Arc magmatism in the Yeongnam massif, Korean Peninsula: Imprints of Columbia and Rodinia supercontinents

Abstract

Sensitive high-resolution ion microprobe (SHRIMP) U–Pb zircon ages and whole-rock chemical compositions are reported here from charnockite, anorthosite and metagranite (orthogneisses) from the Jirishan complex in the southwestern part of the Yeongnam massif, Korea. The charnockite and the Kfs-megacryst metagranite yielded zircon U–Pb ages of ca. 1871–1863Ma. In contrast, the Neoproterozoic porphyritic metagranite and anorthosite yielded zircon U–Pb ages of ca. 908–904Ma. The geochemical signatures of both Paleoproterozoic and Neoproterozoic rocks display enrichment in LREEs and negative Nb, Ta and Ti anomalies. The geochronological and geochemical data suggest that the Proterozoic Jirishan complex preserves the imprints of arc-related magmatism at different periods associated with the formation of the Paleoproterozoic Columbia and the Neoproterozoic Rodinia supercontinents. The ca. 1871–1863Ma ages from the charnockites and metagranites from the Jirishan complex are coeval with similar events in the North China Craton, which also represent arc magmatism in a convergent margin setting related to the amalgamation of the Columbia supercontinent. In contrast, the Neoproterozoic porphyritic metagranite and anorthosite, together with the Neoproterozoic metagranites reported from the western Gyeonggi massif, provide a temporal link to the Neoproterozoic tonalite–granodiorite plutons recently identified in and around the South China Craton. They represent orogenic-type magmas that can be attributed to the amalgamation of the Rodinia supercontinent. However, the foliated granites in the central to southwestern Yeongnam massif are related to an arc setting associated with the Permo–Triassic Paleo-Pacific subduction.