Geochronology of granites of the western Korosten AMCG complex (Ukrainian Shield): implications for the emplacement history and origin of miarolitic pegmatites

Abstract. The origin of large miarolitic (also known as “chamber”) pegmatites is not fully understood although they may have great economic value. formation cavities in magmatic bodies related to melt degassing and gas or fluid flow through partially solidified magma. In this paper, the Volyn pegmatite field, located Palaeoproterozoic Korosten anorthosite–mangerite–charnockite–granite (AMCG) complex, North-Western region Ukrainian Shield, discussed. Pegmatites field host deposits piezoelectric quartz that accompanied by gem-quality beryl topaz. confined granites south-western part complex extends for 22 km along contact with anorthosite massif within plutonic complex. Geological data indicate hybridization basic melts partly crystallized granites, well direct impact fluids derived from on chamber pegmatites. new U–Pb zircon ages obtained confirm rock assemblage northern between 1800 1780 Ma, whereas rocks southern intruded mainly 1768 1755 Ma. were emplaced at 1770–1765 a few million years prior intrusion gabbro–anorthosite (1762–1758 Ma), while these 1760 ± 3 coevally rocks. Ultimately, was reheating semi-crystallized granitic migrating underlying massif.