Researchers from IGG, together with colleagues from the Universities of Firenze and Tunceli (Turkey) published a study on the volcanic rocks of Central Eastern Anatolia based on new isotopic and geochronological data, that allow to reconstruct the temporal and geochemical evolution of volcanic activity, providing important constraints for the reconstruction of the geodynamic evolution of the region over the last 20 million years.

The study is based on radiogenic isotopes (Sr-Nd-Pb) data, geochemical analysis of major and trace elements and K-Ar and 40Ar-39

Ar age determinations by the method carried out on volcanic rocks emplaced in the Sivas-Malatya region (Central Eastern Anatolia). The aim is the geochemical-isotopic characterization of the magmatic rocks fo the studied area, to description of the composition of their mantle sources, the determination of the ages of magma emplacement and the study of the relationships between the volcanic activity and the geodynamics of Central and Eastern Anatolia.

Geochemical and isotopic analyses have shown that the calc-alkaline magmas of the Yamadağ (20-14 Ma) and Kepez Dağ (16-14 Ma) volcanic complexes represent typical arc magmas related to the subduction of the African plate under the Eurasian plate. The sodic-alkaline rocks show decreasing ages from east to west; the oldest magmas emplaced along the transcurrent Kızılırmak fault (Sivas: 17-13 Ma), and showing ages similar to calc-alkaline products. Their geochemical and isotopic characters suggest the persistence of a geochemical signature related to a relict subduction, while younger magmas outcropping along the Malatya-Ovacık transcurrent fault (Arguvan: 16-11 Ma; Kepez Dağ [Late Stage]: 14 Ma), do not show these features. During the Pliocene (6-4 Ma), volcanic activity is concentrated in the Kangal Basin, with the emplacement of potassium-rich alkaline magmas, which are rare considering the products outcropping in different regions of Central-Eastern Anatolia (Elazığ-Tunceli, Di Giuseppe et al [2017], Agostini et al [2019]; Cappadocia, Di Giuseppe et al [2018]). Alkaline magmas mark the transition from a convergent tectonic setting to a tectonic regime dominated by lateral (transcurrent) movements.

 Reference:

Di Giuseppe P, Agostini S, Di Vincenzo G, Manetti P, Savaşçın MY, Conticelli S (2021) From subduction to strike slip-related volcanism: insights from Sr, Nd, and Pb isotopes and geochronology of lavas from Sivas-Malatya region, Central Eastern Anatolia. International Journal of Earth Sciences. doi.org/10.1007/s00531-021-01995-0 

Article available at:

https://link.springer.com/content/pdf/10.1007/s00531-021-01995-0.pdf

For further information:

Samuele Agostini - samuele.agostini@igg.cnr.it

Paolo Di Giuseppe - paolo.digiuseppe(at)igg.cnr.it