GEOLOGIC MAPPING OF JUPITER'S MOON IO AND IMPLICATIONS FOR INTERIOR PROCESSES

Jupiter’s moon Io has been recognized as the most volcanically active object in the Solar System. Powered by intense tidal heating from Jupiter, Io has hundreds of active volcanoes that erupt vast lava flow fields, produce lava lakes in caldera-like depressions, or spew multi-hundred kilometer high plumes containing S₂ and SO₂ gas and silicate ash. Geologic mapping was applied to a series of 1 km/pixel global mosaics produced from the combined image data sets from NASA’s Voyager and Galileo missions, resulting in a 1:15,000,000 geologic map (download the map from: http://pubs.usgs.gov/sim/3168). Geologic mapping using ArcGIS™ software has enabled the whole surface area of Io to be categorized into 19 units of five classes: volcanic plains (65.8%), lava flow fields (28.5%), mountains (3.2%), patera (caldera) floors (2.5), and diffuse plume deposits mantling the other units (covering ~18% of surface). Application of statistical algorithms to the spatial distributions of Io volcanic centers derived from the map data has resulted in insights into Io’s interior processes. Specifically, distance based cluster analysis suggests Io is dominated by asthenospheric heating rather than deep mantle heating, within the limits of the available data (see Hamilton, C.W., C.D. Beggan, S. Still, M. Beuthe, R.M.C. Lopes, D.A. Williams, J. Radebaugh, and W. Wright, 2013, Earth & Planetary Science Letters, 361, 272-286). This presentation will detail the mapping and subsequent spatial analysis results for Io’s surface and interior.