41 Philosophy of Extreme Events and Landscape Evolution on Earth and Other Planets: Thinking Geologically in the Spirit of Victor Baker

This session highlights Victor Baker’s contributions to Earth-based and planetary research on catastrophic events in shaping landscapes and the role of outrageous hypotheses in scientific inquiry. Presentations explore these transformative influences on understanding surface processes.

Sunday, 19 October 2025
1:30 PM - 5:30 PM
HBGCC, 213AB

Arctic gullies as an analog to Martian Lowlands gully formation

Paper number: 41-6
Program: Technical Sessions
Time: 2:55 PM – 3:10 PM

Authors

Abstract

The processes which formed gullies on Mars in the past have been an ongoing scientific question. Martian gullies bear a strong resemblance to terrestrial features that form via the transport of liquid water, although a variety of other processes have been proposed (Conway et al., 2019). Earth’s Arctic is commonly used as an analog to understand landform development in Mars’ cold climate. We mapped and measured gullies in the Northern Lowlands of Mars and in Arctic environments on Earth (Svalbard, Iceland, Greenland, and Alaska) to better understand the formation environments of networked hillslope channel features.

We mapped the gullies’ tributary networks in detail using high-resolution WorldView-3 and HiRISE imagery to calculate the Shreve magnitude and Strahler order of the systems as well as the drainage density and channel sinuosity. 3-D morphometric indices such as slope, volume, and concavity were calculated using DTMs derived from stereo imagery. We find that Martian gullies have moderately high Shreve stream magnitudes, which implies formation by overland flow of water (Parker, 1977). Gullies on Mars and Earth have a smaller apron (deposited) volume than gully (eroded) volume, which is consistent with some volatile content in the gully substrate that is lost after deposition. Avalanche features like Alaskan icy debris fans (Kochel et al., 2018) have a larger deposited volume. Gullies on both planets have similar slopes in their alcoves and aprons below the angle of repose, while the icy debris fans form on much higher slopes. They also have similar ranges in their concavities, with concave longitudinal profiles implying downcutting and erosion of the hillslope.

This suite of morphometric indices quantitatively shows the degree to which material is transported by water in a system (Huang and Gulick, 2025; Gulick et al., 2019; Conway et al., 2015). Gullies with a more fluvial morphology deposit material on lower slopes, have higher concavities along their longitudinal profiles, and have higher stream magnitudes. Martian gullies also display these morphologic characteristics, so the processes that result in this morphology in Earth’s Arctic may have also formed some Martian gullies. This analysis also suggests that Martian gullies, like those on Earth, form along a continuum, with some gullies forming under more fluvial conditions where there is more potential for water to melt.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-413698

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