Detection of Allophane on Mars Through Orbital and In-Situ Thermal-Infrared Spectroscopy

We have collected laboratory thermal IR spectra of the mineraloid allophane and aluminosilicate gels. Using those spectra to model regional TES spectra, we suggest that several areas of Mars contain significant amounts of allophane-like weathering products. The presence of allophane on Mars indicates that 1) significant Al sources, such as feldspar or glass, were weathered; 2) weathering on Mars produced poorly-crystalline aluminosilicates, rather than easily identifiable crystalline minerals; and 3) some Martian weathering proceeded under moderate pH environments, suggesting acid weathering is not the only major alteration mechanism on Mars