South Okhotsk sedimentary basin (Cenozoic) (Southern Sea of Okhotsk, unit Czs) Consists chiefly of clastic sedimentary rocks ranging up to 4 km thick. Seismic investigations reveal two units: (1) a lower, 3-km-thick sequence of acoustically transparent rocks composed of shale and argillite; and (2) an upper, 1-km-thick sequence of coherently bedded turbidite deposits with tuffaceous layers of presumed late Miocene to Pliocene age. REFERENCES: Gnibidenko and Svarichevsky, 1984; Sergeev and Krasny, 1987.