[Parameters: Topic='SOLID EARTH', Term='GEOMORPHIC LANDFORMS/PROCESSES', Variable_Level_1='TECTONIC LANDFORMS']
Geology of the Larsemann Hills 2004Entry ID: lars_geology_2004
Abstract: The Larsemann Hills region is dominated by two major lithological associations, a Palaeoproterozoic felsic/mafic orthogneiss complex (Søstrene 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 Søstrene 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 Søstrene 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 URL given below for further information.
Start Date: 2003-11-16Stop Date: 2004-02-04
ISO Topic Category
Quality A draft geological map (scale 1:25 000) of the Larsemann Hills was generated by Rupert Summerson (National Resource Information Centre) and Dr Doug E Thost (AGSO, = Geoscience Australia, GA) for the Australian Antarctic Division (AAD) on the 27 Jan 1997. Geological information depicted on that map is derived from a number of sources, primarily from unpublished field data of Carson (1991/92, ... 1992/93 and 1993/94), Carson et al. (1995b) and Stüwe et al. (1989), with additional geological interpretation by Doug Thost. That map was not published.
With a view to upgrading that draft map to publication, Dr Chris Carson added new unpublished field data from Stornes Peninsula (Carson and Grew 2003/04, ASAC 2350) and appended and corrected known errors that existed on the original draft map. The current map therefore combines elements of the original draft geological map and the new geological information acquired by Carson and Grew (2003/04). The map is primarily a lithological map, illustrating the distribution of primary rock types present in the Larsemann Hills region.
This work was conducted at SKM Consulting, 214 Northbourne Ave Canberra, between 29 March and 30 April 2004. Carson was assisted by Bruce Donaldson (MapInfo) and Gordon Sue (ArcView).
The current map is overlaid on topographic information provided by Henk Brolsma of the AAD (coastline, rock boundaries, lakes, snowfields etc) that have been previously digitised from aerial photography flown on Jan/Feb 1998, at an elevation of 3000m. The mapping conducted by Carson and Grew during ASAC 2350 used two air photos covering the bulk of northern Stornes Peninsula (ANTC1063, Run 3 frame 96) and the outcrops between the southern end of Thala Fjord and the eastern end of Wilcock Bay (ANTC1063 run 5, frame 16). These photos were projected onto the WGS 1984 using UTM (zone 43) geographical co-ordinates and were then ortho-rectified using contour information based on the 1998 aerial photography to accurately match the provided topographic data.
The new geological map was drafted in MapInfo v_7, lithological contacts were digitised and are either self enclosed or terminate at snow, lake, ice or coastline arcs, or another lithological boundary. The MapInfo layers containing the new geology polylines or arcs and the coastline, rock_bdy and snow polylines (supplied by AAD as *.shx autoCAD files) were then transferred to ArcView.
Access Constraints These data are publicly available for download from the URL given below.
Use Constraints This data set conforms to the PICCCBY Attribution License
Please follow instructions listed in the citation reference provided at the URL below when using these data.
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Distribution Media: HTTP
Distribution Size: 26 MB
Distribution Format: shapefile
Role: TECHNICAL CONTACT
Phone: +61 2 6249 9072
Email: chris.carson at ga.gov.au
Geoscience Australia Corner of Jerrabomberra Av. and Hindmarsh Drv., GPO Box 378
Province or State: Australian Capital Territory
Postal Code: 2609
Phone: +1 207 581 2169
Fax: +1 207 581 2202
Email: esgrew at maine.edu
Department of Geological Sciences University of Maine 5790 Bryand Research Center
Province or State: ME
Postal Code: 04469-5790
Role: DIF AUTHOR
Phone: +61 3 6232 3244
Fax: +61 3 6232 3351
Email: dave.connell at aad.gov.au
Australian Antarctic Division 203 Channel Highway
Province or State: Tasmania
Postal Code: 7050
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Creation and Review Dates
DIF Creation Date: 2007-08-08
Last DIF Revision Date: 2014-09-11