The Proterozoic P^T^t Evolution of the Kemp Land Coast, East Antarctica; Constraints from Si-saturated and Si-undersaturated Metapelites
Integrated metamorphic and geochronological data place new constraints on the metamorphic evolution of a Neoproterozoic orogen in east Antarctica. Granulite-facies rocks from a 150 km stretch of the Kemp Land coast reflect peak conditions involving T 870^9908C at P 74^10 kbar, with pressure increasi...
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
2006
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| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.597.5258 http://petrology.oxfordjournals.org/content/48/7/1321.full.pdf |
| Summary: | Integrated metamorphic and geochronological data place new constraints on the metamorphic evolution of a Neoproterozoic orogen in east Antarctica. Granulite-facies rocks from a 150 km stretch of the Kemp Land coast reflect peak conditions involving T 870^9908C at P 74^10 kbar, with pressure increasing westward towards an Archaean craton. Electron microprobe-derived (ThþU)^Pb monazite ages from metapelitic assemblages indi-cate that the major mineral textures in these rocks developed during the c. 940Ma Rayner Orogeny. Complex compositional zoning in monazite suggests high-T recrystallization over c. 25Myr. Diversity in metapelitic reaction textures reflects silica and ferromagnesian content: Si-saturated Fe-rich metapelites con-tain garnet that is partially pseudomorphed by biotite and sillima-nite, whereas Si-saturated Mg-rich metapelites and Si-undersaturated metapelitic pods have reaction microstructures invol- |
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