Quantifying Morphological Changes & Sediment Transport Pathways on
Comet 67P/Churyumov-Gerasimenko
Abstract
Comets are active geological worlds with primitive surfaces that have
been shaped to varying degrees by sublimation-driven sediment transport
processes. Rosetta’s rendezvous with comet 67P/Churyumov-Gerasimenko
(67P) in 2014 provided data with the necessary spatial and temporal
resolutions to observe how micro-gravity worlds evolve. Rosetta’s
observations have thus far revealed that the majority of changes to the
surface occurred within 67P’s smooth terrains, vast sedimentary deposits
that blanket a significant fraction of the nucleus. Understanding the
global context of these changes, and therefore the sediment transport
pathways that govern the evolution of 67P’s surface requires a thorough
description of their changing morphologies, and an evaluation of
existing global-scale spatial and temporal trends. Accordingly, we
present a time-resolved synthesis of erosion and deposition activity on
comet 67P as it passed through its August 13, 2015 perihelion from
September, 2014 to August, 2016. Our mapping results indicate that,
around perihelion, sediment is globally redistributed inter-regionally
from 67P’s more active south to the north. Equally important, however,
are local, topographically-influenced sediment transport processes, with
large volumes of sediment moving intra-regionally over sub-kilometer
scales. We also show evidence for regions of near-zero net
erosion/deposition between approximately 30–60° latitude, which may act
as terminal sedimentary sinks, with remobilization of these materials
hindered by multiple factors. This work provides a complete mapping of
the sediment transport processes and pathways across 67P observed by the
Rosetta misison, and represents a critical step toward understanding the
global landscape evolution of cometary surfaces.