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Groundwater flow on Mars likely contributed to the formation of several
types of morphologic and mineralogic features, including chaotic
terrains, valley networks, Meridiani Planum geologic units and,
potentially, sulfate and phyllosilicate deposits. A central issue for
these features is the spatial scale of groundwater flow required for
their form...
Contexts in source publication
Context 1
... Conceptually, our model follows the sequence of events depicted in Figure 1. A global aquifer with an initially uniform water table is recharged by meltwater produced at the base of a hypothetical ice sheet. ...
Context 2
... in this initial level are expected to have only a small influence on the timing and location of breakouts: timing is controlled by the lateral propagation of elevated pore pressures, and location is determined largely by the relationship between topography and recharge elevation. As depicted in Figure 1, recharge raises the local water table to the top of the aquifer and proceeds to spread high pore pressures radially outward. If continued increases in pore pressure result in superlithostatic values (and therefore a breakout) at a given location, the head boundary condition at the superlithostatic model cell is moved to the topographic surface, allowing discharge to occur through the upper cell surface, which in turn brings pore pressures down. ...
Citations
... These extremely cold conditions are believed to have characterized most of Mars' post-Noachian geologic history 2 . However, widespread outflow channels that originate in collapsed highland zones (chaotic terrains) suggest that, while infrequent, catastrophic floods of erupted groundwater led to large-scale landscape modifications 2,[8][9][10][11][12][13][14][15] . ...
... Furthermore, this scenario proposes that the hydrosphere was confined beneath an ice-rich cryosphere, and that outbursts instigated by regions of gradient-induced overpressures produced the chaotic terrains. However, this theoretical framework fails to satisfactorily rationalize the distinct spatial clustering of outflow channels and chaotic terrains observed in the circum-Chryse region, and their notable absence in other boundary plains regions 14 . ...
... A reconciliatory view is the sourcing of circum-Chryse outflow channels from compartmentalized, elevated aquifers 5,14 . However, the implied magnitude of compartmentalization would have been hard to achieve within a globally extensive megaregolith due to its high permeability 2,9 . ...
The quest for past Martian life hinges on locating surface formations linked to ancient habitability. While Mars' surface is considered to have become cryogenic ~3.7 Ga, stable subsurface aquifers persisted long after this transition. Their extensive collapse triggered megafloods ~3.4 Ga, and the resulting outflow channel excavation generated voluminous sediment eroded from the highlands. These materials are considered to have extensively covered the northern lowlands. Here, we show evidence that a lacustrine sedimentary residue within Hydraotes Chaos formed due to regional aquifer upwelling and ponding into an interior basin. Unlike the northern lowland counterparts, its sedimentary makeup likely consists of aquifer-expelled materials, offering a potential window into the nature of Mars' subsurface habitability. Furthermore, the lake’s residue’s estimated age is ~1.1 Ga (~2.3 Ga post-peak aquifer drainage during the Late Hesperian), enhancing the prospects for organic matter preservation. This deposit’s inferred fine-grained composition, coupled with the presence of coexisting mud volcanoes and diapirs, suggest that its source aquifer existed within abundant subsurface mudstones, water ice, and evaporites, forming part of the region’s extremely ancient (~ 4 Ga) highland stratigraphy. Our numerical models suggest that magmatically induced phase segregation within these materials generated enormous water-filled chambers. The meltwater, originating from varying thermally affected mudstone depths, could have potentially harbored diverse biosignatures, which could have become concentrated within the lake’s sedimentary residue. Thus, we propose that Hydraotes Chaos merits priority consideration in future missions aiming to detect Martian biosignatures.
... Direct estimates of recharge from previous modeling studies vary between 10 −2 to 10 3 mm/yr, but require the specification of unknown aquifer properties (Harrison and Grimm, 2009;Andrews-Hanna et al., 2007Luo et al., 2011;Horvath and Andrews-Hanna, 2017). Here, we examine the importance of these properties individually, the effects of possible standing bodies of water, and consequences associated with varying recharge distributions on the aquifer using novel analytic and numerical groundwater models. ...
... In some areas, hydrated minerals were found in the overlying light-toned layered deposits (Baioni & Tramontana, 2015;Glotch & Christensen, 2005;Lichtenberg et al., 2010;Massé et al., 2008;Sefton-Nash et al., 2012). Several formation mechanisms were proposed in literature to explain the collapse that generated the disruption of the bedrock in flat-topped blocks: they include groundwater overpressure within a confined aquifer (Andrews-Hanna & Phillips, 2007;Carr, 1979;Harrison & Grimm, 2009;Rodriguez et al., 2005;Warner et al., 2011), melting of a buried icy lake (Manker & Johnson, 1982;Roda et al., 2014;Zegers et al., 2010), interactions between magma and ice or water (Chapman & Tanaka, 2002;Head & Wilson, 2007;Leask et al., 2006;Meresse et al., 2008;Wilson & Head, 2002), intrusion of magmatic bodies and consequent inflation (Korteniemi et al., 2006), and instability of a large amount of underground clathrates (Hoffman, 2000;Kargel et al., 2007). ...
Chaotic terrains are broad regions on Mars characterized by the disruption of the basaltic bedrock into polygonal blocks separated by deep fractures. To date, the proposed genetic scenarios often involve the occurrence of subsurface ice or liquid H2O. Nevertheless, similar features also occur within some craters on the Moon, namely floor-fractured craters (FFCs), where water ice reservoirs are not present. We propose a new formation mechanism for Martian chaotic terrains as well as for lunar and Martian FFCs. The proposed mechanism does not require a major role of water but multiple cycles of inflation and deflation of a buried magma chamber. This process results in a particular type of caldera collapse, called the piecemeal (or chaotic) caldera collapse. A series of analogue experiments show both geometrical and quantitative correspondence with natural case studies: Arsinoes Chaos (Mars), an unnamed FFC (Mars), Komarov crater (FFC on the Moon).
... In Juventae Chasma, the theater-headed valleys are oriented in the direction of orthogonal sets of lineaments within the chasm, while in Ganges Chasma the theater-headed valleys follow the trend of extensional structural features present in the surrounding plateau (Fig. 5).Groundwater available through 'Tharsis recharge'(Andrews-Hanna et al., 2007; Andrews- Hanna and Phillips, 2005; Grimm, 2005, 2004) would have served as a source of the groundwater in the Valles Marineris region. The melting of the ice deposited on the Tharsis region during a high obliquity period would allow the recharge of groundwater(Andrews-Hana et al., 2007;Harrison and Grimm, 2009, 2005, 2004Russell and Head, 2007).This groundwater could have percolated through the Valles Marineris region via zones of fractures and faults. Additionally, precipitation on the Valles Marineris plateau during the episodically warmer paleoclimate(Kite et al., 2011a, 2011b, Mangold et al., 2008, 2004 would also contribute to the groundwater in the Valles Marineris region.The proximity of the groundwater source and the availability of local recharge might have played important roles in the final morphology attained by theater-headed valleys(Marra et al., 2015a). ...
This paper reports high-resolution observations of theater-headed valleys in the Valles Marineris region and proposes an integrated model of their formation and localization across the walls of the canyons of Valles Marineris. These theater-headed valleys have been formed over a long period of time from Middle-Hesperian to Early-Amazonian. The valleys show several common features, namely, proximity to areas of high ejecta mobility on the Tharsis plateau; alignment along the major tectonic features such as wrinkle ridges, grabens, pit crater chains; association with fluvial channels and layered deposits on the plateau adjacent to the valley heads; and occurrences of mass wasting features at the valley mouths. Elevation profiles of the walls of Valles Marineris display ramp and cliff topography indicating mechanical stratification in the wall rocks. These observations reveal multiple controls over the formation and localization of theater-headed valleys in Valles Marineris. However, the major controls appear to be strong-over-weak stratigraphy in the canyon walls and the pre-existing zones of structural weakness in the Valles Marineris region. The source of water could likely be groundwater; however, snowmelt accumulated on the upper parts of the wallrock would additionally facilitate the process. Based on the above observations, we propose a sequence of events for the evolution of theater-headed valleys in the Valles Marineris region.
... Analysis of single-layered ejecta craters suggests that the ice-cemented cryosphere was ∼1.3 km thick at the equator during the Hesperian-Amazonian implying that a cryosphere once existed (Weiss & Head, 2017). Ground ice is presently found, and is stable (or more stable), at higher latitudes (e.g., Dundas et al., 2021;Morgan et al., 2021), but water in underlying aquifers confined at high latitudes could be lost through the breach in confinement at low latitudes (Grimm et al., 2017) unless aquifers are laterally compartmentalized (Harrison & Grimm, 2009 ...
The seismometer deployed by the InSight lander measured the seismic velocity of the Martian crust. We use a rock physics model to interpret those velocities and constrain hydrogeological properties. The seismic velocity of the upper ∼10 km is too low to be ice-saturated. Hence there is no cryosphere that confines deeper aquifers and possibly no aquifers locally. An increase in seismic velocity at depths of ∼10 km could be explained by a few volume percent of mineral cement (1%–5%) in pore space and may document the past depth of aquifers.
... Analysis of single-layered ejecta craters suggests that the ice-cemented cryosphere was ∼1.3 km thick at the equator during the Hesperian-Amazonian implying that a cryosphere once existed (Weiss & Head, 2017). Ground ice is presently found, and is stable (or more stable), at higher latitudes (e.g., Dundas et al., 2021;Morgan et al., 2021), but water in underlying aquifers confined at high latitudes could be lost through the breach in confinement at low latitudes (Grimm et al., 2017) unless aquifers are laterally compartmentalized (Harrison & Grimm, 2009 ...
... Several mechanisms of formation were proposed in literature to 51 explain the nature of the putative collapse responsible for the disruption of the bedrock into 52 polygonal blocks that characterizes the chaotic terrains. The proposed scenarios include: i) a 53 major role played by groundwater and cryosphere, particularly linked to changes of pressure 54 within the aquifer that caused the disruption of the bedrock and subsequent water outflow 55 (Andrews-Hanna & Phillips, 2007;Carr, 1979;Harrison & Grimm, 2009;Rodriguez et al., 56 2005), ii) the occurrence of a buried ice lake that after melting would have caused fracturing 57 and catastrophic outflow (Manker & Johnson, 1982;Roda et al., 2014;Zegers et al., 2010), iii) 58 catastrophic destabilization of buried clathrates (Hoffman, 2000;Kargel et al., 2007), and iv) 59 magma-cryosphere/groundwater interactions (Chapman & Tanaka, 2002;Head & Wilson, 60 2007; Leask et al., 2006;Meresse et al., 2008;Wilson & Head III, 2002). Given the complexity 61 of the current geologic setting of Arsinoes and Pyrrhae Chaos, possibly augmented by several 62 million years of erosion and mantling, a possible interaction between the proposed processes 63 (or singular contributions at different times) must also be considered. ...
**Submitted for publication in Journal of Geophysical Research: Planets **
Arsinoes and Pyrrhae Chaos are two adjacent chaotic terrains located east to Valles Marineris and west to Arabia Terra, on Mars. In this work we produced a morpho-stratigraphic map of the area, characterized by a volcanic bedrock disrupted into polygonal mesas and knobs (Chaotic Terrain Unit) and two non-disrupted units interpreted as sedimentary and presenting a spectral variation, likely associated to hydrated minerals. The reconstructed geological history of the area starts with the collapse that caused the formation of the chaotic terrains. Since volcano-tectonic evidences are widespread all-over the area (e.g. fissure vents/graben, radial and concentric systems of faults, y-shaped conjunctions, lava flows, pit chains), and an intricate system of lava conduits is hypothesized for the occurrence of such features, we propose the possibility that the whole collapse was caused primarily by volcano-tectonic processes. On Earth, polygonal blocks and systems of concentric + radial fissures are originated in the frame of a particular caldera collapse called chaotic or piecemeal. In the study area on Mars, the chaotic collapse would have been triggered by repeated inflation and deflation of a putative magma chamber in depth under the terrain. In a late stage, after the end of the volcano-tectonic activity, a lacustrine/evaporitic depositional environment could have set, with the deposition of the non-disrupted units. The hydrated minerals found in the periphery of the Chaos could be the result of hydrothermal alteration of the basaltic bedrock.
... The mean value of permeability is currently unknown, and estimated to lie in the range (10 −11 -10 −15 ) m 2 (by Hanna and Phillips, 2005) for Mars' upper crust. For Mars' upper crust, permeability likely varies by orders of magnitude regionally (Harrison and Grimm, 2009), and likely also varied with time on Hesperian Mars due to the competition between fracture-sealing processes (such as carbonate mineral precipitation within fractures), and fracture creation (by tectonics, impacts, and cracking to accommodate magmatic intrusions) (Sleep and Zoback, 2007). In effect we assume permeability is high enough that permeability is not limiting for deep, global groundwater circulation. ...
Ancient hydrology is recorded by sedimentary rocks on Mars. The most voluminous sedimentary rocks that formed during Mars' Hesperian period are sulfate-rich rocks, explored by the Opportunity rover from 2004–2012 and soon to be investigated by the Curiosity rover at Gale crater. A leading hypothesis for the origin of these sulfates is that the cations were derived from evaporation of deep-sourced groundwater, as part of a global circulation of groundwater. Global groundwater circulation would imply sustained warm Earthlike conditions on Early Mars. Global circulation of groundwater including infiltration of water initially in equilibrium with Mars' CO2 atmosphere implies subsurface formation of carbonate. We find that the CO2 sequestration implied by the global groundwater hypothesis for the origin of sulfate-rich rocks on Mars is 30–5000 bars if the Opportunity data are representative of Hesperian sulfate-rich rocks, which is so large that (even accounting for volcanic outgassing) it would bury the atmosphere. This disfavors the hypothesis that the cations for Mars' Hesperian sulfates were derived from upwelling of deep-sourced groundwater. If, instead, Hesperian sulfate-rich rocks are approximated as pure Mg-sulfate (no Fe), then the CO2 sequestration is 0.3–400 bars. The low end of this range is consistent with the hypothesis that the cations for Mars' Hesperian sulfates were derived from upwelling of deep-sourced groundwater. In both cases, carbon sequestration by global groundwater circulation actively works to terminate surface habitability, rather than being a passive marker of warm Earthlike conditions. Curiosity will soon be in a position to discriminate between these two hypotheses. Our work links Mars sulfate cation composition, carbon isotopes, and climate change.
... On Mars tectonic, volcanic and erosional activity peaked in the Noachian, but fluvial activity also happened later occasionally (Carr, 1995;Craddock and Howard, 2002;Hauber et al., 2013;Irwin and Howard, 2002), where ice and surface processes related to its melting for short duration might be present during most of the geological history of the planet (Dickson et al., 2009;Fastook et al., 2012). Research activity on fluvial-tectonic interactions previously focused on outflow channels (Hanna, Phillips, 2005) including the role of faults in subsurface liquid migration (Hargitai et al., 2017;Harrison, Grimm, 2009;Okubo, 2006;Montgomery et al., 2007;Reiss and Jaumann 2002;Steinmann, 2019), understanding of flow dynamics (Czechowski et al., 2013(Czechowski et al., , 2014 and recent activity at Athabasca Valles (Berman, Hartmann, 2002), and also global scale hydrology (Philips et al., 2001). Few works also analysed the tectonic role in the formation of older fluvial systems like in north-western Noachis Terra (De et al., 2015), deposition in Eberswalde crater (Rice et al., 2011), or the role of tectonic slopes on valley formation in general (Bernhardt et al., 2016;Irwin et al., 2011). ...
Two areas on Mars in the old Thaumasia region were analysed, where interaction between fluvial and tectonic landforms provided conditions to improve age estimation for valley network formation. An Earth analog terrain was also involved in this work at Villány Hills (Hungary) for reference and to see the relations in tectonic-fluvial interaction. On Mars such interaction was observed by morphology (parallel curvatures of neighbour valleys) and by the comparison of statistical analyses of the fluvial and tectonic lineaments' azimuthal orientation. While in the case of Mars the fluvial network elements' distribution closely follows that of the tectonic elements’ distribution, in the case of the Earth the connection is weaker. The comparison gives an interesting example for tectonic landforms controlling fluvial valley orientations, occasionally producing resembling features in valley tracks, influencing the sediment transport and the locations of deposits.
Because the tectonic faults crossed a much larger area than the fluvial valleys they influenced, crater size frequency distribution based ages could be better measured with them. Using this approach, we found the minimal age of the fluvial network formation to be around 3.7 Ga (or up to 3.9 Ga). This result demonstrates that the small, scattered, and poorly integrated valleys might also have formed at the same period as the larger, branching systems with well determined ages: around the Noachian/Hesperian transition. Thus valley network formation even in the case of small, non-integrated systems might not necessarily extend into the early or middle Noachian ages and might have happened at a potential climatic optimum around 3.7 Ga ago. However the most difficult task remains the exact dating of old and small valleys at other locations on Mars, to confirm this possibility.
... (How much of the initial C dissolved into water at the recharge zone goes into carbonate, and how much survives to reach the upwelling zone)? ( §4. (Harrison & Grimm 2009), and likely also varied with time on Hesperian Mars due to the competition between fracture-sealing processes (such as carbonate mineral precipitation within fractures), and fracture creation (by tectonics, impacts, and cracking to accommodate magmatic intrusions) (Sleep & Zoback 2007). In effect we assume permeability is high enough that permeability is not limiting for deep, global groundwater circulation. ...
Ancient hydrology is recorded by sedimentary rocks on Mars. The most voluminous sedimentary rocks that formed during Mars' Hesperian period are sulfate-rich rocks, explored by the $Opportunity$ rover from 2004-2012 and soon to be investigated by the $Curiosity$ rover at Gale crater. A leading hypothesis for the origin of these sulfates is that the cations were derived from evaporation of deep-sourced groundwater, as part of a global circulation of groundwater. Global groundwater circulation would imply sustained warm Earthlike conditions on Early Mars. Global circulation of groundwater including infiltration of water initially in equilibrium with Mars' CO$_2$ atmosphere implies subsurface formation of carbonate. We find that the CO$_2$ sequestration implied by the global groundwater hypothesis for the origin of sulfate-rich rocks on Mars is 30-5000 bars if the $Opportunity$ data are representative of Hesperian sulfate-rich rocks, which is so large that (even accounting for volcanic outgassing) it would bury the atmosphere. This disfavors the hypothesis that the cations for Mars' Hesperian sulfates were derived from upwelling of deep sourced groundwater. If, instead, Hesperian sulfate-rich rocks are approximated as pure Mg-sulfate (no Fe), then the CO$_2$ sequestration is 0.3-400 bars. The low end of this range is consistent with the hypothesis that the cations for Mars' Hesperian sulfates were derived from upwelling of deep sourced groundwater. In both cases, carbon sequestration by global groundwater circulation actively works to terminate surface habitability, rather than being a passive marker of warm Earthlike conditions. $Curiosity$ will soon be in a position to discriminate between these two hypotheses. Our work links Mars sulfate cation composition, carbon isotopes, and climate change.
