989.tb00612.x ◽

1989 ◽

Vol 7 (5) ◽

pp. 497-505 ◽

Cited By ~ 13

Author(s):

J. H. SEVIGNY ◽

E. D. GHENT

Keyword(s):

British Columbia ◽

Amphibolite Facies ◽

Fluid Composition ◽

Facies Metamorphism

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The Tremolite Isograd near Marble Lake, Ontario

Canadian Journal of Earth Sciences ◽

10.1139/e73-082 ◽

1973 ◽

Vol 10 (6) ◽

pp. 936-947 ◽

Cited By ~ 16

Author(s):

Ian Hutcheon ◽

J. M. Moore

Keyword(s):

Vapor Phase ◽

Experimental Work ◽

Lake Ontario ◽

Amphibolite Facies ◽

High Angle ◽

Grenville Province ◽

Metavolcanic Rocks ◽

Mineral Assemblages ◽

Total P

Marble, metavolcanic rocks, and pelite are found in a northeasterly trending belt near Marble Lake, in the Grenville Province, Ontario. The rocks have been metamorphosed to the lower amphibolite facies in the southwest, the grade increasing to the mid-amphibolite facies towards the northeast. Northwest-trending isograds in the metavolcanic rocks are at a high angle to the northeast-trending tremolite isograd in the marbles. Mineral assemblages indicate total pressures between 4 and 5 kbar and temperatures ranging from approximately 350 °C to over 600 °C. Temperatures estimated by calcite–dolomite solvus geothermometry and applied to experimental work in the system CaO–MgO–SiO2–CO2–H2O indicate: (i) P(total) = P(CO2) + P(H2O) was greater than 3 kbars; (ii) temperatures on the tremolite isograd were from approximately 450 to 550 °C and indicate that the tremolite isograd is not isothermal; (iii) the composition of the vapor phase present during metamorphism was approximately X(CO2) = 0.7 – 0.8; (iv) temperatures in the belt were from less than 400 °C in the southwest to more than 600 °C in the northeast.

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Retrograde contact meta-morphism in the granulite facies terrain of Mont Tremblant Park, Quebec, Canada

Geological Magazine ◽

10.1017/s001675680005487x ◽

1968 ◽

Vol 105 (5) ◽

pp. 487-492 ◽

Cited By ~ 2

Author(s):

Michael B. Katz

Keyword(s):

Late Stage ◽

Granulite Facies ◽

Amphibolite Facies ◽

Grenville Province ◽

South West ◽

Mineral Assemblages ◽

Park Area

SUMMARYThe Pre-Cambrian rocks of the Grenville province of south-west Quebec in the Mont Tremblant Park area consists of granulites and associated gneisses formed under granulite facies conditions which are intruded by members of an anorthosite suite. At the contacts of these intrusives especially the late-stage members, the granulites and gneisses were found to be retrograded into rocks with mineral assemblages typical of the amphibolite facies. The transformation of the granulite facies rocks into rocks of lower amphibolite grade can be attributed to local introduction of water which was supplied during the emplacement and crystallization of this late-stage, volatile-enriched magma of the anorthosite suite.

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Magmatic, hydrothermal and subsolidus evolution of the agpaitic nepheline syenites of the Sushina Hill Complex, India: implications for the metamorphism of peralkaline syenites

Mineralogical Magazine ◽

10.1180/minmag.2016.080.057 ◽

2016 ◽

Vol 80 (7) ◽

pp. 1161-1193 ◽

Cited By ~ 9

Author(s):

A. Chakrabarty ◽

R. H. Mitchell ◽

M. Ren ◽

P. K. Saha ◽

S. Pal ◽

...

Keyword(s):

Low Temperature ◽

Nepheline Syenite ◽

Amphibolite Facies ◽

Mineral Assemblages ◽

Facies Metamorphism ◽

Bona Fide

AbstractThe Proterozoic Sushina Hill Complex is the only agpaitic complex, reported from India and is characterized by a eudialyte-rinkite-bearing nepheline syenite. The complex is considered a ‘metamorphosed agpaitic complex'. This study describes the mineral assemblages formed during successive stages of evolution from magmatic to hydrothermal stages and low-temperature subsolidus re-equilibration assemblage. The primary-late magmatic assemblage is characterized by albite, orthoclase, unaltered nepheline, zoned diopside-hedenbergite, rinkite, late magmatic eudialyte and magnesio-arfvedsonite formed at ∼700°C with maximum aSiO2 of 0.60. In contrast, a deuteric assemblage (400-348°C) is represented by aegirine-jadeite-rich clinopyroxene, post-magmatic eudialyte, sodalite, analcime and the decomposition assemblages formed after eudialyte with decreasing aSiO2 (0.52-0.48). A further low-temperature subsolidus assemblage (≤250°C) represented by late-forming natrolite could be either related to regressive stages of metamorphism or a continuum of the subsolidus processes. Considering the P/T range of the greenschist - lower-amphibolite facies of metamorphism it is evident that the incorporation of a jadeite component within pyroxene is related to a subsolidus process between ∼400°C and 348°C in a silica deficient environment. We emphasize that the deuteric fluid itself acted as an agent of metamorphism and the decomposition assemblage formed after eudialyte is retained even after metamorphism due to the convergence of subsolidus and metamorphic domains. The formation of jadeite-rich aegirine is not considered to result from metamorphism. Overall it is near-impossible to discern any bona fide metamorphic textures or mineral assemblages in these syenites which appear to preserve a relict mineralogy regardless of their occurrence in country rocks which have experienced greenschist - amphibolite facies metamorphism. The Sushina complex is very similar in this respect to the Norra Kärr complex (Sweden).

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DIVING DEEPER INTO THE PICURIS OROGEN: UPPER AMPHIBOLITE FACIES METAMORPHISM AND BRITTLE DEFORMATION ALONG THE PLOMO SHEAR ZONE

10.1130/abs/2020am-354334 ◽

2020 ◽

Author(s):

Adrian E. Castro ◽

◽

Chloe Bonamici ◽

Christopher G. Daniel ◽

Danielle Shannon Sulthaus

Keyword(s):

Shear Zone ◽

Amphibolite Facies ◽

Brittle Deformation ◽

Facies Metamorphism

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REGIONAL LOW-PRESSURE AMPHIBOLITE-FACIES METAMORPHISM AT THE PIPE II MINE, THOMPSON NICKEL BELT, MANITOBA, AND COMPARISON OF METAMORPHIC ISOGRADS IN METAPELITES AND META-IRON FORMATIONS

The Canadian Mineralogist ◽

10.3749/canmin.49.3.721 ◽

2011 ◽

Vol 49 (3) ◽

pp. 721-747 ◽

Cited By ~ 5

Author(s):

C. G. Coueslan ◽

D. R. M. Pattison ◽

D. K. Tinkham

Keyword(s):

Low Pressure ◽

Amphibolite Facies ◽

Facies Metamorphism ◽

Iron Formations

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Metamorphic evolution and U-Pb zircon SHRIMP geochronology of the Belizário ultramafic amphibolite, Encantadas Complex, southernmost Brazil

Anais da Academia Brasileira de Ciências ◽

10.1590/s0001-37652003000300010 ◽

2003 ◽

Vol 75 (3) ◽

pp. 393-403 ◽

Cited By ~ 20

Author(s):

Léo A. Hartmann ◽

João O.S. Santos ◽

Jayme A.D. Leite ◽

Carla C. Porcher ◽

Neal J. Mcnaughton

Keyword(s):

Ultramafic Rock ◽

Greenschist Facies ◽

Amphibolite Facies ◽

Rio De La Plata ◽

Metamorphic Evolution ◽

Río De La Plata ◽

La Plata ◽

Shrimp Geochronology ◽

Facies Metamorphism ◽

Magnesian Basalt

The integrated investigation of metamorphism and zircon U-Pb SHRIMP geochronology of the Belizário ultramafic amphibolite from southernmost Brazil leads to a better understanding of the processes involved in the generation of the Encantadas Complex. Magmatic evidence of the magnesian basalt or pyroxenite protolith is only preserved in cores of zircon crystals, which are dated at 2257 ± 12 Ma. Amphibolite facies metamorphism M1 formed voluminous hornblende in the investigated rock possibly at 1989 ± 21 Ma. This ultramafic rock was re-metamorphosed at 702±21 Ma during a greenschist facies eventM2; the assemblage actinolite + oligoclase + microcline + epidote + titanite + monazite formed by alteration of hornblende. The metamorphic events are probably related to the Encantadas Orogeny (2257±12 Ma) and Camboriú Orogeny (~ 1989 Ma) of the Trans-Amazonian Cycle, followed by an orogenic event (702±21 Ma) of the Brasiliano Cycle. The intervening cratonic period (2000-700 Ma) corresponds to the existence of the Supercontinent Atlantica, known regionally as the Rio de la Plata Craton.

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Zircon U–Pb Dating and Lu-Hf Isotope of the Retrograded Eclogite from Chicheng, Northern Hebei Province, China

Shock and Vibration ◽

10.1155/2021/1445653 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Xu Kong ◽

Xueyuan Qi ◽

Wentian Mi ◽

Xiaoxin Dong

Keyword(s):

Regional Metamorphism ◽

Granulite Facies ◽

Amphibolite Facies ◽

Metamorphic Event ◽

Isotopic Data ◽

Metamorphic Condition ◽

Eu Anomaly ◽

Facies Metamorphism ◽

Eclogite Facies ◽

Plagioclase Gneiss

We report zircon U–Pb ages and Lu-Hf isotopic data from two sample of the retrograded eclogite in the Chicheng area. Two groups of the metamorphic zircons from the Chicheng retrograded eclogite were identified: group one shows characteristics of depletion in LREE and flat in HREE curves and exhibit no significant Eu anomaly, and this may imply that they may form under eclogite facies metamorphic condition; group two is rich in HREE and shows slight negative Eu anomaly indicated that they may form under amphibolite facies metamorphic condition. Zircon Lu-Hf isotopic of εHf from the Chicheng eclogite has larger span range from 6.0 to 18.0, which suggests that the magma of the eclogite protolith may be mixed with partial crustal components. The peak eclogite facies metamorphism of Chicheng eclogite may occur at 348.5–344.2 Ma and its retrograde metamorphism of amphibolite fancies may occur at ca. 325.0 Ma. The Hongqiyingzi Complex may experience multistage metamorphic events mainly including Late Archean (2494–2448 Ma), Late Paleoproterozoic (1900–1734 Ma, peak age = 1824.6 Ma), and Phanerozoic (495–234 Ma, peak age = 323.7 Ma). Thus, the metamorphic event (348.5–325 Ma) of the Chicheng eclogite is in accordance with the Phanerozoic metamorphic event of the Hongqiyingzi Complex. The eclogite facies metamorphic age of the eclogite is in accordance with the metamorphism (granulite facies or amphibolite facies) of its surrounding rocks, which implied that the tectonic subduction and exhumation of the retrograded eclogite may cause the regional metamorphism of garnet biotite plagioclase gneiss.

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Mapping in the Fiskefjord area, southern West Greenland

Rapport Grønlands Geologiske Undersøgelse ◽

10.34194/rapggu.v110.7797 ◽

1982 ◽

Vol 110 ◽

pp. 55-57

Author(s):

A.A Garde ◽

V.R McGregor

Keyword(s):

Granulite Facies ◽

Amphibolite Facies ◽

Isotopic Age ◽

Supracrustal Rock ◽

Granulite Facies Metamorphism ◽

West Greenland ◽

Facies Metamorphism ◽

Geological Work ◽

Age Determinations

Previous geological work on the 1:100000 map sheet 64 V.l N (fig. 15) includes published maps of smaller areas by Berthelsen (1960, 1962) and Lauerma (1964), mapping by Kryolitselskabet Øresund A/S (Bridgwater et al., 1976) and mapping by GGU geologists for the 1:500000 map sheet Frederikshåb Isblink - Søndre Strømfjord (Allaart et al., 1977, 1978). The Amltsoq and Niik gneisses and Malene supracrustal rock units south and east of Godthåbsfjord have not so far been correlated with rocks in the Fiskefjord area. Godthåbsfjord separates the granulite facies gneisses in Nordlandet from amphibolite facies Nûk gneisses on Sadelø and Bjørneøen; the granulite facies metamorphism occurred at about 2850 m.y. (Black et al., 1973), while no published isotopic age determinations from the Fiskefjord area itself are available.

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