Geochronology of the Baie Verte Peninsula, Newfoundland: implications for the tectonic evolution of the Humber and Dunnage Zones of the Appalachian Orogen

Journal Article · Sat Sep 01 04:00:00 EDT 1984 · J. Geol.; (United States)

DOI:https://doi.org/10.1086/628888· OSTI ID:6713908

Dallmeyer, R D; Hibbard, J

U-Pb analyses of zircon from the Burlington Granodiorite suggest intrusion at c. 460-465 Ma. Hornblende and biotite from central portions of the pluton record markedly younger /sup 40/Ar//sup 39/Ar plateau dates (410-420 Ma) which are interpreted to date contact metamorphic effects associated with the widespread emplacement of Silurian-Devonian igneous suites. Northern portions of the Burlington Granodiorite are polydeformed and regionally metamorphosed. Hornblende and biotite from this terrane yield /sup 40/Ar//sup 39/Ar plateau ages of 345-350 Ma. U-Pb analyses of zircon from the Dunamagon Granite indicate emplacement at c. 440-460 Ma, thereby providing an upper limit for tectonic juxtapositioning of the Humber and Dunnage Zones along the Baie Verte Line. Similar ages are also recorded by hornblende and biotite throughout northerly portions of the Mings Bight (Humber Zone) and Pacquet Harbour (Dunnage Zone) Groups. These results indicate that the tectonic evolution of the Baie Verte Line as polygenetic, and involved: (1) regionally significant tectonothermal activity prior to the Middle Ordovician and (2) Middle to Late Paleozoic tectonothermal activity centered along easterly segments of the Baie Verte Line. The regional metamorphism associated with this orogenic activity altered primary U-Pb and Rb-Sr isotopic systems within various igneous suites exposed in northeastern portions of the Burlington Peninsula, which may explain some inconsistent geochronological results previously obtained. 54 references, 6 figures, 5 tables.

• Research Organization: Univ. Georgia, Athens
• OSTI ID: 6713908
• Journal Information: J. Geol.; (United States), Journal Name: J. Geol.; (United States) Vol. 92:5; ISSN JGEOA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580100* -- Geology & Hydrology-- (-1989)
ACTINIDE ISOTOPES
AGE ESTIMATION
APPALACHIAN MOUNTAINS
ARGON ISOTOPES
CANADA
GEOLOGIC HISTORY
GRANITES
GRANODIORITES
IGNEOUS ROCKS
ISLANDS
ISOTOPE DATING
ISOTOPES
LEAD ISOTOPES
MINERALS
MOUNTAINS
NEWFOUNDLAND
NORTH AMERICA
OXYGEN COMPOUNDS
PLUTONIC ROCKS
ROCKS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
TECTONICS
TRANSITION ELEMENT COMPOUNDS
URANIUM ISOTOPES
ZIRCON
ZIRCONIUM COMPOUNDS
ZIRCONIUM SILICATES