Geomorphological analysis of the southwestern margin of Xanadu, Titan:
Insights on tectonics
Abstract
Evidence for tectonic activity on Titan is provided by the presence of
eroded mountain ranges. Xanadu is an equatorial region of Titan
characterized by a complex topography, even though overall it has a
lower average elevation compared to its surroundings. We investigated
Xanadu’s southwestern margin, a part of the region which is comprised of
heavily eroded and rugged terrains to the north and east and of
smoother, more uniform terrains to the west and south. The central
portions of southwestern Xanadu are characterized by an extensive
fluvial network. The presence of such a distinctive feature was the main
reason motivating the study of this area, given its potential to provide
tectonic indications. Through detailed geomorphological mapping (map
scale 1:700,000) on Synthetic Aperture Radar (SAR) data and analysis of
both fluvial drainage patterns and Digital Terrain Models (DTMs), we
identified several putative tectonic structures in this area: normal
faulting to the west and east, thrust faulting to the north, small-scale
strike-slip faulting in its central parts.Pull-apart basins are
depressions bounded by both dip-slip faults and by (overlapping and/or
bending) segments of a major transcurrent fault, i.e., they are basins
generated in transtensional tectonic settings. We propose that central
southwestern Xanadu is a pull-apart basin, bordered by both normal and
thrust faults and formed by transtensional tectonics, which we consider
to be the most recent tectonic phase active in this area. This basin is
characterized by small-scale strike-slip faulting within it, on which a
fluvial network has subsequently imposed.