Significance of ∼1.5 Ga zircon and monazite ages from charnockites in southern Lithuania and NE Poland

The presence of 1.52-1.50 Ga charnockites from the anorthosite-mangerite-charnockite-granite (AMCG) Mazury complex in southern Lithuania and NE Poland, in the western East European Craton (EEC) is revealed by secondary ion mass-spectrometry (SIMS) and EPMA geochronology. Early 1.85-1.82 Ga charnockites are related to major orogeny in the region whereas the newly studied charnockites intrude the already consolidated crust. The 1.52-1.50 Ga charnockite magmatism (SIMS data on zircon) was followed by high-grade metamorphism (EPMA data on monazite), which strongly affected the surrounding rocks. The 1.85-1.81 Ga zircon cores in Lazdijai and 1.81 Ga monazite domains in the Lanowicze charnockites represent the protolith age of a volcanic island arc. The 1.52-1.50 Ga charnockite magmatism and metamorphism are likely related to the distal, Danopolonian, orogeny further to the west, at the margin of Baltica. The c. 1.52-1.50 Ga AMCG magmatism and metamorphism in the western EEC as well as the paired accretionary-rapakivi suites in Amazonia, may be the inboard manifestations of the same early Mesoproterozoic orogeny associated with the juxtaposition of Amazonia and Baltica during the amalgamation of the supercontinent Columbia. (C) 2008 Published by Elsevier B.V. on behalf of International Association for Gondwana Research.