Intrusive granitoids of the Northern Ladoga region: Chemistry, fluids, andoxygen isotopes

Structural and geological data, in combination with rock geochemistry and c rystallization parameters, indicate that asynchronous intrusive granitoid c omplexes in the Northern Ladoga region, which are represented by the Kurkij oki pluton and its satellites, as well as the Lauvatsaari and Tervus pluton s, do not belong to a single magmatic series. The study of fluid inclusions and contents of fluid components in minerals show that the ratio of water to carbon dioxide in fluid increased from older enderbitic to younger grani tic magmas. The temperature of the equilibrium distribution of oxygen isoto pes among minerals decreases in this rock sequence. This variation correspo nds to important events in the pluton formation. The oxygen isotopic ratios in fluids, which were calculated for similar temperatures, are identical a nd may indicate the magma crystallization in a common fluid flow.