Dielectric Properties of the Medusae Fossae Formation and Implications for Ice Content

Campbell, B. A.; Watters, T. R.; Morgan, G. A.

doi:10.1029/2020je006601

Cited by 18 publications

(19 citation statements)

References 46 publications

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“…This range in attenuation corresponds to a range in loss tangent of ∼0.002–0.004. A loss tangent of 0.003 is consistent with previous estimates using MARSIS data (Watters et al., 2007) and those obtained using SHARAD data (Campbell et al., 2021; Campbell & Morgan, 2018). Estimates of the loss tangent of the SPLD range from ∼0.001 to 0.005 (Plaut et al., 2007).…”

Section: Resultssupporting

confidence: 90%

Evidence of Ice‐Rich Layered Deposits in the Medusae Fossae Formation of Mars

Watters,

Campbell,

Leuschen

et al. 2024

Geophysical Research Letters

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Subsurface reflectors in radar sounder data from the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express spacecraft indicate significant dielectric contrasts between layers in the Martian Medusae Fossae Formation (MFF). Large density changes that create dielectric contrasts are less likely in deposits of volcanic ash, eolian sediments, and dust, and compaction models show that homogeneous fine‐grained material cannot readily account for the inferred density and dielectric constant where the deposits are more than a kilometer thick. The presence of subsurface reflectors is consistent with a multi‐layer structure of an ice‐poor cap above an ice‐rich unit analogous to the Martian Polar Layered Deposits. The volume of an ice‐rich component across the entire MFF below a 300–600 m dry cover corresponds to a global equivalent layer of water of ∼1.5 to ∼2.7 m or ∼30%–50% of the total estimated in the North Polar cap.

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Section: Resultssupporting

confidence: 90%

Evidence of Ice‐Rich Layered Deposits in the Medusae Fossae Formation of Mars

Watters,

Campbell,

Leuschen

et al. 2024

Geophysical Research Letters

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“…However, the depth of these reflectors was calculated with a permittivity of 7.8, which is likely too high for materials forming Medusae Fossae Formation and its reworked material. Considering previous estimates of the real dielectric constant of 2–3 in the Medusae Fossae Formation (Campbell et al., 2021; Carter et al., 2009; Watters et al., 2007), the depths are likely underestimated in this study.…”

Section: Sharad Investigationmentioning

confidence: 72%

Revealing Elysium Planitia's Young Geologic History: Constraints on Lava Emplacement, Areas, and Volumes

Voigt,

Hamilton,

Steinbrügge

et al. 2023

JGR Planets

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Elysium Planitia includes several outflow channels that were likely carved by aqueous erosion and subsequently infilled by younger lava flows, making Elysium Planitia the youngest volcanic terrain on Mars. Studying this region is critical for constraining the recent hydrological and thermal evolution of the planet. Here, we investigate the lava flow areas, thicknesses, and volumes in Elysium Planitia using Context (CTX) camera images in combination with SHAllow RADar (SHARAD) sounder data. Compiling 1,777 reflectors over an area of 9,126,790 km2 allows us to reconstruct the subsurface landscape evolution over time. Our findings show that Elysium Planitia is composed of material from about 40 episodes of effusive volcanic activity. We report volumes for individual eruptions of 4,000 ± 1,600 km3 infilling Athabasca Valles, 12,200 ± 2,500 km3 in Marte Vallis, and 16,000 ± 4,000 km3 in Rahway Valles for the major flow units and volumes as small as 100 ± 50 km3 in Cerberus Plains. The surface morphologies and inferred dielectric properties of lobe interfaces suggests that the regions consists of basaltic lava. The region also experienced multiple aqueous flooding events. Although, we found evidence of past lava–water interactions, present‐day ground‐ice (if present) is likely limited to local patches. Further, the pre‐eruption landscape reveals that the aqueously carved Marte Vallis is more areal extensive, but shallower than previously suggested, with a likely paleo‐flow direction from northwest to southeast. The channel is most likely sourced from a segment in the northwestern portion of Cerberus Fossae, and is now buried by multiple Late Amazonian lavas with the same lava flow direction.

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“…As a result, we expect Zephyria Planum, Far East Medusae Fossae A, Far East Medusae Fossae C, and East Medusae Fossae B to have the highest likelihood for water ice detection by GRS/NS. Campbell et al (2021) proposed a two-layer model for the MFF, with the top 300-600 m as a fine-grained, selfcompacting layer, and the bottom 2 km as a thicker layer of possible water ice. If the self-compacting layer proposed by Campbell et al (2021) did in fact extend to shallow depths (<10 m) as well, then it is unlikely that the material would be very rich in ice, though this is difficult to reconcile with the GRS and NS data (e.g., Wilson et al 2018).…”

Section: Implications For the Subsurface Ice Table And In Situ Resour...mentioning

confidence: 99%

“…As the Curiosity rover is headed toward this location, we might have a chance to validate our age and erosion rate estimations. (c) An active subject of debate, some interpretations of the MFF using radar and NS data have suggested the presence of water ice in the subsurface (e.g., Watters et al 2007;Mandt et al 2008;Carter et al 2009;Wilson et al 2018;Campbell et al 2021). The darkest blue color in this figure corresponds to an elevation of −6 km and the brightest yellow corresponds to an elevation of +22 km.…”

Section: Introductionmentioning

confidence: 95%

“…The MFF resembles the upper part of Aeolis Mons, informally known as Mount Sharp, in Gale Crater (Thomson et al 2008;Thomson et al 2011;Zimbelman & Scheidt 2012;Wang et al 2018). Sounding radar, neutron spectroscopy (NS), gamma-ray spectroscopy (GRS), and radar surface reflectivity data suggest that the MFF has shallow ice, but theory predicts shallow ice to be unstable at the equator of Mars, and the question remains open (Watters et al 2007;Carter et al 2009;Pathare et al 2018;Wilson et al 2018;Mouginis-Mark & Zimbelman 2020;Campbell et al 2021).…”

Section: Introductionmentioning

confidence: 99%

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The Age and Erosion Rate of Young Sedimentary Rock on Mars

Kite

Keating

2022

Planet. Sci. J.

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The Medusae Fossae Formation (MFF) is an enigmatic sedimentary unit near the equator of Mars, with an uncertain formation process and absolute age. Due to the heavily wind-eroded surface, it is difficult to determine the absolute model age of the MFF using a one-parameter model based on the crater size–frequency distribution function with existing crater count data. We create a new two-parameter model that estimates both age and a constant erosion rate (β) by treating cratering as a random Poisson process. Our study uses new crater count data collected from Context Camera imagery for both the MFF and other young equatorial sedimentary rock. Based on our new model, the Central MFF formed >1.5 Gyr ago and had low erosion rates (<650 nm yr−1), whereas the East MFF, Far East MFF, and Zephyria Planum most likely formed <1.5 Gyr ago and had higher erosion rates (>740 nm yr−1). The top of Aeolis Mons (informally known as Mount Sharp) in Gale Crater and Eastern Candor have relatively young ages and low erosion rates. Based on the estimated erosion rates (since fast erosion permits metastable shallow ice), we also identify several sites, including Zephyria Planum, as plausible locations for shallow subsurface equatorial water ice that is detectable by gamma-ray spectroscopy or neutron spectroscopy. In addition to confirming <1.5 Gyr sedimentary rock formations on Mars, and distinguishing older and younger MFF sites, we find that fast-eroding locations have younger ages and MFF locations with slower erosion have older best-fit ages.

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Dielectric Properties of the Medusae Fossae Formation and Implications for Ice Content

Cited by 18 publications

References 46 publications

Evidence of Ice‐Rich Layered Deposits in the Medusae Fossae Formation of Mars

Evidence of Ice‐Rich Layered Deposits in the Medusae Fossae Formation of Mars

Revealing Elysium Planitia's Young Geologic History: Constraints on Lava Emplacement, Areas, and Volumes

The Age and Erosion Rate of Young Sedimentary Rock on Mars

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