Mesoproterozoic magmatic suites from the central-western Korean Peninsula: Imprints of Columbia disruption in East Asia

摘要

Middle Mesoproterozoic rift-related magmatisms of mantle plume origin are of global interest in understanding the breakup of the Columbia supercontinent. Here we investigate the age-equivalent basement rocks along the western marginal areas of the northwestern Gyeonggi Massif in the central-western Korean Peninsula. The sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon ages of the late Middle Mesoproterozoic mafic dykes and monzonitic intrusions from the Dongman Island and the early Late Mesoproterozoic syenites from the Kimpo area show 1259 +/- 12 Ma, 1222 +/- 9 Ma, and 1197 +/- 5 Ma, 1194 +/- 6 Ma, respectively, suggesting multiple magmatic pulses. The late Middle Mesoproterozoic monzonitic intrusions and early Late Mesoproterozoic syenites are characterized by A(1)-type granite affinity, formed in continental rifts. The Middle Mesoproterozoic mafic dykes show characteristics of transitional composition between tholeiitic-alkaline basalts to alkaline basalt having geochemical affinity of OIB (WPB) derived from enriched mantle sources, indicating a mantle plume origin. The data presented in this work, together with previous lithological, geochemical, and geochronological information on the magmatic suites from the western margin of the Gyeonggi Massif provide important insight into a Mesoproterozoic continental margin rift setting at ca. 1259-1194 Ma, and are broadly coeval with the Mesoproterozoic hotspot track identified in the Laurentia, North China Craton and Baltica, providing the imprints of the Columbia disruption in Northeast Asia.