Stratigraphy of the Okhotsk–Chukotka Belt in the Headwaters of the Malyi Anyui River (the Vicinity of Kupol Deposit): U–Pb and 40Ar/39Ar Age Data.

U–Pb and 40Ar/39Ar age data obtained for volcanic rocks of the Okhotsk–Chukotka Belt in the headwaters of the Malyi Anyui River (the vicinity of Kupol deposit) indicate at least two main pulses of volcanic activity, 98–93 Ma and 90–84 Ma. The conventional stratigraphic models are not consistent with the new data on the age and composition of volcanic units. The spatial relations between volcanic complexes of different ages imply that volcanic units accumulated under conditions of dissected topography. In the absence of obvious petrographic distinctions between the volcanic sequences of different ages, the composition of detailed geological and paleovolcanological maps requires representative precise isotopic age data. [ABSTRACT FROM AUTHOR]