Boulder Fall Activity in the Jezero Crater, Mars

Abstract

 We report on previously unrecognized boulder fall activity in Jezero craterlanding site of Mars 2020 Perseverance rover  Hazardous boulders bigger (length >2.7 m) than the rover have recently fallen on the front of the western delta deposits within the crater  Recently fallen boulders may have freshly exposed surfaces, which can be ideal targets for astrobiological investigations by the rover

Active Boulder Falls in Terra Sirenum, Mars: Constraints on Timing and Causes

“…Similar to most other feature changes on Mars, environmental processes could be responsible. The main such processes that could contribute are solar insolation-induced thermal stress or seasonal frost, as suggested at other rockfall sites on Mars (Sinha et al, 2020;Tesson et al, 2020). But we would expect more widespread boulder transport in other craters at these latitudes, the geology (e.g., a susceptible lithology) is also important.…”

“…Boulder transport in our study regions is not confined to equator-facing slopes, as observed by Tesson et al (2020) at this latitude, and the location is outside the typical latitude range where frost has been observed (e.g., Schorghofer & Edgett, 2006), reducing the likely importance of thermal effects. Aeolian erosion could also lead to crater wall retreat and boulder fall (e.g., Grant et al, 2008;Sinha et al, 2020), although, again, geology would have to be invoked to explain the localized activity. The relative effectiveness of such a mechanism over a relatively short period of time is unknown (e.g., Williams et al, 2020), but backweathering rates are likely higher in young craters, but decreasing over time (de Haas et al, 2015).…”

“…To date, such significant boulder movement has not been studied in detail at lower latitudes on Mars.On Earth, boulder size and fall frequency have been used as proxies for earthquake location (e.g., Keefer, 1984). On Mars, this correlation has been applied to studies of boulder populations in the graben of Cerberus Fossae (Brown & Roberts, 2019;Roberts et al, 2012), in addition to proposed evidence of recent, localized seismic activity in Valles Marineris, and Jezero Crater (Senthil Kumar et al, 2019;Sinha et al, 2020). However, these studies were restricted to images representing a single time period, and thus no active boulder transport was identified.…”

Jezero crater, Mars: application of the deep learning NOAH-H terrain classification system

“…Stack et al (2020) large aeolian bedforms are ∼10s to several 100s of metres long and <1 to ∼10 m across and small aeolian bedforms are a few 10s of metres long and ∼3 m across. Talus and boulder fields are not equivalent, but talus deposits in Jezero crater have been shown to host boulders (Sinha et al, 2020), so in our comparison large boulder fields on slopes are probably good proxies for talus.…”

Boulder Fall Ejecta: Present Day Activity on Mars

“…Subsequently, several studies have used repeat temporal imaging using HiRISE to identify and study recent boulder falls (Dundas & Daubar, 2020; Dundas et al., 2019; Grindrod et al., 2021). The boulder fall tracks are predominantly present on crater walls and floors, but can originate from any steeply sloping surface (Bickel et al., 2020; Kumar et al., 2019; Sinha et al., 2020; Van der Bogert & Plescia, 2014). Earlier studies have hypothesized that the main drivers for such falls are shallow marsquakes, wind/aeolian activity, impact‐induced falls, and solar insolation (Brown & Roberts, 2019; Burleigh et al., 2012; Kumar et al., 2019; Roberts et al., 2012; Tesson et al., 2020).…”