Constraints on magma ascent, emplacement, and eruption: geochemical and mineralogical data from drill-core samples at Obsidian dome, Inyo chain, California
Systematic chemical and mineralogical variability occurs in samples from drill holes through Obsidian dome, the conduit to the dome, and a nearby associated feeder dike. The drill-hole samples from the margins of the conduit and most of the lower part of the dome are high-Ba, low-silica rhyolites; they contain two populations of phenocrysts and represent commingled magmas, whereas samples from the dike and upper parts of the dome are low-Ba, higher silica rhyolites that do not reflect commingled magmas. Samples from the center of the conduit are low-Ba, higher silica rhyolites that are only slightly mixed. A major part of the variability within the drill-core samples of the dome and conduit reflects the juxtaposition and commingling of two distinct magmas during their passage through the conduit.
- Research Organization:
- Michigan State Univ., East Lansing (USA)
- DOE Contract Number:
- FG02-85ER13321
- OSTI ID:
- 5276172
- Journal Information:
- Geology; (United States), Journal Name: Geology; (United States) Vol. 15:5; ISSN GLGYB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
580202* -- Geophysics-- Volcanology-- (1980-1989)
580400 -- Geochemistry-- (-1989)
CALIFORNIA
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMISTRY
DIKES
DRILL CORES
ELEMENTS
FEDERAL REGION IX
GEOCHEMISTRY
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
MAGMA
METALS
MINERALOGY
MIXING
NORTH AMERICA
OXIDES
OXYGEN COMPOUNDS
TRACE AMOUNTS
USA
VARIATIONS
VOLCANIC REGIONS
VOLCANISM