The Contraction/Expansion History of Charon with implication for its Planetary Scale Tectonic Belt

TL;DR

This study uses a detailed thermo-physical evolution model to explain Charon's surface tectonic features as resulting from contraction and expansion episodes, without requiring a subsurface ocean or warm initial state.

Contribution

It introduces a new model of Charon's evolution that accounts for tectonic belt formation through internal contraction/expansion episodes, challenging previous ocean-based hypotheses.

Findings

Charon experienced two major contraction/expansion episodes.

The tectonic belt likely formed during these episodes, not from a subsurface ocean.

A planetary-scale impact may have shaped the observed features.

Abstract

The New Horizons mission to the Kuiper Belt has recently revealed intriguing features on the surface of Charon, including a network of chasmata, cutting across or around a series of high topography features, conjoining to form a belt. It is proposed that this tectonic belt is a consequence of contraction/expansion episodes in the moon's evolution associated particularly with compaction, differentiation and geochemical reactions of the interior. The proposed scenario involves no need for solidification of a vast subsurface ocean and/or a warm initial state. This scenario is based on a new, detailed thermo-physical evolution model of Charon that includes multiple processes. According to the model, Charon experiences two contraction/expansion episodes in its history that may provide the proper environment for the formation of the tectonic belt. This outcome remains qualitatively the same, for several different initial conditions and parameter variations. The precise orientation of Charon's tectonic belt, and the cryovolcanic features observed south of the tectonic belt may have involved a planetary-scale impact, that occurred only after the belt had already formed.