Abstract

The article considers the formation of Neogene volcanism in the central part of the Lesser Caucasus on the basis of geochemical features. It was found that in the andesite-dasite-rhyolite association rocks, where volcanism is expressed, light lanthanides predominate over weight, and therefore the La/Sm, La/Yb ratios are high. In medium rocks (quartz latites, andesites) the Eu/Eu* ratio is close to unity (Eu/Eu* = 0.94-1.05), in more acidic rocks the weak Eu-minimum (Eu/Eu* = 0.58-0 ,63) and indicates the fractionation of plagioclase in the formation of acidic rocks. Enrichment melts and fluids with a relatively high melting point caused the increase of Ba/Y, Rb/Y, Th/Yb, Nb/Y, Nb/Yb ratios in the association rocks and their enrichment with Ba, Sr, rare earth elements. It was concluded that the source of the enriched mantle played a key role in the formation of andesite-dasite-riolite association rocks of the central part of the Lesser Caucasus. Keywords: Central part of the Lesser Caucasus, Neogene volcanism, distribution of rare earth and rare elements, source of enriched mantle.

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