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Residual glasses and melt inclusions in basalts from DSDP Legs 45 and 46 - Evidence for magma mixingMicroprobe analyses of natural glasses in basalts recovered by Legs 45 and 46 of the Deep Sea Drilling Project are reported and interpreted in the context of other geochemical, petrographic and experimental data on the same rocks (Rhodes et al., 1978). Residual glass compositions in the moderately evolved aphyritic and abundantly phyric basalts within each site indicate that none of the units is related to any other or to a common parent by simple fractional crystallization. The compositional trends, extensive disequilibrium textures in the plagioclase phenocrysts and the presence in evolved lavas of refractory plagioclase and olivine phenocrysts bearing primitive melt inclusions provide evidence that magma mixing had a major role in the genesis of the Leg 45 and 46 basalts. The magma parental to these basalts was most likely characterized by high Mg/(Mg + Fe/+2/), CaO/Al2O3, CaO/Na2O and low lithophile concentrations. A mixing model involving incremental enrichment of magmaphile elements by repeated episodes of mixing of relatively primitive and moderately evolved magmas, followed by a small amount of fractionation is consistent with the characteristics of the basalts studied.
Document ID
19790056256
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Dungan, M. A.
(Lunar and Planetary Institute Houston, Tex., United States)
Rhodes, J. M.
(Lockheed Electronics Co., Inc. Houston, Tex., United States)
Date Acquired
August 9, 2013
Publication Date
January 1, 1978
Publication Information
Publication: Contributions to Mineralogy and Petrology
Volume: 67
Subject Category
Earth Resources And Remote Sensing
Accession Number
79A40269
Funding Number(s)
CONTRACT_GRANT: NSR-09-051-001
Distribution Limits
Public
Copyright
Other

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