Remnant glacial landforms on mars, including lobate debris aprons (LDA), lineated valley fill (LVF), and concentric crater fill (CCF) are widespread in mid-latitudes and together, constitute an…

This is a $412,450.67 grant awarded by the National Aeronautics and Space Administration (NASA) to Colgate University, a private liberal arts college in Hamilton, New York. The grant is for a research project investigating the origin, climatic significance, and in-situ resource utilization (ISRU) potential of ice-rich deposits in the Martian mid-latitudes, known as remnant glacial landforms. The project aims to use High-Resolution Imaging Science Experiment (HiRISE) imagery from the Mars Reconnaissance Orbiter (MRO) to measure boulder size distributions along lobate debris aprons in order to determine if the glacial emplacement on Mars was continuous, episodic, or sporadic during the Amazonian period. This research addresses a priority identified by the Mars Exploration Program Analysis Group (MEPAG) and is directly relevant to NASA's Mars Data Analysis Program (MDAP). The grant does not have a set-aside designation and is intended to run through August 31, 2022.

Remnant glacial landforms on mars, including lobate debris aprons (LDA), lineated valley fill (LVF), and concentric crater fill (CCF) are widespread in mid-latitudes and together, constitute an amazonian-aged, debris-covered water ICE reservoir equal to a global equivalent water layer ~2 m thick. On the basis of crater retention ages and buffered crater counting measurements, glacial landforms on mars were active in the amazonian (~100-1000 MA). However, on the basis of crater counting alone, IT is impossible to determine whether deposition of these major martian ICE deposits occurred episodically during a few, short instances during that time period, or whether glaciation was largely continuous throughout the period of glacier growth. This uncertainty directly limits our ability to use the geologic record to determine the intensity of ICE accumulation events on mars during the amazonian, and thus, determine when, where, and to what extent water has been actively circulating through the martian hydrosphere and cryosphere in the recent past. Accordingly, the objectives of this proposal are to (1) make novel measurements of boulder size distribution on the debris layer overlying LDA, (2) to use these measurements to assess whether glacial emplacement on mars was continuous, episodic, or sporadic during the last ~1 GY, (3) assess whether geographical differences in boulder transport, ICE accumulation, or glacial style are observed, and (4) determine if flow episodicity implied by boulder size distributions can be reproduced by flow modeling. Methodology. To address this goal, we propose to use hirise image data to measure the boulder size-frequency distribution along lobate debris apron flow paths in the northern and southern hemispheres of mars in order to determine whether boulders are finer down-flow (implying long-lived and continuous deposition), whether distinct populations of increasingly smaller boulders are present along the flow direction (implying long-lived and episodic flow), or whether boulder populations are uniform in size along the flow direction (implying short-lived flow). Flow paths will be determined through examination of CTX and themis-VIS data (to identify flowrelated lineations) and through calculation of maximum slope profiles from mola, as well as CTX and hirise stereo dems. Flow modeling will use existing LDA flow models, coupled to sharad observations of bed slope, and modified to include variable accumulation rate. Relevance. The proposed research will use MRO and MGS data to directly improve our understanding of the origin, climatic significance, and isru potential of ICE-rich deposits in the martian mid-latitudes. This work will transform our understanding of LDA from simply characterizing its surface attributes, to understanding its rate of emplacement and role in martian climate. This has been identified as a mepag research priority (goal 2, objective b, investigation 3). Thus, the proposed research is a scientific investigation based on analysis of PDS-archived data from two NASA missions explicitly listed in the mdap program description; therefore, the project is directly relevant to mdap.