The Carthage-Colton mylonite zone (Adirondack Mountains, New York): The site of a cryptic suture in the Grenville Orogen

Journal Article · Tue Sep 01 04:00:00 EDT 1992 · Journal of Geology; (United States)

DOI:https://doi.org/10.1086/629613· OSTI ID:7159395

Mezger, K; Pluijm, B.A. van der; Essene, E J; Halliday, A N ^[1]

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1. Univ. of Michigan, Ann Arbor (United States)

U-Pb ages were determined on metamorphic sphenes and monazites from the Late Proterozoic Adirondack Highlands and Lowlands in the vicinity of the Carthage-Colton mylonite zone. Monazites were extracted from metapelites, and sphenes were separated from marbles, calc-silicate gneisses, and granite gneisses in order to determine the timing and the duration of metamorphism as well as the cooling histories for rocks on either side of the mylonite zone. Monazite ages from the Lowlands range from 1,171-1,137 Ma; sphene ages in the Lowlands range from 1,156-1,103 Ma, those from the Highlands immediately to the east of the mylonite zone range from 1,050-982 ma. The ages indicate that the last high-grade metamorphism in the Highlands is ca. 100 m.y. younger than in the Lowlands and that both terranes had separate cooling histories at least until ca. 1,000 Ma. Sphenes from within the Carthage-Colton mylonite zone yield ages of about 1,098 Ma, which are distinct from sphene ages on either side of the shear zone. The mineral ages, structures, and metamorphic histories suggests that the Carthage-Colton mylonite zone is a fundamental tectonic boundary within the Proterozoic Grenville Orogen of North America.

• OSTI ID: 7159395
• Journal Information: Journal of Geology; (United States), Journal Name: Journal of Geology; (United States) Vol. 100:5; ISSN JGEOAZ; ISSN 0022-1376
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ACTINIDE ISOTOPES
ADIRONDACK MOUNTAINS
AGE ESTIMATION
APPALACHIAN MOUNTAINS
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGIC HISTORY
ISOTOPE DATING
ISOTOPES
LEAD ISOTOPES
MATERIALS
METAMORPHIC ROCKS
METAMORPHISM
MINERALS
MONAZITES
MOUNTAINS
NEW YORK
NORTH AMERICA
PETROGENESIS
PHOSPHATE MINERALS
PRECAMBRIAN ERA
RADIOACTIVE MATERIALS
RADIOACTIVE MINERALS
RARE EARTH COMPOUNDS
ROCKS
SILICATE MINERALS
THORIUM MINERALS
TITANITE
URANIUM ISOTOPES
USA