ALTERNATIVE APPROACHES TO THE STUDY OF MUD VOLCANISM ON MARS (Invited Presentation)

Mud volcanism is a geologic phenomenon known to operate on Earth and suggested to explain the formation of positive-relief landforms (e.g. pitted cones and domes) on Mars. Morphometry, morphology, and geologic setting information about purported mud volcanism features on Mars have been provided by orbital remote sensing datasets. However, knowledge gaps pertaining to the compositional characteristics and formation timescales of putative Martian mud volcanoes remain which we address by: (1) conducting a global examination of suggested mud volcanism features using Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) visible and near-infrared (VNIR) spectroscopy data and (2) investigating the emplacement of proposed mud volcanoes using an analytical model that has been previously applied to domical volcanic structures on Venus, Ceres, and Jupiter’s moon Europa. Pitted cones may have initially had dome-like shapes thus, this model can be applied to these features on Mars.

CRISM VNIR analysis reveals that proposed mud volcanism landforms exhibit variable degrees of hydration, alluding to differences in water content associated with this process across Mars. Two separate features in the Mars canyon system Valles Marineris exhibit VNIR signatures consistent with unaltered hydrated glass and high-Ca pyroxene of potential volcanic origin. Limitations in the detection of minerals known to comprise mud volcanism units on Earth (e.g. phyllosilicates) are likely due to the grain size and/or textural characteristics of Mars mud volcanism materials.

When compared to eruption durations of terrestrial mud flows, lava domes, and pahoehoe toes, preliminary modeling suggests that pitted cones in Acidalia Planitia, Mars may be emplaced on the order of days to months, with maximum eruption durations closer to 1-2 months being most likely. In addition to this northern lowlands site we will discuss modeling results from other regions, such as the southern highlands, thereby revealing new details about the formation of mud volcanoes across Mars.

The methods we apply to the study of mud volcanism on Mars provide insight into landform evolution on a terrestrial planet other than Earth, and demonstrate the value of adopting alternative approaches to the study of this geologic process for comparative planetology purposes.