C-O-H ratios of silicate melt inclusions in basalts from the Galapagos spreading center near 95 degree W: A leaser decrepitation mass spectrometry study

Journal Article · Fri Dec 01 00:00:00 EST 1989 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(89)90095-1· OSTI ID:6713671

Yonover, R N; Sinton, J M ^[1]; Gibson, E K ^[2]; Sommer, M A

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1. Univ. of Hawaii, Honolulu (USA)
2. NASA/Johnson Space Center, Houston, TX (USA)

Volatile ratios (primarily of H{sub 2}O and CO{sub 2}) in individual silicate melt (glass) inclusions in minerals have been analyzed using laser volatilization and mass spectrometry. A Nd-glass laser was used to produce 50-micrometer diameter pits in silicate melt inclusions. Released volatiles were analyzed directly with a computer-controlled quadrupole mass spectrometer. The mean CO{sub 2}/H{sub 2}O from the propagating rift (0.245 {plus minus} 0.068) silicate glass inclusions is significantly lower than that of the actively failing rift (0.641 {plus minus} 0.241); this difference probably reflects different degrees of degassing during contrasting magmatic histories for the two regions. Relatively undifferentiated failing rift magmas must have relatively short crustal residence time prior to eruption and, therefore, have not undergone significant degassing of CO{sub 2}, as would appear to be the case for the more highly fractionated propagating rift magmas. The laser-mass spectrometric system described herein has the ability to act as a point-source probing device that can differentiate between the various volatile sites in minerals and rocks (as well as synthetic materials) on a micrometer scale.

• OSTI ID: 6713671
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Vol. 53:12; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
BASALT
INCLUSIONS
CHEMICAL COMPOSITION
PETROGENESIS
PACIFIC OCEAN
RIFT ZONES
CARBON DIOXIDE
DEGASSING
GEOCHEMISTRY
GEOLOGIC HISTORY
MAGMA
MAGMATISM
MASS SPECTROSCOPY
NEODYMIUM COMPOUNDS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMISTRY
GEOLOGIC STRUCTURES
IGNEOUS ROCKS
OXIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
ROCKS
SEAS
SPECTROSCOPY
SURFACE WATERS
VOLCANIC ROCKS
580000* - Geosciences