Magma-Sediment Interaction Induced Alteration Mineralogy on Mars: Detectability and Analytical Method Comparison Using the Curtis Sandstone as A Terrestrial Analog

Basaltic magmatism is a ubiquitous
feature of the Martian crust, and would have interacted
with sediments and fluids through the geologic history
of Mars to potentially produce higher temperature hydrothermal
systems , and contact metamorphic rocks. On Earth, comparable hydrothermal systems represent
habitable environments, which can be used as an
analog for Mars. Nevertheless, evidence of aforementioned
hydrothermal systems on Mars has remained
elusive, despite the efforts of both orbital and in-situ
analyses. Limited low grade metamorphic minerals typically
indicative of hydrothermal systems (prehnite, zeolites,
serpentine) have been detected in the Martian
crust, though the detections are typically isolated occurrences,
and do not necessarily indicate an in-place metamorphic
sequence.
It is possible that orbital spectroscopy alone is not
capable of detecting such an alteration front, with higher
resolution in-situ analyses being required to detect the
changes in mineralogy and species of alteration minerals
associated with magma-sediment interaction. To
constrain this, we have investigated a terrestrial analog
on the Colorado Plateau, USA, where a mafic dike intrudes
a quartz areinite of the Jurassic Curtis Sandstone.
The investigation was carried out using Mars relevant
instruments: Visible to Near-Infrared (VNIR) spectroscopy
analogous to orbital spectroscopy, and X-ray Diffraction
(XRD) analogous to CheMin on Mars Sample
Laboratory Curiosity. While quartz sandstones
have not been, and are unlikely to be, detected on Mars,
the relatively mineralogically uniform Curtis Sandstone
serves as analog here as it avoids complications of multiple
mineral systems or significant element exchange
with the surrounding area.