Late Miocene volcanism in the Tikves valley (locality Mrzen locality)

Boev, Ivan (2022) Late Miocene volcanism in the Tikves valley (locality Mrzen locality). In: 18th Serbian Geological Congress "Geology solves the problems", 01-04 June 2022, Divcibare, Serbia.

Text LATE MIOCEN VOLCANISM IN THE TIKVES VALLEY-NORTH MACEDONIA.pdf Download (1MB)

Abstract

Late Miocene volcanism in the Tikves valley (locality MRZEN locality) is characterized by the
appearance of volcanic rocks that also mark the beginning of volcanic activity in the southern parts of
the Republic of North Macedonia. This volcanism appears on the transversal tectonic structures with E�W extension that are a consequence of the extension occurring in this region in the period of about 10
MA (in the area of Mrzen, 8.32 MA) and which is a direct consequence of the subduction processes in
the Aegean region.
Detailed microscopic examinations of 5 samples of volcanic rocks show that they have a typical
porphyritic structure, while the texture is trachytic. Phenocrysts that have idiomorphic forms are
represented by: olivine, clinopyroxene, orthopyroxene, plagioclase and magnetite. In some places there
are alterations of phenocrysts to: iddingsite (mixture of smectite-chlorite-goethite), clay and/or zeolites,
and calcite. The ground mass is hypocrystalline and in places it is vitreous.
The chemical and geochemical characteristics of volcanic rocks indicate that they are rocks with an
intermediate character, but in the modal composition of the rock olivine as phenocrystals appears, and,
based on this, these rocks could be defined as alkaline basalts. The content of strontium isotopes
87Sr/86Sr ranges in the interval of 0.706671-0.706795, while neodymium isotopes 143Nd/144Nd it
ranges in the interval of 0.512441-0.512472. Strontium isotopes (87Sr/86Sr) clearly indicate the origin
of the primary magma from which these volcanic rocks differentiated. The source of the magma is
unambiguously in the upper mantle and therefore these rocks differ from the Pliocene volcanism of
Kozuf Mountain where strontium isotopes are in the interval of 0.7080-0.7090 and the source of the
magmas is located in the upper part of the border area of the upper mantle and the lower parts of the
continental crust

Item Type:	Conference or Workshop Item (Other)
Subjects:	Natural sciences > Earth and related environmental sciences
Divisions:	Faculty of Natural and Technical Sciences
Depositing User:	Ivan Boev
Date Deposited:	09 Aug 2022 11:11
Last Modified:	09 Aug 2022 11:11
URI:	https://eprints.ugd.edu.mk/id/eprint/29964

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