Ice, Ice, Maybe? Morphological Analysis of Multi-layer Crater Ejecta in East Tempe Terra, Mars, providing context for Spectral Investigation of Ice

Session: Geomorphology and Surface Processes Across the Solar System

Presenting Author:

Monica Rasmussen

Authors:

Rasmussen, Monica¹, Frigeri, Alessandro², Brossier, Jeremy³, Apuzzo, Andrea⁴, Furnari, Francesca⁵, Trisic Ponce, Janko⁶, Altieri, Francesca⁷, De Sanctis, Maria Cristina⁸

(1) Istituto di Astrofisica e Planetologia Spaziali, Italian National Institute for Astrophysics (INAF), Rome, Italy, (2) Istituto di Astrofisica e Planetologia Spaziali, Italian National Institute for Astrophysics (INAF), Rome, Italy, (3) Istituto di Astrofisica e Planetologia Spaziali, Italian National Institute for Astrophysics (INAF), Rome, Italy, (4) Istituto di Astrofisica e Planetologia Spaziali, Italian National Institute for Astrophysics (INAF), Rome, Italy; Serco, Rome, Italy, (5) Istituto di Astrofisica e Planetologia Spaziali, Italian National Institute for Astrophysics (INAF), Rome, Italy, (6) Istituto di Astrofisica e Planetologia Spaziali, Italian National Institute for Astrophysics (INAF), Rome, Italy, (7) Istituto di Astrofisica e Planetologia Spaziali, Italian National Institute for Astrophysics (INAF), Rome, Italy, (8) Istituto di Astrofisica e Planetologia Spaziali, Italian National Institute for Astrophysics (INAF), Rome, Italy,

Abstract:

Surface and near-surface water ice is a critical resource for future manned missions to Mars. Orbital data provide global coverage for regional-scale investigations of surface morphological and physical properties. High-resolution local-scale mapping is possible on approximately 2.6% of the planet, decreasing to 0.4% if we also consider the topographic expression. Current and future missions to Mars extend surficial exploration to depths with subsurface investigations by drilling or geophysical imaging.

Historically, Mariner and Viking missions have shown evidence for polar ice and peri-glacial morphologies. Currently, ice persists within the Martian ground, from the ice caps to at least the mid-latitudes. Multiple studies hypothesize that layered ejecta morphologies arise from impacts into subsurface volatile-rich reservoirs. Here, we study the distribution and properties of buried volatiles on Eastern Tempe Terra, Mars by studying ejecta morphology in a region where we also explore its geological context (Frigeri et al., this conference) and ice-related spectroscopy (Furnari et al., 2024).

We leverage a simplified Barlow et al. (2000) naming scheme to identify single- or multi-layer ejecta (SLE, MLE), or pedestal ejecta (Pd) morphologies on craters ≥1.0 km diameter within a 300x600 km study area (~300E, 45N), in Eastern Tempe Terra upslope of the highlands-lowlands dichotomy. We use Context Camera images and Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) data acquired aboard the Mars Reconnaissance Orbiter, and Thermal Emission Imaging System day/night data acquired aboard the 2001 Mars Odyssey orbiter. 

We classified 232 craters: 31% SLE, 7% MLE, 4% Pd, 49% no ejecta, and 9% inconclusive. Pd craters only exist in the northern half of the study area above ~45N, and are absent from the youngest unit. Combined, the 13% of MLE and Pd craters exist across the study area, consistent with the presence of subsurface volatiles like CO₂ or H₂O ice. 

In the area, CRISM spectral signatures are consistent with an overabundance of winter water ice over the MLE of one ~1.5 km diameter crater (Furnari et al., 2024). Our study applies an established ejecta morphology analysis within a geologic mapping side-project supplementing the stratigraphic context to our work. Additionally, the study offers the context for quantitative compositional analysis, reporting the actual presence of ice in the ejecta (Furnari et al., 2024).

Acknowledgements: This work is supported by the ASI-INAF Mars Exploration agreement 2023-3-HH 0.