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

• Published in: Antarctic Science
• Main Authors: Smellie, J.L., Mcintosh, W.C., Esser, R., Fretwell, P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2006
• Subjects: Antarc*; Antarctic; Antarctic Peninsula; Antarctic Science; Dundee Island; Ice Sheet; James Ross Island; Paulet Island; Ross Island
• Online Access: http://dx.doi.org/10.1017/s0954102006000447; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102006000447

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. 40 Ar/ 39 Ar 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.