Book contents
- Frontmatter
- Contents
- List of contributors
- 1 Overview of megaflooding: Earth and Mars
- 2 Channel-scale erosional bedforms in bedrock and in loose granular material: character, processes and implications
- 3 A review of open-channel megaflood depositional landforms on Earth and Mars
- 4 Jökulhlaups in Iceland: sources, release and drainage
- 5 Channeled Scabland morphology
- 6 The morphology and sedimentology of landforms created by subglacial megafloods
- 7 Proglacial megaflooding along the margins of the Laurentide Ice Sheet
- 8 Floods from natural rock-material dams
- 9 Surface morphology and origin of outflow channels in the Valles Marineris region
- 10 Floods from fossae: a review of Amazonian-aged extensional–tectonic megaflood channels on Mars
- 11 Large basin overflow floods on Mars
- 12 Criteria for identifying jökulhlaup deposits in the sedimentary record
- 13 Megaflood sedimentary valley fill: Altai Mountains, Siberia
- 14 Modelling of subaerial jökulhlaups in Iceland
- 15 Jökulhlaups from Kverkfjöll volcano, Iceland: modelling transient hydraulic phenomena
- 16 Dynamics of fluid flow in Martian outflow channels
- Index
- Plate section
- References
9 - Surface morphology and origin of outflow channels in the Valles Marineris region
Published online by Cambridge University Press: 04 May 2010
- Frontmatter
- Contents
- List of contributors
- 1 Overview of megaflooding: Earth and Mars
- 2 Channel-scale erosional bedforms in bedrock and in loose granular material: character, processes and implications
- 3 A review of open-channel megaflood depositional landforms on Earth and Mars
- 4 Jökulhlaups in Iceland: sources, release and drainage
- 5 Channeled Scabland morphology
- 6 The morphology and sedimentology of landforms created by subglacial megafloods
- 7 Proglacial megaflooding along the margins of the Laurentide Ice Sheet
- 8 Floods from natural rock-material dams
- 9 Surface morphology and origin of outflow channels in the Valles Marineris region
- 10 Floods from fossae: a review of Amazonian-aged extensional–tectonic megaflood channels on Mars
- 11 Large basin overflow floods on Mars
- 12 Criteria for identifying jökulhlaup deposits in the sedimentary record
- 13 Megaflood sedimentary valley fill: Altai Mountains, Siberia
- 14 Modelling of subaerial jökulhlaups in Iceland
- 15 Jökulhlaups from Kverkfjöll volcano, Iceland: modelling transient hydraulic phenomena
- 16 Dynamics of fluid flow in Martian outflow channels
- Index
- Plate section
- References
Summary
Summary
The outflow channels that emptied into Chryse Planitia provide the best evidence that great quantities of water once flowed on the Martian surface. Some channels were created when the cryosphere ruptured and ground-water discharged from chaos or from cavi along major fault zones. Some chaos formed on channel floors when fluvial erosion thinned the cryosphere, leading to catastrophic breakout of confined groundwater. These chaos can be used to estimate the cryosphere thickness, crustal heat flux and climate trends. At Iamuna Chaos the cryosphere was 700–1000 m thick when Ravi Vallis formed, indicating a cold, long-term climate similar to present-day Mars. The discovery of outflow channels at elevations >2500 m in Ophir Planum shows that Hesperian recharge likely occurred in upslope areas to the west (e.g. Sinai Planum, Tharsis highlands, Syria Planum). The larger circum-Chryse channels were carved by floods that issued directly from the ancestral canyons, which likely were smaller and less interconnected than today. A plausible mechanism for water release was catastrophic drainage of chasm lakes caused by the collapse of topographic barriers or ice-debris dams. We report evidence that a megaflood filled Capri Chasma and overtopped its eastern rim, carving two crossover channels and spectacular dry falls cataracts. This flooding may represent an initial outpouring of canyon lakes via a gateway in eastern Coprates Chasma. The recent discovery of hematite and abundant hydrated sulphates in the Valles Marineris canyons provides compelling evidence of a water-rich history.
- Type
- Chapter
- Information
- Megaflooding on Earth and Mars , pp. 172 - 193Publisher: Cambridge University PressPrint publication year: 2009
References
- 11
- Cited by