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The significance of the melting interval of basaltic magmas at various pressures

Published online by Cambridge University Press:  01 May 2009

S. Maaløe
S. Maaløe
Affiliation:
Institute of General GeologyØstervoldgade 5 1350, Copenhagen K, Denmark
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Summary

The melting intervals of basaltic magmas are investigated in detail at various pressures, as the size of the interval has an important bearing on the genesis of igneous rocks. Tholeiitic magmas do not have a more pronounced four phase proximity at low pressures than at higher ones. This result seems to oppose the generally accepted low pressure character of these magmas; but as there is a general decrease in melting intervals with increasing pressure, the four phase proximity is nevertheless sustained. The melting intervals of alkaline rocks decrease rapidly with increasing pressure. Small variations in the temperature may therefore generate large variations in the composition of the liquids developed at high pressures.

Type
Articles
Information
Geological Magazine , Volume 110 , Issue 2 , March 1973 , pp. 103 - 112
Copyright
Copyright © Cambridge University Press 1973

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