Fiskenaesset Anorthosite Complex: Stable isotope evidence for shallow emplacement into Archean ocean crust

Journal Article · Sat Jun 01 04:00:00 EDT 1996 · Geology

DOI:https://doi.org/10.1130/0091-7613(1996)024<0523:TFACSI>2.3.CO;2· OSTI ID:420916

Peck, W H; Valley, J W ^[1]

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1. Univ. of Wisconsin, Madison, WI (United States)

Oxygen and hydrogen isotope ratios indicate that unusual rocks at the upper contact of the Archean Fiskenaesset Anorthosite Complex at Fiskenaesset Harbor (southwest Greenland) are the products of hydrothermal alteration by seawater at the time of anorthosite intrusion. Subsequent granulite-facies metamorphism of these Ca-poor and Al- and Mg-rich rocks produced sapphirine- and kornerupine-bearing assemblages. Because large amounts of surface waters cannot penetrate to depths of 30 km during granulite-facies metamorphism, the isotopic signature of the contact rocks must have been obtained prior to regional metamorphism. The stable isotope and geochemical characteristics of the contact rocks support a model of shallow emplacement into Archean ocean crust for the Fiskenaesset Anorthosite Complex. 45 refs., 3 figs., 2 tabs.

• DOE Contract Number: FG02-93ER14389
• OSTI ID: 420916
• Journal Information: Geology, Journal Name: Geology Journal Issue: 6 Vol. 24; ISSN 0091-7613; ISSN GLGYBA
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
58 GEOSCIENCES
EARTH CRUST
GEOCHEMISTRY
HYDROGEN
ISOTOPE DATING
ISOTOPE RATIO
METAMORPHIC ROCKS
METAMORPHISM
OXYGEN
SEAWATER