T91 Shake and Bake: Volcanism and Tectonism across the Solar System

Monday, 23 September 2024
8:00 AM - 12:00 PM
213A

INSIGHTS INTO SURFACE EVOLUTION ON IO BASED ON JUNOCAM PJ57 AND PJ58 FLYBYS

Paper number: T91-12
Program: Technical Sessions
Time: 10:45 AM – 11:00 AM

Authors

Abstract

Io is the most volcanically active body in the Solar System, with frequent volcanic eruptions reshaping its surface with lava flows and sulfur-rich diffuse deposits. The abundant tectonic mountains distributed across the body are continually eroding via mechanisms like mass wasting and scarp retreat driven by sapping, which can drive shape changes of both mountains and paterae over geologic time. Because the resurfacing rate on Io is extremely high (proposed to be ~ 0.1-1 cm/year), the rate of feature formation and erosion may be rapid; changes have been detected in previous studies on the decadal timescale between Voyager and Galileo dataset acquisition. In December 2023 and February 2024, the Juno spacecraft did two close flybys of Io (PJ57 and PJ58), imaging the northern region of the moon in never-before-seen detail, twenty years after Galileo imaged Io’s surface. In this study, we examine the imagery collected by JunoCam with a focus on change detection of tectonic features like mountains and their constituent scarps.

While large-scale changes to feature shapes were dominantly not detectable at the given resolution, we present some putative surface modifications. Solar incidence angle strongly contributes to the ability to detect even large topographic features on Io, and JunoCam coverage (particularly near the terminator) provides clarifying context for several previously mapped mountains and paterae; we suggest updates to mapped shape boundaries and classifications of several previously observed features. Coverage of the north polar region of Io illuminates mountains morphologically consistent with their more equatorial counterparts. However, one unique slope is marked by large, kilometer-scale blocks scattered across the layered plains of the adjacent mountain complex. These blocks are isolated features distributed across two units of plains material, and appear related to the steep, lineated, slumping slope directly west of them. We examine the geomorphology of this unique blocky deposit, identify one other possible location it occurs, and explore potential formation mechanisms. The discovery of this surface expression, in context with the whole of the JunoCam coverage, can provide new insights into erosional processes and rates of surface change occurring on Io.

Geological Society of America Abstracts with Programs. Vol. 56, No. 5

doi: 10.1130/abs/2024AM-405067

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