Phase two of the WAVE field programme involved detailed mapping and sample collection from the Mount Murphy Volcanic Complex (MMVC) and a return to the Executive Committee Range (ECR) to complete studies, at the northern end of this line of volcanoes.

The Mount Murphy Volcanic Complex has been deeply eroded to expose sections through the volcano which range from sub aqueous to sub aerial mode of eruption. The volcanic rocks rest on an eroded metamorphic basement complex of high grade metamorphic rocks cut by granitoid intrusions. A single outcrop of low grade sedimentary rock has yielded plant fossils - some of the first insitu fossil material to be discovered in Marie Byrd Land. Detailed study of continuous sections of volcanics up to 600m thick in the vicinity of Turtle Peak, Petril Nunatak, Heden Nunatak and Seechrist Peak has revealed a transition zone from sub aqueous to sub aerial eruption. These relationships together with high precision dating studies by the ⁴⁰Ar/³⁹Ar method promise to reveal much about the glacial-eruptive history of the volcano and to add to the growing knowledge concerning the level of the West Antarctic ice sheet during the Pliocene. Samples collected in association with this mapping will be used to assess the geochemical and penological evolution of the volcano. A number of satellite basaltic scoria cones on the flanks of the eroded MMVC have yielded upper and lower crustal and upper mantle xenoliths from which we can reconstruct a stratigraphic section through the lithosphere beneath the volcano.

For the last 10 days of field work the party transferred to Mount Hampton at the northern end of the Executive Committee Range (ECR). Here, sampling was assisted by close support from a BAS Twin Otter aircraft. This enabled some of the party to sample tephra layers from blue ice in the vicinity of Mount Waesche at the southern end of ECR and a visit to scoria cones of the USAS Escarpment. Samples for dating and geochemical study were collected from Mt Hampton, Whitney Peak (on the NW flank of Hampton) and the USAS Escarpment (Mt Aldaz). Lithospheric xenoliths were collected from scoria cones on Whitney Peak (NW Mt Hampton) and the USAS Escarpment.