Geology Map of the Larsemann Hills 2004

• Other Authors: CARSON, CHRISTOPHER (hasPrincipalInvestigator), CARSON, CHRISTOPHER (processor), GREW, EDWARD (hasPrincipalInvestigator), Australian Antarctic Data Centre (publisher)
• Format: Dataset
• Language: unknown
• Published: Australian Antarctic Data Centre
• Subjects: geoscientificInformation; TECTONIC LANDFORMS; EARTH SCIENCE; SOLID EARTH; GEOMORPHIC LANDFORMS/PROCESSES; METAMORPHIC ROCKS; ROCKS/MINERALS/CRYSTALS; Larsemann Hills; Geology; GIS; Map; VISUAL OBSERVATIONS; AERIAL PHOTOGRAPHS; CONTINENT > ANTARCTICA > GEOGRAPHIC REGION > POLAR; Sostrene; Antarc*; Antarctica
• Online Access: https://researchdata.ands.org.au/geology-map-larsemann-hills-2004/701238; https://doi.org/10.26179/5beba1b8ddecd; https://data.aad.gov.au/metadata/records/lars_geology_2004; http://nla.gov.au/nla.party-617536

The Larsemann Hills region is dominated by two major lithological associations, a Palaeoproterozoic felsic/mafic orthogneiss complex (Sostrene Orthogneiss) which occurs as basement to a sequence of pelitic, psammitic and felsic paragneiss (supergroup = Brattstrand Paragneiss) and felsic intrusives. The depositional age of the Brattstrand Paragneiss sequences are controversial but isotopic data suggest derivation from the basement Sostrene Orthogneiss. Current geochronology indicates that the region experienced medium to low pressure granulite-facies metamorphism during the Early Palaeozoic (~500 Ma). Although the paragneiss sequences record no evidence of earlier metamorphism, relicts of a previous metamorphic event at ~1000 Ma are preserved in the Sostrene Orthogneiss. Within the Larsemann Hills region, the Early Palaeozoic event is characterised by peak metamorphism of ~7 kbar at ~800-850 degrees C, with the post-peak evolution characterised by decompression, with some cooling, to 4 kbars at 750 degrees C, then to 2-3 kbar at 600-650 degrees 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. See the document available for download at the provided URL for further information.