Figure 4. Schematic geological map for the area of the middle course of
the Biryusa River (compiled using the data of G. A. Belozerov and
T. V. Gorbovskaya).
(1) Early Proterozoic granitoids of the Sayan Complex;
(2-3) Late Riphean Karagas Group: (2) Shangulezh and Tagul Formations (bottom of the
sequence); (3) Uda Formation; (4) Nersa dolerite complex (sills and dikes) of
Early Riphean age; (5) fault.