Investigation of the weathering processes and quaternary geology in the Wright Valley and the elevated beach ridges of Marble Point and investigation of the dykes at the Nussbaum Riegel

The weathering processes and quaternary geology was investigated in the Wright Valley, mostly near Lake Vanda but as far east as the Meserve Glacier, the Taylor Valley and at Marble Point. Igneous dykes were also investigated at the Nussbaum Riegel in the Taylor Valley. Within the Wright Valley, several weeks were spent in a previous season in the Lake Vanda region and some tentative conclusions on the weathering processes had been reached, and the purpose of the visit to this region was to check their validity. The Wright Valley is a perfect examples of an area where salt fretting within the soils occurs. Two main soil types were examined, an aired soil which covers most of the Wright Valley and is never flushed out by water and a non-arid soil which is flushed out annually by melting snow. A band which appears to be permanently damp flanks the western side of the valley and extends for several kilometers was investigated to determine its occurrence. Pediments, the term being used in a broad sense and not glacial features, are the most striking landscape forms in the middle part of the Wright Valley and were also investigated. In addition, maximum wind velocities were determined in the Bull Pass area by setting up indicators to determine the strength of the wind. The lower Taylor Valley was reconnaissance with observations of local weathering phenomena (polygons, salt deposits, sand entrained on down valley sides of boulders, ridges, etc). At Marble Point, 12 profiles were measured across the elevated marine shore lines which extend over about half the coast between Gneiss Point and Cape Bernacchi. The dykes at the Nussbaum Riegel contain one of the best exposed and most readily accessible dyke swarms. The various petrological types were collected and the field relations of the dykes were determined. Samples were collected for K/Ar dating and geochemical analysis. The dykes were previously mapped as being entirely lamprophyres but the more detailed studies have shown that they are more correctly termed dolerite.