Dufek and Forrestal Dykes transport Ferrar across Antarctica.
Abstract
Newly acquired aeromagnetic data indicate the presence of a dyke swarm that may have acted as a magma transport and feeder system from the Dufek intrusion to the Ferrar Large Igneous Province (FLIP), a distance of around 3,500 km. The gabbroic Dufek intrusion, Antarctica covers approximately 6,600 km2. It may pinpoint the location of a mantle superplume responsible for Gondwana breakup or may be a feeder for FLIP sills and lavas that extend along the Transantarctic Mountains into Tasmania and New Zealand. Prior to this survey, no feeder dykes or connecting sills have been found. New aeromagnetic data indicate the presence of three sets of dykes. One set of anomalies is spatially related to Cambrian volcanic and intrusive rocks and could be Cambrian in age. The other two sets may be Jurassic; one parallels the Ross orogeny trend, and the other has a more localized trend. We suggest that dykes parallel to the Ross orogeny trend were feeders for the FLIP. Similarities with the Mackenzie dykes and intrusions of Northwest Canada imply that these Jurassic dykes may have been emplaced into the existing Ross extensional regime during doming above a mantle plume. However, our survey area is too small to show the dykes radiating from a focal point that would indicate the plume position.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2001
- Bibcode:
- 2001AGUSM..GP42A06F
- Keywords:
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- 0925 Magnetic and electrical methods;
- 1206 Crustal movements--interplate (8155)