Late Miocene volcanism in the Tikvesh Valley - North Macedonia (locality of Mrzen )

Late Miocene volcanism in the Tikvesh Valley (MRZEN locality) is characterized by the occurrence of volcanic rocks and it is the beginning of volcanic activity in the southern parts of the Republic of North Macedonia; It occurs on the transverse tectonic structures with E - W direction that are a consequence of the extension that occurred in this region in the period of about 10 Ma (in the region of Mrzen 8.32 Ma) and which is a direct consequence of the subduction processes in the Aegean region. The chemical and geochemical characteristics of volcanic rocks indicate that these are rocks that have an intermediate character, but also contain olivine as phenocrysts, so based on that could be defined as alkaline basalts. The PEE content as well as the strontium isotopes (⁸⁷ Sr/ ⁸⁶ Sr) content range in the interval 0.706671 - 0.706795, while the neodymium isotopes ¹⁴³ Nd/¹⁴⁴ Nd range in the interval 0.512441 - 0.512472. Strontium isotopes (⁸⁷ Sr/ ⁸⁶ Sr) clearly indicate the origin of the primary magma from which these volcanic rocks differentiated. The source of the magma is unambiguously in the upper layer and therefore these rocks differ from the Pliocene volcanism on Kozhuf Mountain where the strontium isotopes are in the range 0.7080 - 0.7090. (author)