Hyperspectral reflectance mapping of cinder cones at the summit of Mauna Kea and implications for equivalent observations on Mars

Atmospherically corrected, hyperspectral reflectance data (0.4 to 2.5 μm) derived from the Airborne Visible Infrared Imaging Spectrometer (AVIRIS), validated with field-based traverses and laboratory analyses, were used to map the distribution of ferric oxide, sulfate, and phyllosilicate minerals exposed on fresh and altered cones on the summit of Mauna Kea Volcano, Hawaii. Spectra from 0.4 to 1.1 μm exhibit charge-transfer and electronic transition features related to hematite, nanophase iron oxide, and possibly jarosite, whereas spectra from 2.0 to 2.5 μm are characterized by cation-OH features related to kaolinite, montmorillonite, and saponite. Unaltered cones exhibit concentric zoning of iron oxide signatures with crystalline hematite located near the summits and nanophase iron oxide signatures found at the base of cones and on flow surfaces. Altered cones (Puu Poliahu and Puu Waiau) have exposures of three phyllosilicate and possible jarosite units. In some cases there is zoning with a core of saponite surrounded by montmorillonite. Kaolinite is only found in two exposures on Puu Poliahu with one exposure coinciding with a possible jarosite unit. The relatively small spatial scale associated with alteration zones seen on Mauna Kea demonstrates the importance of obtaining high spatial resolution hyperspectral observations of Mars.