Paleo- to Mesoarchean polymetamorphism in the Barberton Granite-Greenstone Belt, South Africa: Constraints from U-Pb monazite and Lu-Hf garnet geochronology on the tectonic processes that shaped the belt
Kathryn A. Cutts et al., Centre for Crustal Petrology, Dept. of Earth Sciences, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa, firstname.lastname@example.org. Posted online ahead of print on 13 Dec. 2013; http://dx.doi.org/10.1130/B30807.1.
The Barberton Granite Greenstone Belt (BGGB) of South Africa is a well preserved Meso-Paleoarchean metamorphic supracrustal belt. Two hypotheses persist to explain the origin of amphibolite-facies metamorphism in the southern BGGB. The first interprets these rocks to be the consequence of accretionary tectonics, while the second proposes a vertical tectonic process driven by sinking of greenstone layers and doming of the underlying granitoid crust. Metamorphic pressure-temperature (P-T) analysis with garnet Lu-Hf and monazite U-Pb geochronology is used to directly date the amphibolite-facies metamorphism within the southern BGGB. A garnet age of 3233 plus or minus 17 million years (Ma) and a monazite age of 3191 plus or minus 9 Ma were obtained for two samples that reached peak P-T conditions of 8.5 kbar and 640 degrees C with a clockwise P-T evolution. The durat
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