Geological investigation (mapping, geochronology and geochemical analysis) of West Antarctica Volcanics from Marie Byrd Land

The West Antarctica Volcano Exploration (WAVE) project was conducted to gain an understanding of the volcanic and geochemical evolution of intraplate volcanoes in West Antarctica and to compare volcanism and lithospheric structure of West Antarctica with documented parallels in the Ross Sea embayment. In the first season of this project (1989/90) the Executive Committee Range (ECR) was visited. This is a linear, north-south orientated, chain of intraplate volcanoes related to late Cenozoic rifting in West Antarctica. This site was chosen because a) the ECR contains some of the youngest volcanism in West Antarctica, b) the volcanoes are large and particularly well exposed, c) reconnaissance sampling indicated considerable compositional range (from basalt to phonolite and peralkali rhylite) and d) lithospheric xenoliths had been reported from the volcanoes in the range. Detailed mapping and extensive sampling (for geochronological and geochemical study) was undertaken on Mt Sidley and Mt Waesche with reconnaissance sampling at Mt Cumming. Lithospheric xenoliths were recovered from mafic scoria cones and deposits on Mt Waesche, Mt Sidley and Mt Cumming. In the second season of this project (1990/91), the ECR was revisited to complete studies at the northern end of the range. Samples for geochronology and geochemical study and lithospheric xenoliths were collected from Mt Hampton and the USAS Escarpment (Mt Aldaz). The Mount Murphy Volcanic Complex (MMVC) was also visited. Detailed mapping extensive sampling (for geochronology, geochemical analysis and lithospheric xenoliths) was completed at Mt Murphy only due to weather constraints. Examination of lithospheric xenoliths will enable reconstruction of a complete section of the lithosphere from mantle depths to the upper crust.