THE GEOCHEMISTRY OF THE LA GALISSONNIERE PLUTON - A MIDDLE PROTEROZOIC LATE-OROGENIC INTRUSION FROM THE EASTERN GRENVILLE PROVINCE, QUEBEC

The La Galissonniere Pluton is a late-orogenic pluton located in the eastern Grenville Province of Quebec. The pluton contains biotite > hornblende, zircon, titanite, allanite, and apatite, along with secondary sericite and epidote. The pluton features elevated values of Nb, Y, and F. The normalized rare-earth element patterns have light rare-earth element concentrations of 400-500 x chondrite, moderate slopes (10-20), and noticeable Eu anomalies. Trace-element discriminant diagrams suggest that the pluton formed in a late-orogenic environment and indicate a possible period of late Precambrian crustal attenuation in the eastern Grenville Province.