О МЕХАНИЗМЕ ФОРМИРОВАНИЯ КИМБЕРЛИТОВЫХ ДИАТРЕМ АРХАНГЕЛЬСКОЙ АЛМАЗОНОСНОЙ ПРОВИНЦИИ

Abstract

The work deals with the mechanism of diatreme formation that is greatly controlled by formation of “magmatic corks” when magma rises to the surface. It explains: 1) manifestation of explosive effects that influence the peculiarities of rocks composing diatremes; 2) difference in peculiarities of rocks of different phases of intrusion in the same diatremes; 3) difference in the composition of different pipes and the occurence of xenoliths of country rocks not only at the edges of the diatremes but in their central parts as well; 4) existence of “blind pipes”. The assumption on the origin of pipes of different types of the same field from a singe vertical non-homogeneous magmatic hot-bed has been put forward. Difference in the rock composition and the degree of productivity of diatremes inside each field depends on the character of vertical non-homogeneity of the hot-bed that is related with lateral variability of sediments attracted into the subduction zone.