Partial melting of amphibolite to trondhjemite at Nunatak Fiord, St. Elias Mountains, Alaska
Conference
·
· Geol. Soc. Am., Abstr. Programs; (United States)
OSTI ID:6595640
At Nunatak Fiord, 55km NE of Yakutat, Alaska, a uniform layer of Cretaceous basalt ca. 3km thick was metamorphosed ca. 67 million years ago to amphibolite and locally partially melted to pegmatitic trondhjemite. Segregations of plagioclase-quartz+/-biotite rock, leucosomes in amphibolite matrix, range from stringers 5-10mm thick to blunt pods as thick as 6m. They tend to be parallel to foliation of the amphibolite, but crosscutting is common. The assemblage aluminous hornblende-plagioclase-epidote-sphene-quartz gave a hydrous melt that crystallized to plagioclase-quartz+/-biotite pegmatitic trondhjemite. 5-10% of the rock melted. Eu at 2x chondrites is positively anomalous. REE partitioning in melt/residum was controlled largely by hornblende and sphene. Though the mineralogical variability precludes quantitative modeling, partial melting of garnet-free amphibolite to heavy-REE-depleted trondhjemitic melt is a viable process.
- Research Organization:
- Univ. of Maryland, College Park (USA)
- OSTI ID:
- 6595640
- Report Number(s):
- CONF-8510489-
- Conference Information:
- Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
- Country of Publication:
- United States
- Language:
- English
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· Am. Mineral.; (United States)
·
OSTI ID:6894581
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Journal Article
·
Thu Jun 01 00:00:00 EDT 1989
· Geology; (USA)
·
OSTI ID:7000871
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Conference
·
Sun Feb 28 23:00:00 EST 1993
· Geological Society of America, Abstracts with Programs; (United States)
·
OSTI ID:5505882
Related Subjects
58 GEOSCIENCES
580300 -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
580400* -- Geochemistry-- (-1989)
ALASKA
AMPHIBOLITES
ANORTHOSITES
BASALT
BIOTITE
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
CRETACEOUS PERIOD
FEDERAL REGION X
GABBROS
GEOCHEMISTRY
GEOLOGIC AGES
GRANITES
IGNEOUS ROCKS
MAGMATISM
MELTING
MESOZOIC ERA
METAMORPHIC ROCKS
METAMORPHISM
MICA
MINERALOGY
MINERALS
NORTH AMERICA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PEGMATITES
PETROGENESIS
PHASE TRANSFORMATIONS
PLUTONIC ROCKS
QUARTZ
ROCKS
SILICATE MINERALS
SILICON COMPOUNDS
SILICON OXIDES
USA
VOLCANIC ROCKS
580300 -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
580400* -- Geochemistry-- (-1989)
ALASKA
AMPHIBOLITES
ANORTHOSITES
BASALT
BIOTITE
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
CRETACEOUS PERIOD
FEDERAL REGION X
GABBROS
GEOCHEMISTRY
GEOLOGIC AGES
GRANITES
IGNEOUS ROCKS
MAGMATISM
MELTING
MESOZOIC ERA
METAMORPHIC ROCKS
METAMORPHISM
MICA
MINERALOGY
MINERALS
NORTH AMERICA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PEGMATITES
PETROGENESIS
PHASE TRANSFORMATIONS
PLUTONIC ROCKS
QUARTZ
ROCKS
SILICATE MINERALS
SILICON COMPOUNDS
SILICON OXIDES
USA
VOLCANIC ROCKS