U-Pb zircon dates of morin anorthosite suite rocks, Grenville Province, Quebec
- McGill Univ., Montreal, Quebec (Canada)
U-Pb zircon ages of samples of anorthosite, pyroxene monzodiorite (jotunite), and pyroxene quartz monzonite (quartz mangerite) of the Morin anorthosite complex, Grenville Province, Quebec, are 1155 {plus minus} 3, 1146 {plus minus} 4 and 1135 {plus minus} 3 Ma, respectively. These dates are very similar to available dates for equivalent units of the Lac St-Jean and Adirondack anorthosite suite occurrences and slightly predate estimates of 1075-1100 Ma for peak metamorphic conditions during the Grenville orogeny in this region. {sup 87}Sr/{sup 86}Sr initial ratios of 0.7048-0.7051 for the three Morin units sampled permit a comagmatic origin if the different emplacement or cooling times can be reconciled. The mangerite sampled cannot have been formed by fusion of the upper crust, but may have been derived from a relatively juvenile crust at depth. All three units have interacted with continental crust, given the likely depleted nature of the mantle in this region.
- OSTI ID:
- 5528698
- Journal Information:
- Journal of Geology; (United States), Journal Name: Journal of Geology; (United States) Vol. 99:5; ISSN JGEOA; ISSN 0022-1376
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
580000* -- Geosciences
ACTINIDE ISOTOPES
ADIRONDACK MOUNTAINS
AGE ESTIMATION
ALKALINE EARTH ISOTOPES
ANORTHOSITES
APPALACHIAN MOUNTAINS
BETA DECAY RADIOISOTOPES
CANADA
COMPARATIVE EVALUATIONS
CONTINENTAL CRUST
DEVELOPED COUNTRIES
EARTH CRUST
ELECTRON CAPTURE RADIOISOTOPES
EVALUATION
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
GABBROS
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
HOURS LIVING RADIOISOTOPES
IGNEOUS ROCKS
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE DATING
ISOTOPE RATIO
ISOTOPES
LEAD ISOTOPES
MINERALS
MOUNTAINS
NORTH AMERICA
NUCLEI
OXYGEN COMPOUNDS
PLUTONIC ROCKS
PYROXENES
QUEBEC
RADIOISOTOPES
ROCKS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
STABLE ISOTOPES
STRONTIUM 86
STRONTIUM 87
STRONTIUM ISOTOPES
URANIUM ISOTOPES
ZIRCON