eCite Digital Repository

Glass inclusions in magnesian olivine phenocrysts from Tonga: evidence for highly refractory parental magmas in the Tongan arc

Citation

Falloon, TJ and Green, DH, Glass inclusions in magnesian olivine phenocrysts from Tonga: evidence for highly refractory parental magmas in the Tongan arc, Earth and Planetary Science Letters, 81, (1) pp. 95-103. ISSN 0012-821X (1986) [Refereed Article]

Copyright Statement

Copyright 1986 Elsevier

DOI: doi:10.1016/0012-821X(86)90103-2

Abstract

During the 1984 "Natsushima" cruise to the North Tonga arc, fresh volcanic rocks were recovered from the Tongan forearc. Olivine phenocrysts in some of the dredged rocks are highly magnesian (Fo94) and contain large (up to 0.2 mm) glass inclusions. The glass inclusion chemistry, as analysed by electron microprobe, is characterized by high CaO (> 13 wt.%) and low Na2O (< 0.8 wt.%) contents, resulting in very high CaO/Na2O ratios (1829). Such high SCV002SCV0 CaO/Na2O ratios in glasses provide a ready explanation for the occurrence of extremely calcic plagioclase (up to SCV002SCV0 An100) in the Tongan arc lavas. The prevalence of magma mixing and the existence of a spectrum of liquids, ranging to the extremely refractory glasses analysed, is a characteristic of this intra-oceanic island arc environment. High PH2O is not important in precipitation of extremely calcic plagioclase from common low CaO/Na2O liquids, although water SCV002SCV0 plays a significant role in controlling melting in refractory source compositions.

Item Details

Item Type:Refereed Article
Keywords:olivine, glass inclusions, Tongan forearc, calcic plagioclase, Natsushima, boninite
Research Division:Earth Sciences
Research Group:Geology
Research Field:Igneous and Metamorphic Petrology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:Falloon, TJ (Dr Trevor Falloon)
Author:Green, DH (Professor David Green)
ID Code:99198
Year Published:1986
Web of Science® Times Cited:45
Deposited By:Earth Sciences
Deposited On:2015-03-17
Last Modified:2015-04-15
Downloads:0

Repository Staff Only: item control page