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

P. A. Ignatov, Head of Chair, Professor, Doctor of Geologo-Mineralogical Sciences, petrIgnatov@gmail.com

Research and Geology Service, ALROSA, Mirny, Russia:
A. Yu. Kolesnik, Junior Researcher
A. V. Tolstov, Director, Doctor of Geologo-Mineralogical Sciences

Vilyuisk Exploration Service, ALROSA, Mirny, Russia:
M. V. Maltsev, Head of Department

In the new diamond-bearing Syuldyukar field in the Ygyatta district of Yakutia, numerous cross-sections of Cambrian argillaceous carbonate strata enclosing Mid-Paleozoic kimberlites are examined. In the area of 70 km², cores from 230 holes drilled by the spacing pattern of 500×500 m are tested; in the reference kimberlite-bearing site 1 km² in area, 23 cross-sections made by the pattern of 40 by 200 m are studied. Various tectonic viscous and brittle micro-deformations are detected, including signs of compression and tension. Features of kimberlite-bearing shear structures are identified in the form of micro-overfaults, slickensides with horizontal fault trace rifts, small drag faults and schistocity zones. Mapping of these structures reveals the west-northwestward and north-northeastward shear structures. In these zones, manifestations of carbonate-rich breccias produced by fluid fracturing, as well as strings of aggregate carbonate and clayey material with sand grains and pyroclastics are detected. Vein-like bleaching of red argillites is disclosed; the intensive manifestations of such bleaching as in the Nakyn field in Yakutia mark exocontacts of kimberlites. The revealed shear zones are enveloped by the vein-like bleaching. Based on the aggregative data, including anomalous concentrations of Cr, V, Ni and Ba in the vein-like bleaching and fluidized breccias, the areas promising primary diamond deposits are located.

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