Geological, petrological, and geochemical data suggest polygene nature of t
he Ob' complex, which is subdivided into the near-Ob' and Barlak complexes.
Absolute Ar-Ar age of these complexes ranges from 251.5+/-2.4 to 249.7+/-2
.0 and from 235.9+/-2.6 to 233.0+/-1.8 Ma, respectively.