Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Geomorphologic Mapping of Titan's Polar Terrains: Constraining Surface
  Processes and Landscape Evolution   We present a geomorphologic map of Titan's polar terrains. The map was
generated from a combination of Cassini Synthetic Aperture Radar (SAR) and
Imaging Science Subsystem imaging products, as well as altimetry, SARTopo and
radargrammetry topographic datasets. In combining imagery with topographic
data, our geomorphologic map reveals a stratigraphic sequence from which we
infer process interactions between units. In mapping both polar regions with
the same geomorphologic units, we conclude that processes that formed the
terrains of the north polar region also acted to form the landscape we observe
at the south. Uniform, SAR-dark plains are interpreted as sedimentary deposits,
and are bounded by moderately dissected uplands. These plains contain the
highest density of filled and empty lake depressions, and canyons. These units
unconformably overlay a basement rock that outcrops as mountains and SAR-bright
dissected terrains at various elevations across both poles. All these units are
then superposed by surficial units that slope towards the seas, suggestive of
subsequent overland transport of sediment. From estimates of the depths of the
embedded empty depressions and canyons that drain into the seas, the SAR-dark
plains must be >600 m thick in places, though the thickness may vary across the
poles. At the lowest elevations of each polar region, there are large seas,
which are currently liquid methane/ethane filled at the north and empty at the
south. The large plains deposits and the surrounding hillslopes may represent
remnant landforms that are a result of previously vast polar oceans, where
larger liquid bodies may have allowed for a sustained accumulation of soluble
and insoluble sediments, potentially forming layered sedimentary deposits.
Coupled with vertical crustal movements, the resulting layers would be of
varying solubilities and erosional resistances.

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The categories of this paper are: acc-phys
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The categories of this paper are: chem-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: nlin
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The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: econ
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The categories of this paper are: patt-sol
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The categories of this paper are: q-bio
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The categories of this paper are: stat
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: q-fin
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The categories of this paper are: hep-th
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The categories of this paper are: atom-ph