Evolution of the Yakutian Kimberlite Eclogite
Parageneses Compositions

E. A. Bagdasarov VSEGEI, Sredny pr.74, S-Petersburg, 199026, Russia


I. P. Ilupin TSNIGRI, Varshavskoe sh., 129-b, 113145, Moscow, Russia

S. K. Simakov VSEGEI, Sredny pr.74, S-Petersburg, 199026, Russia

There are two main types in Yakutian kimberlite eclogite parageneses: magnesium (I) and magnesium-iron (II). The first one predominates in the South Yakutian kimberlite fields (Botuobinsky, Daldinsky, Alakitsky etc.), and the second one - in the Northern fields (Kuoyksky, Chemurdahsky, Merchimdensky etc.). Pyrope-Ti-knorringite compositions of garnets are character for the first one and almandine- andradite-grossular - for the second one. Clinopyroxene compositions changes in this row from Mg-Cr- rich (with low content of jadeite component) to Fe-Na-Al-Ti-rich. The equilibrium temperatures of garnet-clinopyroxene pairs were calculated by garnet-clinopyroxene thermometer of Mori and Green (1978). Maximum temperatures reach 1400°C for South fields and 1100°C - for Northern ones. Composition, content and relationship of rare elements (Ni, V, Sc, Zr, Yb, Nb, etc) vary in accordance with the mineral compositions. Maximum content of the elements have South eclogite parageneses, meanwhile Northern ones have more low content. Obtained data allow us to come to the conclusion that the main source for eclogites of the first type was upper mantle, meanwhile for the second one - metamorphic rocks of the Earth crust.


Mori, T. & Green, D. H. J., Geol. 86, 83-97 (1978).