SPACE-TIME EVOLUTION OF ANTARCTIC VOLCANOES: A REMOTE SENSING APPROACH

The geologically active, submarine/subglacial West Antarctic rift system is characterized by abundant and widespread Cenozoic volcanism, including large active or dormant volcanoes. To understand how the processes of active volcanism, tectonism, and ice sheet loading/unloading are linked in this unique system, it is essential to improve spatial and chronological records of volcanism. We are using multisource remotely sensed data, integrated with spatially registered data bases, to achieve this in the remote and inaccessible Antarctic terrain. Aerial photography and multispectral imagery with high spatial resolution (SPOT, LANDSAT-7) can be used to map surface cones and flows, but mapping is hampered by the very dark basaltic volcanic surfaces and the stark contrast with high-albedo ice cover. SAR imagery (RADARSAT, ERS, JERS), in contrast, very effectively delineates constructional volcanic features of structural significance, but can not be used to reliably discriminate volcanic rock outcrop from glacial cover. We have shown that SAR penetrates glacial cover in the hyperarid Antarctic environment to reveal subglacial volcanic cones, greatly enhancing our ability to map the spatial distribution of volcanics beneath thin ice cover. Aeromagnetic data reveals the distribution of volcanics on the sea floor and beneath the ice sheets. We are using aeromagnetic data from a recent, relatively high-resolution draped survey to investigate subsurface structural and magmatic features beneath Neogene volcanoes. We use data fusion techniques and have developed a GIS, including co-registered imagery, aeromagnetic data, derivative maps, and geochronological age data, that allow us to overlay data sets and correlate information to obtain an accurate, integrated view of surface and subsurface volcanic materials. Our integrated approach has great potential for unraveling the regional volcanic history and volcanic structure throughout the ice-covered Antarctic region. Future work can incorporate new digital terrain data from radar interferometry and laser altimetry, detection of active volcanic deformation from interferometry, and discrimination of volcanic materials using newly available multispectral data from ASTER.