Investigation of the shape, scale and distribution of irregular zones of fragmental rocks of the Mawson Formation at Coombs Hill to determine the precesses of volcanic vent evolution

The range of contact relationships among contacts between different rock zones within the vent cojmplex, in terms of sharpness, angularity or curvature and scales of irregularity was established. Four subtypes of structureless tuff breccia and lapilli tuff were distunguished. These zones and accompanying clastic dikes, Beacon rafts, pyroclastic raftes, clastic dikes and basalt intrusions were systematically described, catalogued, photographed and sampled.

General and thematic maps were prepared for interpretation of volcanic processes. Around 140 samples were collected from the bedrock and analysed by thin section and geochemical purposes. From the thin sections, quantitative clast-shape and vesicle population data, including vesicle volume and interconnectedness, was determined by image analysis on SEM-generated photographs.