Sergo Ordzhonikidze Russian State Geological Prospecting University, Moscow, Russia:

P. A. Ignatov, Professor, Doctor of Geologo-Mineralogical Sciences, petrignatov@gmail.com

Central Research Institute of Geological Prospecting for Base and Precious Metals, Moscow, Russia:
S. G. Kryazhev, Leading Researcher, Doctor of Geologo-Mineralogical Sciences

ALROSA, Mirny, Russia:
A. V. Tolstov, Director of Research and Exploration Operations, Doctor of Geologo-Mineralogical Sciences
M. V. Maltsev, Head of Geological Exploration Field Party

In addition to classical data of magnetic and electrical geophysical surveys and heavy mineral sampling, it is proposed to use a complex of tectonic, fluid-fracturing and mineralogical-geochemical features during prospecting for diamond deposits on covered areas. They are examined on the basis of core and analytical data study in the Nakyn ore field of Yakutia in which Nyurba and Botuobin kimberlite pipes are mined. They intrude through the sedimentary rocks of the Lower Paleozoic and are overlaid by the Jurassic terrigenous strata. The features are studied by the ranks of the field, clusters and kimberlite bodies. The tectonic position of the Nakyn field (~100 km²) is determined by the structural node formed by faults intersections of I - II orders represented by the trappean dyke belts and the manifestation of paleo seismogenic dislocations of Cambrian and Ordovician sediments. The field is marked by the areas of eruptive breccias of basites, fluid-fracturing carbonate breccias and fluidizite veins, manifestations of skarns and hydrothermal mineralization (pyrite, sphalerite, celestite, barite, calcite, dolomite). Kimberlite clusters represented by pipes and dykes are within areas of first km². They are in the central part of the marked area and are localized at the structural nodes of III-IV order strike-slips intersections. They are concentrated vein and meta-grained manifestations of barite, sphalerite, pyrite and calcite with red and blue photoluminescence, light isotope composition of carbon and oxygen that indicate discharge sites of high temperature waters. Kimberlite pipes and dykes occupy areas of up to 1 km² and are located in the local extension zones of diagonal ore-hosted strike-slip (pull apart, accommodation, intersection of strike-slips) which are established by the micro deformations mapping of the Lower Paleozoic layers. In such areas there are explosive deformations of the host rocks fixed by structural-petrophysical data, manifestations of fluid-fracturing formations, halos of impregnated high-temperature gases (СО₂, СН₄, etc.). The areas are characterized by mineralogical-geochemical, gas-geochemical and isotopegeochemical parameters that reflect local sites of high-temperature waters discharge.

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