Paper
Chemical and Mineral Relationships in Igneous Rocks
Published Apr 1, 1898 · J. P. Iddings
The Journal of Geology
4
Citations
1
Influential Citations
Abstract
THE attempt to correlate the mineral composition of igneous rocks with the chemical composition of their magmas, that is, of each rock as a whole, is rendered difficult by the chemical character of the rock-making minerals themselves, and by the fact that no fixed association of minerals necessarily results from the crystallization of an igneous rock magma, the association in a given case being affected to a greater or less extent by the physical conditions attending the solidification of the magma. The pyrogenetic rock-making minerals are mostly silicates of several elements which may enter in different proportions into the composition of distinct minerals; so that the chemical difference between a number of these minerals lies in the proportions of their chemical components rather than in the kinds. Among the more important rock-making minerals, including the chief silicates, together with quartz and magnetite, there is no element found only in one mineral. Each constituent may enter several of them. Nevertheless there are limitations to the kinds
Igneous rock mineral composition is difficult to correlate with magma composition, as the chemical composition of rock-making minerals varies and the physical conditions during crystallization influence the association of minerals.
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