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Coordinates: 4°13′S 137°14′E / 4.21°S 137.23°E / -4.21; 137.23
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''Curiosity'' rover landed near the end of the Peace Vallis fan. Peace Vallis fan covers {{cvt|80|km2}} and obtained water from an area of {{cvt|730|km2}}. Peace Vallis enters Gale Crater through a {{cvt|15|km|mi|adj=mid|-wide}} gap in its rim. Calculations suggest that the fan has an average thickness of {{cvt|9|m}}. Numerous inverted channels are visible on the western surface of the fan. Runoff through Peace Vallis that made the fan is estimated to be between {{cvt|600|and|6000|m|mi}}; therefore a hydrologic cycle probably lasted at least thousands of years. The water that flowed in Peace Vallis is believed to be from precipitation, possibly in the form of snow.<ref>{{cite journal|doi=10.1002/2013JE004583 |volume=119 |title=The origin and evolution of the Peace Vallis fan system that drains to theCuriositylanding area, Gale Crater, Mars |journal=Journal of Geophysical Research: Planets |pages=705–728 |last1=Palucis |first1=Marisa C.|bibcode=2014JGRE..119..705P}}</ref><ref>{{cite journal |last1=Palucis |first1=M. |last2=Dietrich |first2=W. |last3=Hayes |first3=A. |last4=Williams |first4=R. |last5=Gupta |first5=S. |last6=Mangold |first6=N. |last7=Newsom |first7=H. |last8=Hardgrove |first8=C. |last9=Calef |first9=III |last10=Sumne |first10=D. |year=2014 |title=The origin and evolution of the Peace Vallis fan system that drains to the Curiosity landing area, Gale Crater, Mars |journal=Journal of Geophysical Research: Planets |volume=119 |pages=705–728 |doi=10.1002/2013je004583|bibcode=2014JGRE..119..705P}}</ref>
''Curiosity'' rover landed near the end of the Peace Vallis fan. Peace Vallis fan covers {{cvt|80|km2}} and obtained water from an area of {{cvt|730|km2}}. Peace Vallis enters Gale Crater through a {{cvt|15|km|mi|adj=mid|-wide}} gap in its rim. Calculations suggest that the fan has an average thickness of {{cvt|9|m}}. Numerous inverted channels are visible on the western surface of the fan. Runoff through Peace Vallis that made the fan is estimated to be between {{cvt|600|and|6000|m|mi}}; therefore a hydrologic cycle probably lasted at least thousands of years. The water that flowed in Peace Vallis is believed to be from precipitation, possibly in the form of snow.<ref name=Palucis2014/>


== Images ==
== Images ==

Revision as of 12:58, 13 February 2022

Peace Vallis
Peace Vallis and related alluvial fan near the Curosity rover landing ellipse and landing site (Bradbury Landing) (noted by cross [+]).
Coordinates4°13′S 137°14′E / 4.21°S 137.23°E / -4.21; 137.23
Length35.24 km (21.90 mi)
NamingAdopted by the IAU on September 26, 2012 after the Peace River in British Columbia and Alberta, Canada.[1]

Peace Vallis is an ancient stream valley on the northern rim of Gale Crater on the planet Mars. It is notable for its associated alluvial fan which lies near the Mars Science Laboratory Curiosity landing site (Bradbury Landing). The valley and alluvial fan provide evidence for geologically recent fluvial activity[2][3] and sustained water flow[4] on Mars. Recent high-resolution orbital images of Peace Vallis and its watershed also suggest that at least one glacial episode affected Gale crater.[5] All of this evidence has implications for the history of water on Mars and the planet's long-term habitability.[6] Understanding Peace Vallis and its fan also provides geologic context for the rocks observed on the ground by the Curiosity rover.[7]

Location

The valley is centered at 4°13′S 137°14′E / 4.21°S 137.23°E / -4.21; 137.23[1] in the northeastern Aeolis quadrangle of Mars and drains approximately 1,500 square km of the northwestern rim of Gale Crater.[8] While the stream was active, surface water and groundwater drained to the south into a low-lying plain in the northern interior of the crater (Aeolis Palus) where the stream valley debouched into a large alluvial fan (Peace Vallis fan). Gale crater itself is a 154-km-diameter impact crater that straddles the martian hemispheric dichotomy between the heavily cratered southern highlands and the lower elevation plains (Elysium Planitia) to the north. Gale crater is noteworthy for its enigmatic 5-km-high crescent-shaped central mound, Aeolis Mons (known informally as Mt. Sharp). The crater is late Noachian or Early Hesperian in age (approximately 3.65 to 3.55 billion years old).[9]

Name

Peace Vallis is named after the Peace River in Alberta and British Columbia, Canada. The name was adopted by the International Astronomical Union (IAU) on September 26, 2012. Vallis is the Latin word for valley.[1]

Valley and Drainage Basin

Peace Vallis is a valley network characterized by a branching (dendritic) pattern of tributary valleys that resembles river drainage basins on Earth. They are common on the older heavily cratered regions of Mars. Most planetary scientists agree that valley networks were formed by flowing water, but the source of the water is still debated.[10] Some argue that rainfall on a warm and wet early mars produced them.[11] Others have suggested they were produced by mass wasting,[12] spring sapping,[13] or from snowmelt[14] on an ancient Mars whose climate was dry and cold much like today's.

Main valley and tributaries of Peace Vallis (shown in blue).

Compared with most terrestrial valleys carved by rainfall, the drainage density (stream length per unit area) of Peace Vallis and its tributaries is very low. There is a lack of highly integrated fluvial channels,[15] and the areas between the tributary valleys (interfluves) are undissected by smaller valleys or gullies. Palucis and colleagues (2014) [16] calculated a drainage density for Peace Vallis of 0.15 km–1. Drainage densities of rivers on Earth, in contrast, range from 2 to 30 km–1.[17] Factors that control drainage density include slope, rock type (which determines infiltration capacity)[18] and climate (mainly precipitation). The low drainage density of Peace Vallis suggests an environment of relatively gentle slopes, very low (or infrequent) precipitation, permeable soils or bedrock, or some combination of the three.[19]

The valleys are U-shaped in topographic cross-section with widths ranging from 80 to 900 meters (262 to 2,950 feet) with a mean of 300 meters (984 feet). The main or trunk valley is about 32 km (20 miles) long.[16]

Evidence of water on Mars near Peace Vallis[20][21][22]
"Hottah" rock outcrop on Mars - an ancient streambed viewed by the Curiosity rover (September 14, 2012) (close-up) (3-D version).
"Link" rock outcrop on Mars - compared with a terrestrial fluvial conglomerate - suggesting water "vigorously" flowing in a stream.
Curiosity rover on the way to Glenelg (September 26, 2012).

Curiosity rover landed near the end of the Peace Vallis fan. Peace Vallis fan covers 80 km2 (31 sq mi) and obtained water from an area of 730 km2 (280 sq mi). Peace Vallis enters Gale Crater through a 15 km-wide (9.3 mi) gap in its rim. Calculations suggest that the fan has an average thickness of 9 m (30 ft). Numerous inverted channels are visible on the western surface of the fan. Runoff through Peace Vallis that made the fan is estimated to be between 600 and 6,000 m (0.37 and 3.73 mi); therefore a hydrologic cycle probably lasted at least thousands of years. The water that flowed in Peace Vallis is believed to be from precipitation, possibly in the form of snow.[16]

Images

See also

References

  1. ^ a b c "Gazetteer of Planetary Nomenclature: Peace Vallis". IAU. September 26, 2012. Retrieved September 28, 2012. {{cite web}}: Cite uses deprecated parameter |authors= (help)
  2. ^ Newsom, H.E.; Scuderi, L.A.; Gallegos, Z.E.; Williams, J.M.; Dimitracopoulos, F.D.; Tornabene, L.L.; Wiens, R.C.; Gasnault, O. (2021). Evidence for Glacial and Fluvial Processes on Gale Crater Rim—Dulce Vallis. 52nd Lunar and Planetary Science Conference, Abstract #2256. https://www.hou.usra.edu/meetings/lpsc2021/pdf/2256.pdf.
  3. ^ Ehlmann, B.L.; Buz, J. (2015). Mineralogy and fluvial History of the Watersheds of Gale, Knobel, and Sharp Craters: A Regional Context for the Mars Science Laboratory Curiosity’s Exploration. Geophys. Res. Lett., 42, 264–273, doi:10.1002/2014GL062553.
  4. ^ Williams, R.M.E.; Grotzinger, J.P.; Dietrich, W.E.; Gupta, S.; Sumner, D.Y. et al. (2013). Martian Fluvial Conglomerates at Gale Crater. Science, 340, 1068, doi: 10.1126/science.1237317.
  5. ^ Newsom, H.E.; Scuderi, L.A.; Gallegos, Z.E.; Tornabene, L.L.; Wiens, R.C. (2020). Evidence for Glacial Processes on Gale Crater Rim Surfaces from New HiRise Observations. 51st Lunar and Planetary Science Conference, Abstract #2609. https://www.hou.usra.edu/meetings/lpsc2020/pdf/2609.pdf.
  6. ^ Scuderi, L.A.; Gallegos, Z.E.; Newsom, H.E.; Wiens, R..C. (2019). Amazonian Groundwater Springline at Peace Vallis Fan, Gale Crater; Implications for a Late Period of Surface Habitability. Mars Extant Life: What's Next? Conference, Abstract #5043. https://www.hou.usra.edu/meetings/lifeonmars2019/pdf/5043.pdf.
  7. ^ Palucis, M.C.; Dietrich, W.E.; Hayes, A.; Williams, R.M.E. et al. (2013). Origin and Evolution of the Peace Vallis Fan System that Drains into the Curiosity Landing Area, Gale Crater. ‘’44th Lunar and Planetary Science Conference,’’ Abstract #1607. https://www.lpi.usra.edu/meetings/lpsc2013/pdf/1607.pdf.
  8. ^ Newsom, H.E.; Scuderi, L.A.; Gallegos, Z.E.; Nagle-McNaughton, T.P.; Tornabene, L.L. et al. (2019). Southern Watershed and Fluvial History of the Peace Vallis Fan System, Gale Crater, Mars. 9th International Conference on Mars, Abstract #6119. https://www.hou.usra.edu/meetings/ninthmars2019/pdf/6119.pdf.
  9. ^ Le Deit, L.; Hauber, E.; Fueten, F.; Pondrelli, M.; Pio Rossi, A.; Jaumann, R. (2013). Sequence of Infilling Events in Gale Crater, Mars: Results from Morphology, Stratigraphy, and Mineralogy. J. Geophys. Res., 118, 2439–2473, doi:10.1002/2012JE004322, 2013.
  10. ^ Carr, M.H. The Surface of Mars; Cambridge University Press: New York, 2006
  11. ^ Craddock, R.A.; Howard, A.D. (2002). The Case for Rainfall on a Warm, Wet Early Mars. J. Geophys. Res., 107(E11), 5111, doi:10.1029/2001JE001505. https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2001JE001505.
  12. ^ Carr, M.H. (1995). The Martian Drainage System and the Origin of Valley Networks and Fretted Channels. J. Geophys. Res., 100(E4), 7479–7507.
  13. ^ Squyres, S.W. (1989). Early Mars: Wet and Warm, or Just Wet? 20th Lunar and Planetary Science Conference Abstract #1044.
  14. ^ Carr, M.H. and Head, J.W. (2003). Basal Melting of Snow on Early Mars: A Possible Origin of Some Valley Networks. Geophys. Res. Lett., 30(24), 2245, doi:10.1029/2003GL018575.
  15. ^ Newsom, H.E.; Scuderi, L.A.; Gallegos, Z.E. et al. (2020). New HiRISE Observations of Gale Crater Rim Surfaces—Evidence for Glacial Processes. American Geophysical Union, Fall Meeting, No. P038-01.
  16. ^ a b c Palucis, M.; Dietrich, W.; Hayes, A.; Williams, R. et al. (2014). The Origin and Evolution of the Peace Vallis Fan System That Drains to the Curiosity landing area, Gale Crater, Mars. J. Geophys. Res., 119, 705–728. Bibcode:2014JGRE..119..705P. doi:10.1002/2013je004583. https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2013JE004583.
  17. ^ Carr, M.C. Water on Mars. Oxford University Press: New York, 2006, 229 pp.
  18. ^ Melosh, H.J. Planetary Surface Processes. Cambridge University Press: Cambridge U.K., 2011, 500 pp.
  19. ^ Huggett, R.J. Fundamentals of Geomorphology. Routledge: New York, 2007, 483 pp.
  20. ^ Brown, Dwayne; Cole, Steve; Webster, Guy; Agle, D.C. (September 27, 2012). "NASA Rover Finds Old Streambed On Martian Surface". NASA. Retrieved September 28, 2012.
  21. ^ "NASA's Curiosity Rover Finds Old Streambed on Mars - video (51:40)". NASAtelevision. September 27, 2012. Retrieved September 28, 2012. {{cite web}}: Cite uses deprecated parameter |authors= (help)
  22. ^ Chang, Alicia (September 27, 2012). "Mars rover Curiosity finds signs of ancient stream". AP News. Retrieved September 27, 2012.

External links

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