Abstract
Volcanism has played a major role in modifying the Martian surface. The
Tharsis Volcanic Province dominates the western hemisphere of the planet
with numerous effusive volcanic constructs and deposits. Here, we
present the results of an in-depth study aimed at characterizing and
modelling the emplacement conditions of 40 lava flows in the Tharsis
Volcanic Province. These lava flows display a range of lengths
(~15 – 314 km), widths (~0.5 – 29 m),
and thicknesses (~11 – 91 km). The volumes and flow
masses range from ~1 – 430 km3 and
~1011 – 1014 kg, respectively. Using three different
models, we calculated a range of eruption rates (0.2 – 3.5 x 104 m3/s),
viscosities (104 – 107 Pa s), yield strengths (800 – 104 Pa), and
emplacement times (14 hours – 22 years). While the flow lengths and
volumes are typically larger than terrestrial lava flows by an order of
magnitude, rheologies and eruption rates are similar based on our
findings. Emplacement times suggest that eruptions were active for long
periods of time, which implies the presence and persistence of open
subsurface pathways. Differences in flow morphology and emplacement
conditions across localities within Tharsis highlight different pathways
and volumes of available material between the central volcanoes and the
plains. The scale of the eruptions suggests there could have been
eruption-driven local, regional, and perhaps, global impacts on the
Martian climate. The relatively recent age of the eruptions implies that
Mars has retained the capability of producing significant localized
volcanism.