Antarctic Science



EARTH SCIENCES

The Cape Purvis volcano, Dundee Island (northern Antarctic Peninsula): late Pleistocene age, eruptive processes and implications for a glacial palaeoenvironment


J.L. Smellie a1c1, W.C. Mcintosh a2, R. Esser a2 and P. Fretwell a1
a1 British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
a2 New Mexico Geochronology Research Centre, New Mexico Institute of Mining & Technology, 801 Leroy Place, Socorro, NM 87801-4796, USA

Article author query
smellie jl   [PubMed][Google Scholar] 
mcintosh wc   [PubMed][Google Scholar] 
esser r   [PubMed][Google Scholar] 
fretwell r   [PubMed][Google Scholar] 

Abstract

Cape Purvis is a conspicuous promontory on southern Dundee Island. It forms a prominent mesa that contrasts with the smooth, shield-like (snow-covered) topography of the remainder of the island. The promontory is composed of fresh alkaline basaltic (hawaiite) volcanic rocks compositionally similar to younger lavas on Paulet Island 5 km to the east. The outcrop is one of the youngest and northernmost satellite centres of the James Ross Island Volcanic Group. 40Ar/39Ar isotopic dating indicates that the Cape Purvis volcano is 132 ± 19 ka in age. The examined sequence probably formed as a lava-fed delta during a subglacial eruption late in the glacial period corresponding to Isotope Stage 6, when the ice sheet surface elevation was 300–400 m higher than at present. A remarkable unidirectional age progression is now evident, from volcanic centres in Prince Gustav Channel (c. 2.0–1.6 Ma), through Tabarin Peninsula (1.69–c. 1 Ma) to Cape Purvis and Paulet islands (132–few ka). The age variations are tentatively ascribed to construction of progressively younger volcanic centres at the leading edge of an easterly-opening deep fault system, although the origins of the postulated fault system are unclear.

(Received November 8 2005)
(Accepted April 20 2006)


Key Words: hawaiite; hyaloclastite; ice sheet; lava-fed delta; Pleistocene; subglacial.

Correspondence:
c1 jlsm@bas.ac.uk


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