Mapping P-T conditions in hydrothermal systems using hyperspectral remote sensing and object based techniques

Hydrothermal alteration occurs in active volcanic systems where circulating seawater results in mineral and chemical changes in the volcanic host rocks depending on pressure-temperature conditions and initial chemical composition of the host rock. As by-products of such alteration various precious metals (gold, silver, copper etc) form. Spectral matching techniques are traditionally used in geologic studies using hyperspectral data to generate surface mineral maps which allow to characterize hydrothermal alteration. Using a combination of Al-MgOh and FeOH absorption features we can link spectral features to mineral chemistry thus linking spectroscopy to geochemistry of alteration systems. With contextual image analysis techniques applied to ratio images of combined absorption features we can detect boundaries between alteration zones from hyperspectral data. This allows to reconstruct paleo fluid pathways and interpret these in terms of discharge and recharge areas which are important areas for mineral prospectivity of these systems. The facies successions are important indicators for the genetic nature of these systems. Studying the Australian hydrothermal system of the Pilbara as a proxy to mineral zonations found on the planet Mars allows us to understand the nature of these mineral distributions on Mars.