Análisis de nuevos datos gravimétricos marinos en el entorno de la Isla Decepción (Islas Shetland del Sur, Antártida)

Abstract

Deception Island is the emerged part from an active young volcano located in the Bransfield Strait, that separates the Antarctic Peninsula from the South Shetland Islands. In this work we show the results obtained from a gravity survey made carried out during the DECVOL99 marine geophysical cruise. Two Bouguer anomaly maps, for the interior and the exterior areas of Deception Island have been completed. 4906 gravity data along 48 marine tracks have been processed, including usual corrections, the water-layer effect and the topography and bathymetric terrain corrections using a 1 km grid-size digital elevation model. The Bouguer anomaly maps show well-defined high-gradient areas and gravity anomalies that correlates with previous geophysical and structural data, and allow us to interpret them from a tectonic point of view. In this way, the main Bouguer anomalies present maximum and minimum values along two main orientations NE-SW and NW-SE. High gravity-gradient areas separate maximum and minimum anomalies corresponding to uplifted volcanic blocks and extensional areas with a thick sedimentary infilling. The location and orientation of elongated and sharp Bouguer anomaly gradients are interpreted as fracture zones, that have been observed by other geophysical data, and are in good agreement with structural data from the surface.