Major and trace element and N concentrations and isotope compositions of altered basaltic and basaltic andesitic hyaloclastite whole rocks, mineral separates and thin sections from Antarctica, Iceland and Oregon, U.S.A.

The in-situ and whole rock and mineral separate major and trace element geochemistry and N concentrations and isotopic compositions of altered ancient Antarctic basaltic andesitic and modern subglacial and continental lacustrine basaltic hyaloclastites from Iceland and Oregon were studied. The potential combination of such chemistry with textures are considered that could constitute a compelling biosignature for study of samples from the Mars surface/near-surface. A case is made for altered glassy volcanics as suitable targets for Mars sample-return.