| Abstract: | The paper presents materials on the inner structure of the Late Cenozoic within-plate volcanic province in Central and East
Asia, in which two subprovinces are distinguished: Central Asian and Far Eastern, which comprise a number of autonomously
evolving volcanic areas. Some of the volcanic areas are proved to have evolved for a long time, starting in the Late Mesozoic.
In spite of differences in their age and structural setting, the volcanic areas evolved according to similar scenarios in
the Late Cenozoic. Magmatism in the province was related to a mantle source of the within-plate type. The magmatic associations
are dominated by mafic alkaline high-K rocks. The rocks are geochemically close to basalts of the OIB type, and their isotopic
composition corresponds to a combination of mantle sources of the PREMA, EMI, and EMII types at the predominance of PREMA.
Geological, geochemical, and isotopic lines of evidence suggest that magmatism in the province was related to mantle plumes.
This is consistent with geophysical data, which testify that the volcanic areas are underlain by upwellings of the asthenospheric
mantle or plumes. Seismic tomography data indicate that the “stems” of the plumes can be traced down to the upper and lower
mantle. The province is thought to have been produced when the eastern margin of the Asian plate overlapped one of the branches
of the Pacific superplume at approximately 160 Ma. This branch of the superplume is pronounced in the modern mantle structure
as a cluster of mantle plumes that control (according to seismic tomography data) the interaction zone of the Pacific and
Asian lithospheric plates. |
