ON THE PETROCHEMICAL SERIES OF KIMBERLITE ROCKS

Abstract

Kimberlites are considered to be products of crystallization of melts formed in 'fluidization and magmatic replacement' or by the disintegration and partial melting of rocks from great depth, the incompletely melted remains of which (nodules) are found as xenoliths in kimberlites and alkalic basalts. In studying the manifestations of volcanism in one area 1 have established that kimberlite rocks also form two regular volcanic series, which in many respects correspond to the two series of deep-seated intrusive rocks. The kimberlite rocks of the two series form completely different trends of variation in composition in the series as the 'basaltoid' properties increase. The two series of kimberlite rocks I have distinguished are derivatives of first-order inhomogeneity of the initial mantle substrate. The division of kimberlites into 'mica' and 'mica-free' is more special in character. Both the mica and mica-free varieties of kimberlites are present among the rocks of both the Al and the Fe-Ti volcanic series.