Late Triassic high-potassium trachitic volcanism of the northeast of the Siberian platform: Evidence in the sedimentary record.

The U-Pb (LA-ICP-MS) age was determined for detrital zircons from the Upper Triassic volcanomictic rocks of the Osipai Formation (Bulkur River) of the northeastern Siberian Platform. The mineral composition and textural and structural peculiarities of these rocks indicate their formation as a result of eruptive high-potassium trachitic volcanism 235 Ma ago. More local manifestation of this volcanism in the area of the Lena River is evident from the U-Pb age of detrital zircons from the area of the Khatystakh River, which were previously ascribed to the Carnian Stage. Our data indicate redeposition of the clastic material of the Carnian diamond horizon in the post-Jurassic period. [ABSTRACT FROM AUTHOR]