[1] Syktyvkar State Univ, Oktjabrsky Prospect 55, Syktyvkar 167001, Komi Republic, Russia
[2] Komi Sci Ctr UB RAS, Inst Geol, Pervomaiskaya St 54, Syktyvkar 167982, Komi Republic, Russia
[3] Komi Sci Ctr UB RAS, Inst Phys & Math, Oplesnina St 4, Syktyvkar 167982, Republic Of Kom, Russia
[4] Univ Illinois, 845 W Taylor St,MC 111, Chicago, IL 60607 USA
[5] St Petersburg State Univ, Univ Sky Pr 26, St Petersburg 198504, Russia