Análisis de la deformación de los sistemas de venas y filones hidrotermales de la Península Hurd (Isla Livingston, Antártida Occidental)

Abstract

In Hurd Peninsula (Livingston Island, Western Antarctica) has been analysed the orientation of calcite c-axes and e-twin from the sparitic grains that filled the hydrothermal veins and lodes in this region. The c-axes orientations allow to establish that during the Upper-Cretaceous tectonic episode, when these veins were developed, took place an E-W extension, although other extension direction, e.g. NW-SE, also are active. The analysis of the calcite e-twins show the existence of compressional strain ellipsoids with two different orientations. A first group has an orientation that is compatible with a N-S compression direction, i.e. the same direction associated with the development of the veins. While the other is close to E-W and It is probably related with local tectonic structures. The presence of type I and II e-twins allow to deduce that the deformation temperature ranges between 150 to 300°C. Both, the strain intensity and the temperature increases towards the south part of Hurd Peninsula