Hf ISOTOPIC EVIDENCE FOR PALEOARCHEAN (> 3.5 GA) CRUSTAL COMPONENTS IN THE KOREAN PENINSULA

Abstract

We report in-situ Hf isotopic data on five inherited zircon components, dated at > 3.0 Ga from previous Sensitive High Resolution Ion Microprobe (SHRIMP) U-Pb analyses. These data are useful for constraining the timing and nature of very pristine crustal materials in South Korea.176Hf/177Hf isotope ratios, measured using a laser ablation Multi-collector Induced Coupled Plasma Mass Spectrometer (MC-ICP MS), range from 0.28044 to 0.28075, corresponding to the present-day εHf(0) of −70 to −81. They yield two-stage Hf model ages of ca. 4.1 to 3.5 Ga at the time of zircon crystallization from a magma, depending on tenable crustal evolution models. Our results provide the first Hf isotopic evidence for existence of Paleoarchean (>3.5 Ga) crustal components in the Korean Peninsula.