T54 Planetary Aeolian Geology from Outcrop to Orbit: Nathan Bridges Memorial Session

Sunday, 4 November 2018
1:30 PM - 5:30 PM
Room 136-137

SEASONAL SAND FLUX VARIATIONS ON MARS: NEW MEASUREMENTS AND MODELING AT MEROE PATERA AND GALE CRATER AEOLIAN FIELDS

Paper number: T54-13
Program: Technical Sessions
Time: 4:45 PM – 5:00 PM

Authors

Abstract

Repeated high-resolution orbital imagery has shown seasonally-dependant aeolian activity on Mars for at least one location, Nili Patera (Ayoub et al., 2014; Roback et al., 2018). The seasonal dependance constrains the environmental boundary conditions responsible for initiating and mainting sand movement and quantifies the rate of aeolian landscape change, with implications for aeolian erosion history. Here, we report on new seasonal sand flux measurements for Meroe Patera and Gale Crater together with flux predictions derived from the Mars Weather Research and Forecasting (MarsWRF) atmospheric model.

Our sand flux measurements are partitioned into two measurement types: ripple-derived flux and whole-dune-derived flux. For the former, the automated algorithm COSI-Corr produces ripple displacement maps which we further optimize using principal component analysis (PCA). For the latter measurement, we manually compare the dune slip face positions in the first and last images in a series to derive a whole-dune flux averaged over the time period. These two measurement types further constrain the ratio of ripple to total sand flux and can inform the mechanisms of bedform evolution.

Similar to Nili Patera (Ayoub et al., 2014), ripple flux measurements at Meroe Patera show a seasonal variation in ripple sand flux from ~0.5-4 m3/m/Earth-year (average of 1.57) with lowest fluxes near Mars’ aphelion orbital position (i.e., furthest from the Sun) and maximum fluxes near perihelion (closest solar distance). For Meroe Patera dunes, the time-averaged, whole dune-derived fluxes average 11.3 ± 5.7 m3/m/Earth-year with the lowest fluxes furthest downwind, consistent with previous measurements (Runyon et al., 2017a). The resulting ratio of total-to-ripple flux of ~7 is comparable to the value of ~5 measured at Nili Patera (Bridges et al., 2012).

We will also present initial results from the MarsWRF modeled winds with the predicted sand fluxes.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-321193

© Copyright 2018 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.