Geochemistry and tectonic setting of the late Precambrian Holyrood plutonic series of eastern Newfoundland

Major and trace element chemistry suggest that the Holyrood plutonic series is a co-magnetic calc-alkaline suite, formed at about 5 kb P_H2O by fractionation of plagioclase, amphibole and clinopyroxene from a gabbroic magma which was derived from the upper mantle. It appears unlikely that the series is genetically related to the Harbour Main volcanic rocks, either magmatically or by hybridization. Chemical comparison of the Holyrood series with suites from known tectonic environments suggest that this region approximated a ‘basin and range’ type of tectonic setting during formation of the Holyrood plutonic series.