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On the origin of fore-arc basins: new evidence of formation by rifting from the Jurassic of Alexander Island, Antarctica

Macdonald, D.I.M.; Leat, P.T.; Doubleday, P.A.; Kelly, S.R.A.. 1999 On the origin of fore-arc basins: new evidence of formation by rifting from the Jurassic of Alexander Island, Antarctica. Terra Nova, 11 (4). 186-193. 10.1046/j.1365-3121.1999.00244.x

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Abstract/Summary

The Middle Jurassic–Lower Cretaceous Fossil Bluff Group of Alexander Island, Antarctica represents the fill of a fore-arc basin unconformably overlying an accretionary complex. Like most fore-arc basins, this example had been considered to have a passive origin, as a topographic hollow between the arc and the trench-slope break. Recent discoveries of igneous rock coeval with sedimentation have altered this view. Oxfordian–Kimmeridgian basaltic and rhyolitic sills and lava flows are found in a restricted area at the north of the basin, within a single formation. Chemically, most basalts are high-Nb types, which cannot have originated in a supra-subduction zone setting. Since the age of emplacement of these rocks coincides with a gap in the record of plutonism in the Antarctic Peninsula volcanic arc, it is concluded that a late Jurassic pause in subduction led to active rifting to form the fore-arc basin.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1046/j.1365-3121.1999.00244.x
Programmes: BAS Programmes > Pre 2000 programme
ISSN: 0954-4879
Date made live: 21 Oct 2013 10:47 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/503581

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