T262 Geologic Maps, Digital Geologic Maps, and Derivatives from Geologic and Geophysical Maps (Posters)

Wednesday, 12 October 2011
9:00 AM - 6:00 PM
Hall C

USE OF STEREOSCOPIC SATELLITE IMAGERY FOR 3D MAPPING OF BEDROCK STRUCTURE IN WEST ANTARCTICA: EXAMPLES FROM THE FORD RANGES AND NEOGENE VOLCANOES OF MARIE BYRD LAND

Paper number: T262-2
Program: Technical Sessions
Time: 9:00 AM – 6:00 PM

Authors

Abstract

In West Antarctica, crustal-scale structures of the West Antarctic rift system have been minimally mapped using ground-based methods and airborne geophysics, but extensive continental ice conceals faults, shear zones, and dike arrays that should be factored into tectonic models. The subglacial extent of Neogene volcanoes upon the rift’s thin crust is not known, despite the significance of the volcanoes as sites for onset of alpine glaciations leading to ice sheet growth. A new approach to mapping faults and volcanic edifices, for enhanced understanding of the region’s tectonic framework, is being developed using panchromatic and multispectral imagery draped upon high-resolution DEMs. DEMs of the glacial terrain are created using ERDAS Imagine’s LPS enhanced automated terrain extraction algorithm to derive a dense point cloud of matches between two sequential 0.5 meter resolution Worldview -1 and -2 stereoscopic images calibrated with a single ground control point. MATLAB is used to refine and interpolate the data. Outcomes compare favorably to DEMs produced from NASA’s ATM-LiDAR data for glacier regions.

Sites of tectonic significance under study this year are the Ford Ranges and Land Glacier in western Marie Byrd Land, a region of thin crust created by Cretaceous rifting; the Executive Committee Range and Mt Murphy, centers of effusive volcanism since 10 Ma. Small test areas computed to date demonstrate the presence of distinct lineaments in ice surface topography attributable to bedrock faults and dikes, with initial results indicating that bedrock contacts will also be expressed. Specific structures prioritized for mapping in the Ford Ranges are the South Fosdick detachment zone bounding the Fosdick gneiss dome, footwall structures internal to the dome, and high angle range-bounding faults. The Executive Committee Range and Mt Murphy are targeted for interpolation of the sub-ice extent of alkali basalt flows surrounding volcano summits at elevations 1900- 4200 m.