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Dyke widths and ascent rates of silicic magmas on Venus

Published online by Cambridge University Press:  03 November 2011

Nick Petford
Nick Petford*
Affiliation:
Centre For Earth and Environmental Science Research, Kingston University, Penrhyn Road, Kingston-Upon-Thames, Surrey KTl 2EE, U.K. e-mail:n.pet@king.ac.uk
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Abstract

The ascent of silicic magmas in dykes and diapirs on Venus is investigated using magma transport models for granitic melts on Earth. For fixed planetary thermal and melt properties, differences in critical minimum dyke widths, and hence magma ascent rates, are controlled by gravitational strength alone. For density contrasts of 200–600 kg/m3 and a solidus temperature of 1023 K, minimum critical dyke widths (wc) on Venus range from c. < 1–1200 m for a transport distance of 20 km. Dyke widths are especially sensitive to small changes in the far-field lithospheric temperature at values close to a critical Stefan number (S∝crit) of 0·83 where dyke magma temperatures are equal to the mean surface temperature. Typical magma ascent rates range from 0·02m/s (ηm = 105 Pa s) to 10−9 m/s (ηm = 1017 Pa s) giving transport times of between 12 days and c. 105 years. Dyke ascent velocities for highly viscous melts are compared with diapiric rise of a hot Stokes body of radius comparable with the pancake dome average (c. 12 km), and require dyke widths of the order of 100 times the average width of low viscosity flows to prevent freezing. In both cases, magma flow is characterised by Péclet numbers between 1 and 4, although even at high viscosities (> 1014 Pa s), dyke ascent is still 100 to 1000 times faster than diapiric rise. At a melt viscosity of 1017 Pa s, critical dyke widths are between c. 1% and 5% the diameter of an average width pancake dome on Venus, indicating that even for extreme melt viscosities, domes can easily be fed by dykes. Given the abundance of dome structures and associated surface features related to hyperbasal magmatism, batholithic volumes of silicic rocks may be present on Venus. Intermediate to high silica melts formed by partial melting of the Venusian crust should be compositionally more akin to Na-rich terrestrial adakites and trondhjemites than calc-alkaline dacites or rhyolites.

Keywords

critical minimum widthsdomesgranitesVenus
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 91 , Issue 1-2: Fourth Hutton Symposium: The Origin of Granites and Related Rocks , 2000 , pp. 87 - 95
Copyright
Copyright © Royal Society of Edinburgh 2000

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References

Atherton, M. P. & Petford, N. 1996. Plutonism and the growth of Andean crust at 9°S from 100 to 3 Ma. Journal of South American Earth Science 9, 1–9.Google Scholar
Bridges, N. T. 1997. Ambient effects on basalt and rhyolite lavas under Venusian, subaerial and subaqueous conditions. Journal of Geophysical Research, E102, 9243–55.Google Scholar
Clemens, J. C. & Petford, N. 1999. Granitic melt viscosity and silicic magma dynamics in contrasting tectonic settings. Journal of the Geological Society of London 156, 1057–60.Google Scholar
Ernst, R. E., Head, J. W., Parfitt, E. A., Grosfils, E. & Wilson, L. 1995. Giant radiating dyke swarms on Earth and Venus. Earth Science Reviews 39, 1–58.Google Scholar
Fahrig, W. F. 1987. The tectonic setting of continental mafic dyke swarms: failed arm and early passive margin. In Halls, H. C. & Fahrig, W. F. (eds) Mafic Dyke Swarms, Geological Association of Canada Special Paper 34, 331–48.Google Scholar
Fink, J. H., Bridges, N. T. & Grimm, R. E. 1993. Shapes of Venusian 'Pancake’ domes imply episodic emplacement and silicic composition. Geophysical Research Letters 20, 261—4.Google Scholar
Ford, P. G. 1994. Radar scattering properties of steep-sided domes on Venus. Icarus 112, 204–18.Google Scholar
Head, J. W., Campbell, D. B., Elach, C, Guest, J. E., McKenzie, D. P., Saunders, R. S., Schaber, G. G. & Schubert, G. 1991. Venus volcanism: initial analysis from Magellan data. Science 252, 276–8.Google Scholar
Head, J. W., Crumpler, L. S., Aubele, J. C., Guest, J. E. & Saunders, R. S. 1992. Venus volcanism: classification of volcanic features and structures, associations and global distribution from Magellan data. Journal of Geophysical Research E97, 13153–98.10.1029/92JE01273Google Scholar
Head, J. W. & Wilson, L. 1986. Volcanic processes and landforms on Venus: Theory, predictions and observations. Journal of Geophysical Research B91, 9407–46.Google Scholar
Huppert, H. E. 1992. The propagation of two-dimensional and axisymmetric viscous gravity currents over a rigid horizontal surface. Journal of Fluid Mechanics 121, 43–58.Google Scholar
Kiefer, W. S. & Hager, B. H. 1991. A mantle plume model for the equatorial highlands of Venus. Geophysical Research Letters 20, 265–8.Google Scholar
Koch, D. M. & Manga, M. 1996. Neutrally Buoyant diapirs: a model for Venus coronae. Geophysical Research Letters 23, 225–8.Google Scholar
Lister, J. R. & Kerr, R. C. 1991. Fluid mechanical models of crack propagation and their application to magma transport in dikes. Journal of Geophysical Research B96, 10,049–77.Google Scholar
Mahon, K. I., Harrison, T. M. & Drew, D. A. 1988. Ascent of a grantoid diapir in a temperature varying medium. Journal of Geophysical Research B93, 1,174–88.Google Scholar
McKenzie, D., Ford, P. G., Lui, F. & Prettnegill, G. H. 1992a. Pancakelike domes on Venus. Journal of Geophysical Research E97, 15,967–76.Google Scholar
McKenzie, D., McKenzie, J. M. & Saunders, R. S. 1992b. Dike emplacement on Venus and Earth. Journal of Geophysical Research E97, 15,977–90.Google Scholar
Miller, C. D. 1985. Holocene eruptions of the Inyo volcanic chain, California, implications for possible eruption in the Long Valley caldera. Geology 13, 14–17.Google Scholar
Namiki, N. & Solomon, S. C. 1993. The gabbro eclogite phase transition and the elevation of mountain belts on Venus. Journal of Geophysical Research 98, 15,025–31.Google Scholar
Nimmo, F. 2000. Dike intrusion as a possible cause of linear Martian magnetic anomalies. Geology 28, 391–4.Google Scholar
Nimmo, F. & McKenzie, D. 1996. Modelling plume-related uplift, gravity and melting on Venus. Earth and Planetary Science Letters 145, 109–23.Google Scholar
Nimmo, F. & McKenzie, D. 1998. Volcanism and tectonics on Venus. Annual Review of Earth and Planetary Science 26, 23–51.Google Scholar
Pavri, B., Head, J. W., Klose, K. B. & Wilson, L. 1992. Steep-sided domes on Venus: characteristics, geologic setting, and eruption conditions from Magellan data. Journal of Geophysical Research E97, 13, 445–78.Google Scholar
Petford, N. 1996. Dykes or diapirs? Transactions of the Royal Society of Edinburgh: Earth Sciences 87, 105–14.10.1017/S0263593300006520Google Scholar
Petford, N., Kerr, R. & Lister, J. D. 1993. Dyke transport of granitic magmas. Geology 21, 845–8.Google Scholar
Rapp, R. P., Watson, E. B. & Miller, C. F. 1991. Partial melting of amphibolite/eclogite and the origin of Archean trondhjemites and tonalites. Precambrian Research 51, 1–25.Google Scholar
Sakimoto, S. E. H. & Zuber, M. T. 1995. Effects of planetary thermal structure on the ascent and cooling of magma on Venus. Journal of Volcanology and Geothermal Research 64, 53–60.Google Scholar
Saunders, R. S., Spear, A. J., Allin, P. C., Austin, R. S., Berman, A. L., Chandlee, R. C., Clark, J., Decharon, A. V., Dejong, E. M., Griffith, D. G., Gunn, J. M., Hensley, S., Johnson, W. T. K., Kirby, C. E., Leung, K. S., Lyons, D. T., Michaels, G. A., Miller, J., Morris, R. B., Morrison, A. D., Pierson, R. G., Scott, J. F., Shaffer, S. J., Slonski, J. P., Stofan, E. R., Thompson, T. W. & Wall, S. D. 1992. Magellan Mission Summary. Journal of Geophysical Research E97, 13,067–90.Google Scholar
Sclater, J.G., Jaupart, C. & Galson, D. 1980. The heat flow through oceanic and continental crust and the heat loss of the earth. Review of Geophysics and Space Physics 18, 269–311.Google Scholar
Sen, C. & Dunn, T. 1994. Dehydration melting of basaltic composition amphibolite at 1.5 and 2.0 Gpa: implications for the origin of adakites. Contributions to Mineralogy and Petrology 117, 39-409.Google Scholar
Stofan, E. R., Bindschandler, D. L” Head, J. W. & Parmentier, E. M. 1991. Coronae structures on Venus: models and origin. Journal of Geophysical Research E96, 20,933–6.Google Scholar
Stofan, E. R. & Head, J. W. 1990. Coronae of Mnemosyne Regio: morphology and origin. Icarus 83, 216–43.Google Scholar
Surkov, Y. A., Moskalyeva, L. P., Scheglov, O. P., Kharyukova, V. P., Manvelyan, V. S., Kirichenko, V. S. & Dudin, A. D. 1983. Determination of the elemental composition of rocks on Venus by Venera 13 and Venera 14 (preliminary results). Journal of Geophysical Research 88, 81–93.Google Scholar
Triton, D. J. 1988. Physical Fluid Dynamics. Oxford: Clarendon Press.Google Scholar
Turcotte, D. L. 1987. Physics magma segregation processes. Geochemical Society Special Publication 1, 69–74.Google Scholar
Weinberg, R. E. & Podladchikov, Y. Y. 1994. Diapiric ascent of magmas through power law crust and mantle. Journal of Geophysical Research B99, 9,543–59.Google Scholar
Wilson, L. & Head, J. W. 1994. Mars: review and analysis of volcanic eruption theory and relationships to observed landforms. Review of Geophysics 32, 221–64.Google Scholar
Wilson, L. & Parfitt, E. A. 1990. Widths of dykes on Earth and Mars. Lunar and Planetary Science 21, 1345–6.Google Scholar