TY - JOUR
T1 - Limited role for thermal erosion by turbulent lava in proximal Athabasca Valles, Mars
AU - Cataldo, Vincenzo
AU - Williams, David
AU - Dundas, Colin M.
AU - Keszthelyi, Laszlo P.
N1 - Funding Information:
The investigation by Vincenzo Cataldo and David A. Williams was supported by NASA Planetary Geology and Geophysics grant NNX12AR66G. We used data obtained from the NASA Planetary Data System, and the Ronald Greeley Center for Planetary Studies (the NASA Regional Planetary Information Facility at ASU). We are grateful to all those who were involved in analyzing the data collected by the High Resolution Imaging Science Experiment (HiRISE), Context (CTX), and Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instruments onboard the Mars Reconnaissance Orbiter (MRO) spacecraft. Specifically, the data contained in the Jaeger et al. [2007, 2010] papers enabled production of our results. Finally, we are grateful for the constructive comments by journal reviewers, and Michael Bland and Christopher Edwards.
Publisher Copyright:
©2015. American Geophysical Union. All Rights Reserved.
PY - 2015/11
Y1 - 2015/11
N2 - The Athabasca Valles flood lava is among the most recent (<50 Ma) and best preserved effusive lava flows on Mars and was probably emplaced turbulently. The Williams et al. (2005) model of thermal erosion by lava has been applied to what we term "proximal Athabasca," the 75 km long upstream portion of Athabasca Valles. For emplacement volumes of 5000 and 7500 km3 and average flow thicknesses of 20 and 30 m, the duration of the eruption varies between ∼11 and ∼37 days. The erosion of the lava flow substrate is investigated for three eruption temperatures (1270°C, 1260°C, and 1250°C), and volatile contents equivalent to 0-65 vol % bubbles. The largest erosion depths of ∼3.8-7.5 m are at the lava source, for 20 m thick and bubble-free flows that erupted at their liquidus temperature (1270°C). A substrate containing 25 vol % ice leads to maximum erosion. A lava temperature 20°C below liquidus reduces erosion depths by a factor of ∼2.2. If flow viscosity increases with increasing bubble content in the lava, the presence of 30-50 vol % bubbles leads to erosion depths lower than those relative to bubble-free lava by a factor of ∼2.4. The presence of 25 vol % ice in the substrate increases erosion depths by a factor of 1.3. Nevertheless, modeled erosion depths, consistent with the emplacement volume and flow duration constraints, are far less than the depth of the channel (∼35-100 m). We conclude that thermal erosion does not appear to have had a major role in excavating Athabasca Valles.
AB - The Athabasca Valles flood lava is among the most recent (<50 Ma) and best preserved effusive lava flows on Mars and was probably emplaced turbulently. The Williams et al. (2005) model of thermal erosion by lava has been applied to what we term "proximal Athabasca," the 75 km long upstream portion of Athabasca Valles. For emplacement volumes of 5000 and 7500 km3 and average flow thicknesses of 20 and 30 m, the duration of the eruption varies between ∼11 and ∼37 days. The erosion of the lava flow substrate is investigated for three eruption temperatures (1270°C, 1260°C, and 1250°C), and volatile contents equivalent to 0-65 vol % bubbles. The largest erosion depths of ∼3.8-7.5 m are at the lava source, for 20 m thick and bubble-free flows that erupted at their liquidus temperature (1270°C). A substrate containing 25 vol % ice leads to maximum erosion. A lava temperature 20°C below liquidus reduces erosion depths by a factor of ∼2.2. If flow viscosity increases with increasing bubble content in the lava, the presence of 30-50 vol % bubbles leads to erosion depths lower than those relative to bubble-free lava by a factor of ∼2.4. The presence of 25 vol % ice in the substrate increases erosion depths by a factor of 1.3. Nevertheless, modeled erosion depths, consistent with the emplacement volume and flow duration constraints, are far less than the depth of the channel (∼35-100 m). We conclude that thermal erosion does not appear to have had a major role in excavating Athabasca Valles.
KW - Mars
KW - physical volcanology
KW - thermal erosion by lava
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U2 - 10.1002/2014JE004761
DO - 10.1002/2014JE004761
M3 - Article
AN - SCOPUS:84955193543
SN - 2169-9097
VL - 120
SP - 1800
EP - 1819
JO - Journal of Geophysical Research: Planets
JF - Journal of Geophysical Research: Planets
IS - 11
ER -