Constraints on Thermal History of Mars From Depth of Pore Closure Below InSight

Gyalay, Szilard; Nimmo, F.; Plesa, Ana‐Catalina; Wieczorek, M. A.

doi:10.1029/2020gl088653

Cited by 30 publications

(42 citation statements)

References 40 publications

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“…The depth extent of cracks estimated from laboratory compaction studies of fractured basalt (Birch, 1961;Siegfried et al, 1981) suggests fracture removal takes place at pressures of ≈1-5 kbar (≈9-45 km depth in Mars). For Mars, modeling of higher crustal heat fluxes and the effects of fluids and cementation at depth shows that these processes would decrease the pore closure depth (Gyalay et al, 2020) and by inference, also reduce fracture depth, both of which are consistent with the ≈10 km scattering layer thickness found here.…”

Section: 1029/2020je006670supporting

confidence: 84%

High‐Frequency Seismic Events on Mars Observed by InSight

et al. 2021

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Since the InSight lander (Banerdt et al., 2013) successfully deployed its extremely sensitive seismometer (Lognonné et al., 2019) together with a complete geophysical observatory on the surface of Mars, an unprecedented continuous data stream has become available that has opened new avenues to understanding the red planet. The first results include new observations of atmospheric (Banfield et al., 2020) and magnetic phenomena (Johnson et al., 2020). Seismological data from the very broad band (VBB) instrument that is part of the Seismic Experiment for Interior Structure (SEIS) package (Lognonné et al., 2019) have demonstrated that Mars is seismically active (Banerdt et al., 2020; Giardini et al., 2020), and information

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Section: 1029/2020je006670supporting

confidence: 84%

High‐Frequency Seismic Events on Mars Observed by InSight

et al. 2021

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“…Sequestering 1 bar of CO2 as carbonate cement requires 1 weight % cement over a depth range of 2 km (e.g., Kite and Daswani, 2019). Assuming a heat flow of ~18 mW/m 2 (Parro et al, 2017), a thermal conductivity of 2-3 W/mK (Gyalay et al, 2020), and a mean surface temperature of 70 K below freezing, the melting temperature of ice is reached at a depth of 7.8-11.7 km -with considerable depth uncertainty owing to uncertainty in the heat flow and thermal conductivity. The depth of the velocity increase is similar to the depth at which liquid water would be stable at present and in the past.…”

Section: Discussionmentioning

confidence: 99%

No cryosphere-confined aquifer below InSight on Mars

Manga

Wright²

2021

Preprint

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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. An increase in seismic velocity at depths of ~10 km could be explained by a few volume percent of mineral cement (1-5%) in the pores and may document the past or present depth of aquifers. Plain Language Summary Large amounts of water may be stored in the Martian crust and episodically released to flood the surface. Where this water exists, and even why, is uncertain. The seismometer on the InSight lander measured the speed of seismic waves in the Martian crust. The presence of ice and water affects seismic velocity. We argue that the measurements preclude a layer of ice-filled crust that confines liquid water in an aquifer. Key points • We interpret the seismic wave velocity of the Martian crust measured by InSight. • We quantity the effects of ice and water on seismic velocity using a rock physics model. • Measurements preclude a layer of ice-filled upper crust that confines liquid water in an aquifer. 1. Introduction Large volumes of water are hypothesized to have carved and passed through the Martian outflow channels (e.g., Baker, 2001). Because these channels originate from discrete sources, a groundwater origin is typically invoked (e.g., Head et al., 2003). Given the large discharges needed to create the observed landforms, in some cases a couple orders of magnitude greater than the largest catastrophic floods on Earth (Baker, 1982), large and permeable aquifers would be needed (e.g., Carr, 1979; Manga 2004). While most of the outflow channels are Hesperian (e.g., Tanaka, 1997), their formation continued through the Amazonian (e.g., Rodriguez et al., 2015). Some of the youngest channels originated from fissures in Eastern Elysium Planitia within the past 10s of millions of years (Burr et al., 2002; Voight and Hamilton, 2017). The subsurface of Mars thus appears to have hosted and episodically released large volumes of water over most of Martian history. Hence, detecting the presence and quantifying the volume of subsurface water and ice would help constrain the water budget and cycle from the Noachian to present (Clifford and Parker, 2001). To discharge water at the surface, aquifers must have sufficient pressure for water to reach the surface. One way to achieve hydraulic heads greater than hydrostatic and hence enable surface discharge is to confine aquifers beneath an overlying ice-saturated crust or cryosphere (e.g.

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“…One of the interfaces could potentially represent a transition between fractured and unfractured materials. As shown by Gyalay et al (2020), viscous flow of crustal materials could have removed any pre-existing porosity deep in the crust when the heat flow of Mars was higher in the past. As a result of the exponential dependence of viscosity on temperature, the transition between porous and non-porous materials is expected to be sharp (about a kilometer).…”

Section: Evidence For a Three-layer Martian Crustmentioning

confidence: 99%

“…As a result of the exponential dependence of viscosity on temperature, the transition between porous and non-porous materials is expected to be sharp (about a kilometer). Though Gyalay et al (2020) argued that the shallowest 10 km discontinuity could represent this transition, the mechanism could alternatively explain the intermediate interface instead (though with a somewhat lower heat flow). The other, remaining interface could potentially represent a lithological transition between a pre-existing crust and overlying near surface materials such as lava flows and sediments.…”

Section: Evidence For a Three-layer Martian Crustmentioning

confidence: 99%

Improving Constraints on Planetary Interiors With PPs Receiver Functions

et al. 2021

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Seismological constraints obtained from receiver function (RF) analysis provide important information about the crust and mantle structure. Here, we explore the utility of the free‐surface multiple of the P‐wave (PP) and the corresponding conversions in RF analysis. Using earthquake records, we demonstrate the efficacy of PPs‐RFs before illustrating how they become especially useful when limited data is available in typical planetary missions. Using a transdimensional hierarchical Bayesian deconvolution approach, we compute robust P‐to‐S (Ps)‐ and PPs‐RFs with InSight recordings of five marsquakes. Our Ps‐RF results verify the direct Ps converted phases reported by previous RF analyses with increased coherence and reveal other phases including the primary multiple reverberating within the uppermost layer of the Martian crust. Unlike the Ps‐RFs, our PPs‐RFs lack an arrival at 7.2 s lag time. Whereas Ps‐RFs on Mars could be equally well fit by a two‐ or three‐layer crust, synthetic modeling shows that the disappearance of the 7.2 s phase requires a three‐layer crust, and is highly sensitive to velocity and thickness of intra‐crustal layers. We show that a three‐layer crust is also preferred by S‐to‐P (Sp)‐RFs. While the deepest interface of the three‐layer crust represents the crust‐mantle interface beneath the InSight landing site, the other two interfaces at shallower depths could represent a sharp transition between either fractured and unfractured materials or thick basaltic flows and pre‐existing crustal materials. PPs‐RFs can provide complementary constraints and maximize the extraction of information about crustal structure in data‐constrained circumstances such as planetary missions.

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Constraints on Thermal History of Mars From Depth of Pore Closure Below InSight

Cited by 30 publications

References 40 publications

High‐Frequency Seismic Events on Mars Observed by InSight

High‐Frequency Seismic Events on Mars Observed by InSight

No cryosphere-confined aquifer below InSight on Mars

Improving Constraints on Planetary Interiors With PPs Receiver Functions

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