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Mean density | 5.243 g/cm3 | ||||||||||||||||
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Surface pressure | 92 bar (9.2 MPa) | ||||||||||||||||
NASA's Magellan spacecraft mission discovered that Venus has a geologically young surface with a relatively uniform age of 500±200 Ma (million years).[3] The age of Venus was revealed by the observation of over 900 impact craters on the surface of the planet. These impact craters are nearly uniformly distributed over the surface of Venus and less than 10% have been modified by plains of volcanism or deformation.[4] These observations indicate that a catastrophic resurfacing event took place on Venus around 500 Ma, and was followed by a dramatic decline in resurfacing rate.[5] The radar images from the Magellan missions revealed that the terrestrial style of plate tectonics is not active on Venus and the surface currently appears to be immobile.[6]
Despite these surface observations, there are numerous surface features that indicate an actively convecting interior. The Soviet Venera landings revealed that the surface of Venus is essentially basaltic in composition based on geochemical measurements and morphology of volcanic flows.[7] The surface of Venus is dominated by patterns of basaltic volcanism, and by compressional and extensional tectonic deformation, such as the highly deformed tesserae terrain and the pancake like volcano-tectonic features known as coronae.[8] The planet's surface can be broadly characterized by its low lying plains, which cover about 80% of the surface, 'continental' plateaus and volcanic swells. There is also an abundance of small and large shield volcanoes distributed over the planet's surface. Based on its surface features, it appears that Venus is tectonically and convectively alive but has a lithosphere that is static.
- ^ Seidelmann, P. Kenneth; Archinal, Brent A.; A'Hearn, Michael F.; et al. (2007). "Report of the IAU/IAG Working Group on cartographic coordinates and rotational elements: 2006". Celestial Mechanics and Dynamical Astronomy. 98 (3): 155–180. Bibcode:2007CeMDA..98..155S. doi:10.1007/s10569-007-9072-y.
- ^ Williams, David R. (1 July 2013). "Venus Fact Sheet". NASA. Retrieved 2014-04-20.
- ^ Phillips, R.; Raubertas, Richard F.; Arvidson, Raymond E.; Sarkar, Ila C.; Herrick, Robert R.; Izenberg, Noam; Grimm, Robert E. (1992). "Impact craters and Venus resurfacing history". Journal of Geophysical Research. 97 (10): 15923. Bibcode:1992JGR....9715923P. doi:10.1029/92JE01696.
- ^ Schaber, G.G.; Strom, R. G.; Moore, H. J.; Soderblom, L. A.; Kirk, R. L.; Chadwick, D. J.; Dawson, D. D.; Gaddis, L. R.; Boyce, J. M.; Russell, Joel (1992). "Geology and distribution of impact craters on Venus - What are they telling us". Journal of Geophysical Research. 97 (E8): 13257–13301. Bibcode:1992JGR....9713257S. doi:10.1029/92JE01246.
- ^ Turcotte, D.L.; G. Morein; D. Roberts; B.D. Malamud (1999). "Catastrophic Resurfacing and Episodic Subduction on Venus". Icarus. 139 (1): 49–54. Bibcode:1999Icar..139...49T. doi:10.1006/icar.1999.6084.
- ^ Solomon, S.C.; et al. (1992). "Venus Tectonics - An overview of Magellan observations". Journal of Geophysical Research. 97 (8): 13199–13255. Bibcode:1992JGR....9713199S. doi:10.1029/92je01418.
- ^ Basilevsky, A.; et al. (1985). "The surface of Venus as revealed by the Venera landings". Geological Society of America Bulletin. 96 (1): 137–144. Bibcode:1985GSAB...96..137B. doi:10.1130/0016-7606(1985)96<137:tsovar>2.0.co;2.
- ^ Basilevsky, A.; J. Head (2003). "The surface of Venus". Reports on Progress in Physics. 66 (10): 1699–1734. Bibcode:2003RPPh...66.1699B. doi:10.1088/0034-4885/66/10/r04.