Abstract
The Erebus volcanic province (EVP) is a Cenozoic, alkaline intraplate province on the edge of the West Antarctic rift system. Based on field and source characteristics and geographic locations, the EVP is newly subdivided into five volcanic fields. The EVP rocks are mainly nepheline normative, with rare, quartz normative compositions attributed to wall-rock assimilation. Eruption commenced by at least 18.7 Ma, but by correlation with distal tephra, may have started as early as 25 Ma. Volcanic activity is ongoing today at Mount Erebus, and several other volcanic centres in the region are considered dormant. Several petrological lineages that record crystal fractionation history have been identified in the EVP, with modelling showing olivine + clinopyroxene + ilmenite/magnetite + titanite ± kaersutite ± feldspar to be important fractionating phases. Modelling and geobarometry show depths of melting are greatest beneath Ross Island and the Transantarctic Mountains, relative to Mount Morning and Mount Discovery volcanic fields which lie between these two localities. The generation of relatively undifferentiated magmas in the province can be modelled by < 10 % partial melting of mixed spinel and garnet lherzolite mantle sources. Variable lines of evidence also point to a role for amphibole, enriched mantle-like and carbonatite-like components in the source. Equilibration of radiogenic Sr, Nd, Pb and Hf isotopic systems in relatively undifferentiated rocks are best explained in terms of a high time integrated HIMU 'sensu stricto' component in the mantle source, at least beneath Ross Island. The HIMU signature is likely to be older than 0.5 Ga and is thus unrelated to subduction of the palaeo-Pacific plate beneath East Antarctica at c. 0.5 Ga. Relatively undifferentiated whole rock chemistry from the province can also be modelled to show an eclogite component in the source, with increasing involvement of an eclogitic, oceanic crustal component eastwards.