Abstract:
Glaciation, eustatics and karst readjustment at the southern edge of the Madre de Dios archipelago (Patagonia, Ultima Esperanza Province, Chile). In the channels of Patagonia (Chile), at a latitude of 50° S, lies the Madre de Dios archipelago, a group of islands with limestone zones with the southernmost caves on the planet. Over the course of three expeditions in 2000, 2006 and 2008, alpine caves, marine caves and spectacular karren fields were explored and found to contain karst features in a mountain and fiord environment. Precipitation of 8000 mm/yr and strong winds form exaggerated superficial karst forms. Above all, the legacy of the Quaternary glaciers (dynamics of glacier retreat, eustatic variations in sea level, isostatic rebound), is the subject of this article. At the convergence of the influences of the Andes mountains to the East and the Pacific ocean to the West, the karst with its surface and its subterranean and submarine forms, constitutes a key to the understanding of the landscape. We show that in each stage in this evolution (glacial retreat, sea level rise, isostatic rebound), the karst has developed forms that register 21,000 years of morphogenesis in this unique region.