By Rasik Ravindra
Panikkar Professor, Ministry of Earth Sciences, New Delhi, India.
The coastal regions of east Antarctic, given rise to by the retreat of the ice cap and consequent uplifting of the landmass especially the rocky oases, offer excellent examples of evolution of ice free areas. The geomorphological mapping that has revealed existence of comparatively higher relief of the structural hills with steep escarpment on the northern peripheries of the landmass in the mountain belt, parallel to the Antarctic coast, lend support to these observations. The architectural patterns of most of the Antarctic oases have evolved under the different processes of deposition and erosion, in a periglacial environment. That discontinuous depositional phases and an extensive erosional regime were in force in these ice free areas is indicated by the present disposition and the features present on the landforms. Radiocarbon dating of lake sediments from the central part of the oasis has revealed that the parts of area were deglaciated in the early Holocene or before it, and that a system of lakes had evolved making use of the depressions carved out by glacial scouring. Studies of pollen in sediment cores have established three different climates - warm; humid; and, warm-humid in the past dung post during Last Glacial Maximum (LGM )period. The geochemical analyses of the sediment cores and water samples together with micro-paleontological studies (BSIP) have yielded important tools in understanding the evolution of the Antarctic oases.
Introduction Antarctic is an awe inspiring coldest, windiest and the most inaccessible continent on the surface of the Earth. Most of this continent is covered under a thick mantle of ice except about 2 per cent of the area that shows land exposures (Figure 1). It is from study of such areas that the history of the past events can be built. The ice sheet that covers Antarctic has a history of nearly 30 to 40 million years (Barrett et...