Some Contrasts in Landscapes in British Antarctic Territory

Abstract

Contrast is of the essence of regional description. Some lands, being possessed of st iking contrasts, have always lent themselves to easy?even over-facile? description. One thinks immediately of the contrast between the desert and the sown in the Nile valley, between mountain and plain in the Mediterranean world, between forest and steppe in historic Russia. In all these, and many other instances that will occur to you, there are strong physical contrasts of relief or climate or both together, reflected by contrasts in the natural vegetation and heightened by the handiwork of man. Clearly we can look for nothing of this kind in the Antarctic. Land vegetation is confined to a few moss-covered moraines and rock outcrops in the Antarctic islands of relatively low latitudes (the South Orkneys, 6i? S ; the South Shetlands 62?-63? S) and rare moss and lichen patches in northernmost Graham Land. Land animals are absent and the abundant sea mammals and sea birds are but summer visitors. Neither natural vegetation nor the handiwork of man can be said to soften or to modify the austerity of a landscape where ice in its many forms is dominant, and where naked rock brings welcome relief. It will therefore surprise no one in this audience if I suggest that landscape contrasts in the British Antarctic Territory1 are best discussed under those rather austere terms?structure, process and stage. Structure in the Antarctic means exactly what it means in south-east England, but in lands where nine-tenths or more of the surface is occupied by ice it has only a subordinate part to play in giving character to most landscapes. The chief role of structure is to determine the run of the main relief features or the broad disposition of physiographic provinces. Process is the dominant influence in landscape building and it takes two forms?the climatological process of glacierization in which the lands, and indeed the adjacent sea, may be progressively smothered by ice; and the geomorphological processes by which that ice in its slow descent from higher to lower altitudes and colder to warmer regions, has pared and sculptured the upstanding rock masses in ways to which the forms we now see bear witness. And lastly these forms reveal systematic differences that seem to find their most reasonable explanation if we attribute them to dif? ferent stages in the sequence of glacially sculptured forms. Considered in this way even Antarctic landscapes reveal a fascinating richness and variety. Structural considerations.?The area that I wish to consider lies southward of southernmost South America and has for more than half a century been recognized as having close geological relations with it. South of the fortieth parallel South America narrows abruptly as the immensity of the pampas comes to an end, and the continent continues in essentially peninsular form for another thousand miles. On the west the cordillera of the Andes enters its Magellanic phase, its summits blanketed by ice and snow, its western valleys deeply drowned and in the southern half fiorded. On the east the plateaus of Patagonia form a distinct major physio-