Constraints on the Origin of Nepheline-Normative Primitive Magmas in Island Arcs Inferred from Olivine-hosted Melt Inclusion Compositions

Chemical zonation in olivine-hosted melt inclusions

Significant zonation in major, minor, trace, and volatile elements has been documented in naturally glassy olivine-hosted melt inclusions from the Siqueiros Fracture Zone and the Galapagos Islands. Components with a higher concentration in the host olivine than in the melt (e.g., MgO, FeO, Cr2O3, and MnO) are depleted at the edges of the zoned melt inclusions relative to their centers, whereas ...

Variations in Melt Productivity and Melting Conditions along SWIR (708E^498E): Evidence from Olivine-hosted and Plagioclase-hosted Melt Inclusions

Melt inclusion and host glass compositions from the eastern end of the Southwest IndianRidge showaprogressive depletion in light rare earth elements (LREE), Na8 and (La/Sm)n, but an increase in Fe8, from the NE (648E) towards the SW (498E).These changes indicate an increase in the degree of mantle melting towards the SWand correlate with a shallowing of the ridge axial depth and increase in cru...

FTIR Spectrum of Phenocryst Olivine as an Indicator of Silica Saturation in Magmas

Fourier Transform infrared (FTIR) absorption spectra of hydroxyl were measured on olivine phenocrysts from hydrous basaltic melts that originated in island-arc tectonic settings. The basaltic melts encompass a wide range of silica activities from orthopyroxene-saturated hypersthene-normative to nepheline-normative compositions. The intensities and wavenumber placement of hydroxyl absorption ban...

Oxygen Isotope Compositions of Mineral Separates from Snc Meteorites: Constraints on the Petrogenesis of Martian Magmas

Introduction: Martian (SNC) meteorites are igneous rocks that range from a reduced, trace-element depleted end member to an oxidized, trace-element enriched end member [1-3] (Figure 1). One interpretation of this trend is that relatively reduced, depleted magmas are partial melts of a reduced peridotitic mantle, whereas more oxidized, enriched magmas are mantle-derived magmas contaminated by ox...

NanoSIMS results from olivine-hosted melt embayments: Magma ascent rate during explosive basaltic eruptions