MESOPROTEROZOIC MAGMATIC EVENTS IN THE KOREAN PENINSULA AND THEIR TECTONIC IMPLICATIONS: GEOCHRONOLOGICAL EVIDENCE FROM DETRITAL ZIRCONS IN THE BAENGNYEONGDO

Whether any Grenvillian magmatic records are preserved in the Precambrian basement rocks of the Korean peninsula is a keen issue to understand the Proterozoic tectonic evolution of the peninsula and its correlation not only to the North and South China Blocks but also to the supercontinent Rodinia. Mesoproterozoic to Neoproterozoic sedimentary successions of Sangwon and Guhyeon (Kuhyon) Systems are well exposed in southern North Korea and magmatic events during the Mesoproterozoic Era are indicated by detrital zircons with marked age populations at ca. 1.2 Ga and 1.6 Ga (Hu et al., 2012). New U–Pb age determinations were carried out in this study using LA–MC-ICPMS on detrital zircons from sandstones of the Baengnyeong Group in the Baengnyeongdo (Baengnyeong Island), an island of South Korea, located near the southwest coast of North Korea. The analyzed detrital zircons show ages mainly within the Mesoprotrozoic Era with a few in Paleoproterozoic and one in Neoarchean, with main age populations at ~ 1.2 Ga and 1.6 Ga, indicating possible correlation to the Sangwon System in North Korea. Such age peaks are also similar to the Mesoproterozic detrital zircons from the Tumon Group in the Shandong Peninsula, China, located across the Yellow Sea, suggesting coeval deposition of the Baengnyeong Group in South Korea, Sangwon System in southern North Korea, and the Tumon Group in the Sandong Peninsula, China, along the margin of the Sino-Korean Craton. Significant contributions from Grenviliian magmatic rocks in the Sino-Korean Craton may provide clues to understand the possible geographic position of the Sino-Korean Craton during the assembly of the supercontinent Rodinia.

Hu et al (2012) Gondwana Research, 22, 828-842.