  Rover missions to the rocky bodies of the Solar System and especially to Mars
require light- weight, portable instruments that use minimal power, require no
sample preparation, and provide suitably diagnostic mineralogical information
to an Earth-based exploration team. Short-wave infrared (SWIR) spectroscopic
instruments such as the Portable Infrared Mineral Analyser (PIMA, Integrated
Spectronics Pty Ltd., Baulkham Hills, NSW, Australia) fulfill all these
requirements. We describe an investigation of a possible Mars analogue site
using a PIMA instrument. A survey was carried out on the Strelley Pool Chert,
an outcrop of stro- matolitic, silicified Archean carbonate and clastic
succession in the Pilbara Craton, interpreted as being modified by hydrothermal
processes. The results of this study demonstrate the ca- pability of SWIR
techniques to add significantly to the geological interpretation of such hy-
drothermally altered outcrops. Minerals identified include dolomite, white
micas such as il- lite-muscovite, and chlorite. In addition, the detection of
pyrophyllite in a bleached and altered unit directly beneath the succession
suggests acidic, sulfur-rich hydrothermal activity may have interacted with the
silicified sediments of the Strelley Pool Chert.
