Geochronology of the Lumby Lake greenstone belt: A 3 Ga complex within the Wabigoon subprovince, northwest Ontario

Research Article| June 01, 1988 Geochronology of the Lumby Lake greenstone belt: A 3 Ga complex within the Wabigoon subprovince, northwest Ontario D. W. DAVIS; D. W. DAVIS 1Jack Satterly Geochronology Laboratory, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario, Canada M5S 2C6 Search for other works by this author on: GSW Google Scholar M. C. JACKSON M. C. JACKSON 2Ontario Geological Survey, 77 Grenville Street Toronto, Ontario, Canada M5S 1B3 Search for other works by this author on: GSW Google Scholar Author and Article Information D. W. DAVIS 1Jack Satterly Geochronology Laboratory, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario, Canada M5S 2C6 M. C. JACKSON 2Ontario Geological Survey, 77 Grenville Street Toronto, Ontario, Canada M5S 1B3 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1988) 100 (6): 818–824. https://doi.org/10.1130/0016-7606(1988)100<0818:GOTLLG>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation D. W. DAVIS, M. C. JACKSON; Geochronology of the Lumby Lake greenstone belt: A 3 Ga complex within the Wabigoon subprovince, northwest Ontario. GSA Bulletin 1988;; 100 (6): 818–824. doi: https://doi.org/10.1130/0016-7606(1988)100<0818:GOTLLG>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 SocietyGSA Bulletin Search Advanced Search Abstract The Lumby Lake greenstone belt lies within the central, predominantly metaplutonic terrane of the western Wabigoon subprovince. It is conformable with gneiss of the Marmion Lake tonalite batholith. U-Pb analyses of zircons from two felsic tuffs and a quartz porphyry within the greenstone belt give a scattered lead-loss pattern indicative of early disturbance. The ages of the oldest, concordant fractions agree, however, and define an age of 2999 ± 1 m.y. for emplacement of these felsic units. Zircons from a tonalite gneiss within the Marmion Lake batholith are also somewhat disturbed. The oldest abraded fraction is concordant and has an age of 3003 ± 5 m.y., indicating that the gneiss is probably close in age to the supracrustal rocks.U-Pb analyses of rutile from one of the felsic units give an age of 2690 ± 5 m.y. and record the effect of Late Archean metamorphism. Three titanite fractions from the tonalite gneiss agree within error and have an age of 2809 ± 1 m.y. The age and consistency of the titanite fractions indicate that titanite in this rock was formed as a result of a metamorphic event and was never subsequently disturbed. This age is therefore a minimum estimate for high-grade metamorphism of the gneiss. The presence of a pre-2809 Ma fabric in a gneiss of regional extent suggests that an early metamorphic-deformational event affected this area.These data constitute the first firm evidence for extensive 3.0 Ga crust in the southern Superior province and give the first evidence of a regional deformational event which predates cratonization of the Superior province. 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.