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

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 syst...

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Bibliographic Details
Published in:Antarctic Science
Main Authors: Martin, Adam P., Cooper, Alan F.
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 2010
Subjects:
Geology
Ecology, Evolution, Behavior and Systematics
Oceanography
Antarctic
Ross Sea
Victoria Land
Mount Morning
Gandalf Ridge
Antarc*
Antarctic Science
Antarctica
Online Access:http://dx.doi.org/10.1017/s095410201000026x
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S095410201000026X
Description
Summary: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 .

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