CRYSTAL TEXTURES IN GLASSY LAVA REFLECT ENVIRONMENTAL CONDITIONS OF WATER-LAVA INTERACTIONS AND CAN BE SENSED REMOTELY – FIELD TESTED IN THE WESTERN USA WITH IMPLICATIONS FOR VNIR ON MARS

Volcanic rock textures are sensitive to quench environment, which can include radiation only, air-cooled, or water and ice-quenched. Magma rising through or lava flowing over permafrost may also influence the texture of the final rock as increased cooling rates will limit crystal growth. Microlites typically fill the space between the phenocrysts if given enough time at high temperatures to grow, however, rapid cooling rates due to the presence of ice or water can prevent the growth of these crystals in the outer rim of volcanic products including lava flows. The identification of this crystal texture on Mars would allow for better estimates of the extent of water or ice on the surface or near-surface environment at the time of eruption. Remote sensing techniques that can scan broad regions of volcanic terrains on Mars would be the most effective method to detect water or ice quench environments. To address this issue, we are building a database of basaltic lava and spatter rims textures along with their spectral properties of several common spectrometers available (or soon-available) on Mars including XRF, VNIR, and LIBS. We have shown that microtextures in the rims of lava and spatter bombs with similar SiO₂ can be correlated to the albedo from VNIR spectral data. Glassier textures between similar compositions will have lower albedo while more crystalline rims have slightly higher albedo. We intend to broaden the application of this technique by expanding the database to include more eruptive centers and more chemical compositions, compare it to ASTER satellite data and develop a method for its use on Mars.