Results of U Pb (SIMS) dating of zircon from late riphean plagiogranite porphiries of Northwestern Pay Khoy

The first results of U Pb (SIMS) dating of zircons from plagiogranite porphyries, which compose a subvolcanic body and are similar in chemical composition to effusive volcanic rocks of the Sokolinsk Formation of the northwestern Pay Khoy (Amderma region) are reported. It was established that their age is determined as Late Riphean based on the location of the body in the area of outcrops to the surface of the lower part of the Sokolninsk Formation and U Pb age of zircons is 633 ± 14 Ma. The obtained U Pb age is completely consistent with the dating of detrital zircons from volcanomictic sandstones of the lower part of the Sokolninsk Formation. The assumed comagmatic nature of the subvolcanic and effusive volcanic rocks of the Sokolninsk Formation makes it possible to reasonably state that the age of this suite (at least its lower part) is the Late Riphean.