Evaluation of melting process of the permafrost on Mars: Its implication for surface features

Abstract

[1] For supplying massive liquid water to the outflow channels, igneous melting of the permafrost layer could have played a significant role. We numerically simulate the melting process of the permafrost layer induced by magmatic intrusion. The point of our simulation is incorporation of thermal convection in porous media, which has not been modeled well in previous studies of the melting of the permafrost. Our results show that convection in the melted zone causes drastic change in heat transfer, which results in focusing in the growth of the melt region and enhancement of water generation. The resulting melt zone extends vertically up just next to the surface, like a plume with a single column (mushroom structure). The volume of meltwater is considerably more than that expected in the conduction case. These characteristics suggest that a substantial amount of water may exist very near the surface. In response to compaction, segregated liquid water may have erupted out of the ground to form the fluvial features. Such an event would certainly be accompanied by surface destruction, which we can see as chaotic terrain. We propose a consistent scenario of forming surface features around the outflow channels.

Formation of Mangala Fossa, the source of the Mangala Valles, Mars: Morphological development as a result of volcano‐cryosphere interactions

“…Its average specific heat over the 273 to 210 K temperature range that spans the cryosphere is ∼1900 J kg −1 K −1 , with the average temperature rise to reach the melting point being ∼31.5 K. Thus, for each meter along strike, to warm and melt all of the cryosphere ice in a typical 2 km wide part of the graben requires ∼3.0 × 10 14 J, only one tenth of the amount of heat available from the cooling dike. This implies that even allowing for the fact that the transfer of heat from the cooling dike to the more distal parts of the ice must have been relatively inefficient, despite the assistance of a hydrothermal convection system [ Gulick , 1998; Ogawa et al , 2003], we see no problem with justifying the proposal in section 3 that late stage graben floor subsidence amounts of up to 150 m were caused by this mechanism.…”

“…We calculate the total amount of sensible heat released by a dike 250 m thick cooling from an initial temperature of 1450 K (we assume that the dike was mafic) to some equilibrium temperature which is also taken to be the temperature of both the water and the rock components after cryosphere ice melting has occurred in the remaining 1750 m width of a zone 2 km wide. This zone is heated by a mixture of convection [ Ogawa et al , 2003] in the water component (assumed to be 10% of the volume on the basis of the Hanna and Phillips [2003, 2005b] models) and conduction through the rock component (the remaining 90% of the volume). This calculation is approximate because it neglects any latent heat of crystallization released by the magma and assumes that all of the available heat is confined to a zone with the width of the graben floor, whereas some of this heat may well be convected beyond this zone.…”

Possible evaporite karst in an interior layered deposit in Juventae Chasma, Mars

“…Such an eruptive flow event would catastrophically release subsurface water causing collapse and disruption of the overlying surface. This would lead to outflow channels and chaotic terrains (Ogawa et al, 2003;El Maarry et al, 2012) that were not observed in the investigated area.…”

“…Geothermal melting within permafrost produces a substantial amount of water close to the surface, which may erupt out of the ground (Ogawa et al, 2003). Such an eruptive flow event would catastrophically release subsurface water causing collapse and disruption of the overlying surface.…”

Identifying Evidence for Explosive Volcanism on Mars Through Geomorphologic and Thermophysical Observations

“…While the triggers of these overland flows is debated, the main theories include: (1) melting of subsurface ice by near-surface magmatism (Chapman & Tanaka, 2002;Leask et al, 2006;Meresse et al, 2008;Ogawa, 2003;Rodriguez et al, 2005;Sharp, 1973), (2) release of subsurface water from a pressurized aquifer (Andrews-Hanna & Phillips, 2007;Carr, 1979;Clifford, 1993;Harrison & Grimm, 2009), (3) dewatering of subsurface gas-hydrates or evaporite minerals (Max & Clifford, 2001;Montgomery & Gillespie, 2005), (4) and melting of near-surface buried ice sheets (Roda et al, 2014;Zegers et al, 2010). Chaos terrain-floored craters are common in these dewatering regions, and form due to the release of subsurface groundwater, resulting in the fracturing and subsidence of overlying rock (Rodriguez et al, 2005).…”