Authors / CoAuthors
Carson, C.J. | Grew, E.S. | Thost, D.E.
Abstract
The Larsemann Hills region is dominated by two major lithological associations, a Mesoproterozoic to Neoproterozoic felsic dominated orthogneiss complex (Søstrene Orthogneiss) which occurs as basement to a sequence of pelitic, psammitic and felsic paragneisses (Brattstrand Paragneiss) and felsic intrusives. Recent unpublished data suggest a late Neoproterozoic depositional age for the Brattstrand Paragneiss. Current geochronology indicates that the region experienced medium to low pressure granulite-facies metamorphism during the Early Palaeozoic (~515-530 Ma). Although the paragneiss sequences record no evidence of earlier metamorphism, relics of a previous metamorphic event at ~1000-950 Ma are preserved in the Søstrene Orthogneiss. Within the Larsemann Hills region, the Early Palaeozoic event is characterised by peak metamorphism of ~7 kbar at ~800-850°C, with the post-peak evolution characterised by decompression, with some cooling, to 4 kbars at 750°C, then to 2-3 kbar at 600-650°C during final stages of orogenesis, with exhumation largely driven by crustal extension. Tectonic models generally argue for a continental-continental collisional scenario, with thermal input derived from a thinned mantle lithosphere.
Product Type
document
eCat Id
126688
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Keywords
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- Geology
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- map
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- Published_External
Publication Date
2019-01-31T04:13:55
Creation Date
2019-01-31T00:00:00
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Status
final
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notPlanned
Topic Category
geoscientificInformation
Series Information
Edition 1
Lineage
Not supplied
Parent Information
Extents
[-69.5, -69.33, 75.9, 76.5]
Reference System
WGS84 (CRS:84)
Spatial Resolution
1:25000
Service Information
Associations
Source Information