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Effects of the changes in slope occurring on liquidus and solidus paths in the system diopside-anorthite-albite

Wyllie, Peter J. (1963) Effects of the changes in slope occurring on liquidus and solidus paths in the system diopside-anorthite-albite. In: International Mineralogical Association: Papers and Proceedings of the Third General Meeting. Special paper / Mineralogical Society of America. No.1. Mineralogical Society of America .

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Liquidus and solidus paths in the system diopside-anorthitc-albite exhibit changes in slope. When plagioclase crystallizes alone from a ternary liquid both paths arc steeper than in the system anorthite-albite, but when plagioclasc is joined by diopside both paths become much less step than in the binary system. This fact, together with other evidence, suggests that the liquidus profile of an igneous rock series may be characterized by three shelves (where small temperature changes cause much fusion or crystallization, and large compositional changes) separated by steep slopes (where large temperature changes cause little crystallization or fusion, and small compositional changes). The shelves extend across picritic compositions (upper), basic and intermediate compositions (middle), and acid compositions (lower). The changes in slope may help lo account for the relative proportions of various igneous rocks in different petrographical associations. The origin of primary basaltic and intermediate magmas, and the rarity of intermediate rocks in basic-acid igneous associations are discussed. Marginal zoning, oscillatory zoning, and the development of two generations of crystals (with continuous cooling) are discussed in terms of changes in slope of solidus paths.

Item Type:Book Section
Additional Information:© 1963 Mineralogical Society of America. Contribution No. 61-27 from the College of Mineral Industries. The writer wishes to thank H. I. Drever, P. G. Harris, R. Johnston, W. Q. Kennedy, W. S. Mackenzie, P. L. Roeder and O. F. Tuttle, for kindly reviewing drafts of the manuscript. Their suggestions have led to many improvements in the paper. Parts of this study are being supported by the National Science Foundation.
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Series Name:Special paper / Mineralogical Society of America
Issue or Number:1
Record Number:CaltechAUTHORS:20160331-105203874
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:65803
Deposited By: Tony Diaz
Deposited On:31 Mar 2016 19:41
Last Modified:03 Oct 2019 09:50

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