scholarly journals The History of Granulite-Facies Metamorphism and Crustal Growth from Single Zircon U-Pb Geochronology: Namaqualand, South Africa

1999 ◽  
Vol 40 (12) ◽  
pp. 1747-1770 ◽  
Author(s):  
L. J. Robb ◽  
R. A. Armstrong ◽  
D. J. Waters
Keyword(s):  
South Africa ◽  
Granulite Facies ◽  
Crustal Growth ◽  
Granulite Facies Metamorphism ◽  
Facies Metamorphism ◽  
History Of ◽  
Single Zircon

Metamorphic evolution and zircon geochronology of early Proterozoic granulites in the Aravalli Mountains of northwestern India

2005 ◽  
Vol 142 (3) ◽  
pp. 287-302 ◽  
Author(s):  
A. B. ROY ◽  
ALFRED KRÖNER ◽  
P. K. BHATTACHAYA ◽  
SANJEEV RATHORE
Keyword(s):  
Granite Gneiss ◽  
Granulite Facies ◽  
Granulite Facies Metamorphism ◽  
Granulite Metamorphism ◽  
History Of ◽  
Single Zircon ◽  
Northwest India ◽  
Orogenic Cycle ◽  
Age Range ◽  
Rock Association

Granulites including a charnockite suite, mafic granulites, pelitic granulites, metanorite dykes and their retrograde varieties occur as discontinuous shear zone-bounded bodies within the Archaean basement comprising a granite gneiss–amphibolite–metasedimentary rock association in the central part of the Aravalli Mountains, northwest India. The entire suite, named the Sandmata Complex, preserves a complex history of tectonothermal evolution. Except for their strongly foliated margins, the granulite bodies are largely massive. Partial melting in the ‘country rocks’ led to the development of migmatite gneisses close to the contact of the granulite, a feature not as common in the rocks further away from the granulite contact. Geothermobarometry of massive granulites indicates Tmax>900°C and Pmax∼7.5 kbar. The retrograde granulites, which formed at lower amphibolite/upper greenschist-facies conditions, experienced channelized hydration reactions concomitant with shearing. These rocks locally appear as hornblende–biotite-bearing foliated granulite with or without Cpx or Opx. The rocks seem to have followed an inverse PTt path and have undergone an earlier phase of near-isobaric cooling. Our single zircon Pb–Pb ages indicate that the exhumation of granulites to the shallower amphibolite-facies levels with concomitant melting in the country rocks took place between 1690 Ma and 1621 Ma. Assuming that the granulite-facies metamorphism took place at around 1725 Ma, we relate the entire process of granulite metamorphism and exhumation covering an age range between 1725 and 1621 Ma to the rift basin opening stages of the Delhi Orogenic cycle that culminated at c. 1450 Ma.

Granulite Facies Metamorphism in the Coast Range Crystalline Belt

1975 ◽  
Vol 12 (11) ◽  
pp. 1953-1955 ◽  
Author(s):  
Lincoln S. Hollister
Keyword(s):  
British Columbia ◽  
Granulite Facies ◽  
Coast Range ◽  
Geologic History ◽  
Granulite Facies Metamorphism ◽  
Mineral Assemblages ◽  
Facies Metamorphism ◽  
History Of

Mineral assemblages diagnostic of the granulite facies of metamorphism occur between Terrace and Prince Rupert, British Columbia. The estimated pressure (5–8 kb) and temperature (750–850 °C) of metamorphism are important constraints in unravelling the geologic history of the Coast Range batholithic complex.

Silurian granulite-facies metamorphism, and coeval magmatism and crustal growth in the Tongbai orogen, central China

Lithos ◽  
2011 ◽  
Vol 125 (1-2) ◽  
pp. 249-271 ◽  
Author(s):  
Hao Wang ◽  
Yuan-Bao Wu ◽  
Shan Gao ◽  
Hong-Fei Zhang ◽  
Xiao-Chi Liu ◽  
...  
Keyword(s):  
Granulite Facies ◽  
Central China ◽  
Crustal Growth ◽  
Granulite Facies Metamorphism ◽  
Facies Metamorphism

Tectonic history of the Grenville-age Trenton Prong inlier, Central Appalachians, USA: Evidence from SHRIMP U–Pb geochronology

2021 ◽  
Author(s):  
Richard Volkert ◽  
John N. Aleinikoff
Keyword(s):  
Granulite Facies ◽  
Small Population ◽  
Local Source ◽  
Thermal Activity ◽  
Granulite Facies Metamorphism ◽  
Magmatic Arc ◽  
Tectonic History ◽  
Facies Metamorphism ◽  
Minimum Age ◽  
History Of

New zircon U–Pb geochronologic data from the Grenville-age Trenton Prong provide information on the age of magmatism, timing of metamorphism, and post-metamorphic history of the inlier. Diorite gneiss (1318 ± 13 Ma) of the Colonial Lake Suite temporally correlates to magmatic arc sequences that formed along the eastern margin of Laurentia at <1.4 Ga. Metasedimentary gneisses yielded detrital zircon ages of ca. 1319-1133 Ma and ca. 1370-1207, consistent with sediment derived from a similar local source of Laurentian affinity. A small population of zircon (either detrital or igneous in origin) in one sample yielded ages of ca. 1074-1037 Ma. Possible interpretations for their formation are explored. Ca. 1060 Ma overgrowths on zircon in the northern part of the inlier constrain the timing of granulite-facies metamorphism to the Ottawan phase of the Grenvillian Orogeny. The undeformed Assunpink Creek Granite (1041 ± 6 Ma) intruded country rocks as small bodies of late-orogenic syenogranite. It provides a minimum age for amphibolite-facies metamorphism and Ottawan orogenesis elsewhere in the inlier. Regionally, zircon rim ages of ca. 1010–960 Ma record continued thermal activity during the Rigolet phase of the orogen that resulted in migmatization of paragneiss at ca. 1004 Ma and juxtaposition of upper- and mid-crustal rocks during orogenic collapse. The lithologic ages and tectonic history of the Trenton Prong correlate to those in other Appalachian Mesoproterozoic inliers, and parts of the Canadian Grenville Province, confirming it is not an exotic terrane that was accreted to eastern Laurentia during Grenvillian orogenesis.

Regional geothermobarometry in the granulite facies terrane of South India

1983 ◽  
Vol 73 (4) ◽  
pp. 221-244 ◽  
Author(s):  
M. Raith ◽  
P. Raase ◽  
D. Ackermand ◽  
R. K. Lal
Keyword(s):  
South India ◽  
Analytical Data ◽  
Granulite Facies ◽  
Critical Discussion ◽  
Granulite Facies Metamorphism ◽  
Northern Margin ◽  
Mineral Equilibria ◽  
Metamorphic History ◽  
Facies Metamorphism ◽  
History Of

ABSTRACTIn the southern part of the Archaean craton of South India, an approximately 3.4–2.9 b.y. old migmatite–gneiss terrane (Peninsular gneiss complex) has been subjected to granulite facies metamorphism about 2.6 b.y. ago. During this event, the extensive charnockite-khondalite zone of southern India developed. A younger metamorphism (Proterozoic?) led to retrogression of the charnockites and khondalites, mainly under the conditions of the amphibolite facies.The physical conditions of metamorphism have been evaluated by applying methods of geothermobarometry to the widespread charnockitic assemblages with garnet, orthopyroxene, clinopyroxene, plagioclase, and quartz. The interpretation of the P–T estimates includes a critical discussion of potential error sources, e.g. errors of the analytical data and the calibrations of the models, and takes into account the complex metamorphic history of the rocks and the kinetics of the mineral equilibria.P-T estimates were obtained for seven subareas from the rim compositions of the coexisting minerals: Shevaroy Hills 680±55°C—7·4±1 kb; Kollaimalai area 680±40°C—8·6± 1 kb; Nilgiri Hills 680±90°C—6·6±0.8kb (upland massif) and 705±60°C—9·3±0.8 kb (northern margin); Bhavani Sagar area 650±50°C—7·2± 1 kb; Sargur-Mysore area 690±60°C—7·6 kb; Bangalore-Kunigal-Satnur area 760±50°C—6 kb. Except for the last subarea, the P-T model data reflect the conditions of a late annealing stage probably related to the retrogressive metamorphism. Conditions near the peak of granulite facies metamorphism (730–800°C—6·5–9·5 kb) are recorded by the core compositions of the minerals. Although a rather uniform cooling history of the main part of the charnockite-khondalite terrane is suggested from the temperature data, differential uplift of smaller blocks is indicated by the regional variation of the pressure data.

Petrological evolution in the roof of the high-grade metamorphic Central Zone of the Limpopo Belt, South Africa

2005 ◽  
Vol 142 (3) ◽  
pp. 229-240 ◽  
Author(s):  
ARMIN ZEH ◽  
REINER KLEMD ◽  
JAY M. BARTON
Keyword(s):  
South Africa ◽  
Temperature Increase ◽  
Central Zone ◽  
Granulite Facies ◽  
High Grade ◽  
Metamorphic Overprint ◽  
Granulite Facies Metamorphism ◽  
Facies Metamorphism ◽  
Zonation Patterns ◽  
Limpopo Belt

In this study we present new petrological results from the Endora Klippe in the Central Zone of the Limpopo Belt, which may result from horizontal tectonics during the Proterozoic at c. 2.0Ga. Microstructures, assemblages and garnet zonation patterns observed in metapelitic rocks provide evidence that the Endora Klippe rocks underwent a contemporaneous pressure–temperature increase from c. 600°C/5kbar to 650°C/6.5kbar. This is inferred by the use of conventional geothermobarometry and interpretations based on quantitative phase diagrams in the system MnO–(TiO2)–(CaO)–(Na2O)–K2O–MgO–Al2O3–SiO2–H2O. Thus, the petrological results indicate that this part of the Central Zone only underwent a medium-grade metamorphic overprint during a single orogenic event and was never affected by granulite-facies metamorphism, as reported from other parts of the Limpopo Belt. The inferred P–T path, in combination with previous structural and petrological results, leads to the conclusion that the area surrounding the Endora Klippe forms the roof zone of the c. 2.0Ga old granulite-facies rocks forming wide parts of the Limpopo Central Zone.

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