TERRIGENOUS ROCKS OF THE KODAR GROUP IN THE UDOKAN SUBZONE OF THE KODAR-UDOKAN TROUGH, THE ALDAN SHIELD: AGE, SOURCES, AND PROVENANCE AREAS

Abstract

The article presents the results of U–Th–Pb (LA-ICP-MS) geochronological studies of detrital zircon from metasandstones of the Kodar Group of the Udokan Complex, the Aldan Shield. It has been established that the Kodar Group of the Udokan subzone of the Kodar-Udokan trough have an age of 2.08–2.05 Ga. The sources of the Kodar Group deposits were the Archean (ca. 2.65, 2.83, and 3.23 Ga) igneous and metamorphic complexes of the Chara-Olekma geoblock of the Aldan Shield and the adjacent areas of the Stanovoi suture zone, as well as unidentified on the present erosion level the Paleoproterozoic (ca. 2.08 Ga) island arcs or active continental margin complexes that existed in the southern frame of the Archean Chara-Olekma geoblock. It is assumed that rocks of different ages, belonging both to the Kodar Group of the Udokan Complex and to the metamorphic complexes of the Stanovoi suture zone, can be tectonically juxtaposed in the southern part of the Udokan subzone of the Kodar-Udokan trough.