Weathering crusts and their role in formation of post-kimberlite sedimentary sequences

The principal suppliers of terrigenous material to forming ancient diamond placers are characterized based on the main diamond-bearing districts Siberian platform as an example. A special attention is paid characteristics local sources allothigenous washed out into sedimentation basins period specified, which were weathering crusts formed upon terrigenouscarbonate rocks, trappean formations (dolerites, tuffs, and tuffaceous rock sequences), kimberlites. comprehensive comparative investigation rocks various chemical mineralogical composition allowed tracing specific features their hypergene alteration typomorphic indications eluvial products. same varieties primary minerals in redeposited products may be differentiated at structural level, secondary phyllosilicates identified either by occupation octahedral positions structure, or mutual superposition individual silicate layers, polytypic character. Redeposition near denudation areas predominant accumulation freshwater basins, well a small thickness sedimentary layers insignificant burial, had determined weak hydrodynamic impact environment (argillaceous, first all), did not lead sufficient diagenetic alteration. Therefore, types crusts, sequences, retain crystal-chemical peculiarities relation masses, allows ways arrival (including diamondiferous) basins.