Uda volcanic-plutonic belt 

(Late Jurassic and Early Cretaceous) 

(Southern part of Russian Northeast, units Js, Jpf, KJvi, lJvi)

Consists chiefly of basalt, andesite-basalt, andesite, and tuff that are interlayered with nonmarine 
sandstone, siltstone, conglomerate, and coal with a Late Jurassic and Early Cretaceous flora. The lower 
level of the belt that overlaps the southern part of the eastern Stanovoy block (unit NSS) and may be Late 
Jurassic in age (Zmievsky and others, 1990). Volcanic rocks have K-Ar ages of 118-176 Ma and associated 
granitic rocks of 150-190 Ma. A Berriasian to Valanginian flora is well developed in the center of the belt 
(Lebedev and others, 1989). In the extreme north, a Early Cretaceous (Neocomian) flora occurs along with 
possible Upper Jurassic deposits. The plutonic part of the belt intrudes the southeastern margin of the 
Stanovoy block of the North Asian craton (unit NSS), the Okhotsk terrane, and the southern margin of the 
Kular-Nera and Viliga terranes. Also included are Jurassic granitic rocks, including granodiorite, diorite, 
and granite, that extend to the west along the southern margin of the North Asian craton (unit NSC). The 
granitic rocks of the belt yield reliable isotopic ages that range from 130 to 200 Ma. REFERENCES: 
Sosunov and others, 1982; Filatova, 1988; Lebedev and others, 1989; Zmievsky and others, 1990.