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The fluid dynamics of crustal melting by injection of basaltic sills

Published online by Cambridge University Press:  03 November 2011

Herbert E. Huppert ,
R. Stephen  and
J. Sparks
Herbert E. Huppert
Affiliation:
Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW, U.K.
R. Stephen
Affiliation:
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB23EQ, U.K.
J. Sparks
Affiliation:
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB23EQ, U.K.
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Abstract

When basaltic magma is emplaced into continental crust, melting and generation of granitic magma can occur. We present experimental and theoretical investigations of the fluid dynamical and heat transfer processes at the roof and floor of a basaltic sill in which the wall rocks melt. At the floor, relatively low density crustal melt rises and mixes into the overlying magma, which would form hybrid andesitic magma. Below the roof the low-density melt forms a stable layer with negligible mixing between it and the underlying hotter, denser magma. Our calculations applied to basaltic sills in hot crust predict that sills from 10-1500 m thick require only 2-200 years to solidify, during which time large volumes of overlying layers of convecting silicic magma are formed. These time scales are very short compared with the lifetimes of large silicic magma systems of around 106 years, and also with the time scale of 107 years for thermal relaxation of the continental crust. An important feature of the process is that crystallisation and melting occur simultaneously, though in different spots of the source region. The granitic magmas formed are thus a mixture of igneous phenocrysts and lesser amounts of restite crystals. Several features of either plutonic or volcanic silicic systems can be explained without requiring large, high-level, long-lived magma chambers.

Keywords

crystallisationgraniteshybridisationintrusionsmagma chambersmelting of continental crustrestite
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 79 , Issue 2-3: The Origin of Granites , 1988 , pp. 237 - 243
Copyright
Copyright © Royal Society of Edinburgh 1988

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References

Campbell, I. H. & Turner, J. S. 1987. A laboratory investigation of assimilation at the top of a basaltic magma chamber. J GEOL 95, 155–173.CrossRefGoogle Scholar
Chappell, B. W., White, A. J. R. & Wyborn, D. 1987. The importance of residual source material (restite) in granite petrogenesis. J PETROL 28, 1111–1138.CrossRefGoogle Scholar
Francis, P. W., Sparks, R. S. J., Hawkesworth, C. J., Thorpe, R. S., Pyle, D. M. & Tait, S. R. 1988. Petrogenesis of dacitic magmas of the Cerro Galan Caldera, N.W. Argentina. GEOL MAG (in press).Google Scholar
Hildreth, W. 1981. Gradients in silicic magma chambers: implications for silicic magmatism. J GEOPHYS RES 86, 10153–10192.CrossRefGoogle Scholar
Huppert, H. E. (in prep.). The response to the initiation of a hot, turbulent flow over a cold, solid surface. J FLUID MECH (submitted).Google Scholar
Huppert, H. E. & Sparks, R. S. J. 1985. Cooling and contamination of mafic and ultramafic magmas during ascent through continental crust. J EARTH PLANET SCI LETT 74, 371–386.CrossRefGoogle Scholar
Huppert, H. E. & Sparks, R. S. J. 1988a. Melting of the roof of a chamber containing hot, turbulently convecting fluid. J FLUID MECH 188, 107–131.CrossRefGoogle Scholar
Huppert, H. E. & Sparks, R. S. J. 1988b. The generation of granitic magmas by intrusion of basalt into continental crust. J PETROL (in press).CrossRefGoogle Scholar
Irvine, T. N. 1970. Heat transfer during solidification of layered intrusions. I. Sheets and sills. CAN J EARTH SCIS 1, 1031–1061.CrossRefGoogle Scholar
Iyer, H. M. 1984. Geophysical evidence for the location, shapes and sizes, and internal structures of magma chambers beneath regions of Quaternary volcanism. PHILOS TRANS R SOC LONDON A310, 473–510.Google Scholar
Lipman, P. W. 1984. The roots of ash-flow calderas in Western North America; windows into the tops of granitic batholiths. J GEOPHYS RES 89, 8801–8841.CrossRefGoogle Scholar
Pitcher, W. S. 1986. A multiple and composite batholith. In Pitcher, W. S., Atherton, M. P., Cobbing, E. J. & Backinsale, R. D. (eds) Magmatism at a Plate Edge, 93–101. Glasgow and London: Blackie Halstead Press.Google Scholar
Ryan, M. P. 1987. Neutral buoyancy and the mechanical evolution of magmatic systems. In Mysen, B. O. (ed.) Magmatic Processes: Physicochemical Principles, Special Publication No. 1 of The Geochemical Society, 259–288. Dayton: The Geochemical Society.Google Scholar
Turner, J. S. 1973. Buoyancy Effects in Fluids. Cambridge: Cambridge University Press.CrossRefGoogle Scholar
Wall, V. J., Clemens, J. D. & Clarke, D. B. 1987. Models for granitoid evolution and source compositions. J GEOL 95, 731–750.CrossRefGoogle Scholar
Whitney, J. A. & Stormer, J. C. 1986. Mineralogy, petrology and magmatic conditions from the Fish Canyon Tuff, Central San Juan Mountain Field, Colorado. J PETROL 26, 726–762.CrossRefGoogle Scholar
Wickham, S. M. 1987a. Crustal anataxis and granite petrogenesis during low-pressure regional metamorphism: the Trois Seigneurs Massif, Pyrenees, France. J PETROL 28, 127–169.CrossRefGoogle Scholar
Wickham, S. M. 1987b. The segregation and emplacement of granitic magmas. J GEOL SOC LONDON 144, 281–298.CrossRefGoogle Scholar
Wyborn, D. & Chappell, B. W. 1986. The petrogenetic significance of chemically related plutonic and volcanic rock units. GEOL MAG 123, 619–628.CrossRefGoogle Scholar
Wyllie, P. J. 1984. Constraints imposed by experimental petrology on possible and impossible magma sources and products. PHILOS TRANS R SOC LONDON A310, 439–456.Google Scholar