Stratigraphic Studies and Surface-Layer Formation. A Case Study: Eastern Wilkes Land, East Antarctica (Abstract)

Abstract

This paper presents the results of a detailed study on the geomorphic and diagenetic processes of surface-layer formation and its subsequent preservation in the stratigraphic record. The study supplemented stratigraphic studies carried out along a 750 km ANARE traverse route along the 69 °S parallel between 112° and 131 °E (which approximately follows the 2000 m contour) in the katabatic wind zone of eastern Wilkes Land.A 100 cane farm was established at GD03 (69 °S, 115°E; 1835 m a.s.l.), adjacent to a 30 m deep firn-core drill site. The cane farm was used to monitor seasonal changes in snow accumulation and the type, size, distribution and orientation of the surface micro-relief.The annual snow accumulation at GD03 is equivalent to 300 kg m−2 of water. This annual layer is visibly marked by a multi-layered ice crust, typically 1–2 mm thick, which is formed in autumn during a hiatus in snow supply. Within the annual layer, single-layered thin ice crusts were observed. These correspond to short hiatus periods, of the order of 2–3 weeks, during late winter–early spring, and radiation glazes formed during summer.Density and oxygen-isotope–depth profiles display annual cyclicity within the snow-pack. Considerable horizontal variation was found in a single annual-layer thickness, with respect to ice-crust thickness, snow-density and oxygen-isotope values, and depth-hoar development, when traced in 21 2 m cores drilled at 5 m horizontal spacing.The observed changes in surface micro-relief distributions over the cane farm have enabled a greater understanding of vertical variations between annual layers observed in the 30 m firn core.