Open AccessEvidence of silicate immiscibility within flood basalts from the Central Atlantic Magmatic Province
Author(s) -
Shellnutt J. G.,
Dostal J.,
Iizuka Y.
Publication year - 2013
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1002/2013gc004977
Subject(s) - geology , geochemistry , silicate , sanidine , plagioclase , igneous rock , mafic , basalt , felsic , flood basalt , melt inclusions , silicic , magma , quartz , ilmenite , petrology , volcano , volcanism , chemical engineering , engineering , tectonics , paleontology
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% SiO 2 ) 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.