U-Pb Dating of the Sill-Like (Plated) Bodies of the Early Kinematic Series of Gabbrodiorite-Granodiorites in the Svecofennian Fold-and-Thrust Assemblage of the Ladoga Region

The first results of the geochronological dating of the specific sill-like gabbrodiorite-granodiorite intrusive bodies within the areal extent of the Paleoproterozoic Ladoga complex, singled out at an early stage of the tectono-metamorphic evolution of the Svecofennides in the southeastern part of the Fennoscandian Shield are presented. Their affinity to the fold-and-thrust paragenetic assemblage of the Meyeri zone, which separates the northern and southern domains of the Ladoga region, in the shape of plated or tabular-like magmatic bodies that fill the feather joints of low-angle thrust faults, is shown. The results of zircon dating by two technologies of the U-Pb method, indicating the time span of the early kinematic stage of the Svecofennian tectogenesis and the according plutonic igneous and metamorphic events at ca. 1.87 Ga, as well as the time limit of the imprinted folding event of the second deformation stage at about 1.83 Ga, are compared.

Automated summary

The first results of geochronological dating of specific intrusive bodies in the Paleoproterozoic Ladoga complex are presented. The affinity of these bodies to the Meyeri zone and their role in the tectonic evolution of the Svecofennides are discussed. Zircon dating indicates the timing of early kinematic stages and folding events in the region.