We present the SHRIMP U-Pb detrital zircon and K-Ar illite 1Md/1M and 2M1 ages, suggesting new insight into the Phanerozoic polyphase orogenies preserved in the northeastern Okcheon Belt, Korea since the initial basin formation during Neoproterozoic rifting through several successive contractional orogens. The U-Pb detrital zircon ages from the Early Paleozoic strata of the Taebaeksan Zone suggest a Cambrian maximum deposition age, and are supported by trilobite and conodont biostratigraphy. Although the age spectra from two sedimentary groups, the Yeongwol and Taebaek Groups, show similar continuous distributions from the Late Paleoproterozoic to Early Paleozoic ages, a Grenville-age hiatus (1.3–0.9 Ga) in the continuous stratigraphic sequence from the Taebaek Group suggests the existence of different peripheral clastic sources along rifted continental margin(s). In addition, we present the K-Ar illite 1Md/1M ages of the fault gouges, which confirm fault formation/reactivation during the Late Cretaceous to Early Paleogene (ca. 82–62 Ma) and the Early Miocene (ca. 20–18 Ma). The 2M1 illite ages, at least those younger than the host rock ages, provide episodes of deformation, metamorphism and hydrothermal effects related to the tectonic events during the Devonian (ca.410 Ma) and Permo-Triassic (ca. 285–240 Ma). These results indicate that the northeastern Okcheon Belt experienced polyphase orogenic events, namely the Okcheon (Middle Paleozoic), Songrim (Late Paleozoic to Early Mesozoic), Daebo (Middle Mesozoic) and Bulguksa (Late Mesozoic to Early Cenozoic) Orogenies, reflecting the Phanerozoic tectonic evolution of the Korean Peninsula along the East Asian continental margin.
Bibliographical noteFunding Information:
The K-Ar illite age determination in this research was supported by the Korea Institute of Geoscience and Mineral Resources (KIGAM) research project (2015-11-1637; Development of IOR/EOR technologies and field verification for carbonate reservoir in UAE), funded by the Ministry of Science and ICT (Information, Communication and Technology), Korea . This research was also supported by the Basic Science Research Program (2015-11-1315) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology, Korea . Dr. S.W. Kim acknowledges the partial support by a Basic Research Project (GP2017-021; Development of integrated geological information based on digital mapping) of the Korea Institute of Geoscience and Mineral Resources (KIGAM), funded by the Ministry of Science, ICT, and Future Planning, Korea. This work represents part of Y. Jang’s Ph.D. Research performed at Yonsei University. Appendix A
© 2017 Elsevier Ltd
All Science Journal Classification (ASJC) codes
- Earth-Surface Processes