Igneous and tectonic evolution of the Batchawana Greenstone Belt, Superior Province: a U-Pb zircon and titanite study
U-Pb isotopic dating of zircon and titanite from all the major litho-tectonic units of the Batchawana belt, an Archean greenstone belt of the Abitibi Subprovince of the Superior Province in Canada, shows that the belt evolved during a period of about 60 Ma between about 2730 and 2670 Ma ago. Subsequent deformation of the supracrustal sequences produced isoclinal folding and culminated in metamorphism ranging from lower greenschist to amphibolite facies and anatexis related to the intrusion of syn- to late-tectonic plutons, four phases of which have ages of 2678 +4/-2 Ma, 2677 +/- 2 Ma, 2677 +/- 3 Ma, and 2676 +/- 2 Ma. Two post-tectonic granitoid plutons in the center of the belt were intruded 2674 +/- 3 Ma and 2673 +/- 5 Ma ago and were followed by the emplacement of a composite mafic to felsic intrusion; a monzonite and a hornblendite from this intrusion yield identical ages of 2668 +/- 2 Ma. Titanite ages are identical or younger than the ages of coexisting zircons and reflect regional metamorphism and post-tectonic plutonism, but in a few cases they are younger and may record increased fluid activity along faults and the intrusion of mafic dikes. U-Pb zircon systematics, together with age and lithological relationships, suggests that the greenstone belt formed in an oceanic environment from material derived initially mainly from the mantle. Subsequent melting at the base of the thickening volcanic succession produced intermediate to felsic volcanic rocks, tonalites, and later granodioritic to granitic plutons leading to the final consolidation of the granite-greenstone terrain. 47 references.
- Research Organization:
- Ontario Geological Survey, Toronto
- OSTI ID:
- 5648906
- Journal Information:
- J. Geol.; (United States), Journal Name: J. Geol.; (United States) Vol. 95:1; ISSN JGEOA
- Country of Publication:
- United States
- Language:
- English
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580100* -- Geology & Hydrology-- (-1989)
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ACTINIDE ISOTOPES
AGE ESTIMATION
CANADA
DEFORMATION
DIKES
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
IGNEOUS ROCKS
ISOTOPE DATING
ISOTOPES
LEAD ISOTOPES
METAMORPHISM
MINERALS
NORTH AMERICA
OXYGEN COMPOUNDS
PLUTONIC ROCKS
ROCKS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
TECTONICS
TITANITE
TRANSITION ELEMENT COMPOUNDS
URANIUM ISOTOPES
VOLCANIC ROCKS
ZIRCON
ZIRCONIUM COMPOUNDS
ZIRCONIUM SILICATES