Geological mapping and reconnaissance of the Edward VII Peninsula, Marie Byrd Land

A field expedition visited all of the rock outcrops in the Edward VII Peninsula, Marie Byrd Land. The principal objective was to undertake geological studies and make collections for future geochronological and geochemical work in New Zealand. The expedition was the first to make complete ground coverage of Edward VII Peninsula and the opportunity was taken to visit all the peaks and scraps in the Rockefeller and Alexandra Mountains to have a comprehensive overview of the geology of the region. The journey was made in two stages; a relatively long (300km) northward loop from a central put in site to visit the rather dispersed peaks of the Alexandra Mountains and then a shorter (150km) southward loop having a more concentrated look at the Rockefeller Mountains. All rock outcrops in the Alexandra and Rockefeller Mountains were mapped and despite some steep and icy scarp slopes, all but one rock mass (Mt Manger) was visited. In total, over 250 rocks were collected for laboratory studies. Field observations on the major rock types were recorded, including i) unfoliated granitoids varying from leucogranite to biotite-granodiorite, ii) low grade metasediments, mainly weakly foliated metagreywacke/slate and iii) heterogenous paragneiss (and some orthogneiss) of high metamorphic grade. A revision and extension of the geological map of the area was conducted and comprehensive rock collections were analysed for petrographic descriptions, potassium-argon (K-Ar) and rubidium-strontium (Rb-Sr) dating and geochemical (XRF) analysis.