Neoproterozoic arc magmatism in or around the Korean Peninsula provides important insights into the history of the Rodinia supercontinent. Here we report the petrology, zircon U-Pb ages, geochemistry, and Hf isotope data from the Early Neoproterozoic (ca. 913–895 Ma) igneous complexes (gabbro, diorite and granitic dyke) in the northern part of the Gogunsan Islands along the southwestern margin of the Hongseong–Imjingang Belt in the central–western Korean Peninsula. The gabbro and diorite- yielded zircon U–Pb ages of ca. 913 Ma, and ca. 909–899 Ma, respectively. The granitic dykes within this complex show ages of ca. 903–895 Ma. The gabbro-diorite, and granite belong to the subalkaline series, and are characterized by large ion lithophile element (LILE) enrichments, Nb–Ta troughs, and depletion in P and Ti anomalies similar to magmatism in the continental arc setting. The initial 176Hf/177Hf ratios and εHf( t ) values obtained of zircon grains are in the ranges of 0.282132–0.282268 and –2.7 to 2.3 for gabbro, 0.282010–0.282363 and –6.4 to 6.0 for diorite, and 0.282071–0.282285 and –5.0 to 2.6 for granitic dykes, suggesting juvenile crust production with mixing of older crust materials. In combination with previously published U-Pb ages and geochemical features of Late Paleoproterozoic, Mesoproterozoic, and Early Neoproterozoic rift-related rocks in and around the central–western Korean Peninsula, the Early Neoproterozoic arc magmatism reported in this study provides clear evidence for a tectonic transition from the disruption of the Columbia supercontinent to the amalgamation and disruption of Rodinia supercontinent.
Bibliographical noteFunding Information:
We thank the editor Prof. Guochun Zhao, and two anonymous reviewers for their constructive and helpful comments. This work was supported by a Basic Research Project (GP2017-002; 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 and ICT (Information, Communication and Technology). S.K. appreciates the partial support from NRF-2017R1A6A1A07015374 (Multi-disciplinary study for assessment of large earthquake potentials in the Korean Peninsula) and NRF-2019R1A2C1002211 through the National Research Foundation of Korea funded by the Ministry of Science and ICT, Korea.
All Science Journal Classification (ASJC) codes
- Geochemistry and Petrology