40Ar/39Ar Age of Phengite from Sandstone of the Ophiolite-Derived Clastic Sequence of the Basin of the Rassokha River, Collision Belt of the Chersky Range.

The Early Permian (275.3 ± 3.1 Ma) ⁴⁰Ar/³⁹Ar plateau age of detrital mica (Cr-phengite) from clasts in listvenite sandstones of the ophiolite-derived clastic sequence of the Rassokha Terrane of the Chersky Range probably corresponds (or is close) to the time of the formation of listvenites of the provenance (ophiolitic massifs of the range) and restricts the maximum deposition age of clastic rocks. A partial loss of Ar by mica as a result of deformations and postsedimentation transformation of rocks of the ophiolite-derived clastic sequence in the Early Permian is possible but it is less probable. [ABSTRACT FROM AUTHOR]