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Geomorphology and Landforms of Venus

Geomorphology and Landforms of Venus. Ariana Boyd GE254: Principles of Geomorphology May 8, 2014. Introduction. Closest planet to Earth Often called Earth’s ‘sibling planet’ Similar size Similar layers Presence of atmosphere Surface conditions: hot (480º C) and pressurized (95 bars).

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Geomorphology and Landforms of Venus

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  1. Geomorphology and Landforms of Venus Ariana Boyd GE254: Principles of Geomorphology May 8, 2014

  2. Introduction • Closest planet to Earth • Often called Earth’s ‘sibling planet’ • Similar size • Similar layers • Presence of atmosphere • Surface conditions: hot (480º C) and pressurized (95 bars)

  3. History • Soviet Venera landers provided first images of surface in 1970s and later in 1980s • 1990- NASA’s Magellan began collecting data • Imaged over 98% of planet • Magellan images remain our primary source for understanding Venus

  4. Venus: surface and interior • Likely to have core, mantle, and crust • Probably basaltic lowlands, maybe more silicic highlands • Crustal thickness between 20-40 km

  5. Chasmata • Venusian rift valleys • Indicate areas of crustal extension • Found along equator and in southern hemisphere • Hottest average surface temperature

  6. Impact craters • Fewer than 1,000 on entire surface of Venus • Suggests maximum surface age of 750 Ma • Craters range from 10-50 km in diameter (‘complex structures’) to over 270 km (larger than 50 km = ‘multi-ring structures’)

  7. Complex structure Image credit: NASA

  8. Multi-ring structure Image credit: NASA

  9. Volcanoes • Volcanoes dominate Venusian surface • Shield volcanoes, not composite volcanoes • May be due to strong crust acting as ‘lid’ and trapping heat, thus creating individual hot spots • Extensive lava plains mean lava must have remained extremely hot • Ultramafic rocks

  10. Coronae • Circular 200-600-km-wide features with ridges, grooves, in concentric patterns • Found on flanks of gentle domes or shallow depressions • Likely represent crustal deformation surrounding upwelling mantle plumes

  11. Coronae surrounding depression Image credit: NASA

  12. Conclusions • No water, hot surface, and high pressure account for many features of Venus, and their difference from Earth’s features • More data needed; Europe is working on it

  13. References • Aittola, M., T. Ohman, J.J. Leitner, and J. Ritala, 2007: The Characteristics of Polygonal Impact • Craters on Venus. Earth Moon Planet, vol. 101, pp 41-53. • Bleamaster III, L.F., and V.L. Hansen, 2004: Effects of crustal heterogeneity on the morphology • of chasmata, Venus. Journal of Geophysical Research, vol. 109, E02004, doi:10.1029/2003JE002193. • Bourke, M.C., N. Lancaster, L.K. Fenton, E.J.R. Parteli, J.R. Zimbelman, and J. Radebaugh, • 2010: Extraterrestrial dunes: An introduction to the special issue on planetary dune systems. Geomorphology, vol. 121, pp. 1-14. • Byrnes, J.M., and D.A. Crown, 2002: Morphology, stratigraphy, and surface roughness • properties of Venusian lava flow fields. Journal of Geophysical Research, vol. 107, pp. 9-1-9-22. • Greeley, R., 2013: Planetary Geomorphology. • Head, J.W., D.B. Campbell, C. Elachi, J.E. Guest, D.P. McKenzie, R.S. Saunders, G.G. Schaber, • and G. Schubert, 1991: Venus Volcanism: Initial Analysis from Magellan Data. Science, vol. 252, pp. 276-288. • Head, J.W., and L. Wilson, 1986: Volcanic Processes and Landforms on Venus: Theory, • Predictions, and Observations. Journal of Geophysical Research, vol. 91, pp. 9407-9446. • Herrick, R.R., 1994: Resurfacing history of Venus. Science, vol. 22, pp. 703-706. • Ivanov, M., 2001: Morphology of the tessera terrain on Venus: Implications for the composition • of tessera material. Solar Systems Research, vol. 35, pp. 1-17. • Komatsu, G., V.C. Gulick, and V.R. Baker, 1999: Valley networks on Venus. Geomorphology, • vol. 37, pp. 225-240. • Kucinskas, A., D. Turcotte, and J. Arkani-Hamed, 1996: Isostatic compensation of Ishtar Terra, • Venus. Journal of Geophysical Research, vol. 101, pp. 4725-4736. • McKenzie, D., P.G. Ford, C. Johnson, B. Parsons, D. Sandwell, S. Saunders, and S.C. Solomon, • 1992a: Features on Venus Generated by Plate Boundary Processes. Journal of Geophysical Research, vol. 97, pp. 13533-13544. • McKenzie, D., P.G. Ford, F. Liu and G.H. Pettengill, 1992b: Pancakelike Domes on Venus. • Journal of Geophysical Research, vol. 97, pp. 15967-15976. • Mouginis-Mark, P.J., and S.K. Rowland, 2001: The geomorphology of planetary calderas. • Geomorphology, vol. 37, pp. 201-223. • Parker, T.J., and D.R. Currey, 2001: Extraterrestrial coastal geomorphology. Geomorphology, • vol. 37, pp. 303-328. • Phillips, R.J., Arvidson, R.E., Boyce, J.M., Campbell, D.B., Guest, J.E., Schaber, G.G., and • Soderblom, L.A., 1991: Impact Craters on Venus: Initial Analysis from Magellan. Science, vol. 252, pp. 288-297. • Phillips, R.J., and V.L. Hansen, 1994: Tectonic and magmatic evolution of Venus. Annual • Review of Earth and Planetary Science, vol. 22, pp. 597-654. • Sugita, S., and P.H. Schultz, 2001: Impact of Run-Out Flows on Venus by Oblique Impacts. • Icarus, vol. 155, pp. 265-284. • Urrutia-Fucugauchi, J., and L. Perez-Cruz, 2011: Buried impact basins, the evolution of • planetary surfaces and the Chicxulub multi-ring crater. Geology Today, vol. 27, pp. 220-225. • Vita-Finzi, C., Howarth, R.J., Tapper, S., and C. Robinson, 2004: Venusian craters and the origin • of coronae. Lunar and Planetary Science Conference – Abstracts, vol. 35, unpaginated.

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