V.E. GUZEV, А.V. MOLCHANOV, E.I. KHOROKHORINA, V.V. SEMENOVA (VSEGEI)

Petrological and geochemical characteristics of carbonatite in the Maldzhangar massif (Anabar shield)

The paper presents results of the petrological and geochemical study of the Maldzhangar carbonatite located in the southeastern part of the Billyakh zone of tectonic melange (southeastern periphery of the Anabar shield). According to results of the U­Pb pyrochlore dating (SHRIMP II), the carbonatite generated about 167 Ma ago. It is established that the carbonatite is represented by three mineral types: calcite, dolomite and calcite­dolomite. The carbonatite composi-tion evolved from early calcitic to calcite­dolomitic and dolomitic. The geochemical similarity of all the varieties of carbonatite indicates that all of them originated from the same melt. The carbonatite is enriched in a wide range of el-ements: LREE, Nb, Sr, As, MREE, Th, Ba, Ta, Y, Zn, Pb, and Au. Carbonatite geochemical features closely match the mineral composition. LREEs are the major and useful component of commercial interest. Nb, Ta, Y, P, Sr, and Ba may be of commercial interest as minor components. The data obtained suggest that the Maldzhangar carbonatite massif is a source of rare earth and rare metal elements.
Keywords: Anabar shield, Maldzhangar massif, carbonatite, REE, mineralization