Hyperspectral mapping of an ancient hydrothermal system [abstract # 12979
Hydrothermal deposits have been suggested as locations of high importance in the search for fossilized forms of ancient biota on Earth [Walter and Des Marais, 1993; Farmer and Des Marais, 1999]. They occur where spatially confined warm (50 O) to hot (500O) fluids are in disequilibrium with their hos...
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| Format: | Text |
| Language: | English |
| Published: |
2003
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.521.642 http://abrown.seti.org/AdrianBrownPhD/downloads/AJ Brown NAI Abstract 2003.pdf |
| Summary: | Hydrothermal deposits have been suggested as locations of high importance in the search for fossilized forms of ancient biota on Earth [Walter and Des Marais, 1993; Farmer and Des Marais, 1999]. They occur where spatially confined warm (50 O) to hot (500O) fluids are in disequilibrium with their host rocks [Piranjo, 1992]. By the action of such a system, solutes can be concentrated to form ores at certain horizons within or on the surface of a rock body. Such concentrations may be developed where a drop in temperature, pressure, or alteration of the permeability or chemistry of the host rocks created conditions suitable for the solute to be precipitated from the hot fluid. It has been suggested by many researchers that alteration of host rock in hydrothermal systems typically produces halos of chlorites and white micas [Yang et al., 2000; Cudahy et al., 2002]. Hydrothermal systems can therefore be characterized by layered horizons of altered rocks which are able to be detected using hyperspectral remote sensing surveys [Huntington, 1996]. Such a survey has recently been carried out in the ancient Pilbara craton of Western Australia. The target of this survey was the North Pole Dome, a 600 sq. km region of the Pilbara which underwent alteration by a shallow marine low temperature hydrothermal system [Nijman et al., 1998; Van Kranendonk, 2000]. The survey was conducted over a half day period using the Hymap instrument [Cocks et al., 1998]. The North Pole Dome is home to many stromatolite horizons and has featured in many papers on |
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