TY - JOUR

T1 - Age and Sources of Rocks of the Kodar Group of the Udokan Complex (Aldan Shield): Results of Geochemical, U–Th–Pb (LA-ICP-MS) Geochronological and Nd–Hf Isotopic Studies

AU - Kovach, V. P.

AU - Adamskaya, E. V.

AU - Kotov, A. B.

AU - Podkovyrov, V. N.

AU - Larin, A. M.

AU - Sklyarov, E. V.

AU - Zagornaya, N. Yu

AU - Skovitina, T. M.

AU - Plotkina, Yu V.

AU - Fedoseenko, A. M.

AU - Ton, Y.

PY - 2024/9/20

Y1 - 2024/9/20

N2 - Abstract: The results of geochemical and Nd isotopic studies of rocks and U–Th–Pb (LA-ICP-MS) geochronological and Hf isotopic studies of detrital zircon from metaterrigenous rocks of the Kodar Group of the Udokan Complex (Aldan Shield) are presented. It is established that the age of rocks of the Kodar Group is 1.99–1.91 Ga, whereas the age of rocks of the Chinei and Kemen groups of the Udokan Complex is 1.90–1.87 Ga (Kovach et al., 2018, 2023a). This allows us to raise the issue of recognition of the Kodar Group as an independent stratigraphic subdivision. The terrigenous rocks of the group were sourced from the Archean igneous and metamorphic rock of the Chara–Olekma Geoblock and probably the Kalar and Kurulta blocks of the Stanovoi suture zone, as well as the Paleoproterozoic (2.04–1.99, 2.08, 2.20, and 2.30 Ga) complexes of active continental margins or ensialic island arcs in the western–northwestern and southern (in the present-day coordinates) frame of the Chara–Olekma Geoblock, which are unidentified in the region at the current erosion level. Erosion of rocks of magmatic arcs and the continental slope led to the deposition of rocks of the Kodar Group in a retroarc foreland basin, whereas further collapse of the orogen and the formation of an intracontinental extension basin were responsible for the deposition of terrigenous rocks of the Chinei and Kemen groups. The obtained data indicate widespread previously unidentified Paleoproterozoic continental crust formation at about 2.04–1.97 Ga in the western part of the Aldan Shield.

AB - Abstract: The results of geochemical and Nd isotopic studies of rocks and U–Th–Pb (LA-ICP-MS) geochronological and Hf isotopic studies of detrital zircon from metaterrigenous rocks of the Kodar Group of the Udokan Complex (Aldan Shield) are presented. It is established that the age of rocks of the Kodar Group is 1.99–1.91 Ga, whereas the age of rocks of the Chinei and Kemen groups of the Udokan Complex is 1.90–1.87 Ga (Kovach et al., 2018, 2023a). This allows us to raise the issue of recognition of the Kodar Group as an independent stratigraphic subdivision. The terrigenous rocks of the group were sourced from the Archean igneous and metamorphic rock of the Chara–Olekma Geoblock and probably the Kalar and Kurulta blocks of the Stanovoi suture zone, as well as the Paleoproterozoic (2.04–1.99, 2.08, 2.20, and 2.30 Ga) complexes of active continental margins or ensialic island arcs in the western–northwestern and southern (in the present-day coordinates) frame of the Chara–Olekma Geoblock, which are unidentified in the region at the current erosion level. Erosion of rocks of magmatic arcs and the continental slope led to the deposition of rocks of the Kodar Group in a retroarc foreland basin, whereas further collapse of the orogen and the formation of an intracontinental extension basin were responsible for the deposition of terrigenous rocks of the Chinei and Kemen groups. The obtained data indicate widespread previously unidentified Paleoproterozoic continental crust formation at about 2.04–1.97 Ga in the western part of the Aldan Shield.

KW - Aldan Shield

KW - Kodar Group

KW - Udokan Complex

KW - detrital zircon

KW - geochronology

KW - tectonic evolution

UR - https://www.mendeley.com/catalogue/85a5a8e4-9dae-301d-8e8f-276b325f3f10/

U2 - 10.1134/S0869593824700102

DO - 10.1134/S0869593824700102

M3 - Article

VL - 32

SP - 445

EP - 468

JO - Stratigraphy and Geological Correlation

JF - Stratigraphy and Geological Correlation

SN - 0869-5938

IS - 5

ER -