T131 Basaltic Volcanism on Earth and Beyond: Exploring the Physical Controls on Eruptive Styles and Associated Deposits (Posters)

Monday, 23 September 2019
9:00 AM - 6:30 PM
Hall AB, North Building

THE USE OF VISIBLE NEAR INFRARED SPECTROSCOPY TO QUANTIFY WATER-LAVA INTERACTIONS ON THE COLUMBIA RIVER FLOOD BASALTS; APPLICATION TO MARS

Paper number: T131-4
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

Glassy textures and fracture patterns in lava can indicate that water was present at the time of cooling therefore these features in volcanic rocks may be used to locate prime habitat for past microbial organisms on other planets, such as Mars. Different basalt structures have various cooling rates from the exterior to the interior. Quicker cooling rates occur towards the exterior margin where it will quench rapidly and restrict crystal growth and column size. While the interior margins cool at a slower rate resulting in larger crystals and larger columns. Glassier textures also appear in samples where magma has contacted water, such as pillow basalts. Rocks that are less glassy and more crystal-rich, emit higher levels of reflected light. We collected in-situ visible-near-infrared (VNIR) spectroscopy to measure reflected light on interior and exterior samples of columnar, entablature, and pillow basalts to estimate the crystal content. The average albedo over a wavelength of 500 nm to 2500 nm was calculated from VNIR triplicates. Using a Scanning Electron Microscope (SEM) along the sample quenched margins, we photographed the rock and collected element maps. Using photoshop to isolate the different minerals and the amount of glass in each SEM photograph and map, we quantified glass modal percentages along the sample quench margins and related them to the average albedo VNIR results. Our results indicate in-situ VNIR analysis of lava can identify where glassy textures exist and where cooling rates may have been accelerated by water interaction.

Geological Society of America Abstracts with Programs. Vol. 51, No. 5

doi: 10.1130/abs/2019AM-337763

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