Geochemical Model of Basalt Magma Hybridization Exemplified by the Tulai-Kiryaka Intrusion ( Taimyr )

Exemplified by the layered Tulai-Kiryaka intrusive sheet, interaction of basalt magma with enclosing rocks of terrigenous argillite-aleurolite unit has been investigated. There are three stages in intrusive rock formation: magmatic differentiation of initial magma, contamination of residual melts by terrigeneous rocks and their anatectic melting in the upper exocontact zone. Two last processes are accompanied by ahead metasomatic alteration of terrigenous rocks. The direct crust contamination is stated to change geochemical specific nature of crystallization products of residual basaltic magmas toward increasing the contents of the most mobile incoherent elements (Ba, Rb, K, etc.) and increasing 87Sr/86Sr ratios according to the model of mixing. In their composition, the anatectic granites are the closest to the palingenetic granites of calc-alkaline series.