Paleozoic tholeiite magmatism in the kola igneous province: Spatial distribution, age, relations with alkaline magmatism

Abstract

205 One of the most important manifestations of the processes of plume-lithosphere interaction are large intrusions of mantlederived melts with a predomi� nance of tholeiite magma into the upper crust. There are high volumes of basalt magma, forming large igneous provinces (LIPs) on the platforms, as well as in ancient cratonized areas. In these areas, the spatial and temporary connection of the continental plateau basalts with alkaline magmatism is observed. As an example, there are many large alkaline prov� inces, such as MaimechaKotui, whose formation is close to the age of formation of the effusions of Sibe� rian traps; the South African one, formed during an unified cycle of magmatic activity together with effu� sions of the Etendeka plateau basalts; the West Indian one, connected with the Reunion Plume, caused the formation of the Deccan plateau basalts; and other alkaline provinces. Based on empirical data, some researchers have offered hypothesis to justify the genetic relationship between alkaline and tholeiite magmas formed during the processes of plume-litho� sphere interaction (1-4). The Kola alkaline province, formed within the period of 380-360Ma in the northeastern part of the Fennoscandinavian Shield (5) is characterized by fea� tures, which give logical reasons to consider them as the typical manifestations of plume magmatism (6). Provinces include large plutons, made up of agpaitic syenites, carbonatite intrusions, and numerous dikes of alkaline rocks, as well as remnants of subalkaline and alkaline extrusives. Manifestations of tholeiite magmatism in the region have not yet been identified definitively.