Post-Taconic blueschist suture in the northern Appalachians of northern New Brunswick, Canada

Journal Article · Thu Nov 01 00:00:00 EST 1990 · Geology; (USA)

DOI:https://doi.org/10.1130/0091-7613(1990)018<1073:PTBSIT>2.3.CO;2· OSTI ID:5796820

van Staal, C R; Ravenhurst, C E; Roddick, J C ^[1]; Winchester, J A ^[2]; Langton, J P ^[3]

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1. Geological Survey of Canada, Ottawa, Ontario (Canada)
2. Univ. of Keele (England)
3. Queen's Univ., Kingston, Ontario (Canada)

A narrow belt of Late Ordovician-Early Silurian blueschist, at least 70 km long, separates an allochthonous fragment of back-arc oceanic crust of the Middle Ordovician Fournier Group from underlying, rift-related volcanic rocks of the Middle Ordovician Tetagouche Group in northern New Brunswick, Canada. The basalts on both sides of the blueschist belt are predominantly metamorphosed to greenschist facies conditions. The blueschist belt is interpreted to be an out-of-sequence thrust zone that accommodated tectonic transport of higher pressure rocks on top of lower pressure rocks during post-peak blueschist facies metamorphism. The blueschists have higher Fe{sub 2}O{sub 3}/FeO ratios and total iron contents in comparison to otherwise chemically equivalent basalts of the Fournier and Tetagouche Groups that have been metamorphosed into greenschists. The blueschist belt was probably the site of channelized flow of oxidizing fluids during active deformation ina subduction complex formed during the closure of a wide Taconic back-arac basin in Late Ordovician-Silurian time.

• OSTI ID: 5796820
• Journal Information: Geology; (USA), Vol. 18:11; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
APPALACHIAN MOUNTAINS
STRATIGRAPHY
TECTONICS
NEW BRUNSWICK
BASALT
DEFORMATION
GEOCHEMISTRY
GEOLOGIC FORMATIONS
GEOLOGY
IRON OXIDES
METAMORPHIC ROCKS
METAMORPHISM
ORDOVICIAN PERIOD
SCHISTS
SILURIAN PERIOD
SUBDUCTION ZONES
VOLCANIC ROCKS
CANADA
CHALCOGENIDES
CHEMISTRY
GEOLOGIC AGES
IGNEOUS ROCKS
IRON COMPOUNDS
MOUNTAINS
NORTH AMERICA
OXIDES
OXYGEN COMPOUNDS
PALEOZOIC ERA
ROCKS
TRANSITION ELEMENT COMPOUNDS
580000* - Geosciences