Evidence for a “Cadomian” ophiolite and magmatic-arc complex in SW Bulgaria

New geochronological and geochemical data from the magmatic rocks of the Kraishte area (SW Bulgaria) reveal the existence of Cadomian arc magmatism intruding an ophiolitic complex. Similar geochemical signatures and crystallization ages of the basic to acidic rocks of the Struma Unit and the Osogovo–Lisets Complex suggest that these rocks were derived from one calc-alkaline magma source. They were parts of a magmatic arc associated during Ediacaran–Early Cambrian (560–540 Ma) times with subduction of the Proterozoic Prototethys Ocean. The geochemical analysis of the coeval calc-alkaline granitic magmatism (577–551 Ma) in the Morava Nappe reveals a trend from a within-plate towards volcanic-arc affinity.