Umlekan-Ogodzhin volcanic-plutonic belt 

(Jurassic and Cretaceous) 

(Northeastern part of Russian Southeast, units Js, KJpf, Kpf, Kvi)

Consists chiefly of: (1) Lower Cretaceous sandstone, conglomerate, and mudstone with sparse flora and 
freshwater fauna; (2) Lower Cretaceous calc-alkalic andesite, dacite, and tuff that yield K-Ar ages of 112-
135 Ma; and (3) Upper Cretaceous alkalic basalt and rhyolite. Intruded by coeval Early Cretaceous granite, 
granodiorite, diorite, and monzodiorite. Some granitic plutons are probably Late Jurassic, or older because 
their detritus were shed into the Early Cretaceous part of section. Belt deposited on Gonzha terrane, and on 
Mamyn and Turan terranes of Bureya superterrane after collision of these terranes with the Tukuringra-
Dzhagdinsk terrane. REFERENCES: Volsky, 1983; Kozlovsky and others, 1988.