Thermal emission data as a tool for mineral and lithological mapping on the Antarctic Peninsula

Geological maps are a primary source of information for understanding much about an area's potential (e.g. mineral resources, engineering/construction suitability) through to anticipating and mitigating natural events (e.g. landslides, earthquakes). Geological maps exist for almost the entire planet and some maps (e.g. British Isles) have been continually refined and updated over the last 150 years. The Polar and highly mountainous regions of the world pose major logistical problems to gain access to certain areas, such that the geology of some regions remains poorly understood or completely unknown. The Antarctic Peninsula is one example where the glaciated terrain and mountainous relief have prevented access to field geologists. Over 50 years of geological mapping on the Antarctic Peninsula has led to a good understanding of its geological history and its links to the Andes and the supercontinent, Gondwana, of which Antarctica formed a part. However, some very large areas (100s km2) still remain poorly known or unexplored. The geological evolution of the Antarctic Peninsula can only be fully understood with a more complete knowledge of the rock types present. Although there is no substitute for fieldwork, gathering data from aircraft-mounted instruments or satellites offers the potential of providing geologists a first order method of remotely identifying rock types. Geologists working on the Antarctic Peninsula already make use of aeromagnetic and aerogravity data to help understand the sub-ice geology and a recent study has used satellite data for identifying minerals using reflectance data This, however proved to have limitations as comparatively few of the major rock-forming minerals display diagnostic absorption features. In contrast, almost all rock forming minerals display diagnostic spectral emission features in the thermal infrared region, which has the potential to be a valuable tool in distinguishing features for igneous and sedimentary rocks. Thermal data from satellites is available, but it has limited spectral bands that would not yield the resolution required to differentiate between minerals. Funding through the Foreign and Commonwealth Office, UK has already been secured (Biological Sciences, BAS) for a survey to assess vegetation type and extent at sites on Adelaide Island on the Antarctic Peninsula. The survey will be conducted using an instrument owned by a Canadian research company (ITRES); such an instrument is not currently available to NERC. The Canadian owned, 64-band thermal imaging instrument (Thermal Airborne Spectrographic Imager: TASI) is capable of generating high spatial and spectral resolution thermal emission data. It can be fitted to a British Antarctic Survey Twin Otter aircraft and is able to generate very high quality data that can map the type and extent of vegetation at several sites along the Antarctic Peninsula. The instrument can also be used in conjunction with other survey flying to optimise time and resources. Funding is sought here to use the same vegetation survey dataset, but to investigate its potential to identify different minerals and rock types. If funding is secured a ground-based spectral study would be done in conjunction with the airborne survey to calibrate the data. This study would be carried out in an area where the geology is well described and understood, such that a proof of concept could be established before extending the techniques to areas where geological understanding is poor or absent. If successful, the intention would be to extend the work into other polar regions or highly mountainous, difficult to access regions and develop the techniques further.