Magma can be defined as high-temperature molten rock. Its familiar extruded form is volcanic lava, but the term “magma” covers the physical melt from the point of its generation deep in the Earth to the point of its solidification either within or at the surface of the Earth. Magmas may contain substantial proportions of dissolved volatiles (H2O, CO2, etc.—Wyllie, 1979) that are lost, often spectacularly, during volcanic eruptions, but that play an important role in the generation and subsequent differentiation and behavior of the magma. They may also contain suspended crystals that have precipitated out of, or settled into, the magma, or that are remnants of its source rock. For practical purposes, the term magma is also used in a more specific manner, particularly when discussing the petrogenesis and chemistry of igneous rocks, to refer essentially to the liquid silicate portion, free from volatiles and suspended crystals. The reasoning behind this restriction is that (1)...
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Bibliography
Bailey, D. K., 1980, Volatile flux, geotherms and the generation of the kimberlite–carbonatite–alkaline magma spectrum, Mineral. Mag. 43, 695–699.
Bailey, D. K., J. Tarney, and K. C. Dunham, eds., 1980, The Evidence for Chemical Heterogeneity in the Earth's Mantle, Phil. Trans. R. Soc. London A297.
Bottinga, Y. and D. F. Weill, 1972, The viscosity of magmatic silicate liquids: a model for calculation, Am. J. Sci. 272, 438–475.
Bowen, N. L., 1928, The Evolution of the Igneous Rocks. Princeton University Press.
Kuno, H., 1968, Differentiation of basalt magmas, in H. H. Hess and A. Poldervaart, ed., Basalts, Vol. 2. New York: Wiley Interscience, 623–688.
Kushiro, I., 1980, Viscosity, density and structure of silicate melts at high pressures, and their petrological applications, in R. B. Hargraves, ed., Physics of Magmatic Processes. Princeton University Press, 93–120.
Maaløe, S., 1985, Principles of Igneous Petrology. New York: Springer-Verlag.
Murase, T. and A. R. McBirney, 1973, Properties of some common igneous rocks and their melts at high temperatures, Bull. Geol. Soc. Am. 84, 3563–3592.
Scarfe, C. M., B. O. Mysen, and D. Virgo, 1979, Changes in viscosity and density of melts of sodium disilicate, sodium metasilicate, and diopside composition with pressure, Carnegie Inst. Washington Yearbk 78, 547–551.
Wyllie, P. J., 1979, Magmas and volatile components, Am. Mineral. 64, 469–500.
Cross-references
Rights and permissions
Copyright information
© 1989 Van Nostrand Reinhold
About this entry
Cite this entry
Tarney, J. (1989). Magma . In: Petrology. Encyclopedia of Earth Science. Springer, Boston, MA. https://doi.org/10.1007/0-387-30845-8_126
Download citation
DOI: https://doi.org/10.1007/0-387-30845-8_126
Publisher Name: Springer, Boston, MA
Print ISBN: 978-0-442-20623-9
Online ISBN: 978-0-387-30845-6
eBook Packages: Springer Book Archive