Research Article| March 01, 1994 1.45 Ga granulites in the southwestern Grenville province: Geologic setting, P-T conditions, and U-Pb geochronology J.W.F. Ketchum; J.W.F. Ketchum 1Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H 3J5, Canada Search for other works by this author on: GSW Google Scholar R. A. Jamieson; R. A. Jamieson 1Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H 3J5, Canada Search for other works by this author on: GSW Google Scholar L. M. Heaman; L. M. Heaman 2Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada Search for other works by this author on: GSW Google Scholar N. G. Culshaw; N. G. Culshaw 1Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H 3J5, Canada Search for other works by this author on: GSW Google Scholar T. E. Krogh T. E. Krogh 2Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information J.W.F. Ketchum 1Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H 3J5, Canada R. A. Jamieson 1Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H 3J5, Canada L. M. Heaman 2Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada N. G. Culshaw 1Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H 3J5, Canada T. E. Krogh 2Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1994) 22 (3): 215–218. https://doi.org/10.1130/0091-7613(1994)022<0215:GGITSG>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation J.W.F. Ketchum, R. A. Jamieson, L. M. Heaman, N. G. Culshaw, T. E. Krogh; 1.45 Ga granulites in the southwestern Grenville province: Geologic setting, P-T conditions, and U-Pb geochronology. Geology 1994;; 22 (3): 215–218. doi: https://doi.org/10.1130/0091-7613(1994)022<0215:GGITSG>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract In the southwestern Grenville province, the parautochthonous Britt domain includes a variety of pre-Grenvillian metamorphic and plutonic rocks that were reworked at upper amphibolite facies during the Grenvillian orogeny. Near Pointe-au-Baril, Ontario, a crustal block containing pre-Grenvillian granulite facies mineral assemblages and pre-Grenvillian to early Grenvillian tectonic fabrics has been identified. The block is bounded on the northwest and southeast by extensional shear zones that may have isolated it from regional late Gren- villian deformation. Multiequilibria pressure-temperature (P-T) calculations for orthopyroxene-bearing mafic rocks suggest conditions of 625-700 °C and 7.2-8.4 kbar for the pre-Grenvillian metamorphism. The granulite facies assemblages were locally overprinted during higher pressure Grenvillian metamorphism, which peaked at 720-775 °C and 10.8-11.5 kbar. U-Pb zircon data from migmatitic, mafic supracrustal gneiss indicate metamorphism and leucosome development at ca. 1450-1430 Ma, in agreement with other pre-Grenvillian metamorphic ages for the Central gneiss belt and Grenville Front tectonic zone. An expanding data base on pre-Grenvillian events in the southwestern Grenville province indicates that high-grade metamorphism at ca. 1450-1430 Ma affected a large region of crust and was coeval with widespread felsic to intermediate plutonism. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.