Pressurized groundwater systems in Lunae and Ophir Plana (Mars): Insights from small-scale morphology and experiments

Abstract

a b s t r a c tOutflow channels on Mars reveal the past presence of water, possibly released from pressurized groundwater reservoirs. We aim to improve our understanding of such outflow systems in order to better constrain past hydrological conditions on Mars. We investigate the morphology of possible pressurized groundwater outflow systems on Mars and compare them to landscape evolution experiments. These experiments show that incised channels, like the classic outflow channels, form in a last, erosional, stage in morphological development. This is preceded by the formation of sedimentary lobes due to rapid water loss by infiltration. On Mars, we observe similar morphologies related to different stages of groundwater outflow in Lunae and Ophir Plana. In the experiments, pits formed by the pressure of the groundwater, whereas the pits in the source regions of the outflow channels relate to the regional tectonic structure and are not formed by groundwater alone. Faulting, subsidence and collapse likely triggered outflow from a pressurized aquifer. This scenario is consistent with the presence of one or several cryosphere-confined aquifers from the Early Hesperian to at least the middle Amazonian. A pronounced spatial trend of larger and further developed outflow systems at lower elevations suggests that features ranging from small lobes to large outflow channels were sourced from a common aquifer or from aquifers with similar pressures. The required cryosphere indicates a cold climate and enables groundwater outflow even under atmospheric conditions unfavorable for sustained presence of liquid water.

Geological Evidence of Planet‐Wide Groundwater System on Mars

“…The outflow channels also form part of this emerging picture of a planet-wide groundwater table linked to the ocean. The outflow channels might have been fed by this groundwater system as suggested by previous authors for specific areas (Marra et al, 2015;J. A. P. Rodriguez, Kargel, et al, 2015).…”

Megaflood Erosion on Mars—How Lava‐Filled Craters Became Mesas (With Insights From Lava Physics, Stream Power, and Rock Mechanics)

“…(2009), and Marra et al. (2015). They examined the evidence for outflows from the Ophir Catenae structural system and discussed possible groundwater sources for these flows.…”

“…Additional research on the channels of this region was performed by Komatsu et al (2009), Lucas et al (2009), and Marra et al (2015). They examined the evidence for outflows from the Ophir Catenae structural system and discussed possible groundwater sources for these flows.…”

Pit Crater Chains Across the Solar System: Evidence for Subterranean Tectonic Caves, Porosity and Permeability Pathways on Planetary Bodies

“…For example, circumferential and radial pit crater chains surrounding Elysium Mons transition to outflow channels further downslope. Similarly, outflow channels have been mapped directly emanating from pit crater chains, such as the Ganges and Ophir Catena, which are interpreted to have been structurally controlling the groundwater in the region (Coleman et al., 2007; Marra et al., 2015).…”