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Icarus 421 (2024) 116215
Available online 11 July 2024
0019-1035/© 2024 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Detailed
chemical
composition
analysis
of the Soi crater
region
on Titan
A. Solomonidou
a,b,*
, M.J.
Malaska
c
, R.M.C.
Lopes
c
, A. Coustenis
b
, A.M.
Schoenfeld
c
,
B. Schmitt
d
, S.P.D.
Birch
e
, A. Le Gall
f,g
, K. Lawrence
c
, C. Matsoukas
h
, S.D. Wall
i
, C. Elachi
i
a
Hellenic
Space
Center,
Athens,
Greece
b
LESIA,
Paris
Observatory-PSL,
CNRS,
Sorbonne
Univ.,
Univ.
de Paris
Cit
́
e, Meudon,
France
c
Jet Propulsion
Laboratory,
California
Institute
of Technology,
Pasadena,
CA, USA
d
Univ.
Grenoble
Alpes,
IPAG,
F-38000
Grenoble,
France
e
Department
of Earth,
Environmental
and Planetary
Sciences,
Brown
University,
Providence
RI, USA
f
LATMOS/IPSL,
UVSQ
Universit
́
e Paris-Saclay,
Sorbonne
Universit
́
e, CNRS,
France
g
Institut
Universitaire
de France,
Paris,
France
h
KTH
Royal
Institute
of Technology,
Stockholm,
Sweden
i
California
Institute
of Technology,
Pasadena,
CA, USA
ARTICLE
INFO
Keywords:
Titan
Surface
composition
Radiative
transfer
Ocean
worlds
Icy satellites
ABSTRACT
The Soi crater
region
(0
to 60
N, 180
W to
110
W), which
includes
the well-preserved
Soi crater
in its center,
spans
a region
from
Titan
s aeolian-dominated
equatorial
regions
to fluvially-dominated
high
northern
latitudes.
This
provides
a rich diversity
of landscapes,
one that is also representative
of the diversity
encountered
across
Titan.
Schoenfeld
et al. (2023)
mapped
this region
at 1:800,000
scale
and produced
a geomorphological
map
showing
that
the area
consists
of 22 types
of geomorphological
units.
The Visual
and Infrared
Mapping
Spec-
trometer
(VIMS)
coverage
of the region
enabled
the detailed
analysis
of spectra
of 261 different
locations
using
a
radiative
transfer
technique
and a mixing
model,
yielding
compositional
constraints
on Titan
s optical
surface
layer.
Additional
constraints
on composition
on the near-surface
substrate
were
obtained
from
microwave
emissivity.
We have
derived
combinations
of top surface
materials
between
dark
materials,
tholins,
water-ice,
and methane
suggesting
that
dark
mobile
organic
material
at equatorial
and high
latitudes
indicates
young
terrains
and compositions,
while
tholin/water-ice
mixtures
that
dominate
areas
around
latitude
35
N show
a
material
that is older
plains
deposits
that we interpret
to be the end stage
of aeolian
and fluvial
transport
and
deposition.
We found
no spectral
evidence
of CO
2
, HC
3
N, and NH
3
ice. We use the stratigraphic
relations
between
the various
mapping
units
and the relation
between
the geomorphology
and the composition
of the surface
layers
to build
hypotheses
on the origin
and evolution
of the regional
geology.
We suggest
that sedimentary
deposits,
likely
aeolian,
are dominant
in the region
with
fluvial
activity
and leaching
changing
the nature
of the top
surfaces
of the midlatitude
areas
of the Soi crater
region.
1. Introduction
The surface
of Saturn
s moon
Titan
has been
revealed
by the Cassini-
Huygens
spacecraft
to be geologically
complex
with
both
exogenic
and
putative
endogenic
processes
modifying
its appearance.
Titan
s dense
atmosphere
and
active
methane
cycle
has enabled
aeolian,
fluvial,
pluvial,
and lacustrial
processes,
causing
erosion
and deposition.
Few
impact
craters
are seen,
attesting
that the surface
is geologically
young
(e.g.,
Wood
et al., 2010
; Hedgepeth
et al., 2020
). Tectonism
and possibly
cryovolcanism
have
also contributed
to surface
modification
(Jaumann
et al., 2009
; Mitri
et al., 2008,
2010
; Radebaugh
et al., 2007
; Lopes
et al.,
2013,
2019
; Wall
et al., 2009
; Nelson
et al., 2009
; Solomonidou
et al.,
2013,
2016
; Sohl
et al., 2014
; Wood
and Radebaugh,
2020
). The rich
variety
of geologic
features
on Titan
and
how
the processes
have
dominated
different
latitudes
have
been
discussed
in previous
works.
For example,
lakes
and seas
are present
at high
latitudes
(e.g.,
Stofan
et al., 2007
; Bratsolis
et al., 2012
; Birch
et al., 2016
), while
dunes
of
organic
materials
are concentrated
at low latitudes
(Lorenz
et al., 2006
;
Radebaugh
et al., 2008
; Lopes
et al., 2010
; Rodriguez
et al., 2014
).
Fluvial
channel
networks
are present
across
large
areas
of the surface
(Jaumann
et al., 2008
; Malaska
et al., 2011
; Langhans
et al., 2012
; Burr
et al., 2013
; Radebaugh
et al., 2016
; Miller
et al., 2021
), with
a rich
* Corresponding
author
at: 178 Kifissias
Avenue,
Athens
15231,
Greece.
E-mail
address:
anezina.solomonidou@hsc.gov.gr
(A. Solomonidou).
Contents
lists available
at ScienceDirect
Icarus
journal
homepage:
www.elsevi
er.com/loc
ate/icarus
https://doi.org/10.1016/j.icarus.2024.116215
Received
14 January
2023;
Received
in revised
form
8 July
2024;
Accepted
8 July
2024