Amphibole bearing mantle beneath Leningrad kimberlite pipe, West Ukukit field, NE Yakutia

            In the mantle column beneath the Leningrad pipe W Ukukit, the Cr-bearing amphiboles prevail on the clinopyroxenes. The amphiboles are varying from the Cr hornblendes  near the Moho to  Cr pargasites (to more Cr- bearing in the middle part of mantle columns and to K-Na near the lithosphere base. All amphiboles  from hornblendes to  richterites form nearly continuous range. With the inflection (Peak in Cr in pargasited and growth of K. Fe at the lithosphere base.

            The single grain thermobarometry for the garnets suggest the division to at least 7 horizons which from paleo subduction slabs. The ilmenite trend from 7.5 GPa suggest the vast range of metasomatism in the lower part and continuous trend to 3 GPA. Amphiboles compiles the HT branch from 3.5 GPA typical for basaltic melts and with the most Cr rich beginning and decreasing of Cr to the MOHO. Cr pargasites refer to 40mw/m2 geotherm together with the prevailing eclogites. An opposite the trend for the richterites also is dividing in to LT and HT branches. The eclogites compile dense MT branch in the middle part of mantle column with the highly inclined P-Fe# trend.

            The richterites in the LAB show the highly inclined and enriched TRE patterns with high LILE, SRSR and troughs in Nb Pb. The Na- rich have Rb, Ba, variable Th peaks and essentially lower REEE with the MREE depressions (created in harzburgites).  The pargasites and Hornblendes show contrasting Eu peaks (for enriched) and troughs (for depleted varieties in REE). They real subduction related Ba, U, Sr peaks and troughs in HFSE.

CPX are variable mostly showing TH, U Sr peaks related to plume carbonatitic melts

Abundance of unremelted subduction material  s suggests that in Khapchan zone the growth of the continents was accompanied by subduction fluids and possibly with nearly   sub vertical subductions. Khapchan terrane as a collision terrane and contain anomalous amount of eclogitic material which was not hybridized with peridotites like in in common granite-green-stone protocontinents. RFBR grant 19-05-00788