Antarctic Science
- Antarctic Science / Volume 22 / Issue 05 / October 2010, pp 513-521
- Copyright © Antarctic Science Ltd 2010
- DOI: http://dx.doi.org/10.1017/S095410201000026X (About DOI), Published online: 21 June 2010
Earth Sciences
Post 3.9 Ma fault activity within the West Antarctic rift system: onshore evidence from Gandalf Ridge, Mount Morning eruptive centre, southern Victoria Land, Antarctica
Adam P. Martina1 c1 and Alan F. Coopera1
a1 Department of Geology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
Abstract
A hawaiite dyke dated at 3.88 ± 0.05 Ma from the Mount Morning eruptive centre intrudes a diamictite deposit at Gandalf Ridge in the southern Ross Sea. The dyke has been dextrally offset up to 6 m horizontally by faults interpreted as the onshore continuation of the West Antarctic rift system (WARS) fault array. Felsic dykes emplaced during the Miocene are also present at Gandalf Ridge. The offset of the Miocene dykes is equivalent to the offset on the hawaiite dyke, suggesting that at this locality movement on faults within WARS has been restricted to a period more recent than c. 3.88 Ma. Over this period the minimum average rate of movement on these faults within WARS is 0.0015 mm yr-1.
(Received November 26 2009)
(Accepted March 25 2010)
(Online publication June 21 2010)
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