Eocene Granitoids of the Okhotsk Granodiorite Complex (South Sakhalin)
- Authors: Alexandrov I.A.1, Liao J.2, Jahn B.2, Golozoubov V.V.1, Ivin V.V.1, Stepnova Y.A.1
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Affiliations:
- Far East Geological Institute, Far East Branch, Russian Academy of Sciences
- Department of Geosciences, National Taiwan University
- Issue: Vol 483, No 2 (2018)
- Pages: 1499-1503
- Section: Geology
- URL: https://journals.rcsi.science/1028-334X/article/view/194406
- DOI: https://doi.org/10.1134/S1028334X18120103
- ID: 194406
Cite item
Abstract
As a result of U–Pb dating by LA-ICP-MS, the age of zircons from granitoids was determined to be 42.1–44.3 Ma for the rocks of first phase and 42.4–42.7 Ma for rhyolites from dikes of the second phase. On the basis of the geochemical studies of rocks, it was found for the first time that granodiorites of the Okhotsk massif (first phase) refer to A2-type granitoids. The most likely explanation of petrogenesis for A2-type granitoids of the Okhotsk complex is the gradual cessation of subduction as a result of deceleration of the Pacific Plate and the transition of the Ozerskii terrane to transform northward motion along the Merei suture zone with a certain role of syn-shear extension. Thus, the data obtained on the age and geochemistry of the Okhotsk complex granitoids suggest the possible time of geodynamic regime change in this area as about 43 Ma ago.
About the authors
I. A. Alexandrov
Far East Geological Institute, Far East Branch,Russian Academy of Sciences
Author for correspondence.
Email: alexandrov@fegi.ru
Russian Federation, Vladivostok, 690022
J.-P. Liao
Department of Geosciences, National Taiwan University
Email: alexandrov@fegi.ru
Taiwan, Province of China, Taipei, 10617
B.-M. Jahn
Department of Geosciences, National Taiwan University
Email: alexandrov@fegi.ru
Taiwan, Province of China, Taipei, 10617
V. V. Golozoubov
Far East Geological Institute, Far East Branch,Russian Academy of Sciences
Email: alexandrov@fegi.ru
Russian Federation, Vladivostok, 690022
V. V. Ivin
Far East Geological Institute, Far East Branch,Russian Academy of Sciences
Email: alexandrov@fegi.ru
Russian Federation, Vladivostok, 690022
Yu. A. Stepnova
Far East Geological Institute, Far East Branch,Russian Academy of Sciences
Email: alexandrov@fegi.ru
Russian Federation, Vladivostok, 690022