Evolution of the Meyeri Thrust Zone of the Northern Ladoga Region (Republic of Karelia, Northwest Russia): PT Conditions for the Formation of Mineral Parageneses and Geodynamic Reconstructions

In our study we characterize the thermodynamic regimes in the thrust zone of the newly formed Paleoproterozoic continental crust of the Svecofennian mobile belt on the outskirts of the Archean Karelian continent along the sublatitudinal, in modern coordinates, powerful strike-slip zone of the Northern Ladoga area. The Meyeri thrust zone is divided into northern and southern domains, considered allochthonous and autochthonous blocks according to material composition and structural features. The autochthonous block of the northern domain is different from the allochthonous block of the southern one by the presence of gneiss domes with Archean rocks in the cores. The allochthonous block is composed only of Paleoproterozoic rocks. During the formation of the thrust zone 1.86-1.85 Ga ago, the low-temperature amphibolite facies of biotite-muscovite parageneses were developed after the early mineral parageneses of the high-temperature amphibolite and granulite facies.