SATELLITE-BASED GEOLOGIC MAPPING OF THE CENTRAL TIBESTI VOLCANIC PROVINCE, CHAD

Located within the Sahara Desert in northern Chad, the Tibesti Volcanic Province [TVP] is one of the most prominent regions for Cenozoic intracontinental volcanism on Earth. With the exception of Emi Koussi in the eastern TVP, the region has been largely neglected by researchers in recent years due to challenging access and climate, along with political instability. Recent global coverage of satellite imagery has afforded the ability to enhance the reconnaissance geologic maps published prior to 1960. To accomplish this, we applied image processing techniques to Advanced Satellite Thermal Emission and Reflectance Radiometer (ASTER) data to produce a digital map of volcanic units and structural features within the central part of the TVP. Analysis of visible, near infrared and short-wave infrared spectra allowed discrimination of mafic and felsic units including ignimbrites and lava flows surrounding Tarso Yega, Tarso Voon, and Tarso Toon calderas. The relative ages of volcanic units were interpreted from high spatial resolution imagery and enhanced by warping the geologic map over digital topography. Caldera boundary remnants on an older volcano, and previously unmapped structural features were also been mapped. These results and perspectives from digital 3-D elevation models will be presented.