Rocks from this volcanic field are generally rich in sodium and silica and their content has increased during the evolution of the volcanic field. Some of the oldest erupted rocks on the other hand had high potassium-sodium ratios. Benmoreite, nephelinites, pantellerites and kulaite are found here. Some of the magmatic differentiation may have occurred in closed magma chambers. Udokan is the only volcanic field in the Baikal rift with silicic differentiation of its rocks. The magma generation changed during the lifespan of the system, either it became deeper or was formed by smaller degrees of partial melting.