Detrital zircon U-Pb ages of the Machollyong Group in Korean Peninsula: Regional correlation and tectonic implications

The meta-sedimentary successions in the intra-cratonic mobile belts encapsulate essential information for deciphering the convergent and divergent geodynamic processes of constituent terranes during the construction of early supercontinents. The detrital zircon geochronology presents a key to probing it. With a view to bridging the gap in the characterization of massive meta-sedimentary successions in the most representative Paleoproterozoic mobile belts (i. e., the Liao-Ji-Korea mobile belt) in the North China Craton, this study carried out a detrital zircon SIMS U-Pb dating on the Machollyong Group at Komdok, Korean Peninsula. Zircons from one meta-pyroclastic sample of the Puktaechon formation yielded a dominant peak age of ca. 2. 53Ga and a youngest peak age of ca. 2. 19Ga, constraining their formation time to later than 2. 2Ga. Detrital zircons from one meta-sedimentary sample of the Namdaechon formation yielded a dominant peak age span from 2. 02 to 2. 18Ga, a subordinate peak age of ca. 2. 46Ga and a few older ages from 2. 78 to 3. 30Ga, reflecting dual provenances of the Paleoproterozoic plutons in the Rangnim Massif and the Neoarchean and Mesoarchean crusts in the neighboring terranes. The youngest detrital age constrains the maximum deposition time of the Namdaechon formation at ca. 2. 02Ga. Regional comparison suggests that the Machollyong Group shows consistent detrital zircon age spectra with the Liaohe Group and Ji' an/Laoling groups in the Liao-Ji mobile belt. Such consistency indicates their synchronization in deposition and similarity in provenance. These coeval and consanguineous litho-stratigraphic sequences can provide insightful reference for calibrating the tectonic affinity in the Liao-Ji and Korea mobile belt during the Paleoproterozoic. The dominance of detrital zircons with ages close to the depositional age is characteristic of various basins on convergent plate margins, but inconsistent with rift basins commonly featuring much older detrital zircons than the depositional age.