HR: 0800h
AN: V11D-0808    [Abstracts]
TI: Satellite-based Morphotectonics of the Tibesti Lineament and its Relationship to Volcanism, Tibesti Massif, Chad
AU: * Van Arsdall, L E
EM: levanars@edisto.cofc.edu
AF: Geology and Environmental Geosciences, College of Charleston 66 George Street, Charleston, SC 29424, United States
AU: Nusbaum, R L
EM: nusbaumr@cofc.edu
AF: Geology and Environmental Geosciences, College of Charleston 66 George Street, Charleston, SC 29424, United States
AB: Intra-plate volcanism on continental often occurs at 'hotspots' where the crust has been weakened and reworked by either thermal or tectonic processes. We investigate the relationship between intraplate volcanism and faulting along the Tibesti Lineament, northern Chad. Forty-two digital elevation models (DEMs) extracted from Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) datasets provided the basis for much of our analysis. The DEMs were used to create shaded relief maps, three-dimensional perspectives, and topographic profiles. Rose diagrams based on hill shade drainage and joint patterns delineate dominant Precambrian and younger lineation fabrics. Shaded relief images were also used to establish relative ages of volcanic shields, calderas, and scoria fields. Our results indicate a recent (Cenozoic) NW-SE trending normal fault where the Tibesti Lineament traverses the study area. The normal fault herein defined as the Tibesti Fault may be a reactivated reverse fault. The most recent volcanism of sizable volume lies near the intersection of the Tibesti Fault and a newly recognized fault oriented perpendicular to it. Morphotectonic analysis of that region indicates uplift near the intersection of the two faults acted as a mechanism that may have enabled decompression melting. This suggests that extension played a active role in Eocene-Holocene volcanism at Tibesti.
DE: 8010 Fractures and faults
DE: 8040 Remote sensing
DE: 8415 Intra-plate processes (1033, 3615)
DE: 9305 Africa
DE: 9604 Cenozoic
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting