The Mesoarchean Tonalite-Trondhjemite-Granodiorite Associations of Eastern Sarmatia: Age and Geological Setting

Abstract

Two episodes of Mesoarchean magmatism (ca. 2.95 and 3.03 Ga) have been recognized within the Kursk domain of Eastern Sarmatia. They led to the formation of the Saltyki granitoid complex, which is similar in composition to the granitoids of the typical tonalite–trondhjemite–granodiorite (TTG) associations of Archean cratons. These episodes correlate well with the previously determined emplacement start and completion dates of the Mesoarchean TTG associations in the Middle Dnieper and Azov domains of the Ukrainian shield. This confirms the assumption that the Kursk domain is a part of the joint Mesoarchean nucleus of Eastern Sarmatia. The geochemistry and Sm–Nd isotope characteristics of the Mesoarchean Saltyki granitoids suggest that their protoliths were the more ancient TTG-gneisses.