Age, field, and petrological relationships of the Hyde School Gneiss, Adirondack lowlands, New York: Criteria for an intrusive igneous origin

Journal Article · Wed Jan 01 00:00:00 EST 1992 · Journal of Geology; (United States)

DOI:https://doi.org/10.1086/629572· OSTI ID:7031489

McLelland, J ^[1]; Perham, A ^[2]; Chiarenzelli, J

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1. Colgate Univ., Hamilton, NY (United States)
2. Miami Univ., Oxford, OH (United States)

Alaskitic and tonalitic rocks constituting Hyde School Gneiss (HSG) occur in 14 domical bodies in the Adirondack lowlands. Recent models have interpreted these bodies as metamorphosed rhyolitic and dacitic ash-flow deposits forming the basal member of a regional stratigraphic package. In contrast, this paper presents criteria and evidence for an intrusive origin for HSG. Field evidence includes intrusion breccias and complex crosscutting relationships involving mafic layers resembling synplutonic dikes. Petrologic constraints supporting an intrusive origin include: (1) the common occurrence of quartz-mesoperthite hypersolvus assemblages; (2) magmatic features in tonalitic, trondhjemitic, and alaskitic facies, (3) local occurrences of orthopyroxene in all facies of HSG; and (4) the development of marginal garnet-sillimanite gneiss with corundum-spinel-garnet-sillimanite assemblages yielding paleotemperatures of 780-810C and interpreted as restite remaining after anatexis of country rock metapelite by intrusions of hypersolvus granitoids. U-Pb zircon ages reported here suggest that the majority of the HSG was intruded at ca. 1230 Ma, contemporaneous with high-grade metamorphic activity in the Adirondacks and elsewhere in the SW sector of the Grenville Province. Geochronological evidence from a leucogranitic rock crosscutting metasediments on Wellesley Island suggest that these metasediments are older than 1416 {plus minus} 5 Ma.

• OSTI ID: 7031489
• Journal Information: Journal of Geology; (United States), Vol. 100:1; ISSN 0022-1376
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
GNEISSES
ISOTOPE DATING
PETROGENESIS
PETROLOGY
NEW YORK
GEOLOGIC FORMATIONS
CORUNDUM
GARNETS
GEOLOGIC HISTORY
LEAD ISOTOPES
METAMORPHISM
MINERALOGY
SPINELS
URANIUM ISOTOPES
ZIRCON
ACTINIDE ISOTOPES
AGE ESTIMATION
DEVELOPED COUNTRIES
GEOLOGY
ISOTOPES
METAMORPHIC ROCKS
MINERALS
NORTH AMERICA
OXIDE MINERALS
OXYGEN COMPOUNDS
ROCKS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
USA
580000* - Geosciences