The Geology of Pluto and Charon Through the Eyes of New Horizons

TL;DR

NASA's New Horizons mission revealed complex and active geology on Pluto and Charon, including cryovolcanic features, glacial flows, and recent surface activity, providing insights into their geological history and processes.

Contribution

This study provides the first detailed geological analysis of Pluto and Charon based on New Horizons data, highlighting active processes and geological history.

Findings

Pluto's surface shows ongoing geological activity and recent crater retention age (~10 Ma).

Charon experienced major tectonism and resurfacing nearly 4 billion years ago.

Impact crater populations challenge existing Kuiper belt impactor models.

Abstract

NASA's New Horizons spacecraft has revealed the complex geology of Pluto and Charon. Pluto's encounter hemisphere shows ongoing surface geological activity centered on a vast basin containing a thick layer of volatile ices that appears to be involved in convection and advection, with a crater retention age no greater than $\approx$10 Ma. Surrounding terrains show active glacial flow, apparent transport and rotation of large buoyant water-ice crustal blocks, and pitting, likely by sublimation erosion and/or collapse. More enigmatic features include tall mounds with central depressions that are conceivably cryovolcanic, and ridges with complex bladed textures. Pluto also has ancient cratered terrains up to ~4 Ga old that are extensionally fractured and extensively mantled and perhaps eroded by glacial or other processes. Charon does not appear to be currently active, but experienced major extensional tectonism and resurfacing (probably cryovolcanic) nearly 4 billion years ago. Impact crater populations on Pluto and Charon are not consistent with the steepest proposed impactor size-frequency distributions proposed for the Kuiper belt.