Evidence of silicate immiscibility within flood basalts from the Central Atlantic Magmatic Province

J. G. Shellnutt, J. Dostal, Y. Iizuka

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The role silicate-liquid immiscibility plays in the formation of macro-scale, bimodal volcanic/plutonic igneous complexes, and Fe-Ti oxide deposits is debated as the rock compositions produced by immiscibility are similar to those produced by other petrological processes. Within the flows of the North Mountain basalt of the Central Atlantic Magmatic Province are centimeter-thick granophyre layers. The granophyre layers are a mixture of mafic (i.e., ilmenite, magnetite, ferroaugite, plagioclase, stilpnomelane, ferrorichterite) and felsic (i.e., sanidine, quartz) minerals and highly siliceous (>75 wt% SiO2) mesostases. Petrological modeling indicates that the siliceous mesostasis + sanidine + quartz ± ferrorichterite represents a Si-rich silicate immiscible melt whereas the ferroaugite + plagioclase + stilpnomelane represent the Fe-rich silicate immiscible liquid. The identification of naturally occurring silicate-liquid immiscibility at scales greater than micron level is an important observation which may be useful in identifying volcanic and plutonic rocks which formed by macro-scale silicate-liquid immiscibility. Key Points The Early Jurassic North Mountain flood basalts contain silicic mesostases The mesostasis + sanidine + quartz represent an immiscible silicic liquid Silicate immiscibility may be an important process in volcanic systems

Original languageEnglish
Pages (from-to)4921-4935
Number of pages15
JournalGeochemistry, Geophysics, Geosystems
Volume14
Issue number11
DOIs
Publication statusPublished - 2013 Nov 1

Keywords

  • Central Atlantic Magmatic Province
  • Early Jurassic
  • Nova Scotia
  • fractional crystallization
  • silicate-liquid immiscibility
  • tholeiitic basalt

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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