Crustal growth history of the Korean Peninsula: Constraints from detrital zircon ages in modern river sediments

• Detrital zircon ages of South Korean river sediments range from 3566 Ma to 48 Ma.
• Crustal growth of South Korea occurred mainly in Mesozoic and Paleoproterozoic time.
• Pre-Mesozoic crustal growth history of North and South Korea is almost identical.
• Mesozoic arc magmatism was focused on southern Korean Peninsula.

U-Pb analyses were carried out on detrital zircon grains from major river-mouth sediments draining South Korea to infer provenance characteristics and the crustal growth history of the southern Korean Peninsula, using a laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS). The Korean Peninsula is located in the East Asian continental margin and mainly comprises three Precambrian massifs and two metamorphic belts in between them. We obtained 515 concordant to slightly discordant zircon ages ranging from ca. 3566 to ca. 48 Ma. Regardless of river-mouth location, predominance of Mesozoic (249–79 Ma) and Paleoproterozoic (2491–1691 Ma) ages with subordinate Archean ages indicates that the zircon ages reflect present exposures of plutonic/metamorphic rocks in the drainage basins of the South Korean rivers and the crustal growth of the southern Korean Peninsula was focused in these two periods. Comparison of detrital zircon-age data between the North and South Korean river sediments reveals that the Paleoproterozoic zircon age distributions of both regions are nearly identical, while the Neoproterozoic–Paleozoic ages exist and the Mesozoic ages are dominant in southern Korean Peninsula. This result suggests that Precambrian terrains in Korea record the similar pre-Mesozoic magmatic history and that the influence of Mesozoic magmatism was mainly focused in South Korea.

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