La función morfogenética de las Islas del Cabo de Hornos en el Wurm Superior

Abstract

In the southern end of Chile and South America (55 to 56 S.) there are forms wich allow to formulate the following by pothesis:

In the southern end, the action and movement field of the ice field during the last glaciation must be reconstructed as it follows: The mountain range Peninsula Hardy (Hoste Island) Wollaston Islands, wich is proposed to appeal Cape Horn (Hoste Island) Wollaston Islands, wich is proposed to appeal Cape Horn Cordillera in the paleogeographic sense, was the break up center of the ice field toward the North as well as the South. Consequently, Nassau Bay acted as glacigenic piedmont during an alaskian type glaciation.The morainic system of the southern coast of Navarino and Lennox islands is related to the genesis of the Windhond Bay lobe in an area of piedmont lakes, showing the push of the ice mantle from the South on the platform wich-paleogeographically can be called Nassau- Windhond glacigenic piedmont.

This hypothesis is different to that of KRANCK and CALDENIUS, whose theory assumes that the ice push was from the N W (Darwin Range). The new hypothesis is proved with the use of morphological stratigraphical, sedimentological and geochronological methods.

The results show that during the Dryas (Gotiglacial and Finiglacial) the ice advanced fragging eroded materials from the Cape Horn mountains range. This involucres new criteria to establish the age of the glacigenic and coastal forms in the area, with reference to Upper Wurm's stadia.