Assimilation is the process whereby solid or fluid foreign material is incorporated into magma. The term implies no specific mechanism and the process depends on many factors, including temperature, cooling rate of the magma, gas pressure, and the composition of the material being assimilated. The result is a contaminated magma and, on cooling, rocks that are referred to as being contaminated. Wholesale assimilation requires the magma to be superheated, which is rarely the case for a fractionating magma. Hybridization can be synonymous with contamination but most commonly it refers either to mixing of two magmas or to one magma digesting earlier-formed magmatic material.
Reactions involved in the assimilation of sedimentary material by basic magma are given by Bowen (1928): magma crystallizing early-formed high-temperature members of the continuous and discontinuous reaction series incorporate the lower-temperature phases in the sedimentary material into the liquid fraction....
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
Bowen, N. L., 1928, The Evolution of the Igneous Rocks. Princeton University Press.
Daly, R. A., 1910, Origin of alkaline rocks, Bull. Geol. Soc. Am. 21, 87–118.
Gribble, C. D., 1968, The cordierite-bearing rocks of the Haddo House and Arnage districts, Aberdeenshire, Contrib. Mineral. Petrol. 17, 315–330.
Hall, A., 1987, Igneous Petrology. Harlow, U.K.: Longman, 260–285.
Irvine, T. N., 1975, Crystallization sequences in the Muskox intrusion and other layered intrusions, Geochim. Cosmochim. Acta 39, 991–1021.
Joplin, G. A., 1935, Diorite-limestone reaction at Ben Bullen, New South Wales: a study in contamination, Geol. Mag. 72, 97–116.
Kelemen, P. B., 1986, Assimilation of ultramafic rock in subduction-related magmatic arcs, J. Geol. 94, 829–843.
McBirney, A. R., 1979, Effects of assimilation, in H. S. Yoder, ed., The Evolution of the Igneous Rocks: Fiftieth Anniversary Perspectives. Princeton University Press, 307–338.
Nicholls, J. and M. Z. Stout, 1982, Heat effects of assimilation, crystallization and vesiculation in magmas, Contrib. Mineral. Petrol. 81, 328–339.
Oxburgh, E. R. and T. McRae, 1984, Physical constraints on magma contamination in the continental crust: an example, the Adamello complex, Phil Trans. R. Soc. London A310, 457–472.
Pankhurst, R. J., 1969, Strontium isotope studies related to petrogenesis in the Caledonian basic igneous province of NE Scotland, J. Petrol. 10, 115–143.
Tilley, C. E. and H. F. Harwood, 1931, The dolerite-chalk contact of Scawt Hill, Co. Antrim, Ireland, Mineral. Mag. 22, 439–468.
Watson, E. B., 1982, Basalt contamination by continental crust: some experiments and models, Contrib. Mineral. Petrol. 80, 73–87.
Cross-references
Rights and permissions
Copyright information
© 1989 Van Nostrand Reinhold
About this entry
Cite this entry
Gribble, C.D. (1989). Assimilation . In: Petrology. Encyclopedia of Earth Science. Springer, Boston, MA. https://doi.org/10.1007/0-387-30845-8_18
Download citation
DOI: https://doi.org/10.1007/0-387-30845-8_18
Publisher Name: Springer, Boston, MA
Print ISBN: 978-0-442-20623-9
Online ISBN: 978-0-387-30845-6
eBook Packages: Springer Book Archive