Buldym Lake, Vishnevye (Vishnyovye) Mts, Chelyabinsk Oblast', Southern Urals, Urals Region, Russia

Ultramafic massif in the northern part of the Il’mensky–Vishnevogorsky alkaline complex, surrounded by metamorphic rocks of the Paleoproterozoic Vishnevogorsky Formation. The lenticular body consists of olivine, olivine–enstatite, and olivine–enstatite–anthophyllite rocks serpentinized to various extents, and affected by fenitization. The Buldym massif hosts extended zonal carbonatite bodies that are controlled by a near-latitudinal fault system and plunging to the northwest. The bodies are hundreds of meters long and up to 50m thick. Their inner zone is composed of dolomite–calcite rock that gives way outward to tetraferriphlogopite–dolomite–calcite and then dolomite–calcite–phlogopite–richterite metasomatic rocks. The marginal zone consists of chlorite–carbonate–amphibole metasomatic rock that contains abundant dolomite, less abundant calcite, and relict olivine and enstatite of ultramafic hosts, commonly serpentinized.

References:
- Nedosekova, I.L. (2007): New Data on Carbonatites of the Il’mensky–Vishnevogorsky Alkaline Complex, the Southern Urals, Russia. Geology of Ore Deposits 49(2), 129-146.