The indication of Martian gully formation processes by slope–area analysis

Abstract

44The formation process of recent gullies on Mars is currently under debate. This study aims to 45 discriminate between the proposed formation processes: pure water flow, debris flow and dry 46 mass wasting, through the application of geomorphological indices commonly used in 47 terrestrial geomorphology. We used high resolution digital elevation models of Earth and 48Mars to evaluate the drainage characteristics of small slope sections. We have used the data 49 from Earth to validate the hillslope, debris flow and alluvial process domains previously 50 found for large fluvial catchments on Earth, and have applied these domains to gullied and 51 ungullied slopes on Mars. In accordance with other studies our results indicate that debris 52 flow is one of the main processes forming the martian gullies that we studied. The source of 53 the water is predominantly distributed surface melting, not an underground aquifer. We also 54 present evidence that other processes may have shaped martian crater slopes, such as ice 55 assisted creep and solifluction, in agreement with proposed recent martian glacial and 56 periglacial climate. Our results suggest that, within impact craters, different processes are 57 acting on differently oriented slopes, but further work is needed to investigate the potential 58 link between these observations and changes in martian climate. 59 60 61 4

Constraints on mechanisms for the growth of gully alcoves in Gasa crater, Mars, from two-dimensional stability assessments of rock slopes

“…Gasa crater is selected for this study because the alcoves within it are well exposed, have clear exposures of bedrock, and have been imaged in high-resolution stereo and in high spectral resolution data. This paper complements other recent work in Gasa crater (Lanza et al, 2010;Kolb et al, 2010a;Conway et al, 2010) that use distinct and independent techniques for utilizing high-resolution topography to investigate potential mechanisms for gully formation.…”

“…Recently, Conway et al (2010) analyzed HiRISE DEMs of gullies in Gasa, plus three other southern hemisphere craters. By comparison with terrestrial gullies and hollows, the drainage morphologies of the martian gullies are found to be most consistent with formation through debris flow activity.…”

Recent (Late Amazonian) enhanced backweathering rates on Mars: Paracratering evidence from gully alcoves

“…The sharp divides between the alcoves and the upper rims often expose fractured bedrock material, which appears to be highly brecciated and contains many boulders. The alcoves are connected to large gully fans, whose stratigraphy and morphometry suggest formation by aqueous flows [ Conway et al , ; Schon et al , ; Schon and Head , ; Johnsson et al , ; De Haas et al , , ]. The nonpole‐facing, eastern, southern, and western walls of these craters are characterized by poorly developed, narrower and shallower, alcoves.…”

Perspective – synthetic DEMs: A vital underpinning for the quantitative future of landform analysis?

“…2-D Gaussian, rotated parabola) are formulated based upon visual or statistical fitting of the functions to measured morphologies (e.g. Conway et al, 2011;Hillier and Smith, 2012;Pelletier, 2013) (Fig. 3); fits may not be perfect (Fig.…”