First-order major element variation in basalt glasses from the mid-Atlantic ridge: 29oN to 73oN.

Document Type

Article

Date of Original Version

1-1-1981

Abstract

Basaltic glasses from 29oN to 73oN on the Mid-Atlantic Ridge define two geographic and compositional groups that are characterized by different major element concentrations, phase assemblages and partition coefficients. The range of glass compositions in the two groups forms two distinct but parallel cotectic trends within the basalt tetrahedron, which are believed to define the quaternary univariant line O1-P1-Cpx-Liq along which the magmas evolved during fractionation at low to intermediate pressure. It is proposed that the shift in phase boundaries and univariant lines reflects differences in melt and source compositions of the two groups. The distribution of the two groups is thus taken to indicate two major petrographic provines of the Mid-Atlantic Ridge.-from Author

Publication Title, e.g., Journal

Journal of Geophysical Research

Volume

86

Issue

B10

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