Open AccessSources of eocene magmatism of Western Kamchatka (according to geochemical and isotope Sr-Nd-Pb characteristics of basites)
Author(s) -
П. И. Федоров,
A. B. Perepelov,
Д. В. Коваленко,
S. I. Dril,
K. V. Lobanov
Publication year - 2019
Publication title -
doklady akademii nauk. rossijskaâ akademiâ nauk
Language(s) - English
Resource type - Journals
ISSN - 0869-5652
DOI - 10.31857/s0869-56524873293-298
Subject(s) - magmatism , geology , basalt , geochemistry , igneous rock , petrogenesis , mantle (geology) , volcanism , subduction , rift , paleontology , tectonics
The isotope-geochemical characteristics of the Eocene-Oligocene magmatic rocks of Western Kamchatka were studied. It is shown that the igneous rocks of the Eocene (45-53 Ma) Kinkil complex of Western Kamchatka are characterized by geochemical signs of super-subduction volcanism. Their isotopic composition of Sr, Nd and Pb, low concentrations of HFSE and HREE relative to the composition of MORB, suggest the formation of primary melts from depleted or poorly enriched in isotopic composition of the mantle wedge sources in different contaminated quartz-feldspath sialic sediments. From the end of the Middle Eocene on the territory of Western Kamchatka, K-Na alkaline-basalt magmatism (46-31 million years), whose geochemical characteristics are similar to E-MORB, as well as ultrapotassic alkaline-basalt magmatism, which continued to develop to the early Miocene (35-17 million years). The geodynamic nature of Late Paleogene alkaline magmatism involves the implementation of processes of diffuse rifting.