Publication Type:Journal Article
Source:Journal of PetrologyJournal of Petrology, Clarendon Press, Oxford, United Kingdom, Volume 40, Number 3, p.423-450 (1999)
Keywords:Aluminum, Canada, dike swarms, eastern canada, emplacement, geochemistry, intrusions, layered intrusions, lithogeochemistry, magmas, metals, Ontario, Paleoproterozoic, partial melting, Precambrian, proterozoic, Sudbury District Ontario, sulfur, tholeiitic composition, titanium, upper Precambrian
The 2100 m thick 2491 m.y. Agnew intrusion, Ontario, is a layered leucogabbroic norite to gabbro norite pluton intruded as a sill between the Archaean basement and the overlying Palaeoproterozoic flood basalts. Three magma pulses gave sequentially the marginal, lower and upper series with the last grading from olivine norites at the base to ferro-syenites and alkali feldspar granites at the top, the parental magmas being S-undersaturated, high Al and low Ti tholeiites with some affinities with boninites. The magmas have major elements similar to model parents proposed for the mafic parts of the Stillwater and Bushveld complexes. The Hearst-Matachewan dyke swarm is coeval and the geochemistry of the swarm is also considered. Major, trace, REE and PGE analyses are given for the tholeiitic dykes, granites, gabbro norites, leucogabbros and ferro-syenites.
GeoRef, Copyright 2018, American Geological Institute.<br/>1999-034201<br/>Agnew Intrusion