Antarctic Science



Major eruption-induced changes to the McDonald Islands, southern Indian Ocean


JON STEPHENSON a1, G.M. BUDD a2, J. MANNING a3 and P. HANSBRO a4
a1 School of Earth Sciences, James Cook University, Douglas, Townsville, QLD 4811, Australia, jon.stephenson@jcu.edu.au
a2 School of Exercise and Sport Science, Faculty of Health Sciences, The University of Sydney, PO Box 170, Lidcombe, NSW 2141, Australia
a3 Geoscience Australia, GPO Box 378, Canberra, ACT 2601, Australia
a4 Department of Immunology & Microbiology, Faculty of Medicine and Health Science, University of Newcastle, Royal Newcastle Hospital, Newcastle, NSW 2300, Australia

Article author query
stephenson j   [PubMed][Google Scholar] 
budd gm   [PubMed][Google Scholar] 
manning j   [PubMed][Google Scholar] 
hansbro p   [PubMed][Google Scholar] 

Abstract

The McDonald Islands (53°S, 73°E) originally comprised three small islands that lie on the Kerguelen Plateau, 44 km west of Heard Island. No volcanic activity was observed since their discovery in 1874 until 1997, when two passing ships recorded major changes and eruptive behaviour. A 2001 satellite image showed that the main island had doubled its area. This paper reports observations made from a cruise ship in November 2002, supplemented by a high-resolution satellite image acquired in March 2003. A new volcanic complex comprises lava domes, spines and flows, all assumed to be phonolitic, similar to the older volcanic rocks. The complex shows dormant volcanic activity, with numerous fumaroles, recent spine evolution and lava flows. Changes in relative sea level have connected Flat and McDonald Islands. A spit about 1km long with extensive shoals beyond, now extends eastward from McDonald Island and presents new hazards to shipping. Biological changes include colonization by king penguins (Aptenodytes patagonica), previously absent, and a large reduction in numbers of formerly widespread macaroni penguins (Eudyptes chrysolophus chrysolophus).

(Received August 10 2004)
(Accepted January 11 2005)


Key Words: fauna; king penguin; lava domes; lava spines; ship hazards; sub-Antarctic; volcanism.


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