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Rover missions to the rocky bodies of the Solar System and especially to Mars require lightweight, 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 stromatolitic, silicified Archean carbonate and clastic succession in the Pilbara Craton, interpreted as being modified by hydrothermal processes. The results of this study demonstrate the capability of SWIR techniques to add significantly to the geological interpretation of such hydrothermally altered outcrops. Minerals identified include dolomite, white micas such as illite-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.

An airborne hyperspectral remote sensing dataset was obtained of the North Pole Dome region of the Pilbara Craton in October 2002. It has been analyzed for indications of hydrothermal minerals. Here we report on the identification and mapping of hydrothermal minerals in the 3.459 Ga Panorama Formation and surrounding strata. The spatial distribution of a pattern of subvertical pyrophyllite rich veins connected to a pyrophyllite rich palaeohorizontal layer is interpreted to represent the base of an acid-sulfate epithermal system that is unconformably overlain by the stromatolitic 3.42 Ga Strelley Pool Chert., 29 pages, 9 figures, 2 tables

A visible and near infrared (VNIR) to shortwave infrared (SWIR) hyperspectral dataset of the Early Archaean North Pole Dome, Pilbara Craton, Western Australia, has been analysed for indications of hydrothermal alteration. Occurrence maps of hydrothermal alteration minerals were produced. It was found that using a spatial resolution on the ground of approximately 5 m and spectral coverage from 0.4 to 2.5 mm was sufficient to delineate several hydrothermal alteration zones and associated veins, including phyllic, serpentinitic and chloritic alteration. These results suggest this level of spectral and spatial resolution would be ideal for localising shallow epithermal activity, should such activity have existed, on the surface of Mars.

The European hyperspectral imaging instrument OMEGA has been in operation around Mars since early 2004. OMEGA has constructed imaging maps covering almost the entire Martian surface (Bibring et al., 2005). The OMEGA science team have identified a 60 x 200km deposit rich in Ca-sulfates, most likely gypsum, near the Martian northern polar cap (Langevin et al., 2005). They have suggested an evaporation origin linked to varying Martian obliquity, warming the poles during periods of high obliquity, causing the melting of water ice, and then evaporation of this ephemeral water, leaving behind salty brines adjacent to the frozen ice cap. In 2004, a hyperspectral imaging survey of the Yilgarn Craton was carried out using the HyMap instrument (Cocks et al., 1998). The Yilgarn is a good Mars analog due to the presence of ultramafic-mafic volcanic basalt flows. We have therefore analysed this hyperspectral coverage of the evaporite deposits of the Yilgarn Craton to compare an accessible, Earth-based evaporate analog with the Mars sulfate deposits. Using standard hyperspectral analysis methods, we have mapped gypsum in Western Australian dry lake evaporite deposits near Kalgoorlie. In the future, we shall use an absorption band modelling method (Brown et. al., 2005) to determine the shape, position and intensity of absorption bands that are due to sulfates. Fieldwork in this area has enabled a laboratory based evaluation of hand samples of gypsum taken from the Western Australian deposits. Evaluation of this data and comparison to future Martian hyperspectral data will lead to a greater understanding of the hydration state and cation type of Martian sulfate deposits.

The final deformation in a polydeformed unit of Ordovician turbidites along the NSW south coast, produced kinks at scales from centimetres (mesoscopic kinks) to kilometres (megakinks). At the outcrop‐scale, crenulation cleavages and fractures also developed. The mesoscopic kinks are of the reverse type, have orthorhombic to monoclinic symmetry and generally show a small dilation of the kink short‐limb. An S3 crenulation cleavage is associated with the kinks and shows variable morphology and orientation. The kinks are interpreted to have formed by a modified “kink rotation model’, in which kink‐band foliation shortens during kink formation. The mesoscopic kink geometry does not uphold both the kink proportion compressional analysis and the conjugate kink bisector method for determining the axis of principal compression. Nevertheless, both methods suggest that the mesoscopic kinks predate the megakink rotation.