The rock abrasion record at Gale Crater: Mars Science Laboratory results from Bradbury Landing to Rocknest

Abstract

Ventifacts, rocks abraded by wind-borne particles, are found in Gale Crater, Mars. In the eastward drive from "Bradbury Landing" to "Rocknest," they account for about half of the float and outcrop seen by Curiosity's cameras. Many are faceted and exhibit abrasion textures found at a range of scales, from submillimeter lineations to centimeter-scale facets, scallops, flutes, and grooves. The drive path geometry in the first 100 sols of the mission emphasized the identification of abrasion facets and textures formed by westerly flow. This upwind direction is inconsistent with predictions based on models and the orientation of regional dunes, suggesting that these ventifact features formed from very rare high-speed winds. The absence of active sand and evidence for deflation in the area indicates that most of the ventifacts are fossil features experiencing little abrasion today.

A terrestrial weathering and wind abrasion analog for mound and moat morphology of Gale crater, Mars

“…In support of an eolian-dominated landscape, observations of ventifacts, yardangs, dunes, and wind streaks in Gale crater [e.g., Bridges et al, 2014; are indeed reliable indicators of wind direction that agree with model results. In support of an eolian-dominated landscape, observations of ventifacts, yardangs, dunes, and wind streaks in Gale crater [e.g., Bridges et al, 2014; are indeed reliable indicators of wind direction that agree with model results.…”

“…Turbulent vortices trap and transport sand, abrading the central deposit and causing it to become a reduced mound that retreats to the center until all material is eroded away. The physical proxy evidence for wind erosion and abrasion at Gale crater consists of yardangs, ventifacts, dune sand, wind streaks, and streamlined bedrock nodules with elongate tails in the lee side of the nodules [Bridges et al, 2014;Stack et al, 2014]. A local area of deformed sandstone could have caused anisotropies that facilitated erosion around a pillar form toward the center of the pit.…”

Wind in Jezero Crater, Mars

“…Observations from the Mars 2020 rover will allow for more detailed analysis of local winds with the Mars Environmental Dynamics Analyzer instrument (Pérez-Izquierdo et al, 2018;Rodriguez-Manfredi et al, 2014) and with imaging of ventifacts (Bridges et al, 2014;Laity & Bridges, 2009), sand shadows, and abrasion textures, as has been conducted for Gale crater with data from the Mars Science Laboratory rover, Curiosity (e.g., Blake et al, 2013;Stack et al, 2014). In this work, we focus only on currently available observations from orbit.…”

Gale crater and impact processes – Curiosity’s first 364 Sols on Mars

“…However, the alteration minerals identified in the Sheepbed drill samples form at low-temperature (e.g. McLennan et al, 2014;Bridges et al, 2014), and the lack of chemical fractionations of elements expected for alteration has led to a model for the in situ (diagenetic) alteration of the Sheepbed mudstones (McLennan et al, 2014). The lacustrine deposits of the Sheepbed mudstone and Gillespie sandstone that are part of the bright fractured materials found in Yellowknife Bay in the Glenelg area (e.g.…”

“…8 and 9). The removal by abrasion of the blocks found on crater rims is governed by the aeolian processes discussed at length by Bridges et al (2014), which leads initially to the formation of ventifacts. Therefore, on the HP unit, the resurfacing rate consists of multiple processes, including enhanced aeolian erosion of crater rim material and projecting blocks, erosion on the floors of valleys that concentrate mobile sand deposits, and aeolian deposition in craters and swales.…”