Comments to “A composite mineralogical map of Ganges Chasma and surroundings, Valles Marineris, Mars” by Selby Cull-Hearth and M. Caroline Clark (Planetary and Space Science 142, 1–8)

Leone, Giovanni

doi:10.1016/j.pss.2018.08.002

“…Vastitas Borealis and Utopia Planitia also received the lava flows coming from Tharsis (Ivanov & Head, 2006) and Elysium (Hopper & Leverington, 2014), respectively. The olivine naturally contained in lava appears globally unaltered since the Noachian (Ehlmann et al, 2010;Leone, 2017Leone, , 2019Leverington, 2009Leverington, , 2011Leverington, , 2019aMcSween, Wyatt, et al, 2006) as can also be seen from the corresponding units in the geochronological map of Mars (Tanaka et al, 2014). After such an abundant evidence, it was recently suggested that the outflow channels of Tharsis would have fed an ocean in the lowlands thought to exist at the frozen state until the Hesperian (Carr & Head, 2019).…”

Section: Problems Related To the Ocean Hypothesismentioning

confidence: 95%

“…Nothing different than something already observed at Gusev (McSween, Wyatt, et al, 2006;McSween, Ruff, 2006), Palos (Leverington, 2006), or elsewhere on Mars (Leone, 2016). After the initial post-Mariner (Leighton et al, 1965) and post-Viking views (Baird & Clark, 1984), there is now a growing literature that shows compelling evidence of lava as the main fluid carving the outflow channels and the fluvial networks (Hopper & Leverington, 2014;Leone, 2014Leone, , 2016Leone, , 2017Leone, , 2019Leverington, 2004Leverington, , 2007Leverington, , 2009Leverington, , 2011Leverington & Maxwell, 2004). Such evidence is also supported by the scarcity of the sources that should have provided the amounts of water necessary to fill the lowlands with enough water to form an ocean.…”

Section: Arguments In Favor Of Lavamentioning

confidence: 97%

“…Earth and Space Science Outflow processes fed by groundwater are in fact unable to explain the formation of large outflow channels from a single event (Marra et al, 2014). There is a volumetric discrepancy between the outflow channels and the water resources that would be necessary to their formation (Leone, 2014(Leone, , 2016(Leone, , 2017(Leone, , 2019Leverington, 2009Leverington, , 2011Leverington, , 2019a. The volume of terrain removed to form Valles Marineris and Kasei Valles was estimated at 12.90 × 10 6 km 3 , a lower estimate that includes the lava filling of the two channels (Leone, 2014).…”

Section: 1029/2019ea001031mentioning

confidence: 99%

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The absence of an ocean and the fate of water all over the Martian history

Leone

¹

2019

Preprint

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Existing data returned in >40 years of planetary missions to Mars provided a good basis to understand that an ocean never existed on the surface of the planet during its whole history. The presence of environmental indicators like unaltered jarosite and olivine deposited by the early volcanic activity can be seen as evidence that liquid water was never abundant nor widespread on the surface of Mars since the pre-Noachian or Noachian at least. There is a dramatic mismatch with the water equivalent volume of the outflow channels sources with the volume needed to form an ocean. The ubiquitous presence of large volcanoes, with their huge lava fields exactly where liquid water was claimed to be abundant during the Noachian age, makes now very clear that lava and not water was involved in the formation of the outflow channels and the fluvial networks. As a consequence, cheaper robotic exploration might be favored with respect to the ambitious human exploration program planned for Mars. Unless enough water supplies will be brought to the equatorial regions from the poles through long pipelines, or from nearby asteroids through cargo ships, it will be very difficult to exploit the rich equatorial resources brought up from the mantle by the massive volcanism that characterized the early history of the planet. Digging deeply the equatorial regions searching for water would be too expensive, of uncertain reward, and thus unpractical.

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“…Nothing different than something already observed at Gusev (McSween, Wyatt, et al, 2006; McSween, Ruff, 2006), Palos (Leverington, 2006), or elsewhere on Mars (Leone, 2016). After the initial post‐Mariner (Leighton et al, 1965) and post‐Viking views (Baird & Clark, 1984), there is now a growing literature that shows compelling evidence of lava as the main fluid carving the outflow channels and the fluvial networks (Hopper & Leverington, 2014; Leone, 2014, 2016, 2017, 2019; Leverington, 2004, 2007, 2009, 2011; Leverington & Maxwell, 2004). Such evidence is also supported by the scarcity of the sources that should have provided the amounts of water necessary to fill the lowlands with enough water to form an ocean.…”

Section: Arguments In Favor Of Lavamentioning

confidence: 99%

“…Vastitas Borealis and Utopia Planitia also received the lava flows coming from Tharsis (Ivanov & Head, 2006) and Elysium (Hopper & Leverington, 2014), respectively. The olivine naturally contained in lava appears globally unaltered since the Noachian (Ehlmann et al, 2010; Leone, 2017, 2019; Leverington, 2009, 2011, 2019a; McSween, Wyatt, et al, 2006) as can also be seen from the corresponding units in the geochronological map of Mars (Tanaka et al, 2014). After such an abundant evidence, it was recently suggested that the outflow channels of Tharsis would have fed an ocean in the lowlands thought to exist at the frozen state until the Hesperian (Carr & Head, 2019).…”

Section: Introductionmentioning

confidence: 98%

The Absence of an Ocean and the Fate of Water all Over the Martian History

Leone

¹

2020

Earth and Space Science

Self Cite

12

0

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Existing data returned in >40 years of planetary missions to Mars provided a good basis to understand that an ocean never existed on the surface of the planet during its whole history. The presence of environmental indicators like unaltered jarosite and olivine deposited by the early volcanic activity can be seen as evidence that liquid water was never abundant nor widespread on the surface of Mars since the pre-Noachian or Noachian at least. There is a dramatic mismatch with the water equivalent volume of the outflow channels sources with the volume needed to form an ocean. The ubiquitous presence of large volcanoes, with their huge lava fields exactly where liquid water was claimed to be abundant during the Noachian age, makes now very clear that lava and not water was involved in the formation of the outflow channels and the fluvial networks. As a consequence, cheaper robotic exploration might be favored with respect to the ambitious human exploration program planned for Mars. Unless enough water supplies will be brought to the equatorial regions from the poles through long pipelines, or from nearby asteroids through cargo ships, it will be very difficult to exploit the rich equatorial resources brought up from the mantle by the massive volcanism that characterized the early history of the planet. Digging deeply the equatorial regions searching for water would be too expensive, of uncertain reward, and thus unpractical. et al., 1997), on the other side of Chryse Planitia far away from the landing site of

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