Detrital zircon U-Pb and Hf isotope characteristics of the Early Neoproterozoic successions in the central-western Korean Peninsula: Implication for the Precambrian tectonic history of East Asia

摘要

The Early Neoproterozoic successions in the central-western Korean Peninsula preserve important geological records of the Late Paleoproterozoic to Mesoproterozoic events associated with the disruption of the Columbia supercontinent, and the amalgamation and disruption of the Rodinia supercontinent. In this study, we present SHRIMP and LA-MC-ICPMS U-Pb ages and Hf isotope signatures of detrital zircon grains from metasedimentary rocks of the Jangbong Formation in the Hongseong-Imjingang Belt and the Sangwon System in the Nangnim Massif. Most zircon grains from all the samples are magmatic in origin, yielding similar U-Pb age spectra ranging from Neoarchean to Late Mesoproterozoic or Early Neoproterozoic, with multiple age peaks within the Late Paleoproterozoic to Mesoproterozoic range (ca. 1876 Ma, ca. 1744 Ma, ca. 1578 Ma, and ca. 1168 Ma in the Jangbong Formation and ca. 1754 Ma, ca. 1588 Ma, ca. 1450 Ma, and ca. 1160 Ma in the Sangwon System). The maximum ages of deposition estimated from the youngest concordant detrital zircons are ca. 1.0 - 0.96 Ga from the Jangbong Formation and ca. 0.98 Ga from the Sangwon System. Ages and Hf isotope signatures of dominant Late Paleoproterozoic to Mesoproterozoic detrital zircon populations reflect magmatic history involving juvenile input and crustal reworking. In contrast, the minor magmatic detrital zircon populations with Neoarchean to Middle Paleoproterozoic ages show negligible contribution from basement source materials of the adjacent Gyeonggi and Nangnim massifs. The dominant Late Paleoproterozoic to Mesoproterozoic zircon populations examined in this study in conjunction with available data from the Korean Peninsula correlate with the geological and geochronological evidence from the North China Craton associated with rifting along the north-eastern margin of the southeastern domain of the Columbia during the Late Paleoproterozoic to Early Neoproterozoic.