HR: 14:10h
AN: P53A-03    [Abstracts]
TI: Hyperspectral Mapping of Ancient Hydrothermal Systems and Applications for Mars
AU: * Brown, A J
EM: abrown@els.mq.edu.au
AF: Australian Centre for Astrobiology, Macquarie University, Sydney, NSW 2109 Australia
AU: Walter, M
EM: mwalter@els.mq.edu.au
AF: Australian Centre for Astrobiology, Macquarie University, Sydney, NSW 2109 Australia
AU: Cudahy, T
EM: thomas.cudahy@csiro.au
AF: Australian Centre for Astrobiology, Macquarie University, Sydney, NSW 2109 Australia
AU: Cudahy, T
EM: thomas.cudahy@csiro.au
AF: CSIRO Exploration and Mining, 26 Dick Perry Ave, Kensington, WA 6105 Australia
AB: In October 2002 a VNIR-SWIR airborne hyperspectral study was commenced by the CSIRO and the Australian Centre for Astrobiology over a 600 km2 area of the Pilbara Craton termed the North Pole Dome (NPD). The NPD is largely constituted by volcanic rocks of the 3.5 Ga Warrawoona Group with some minor, but important interbedded sediments. These sediments have been reported to hold evidence of the Earth's earliest biota [1,2] although this has recently been the subject of much debate in the Astrobiological community [3]. Mapping the extent and spatial distribution of hydrothermal activity that may have supported this putative biota is the goal of this hyperspectral survey. The HyMap instrument [4] was used to collect the airborne hyperspectral dataset. It has similar capabilities to AVIRIS and has been extensively used in Australia and also recently in the U.S. The Pilbara coverage was collected as 14 swathes, each 2km wide, covering nearly 600 km2. The instrument was flown at approximately 2.5km, or 8200ft AMSL. Spectral coverage was between 0.4-2.5 microns in 126 contiguous bands. Here we present the results of a three year PhD project to reduce this hyperspectral dataset. The hyperspectral dataset was analyzed using custom written IDL code, designed to curve fit Short Wave Infra Red (SWIR: 2-2.5 micron) absorption bands due to hydroxyl bands. This allowed accurate mapping of important hydrothermal minerals such as kaolinite, white micas, fe-and mg-chlorite, fe and mg-clinoamphiboles and chert/silica. The resultant maps yield information on the extent and intensity of three different Archean hydrothermal events. The OMEGA hyperspectral instrument is now returning information on possible hydrothermal minerals on Mars. The CRISM hyperspectral instrument is on its way and will be returning data in mid-2006. These instruments have the potential to map hydrothermal zones on Mars in much the same way as this project. Potential uses of the methods developed during this project will be discussed. [1] Walter, M. R., Buick, R. and Dunlop, J. S. R. (1980) Nature, 284, 443-445. [2] Schopf, J. W. and Packer, B. M. (1987) Science, 237 (4810), 70-73. [3] Brasier, M. D., Green, O. R., Jephcoat, A. P., Kleppe, A. K., Van Kranendonk, M. J., Lindsay, J. F., Steele, A. and Grassineau, N. V. (2002). Nature, 416 (6876), 76-81. [4] http://www.intspec.com
UR: http://aca.mq.edu.au/abrown.htm
DE: 3617 Alteration and weathering processes (1039)
DE: 5220 Hydrothermal systems and weathering on other planets
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: Fall Meeting 2005