U-Pb zircon age dating of a rapakivi granite batholith in Rangni massif, North Korea

摘要

Rapakivi granites and several small leucogabbroic and gabbroic bodies are located in the Rangnim Massif, North Korea. The largest batholith in the Myohyang Mountains covers an area of 300 km(2) and was intruded into Precambrian metamorphosed rocks. It has a SHRIMP U-Pb zircon weighted mean (207)ph/Pb-206 age of 1861 +/- 7 Ma. The country rocks of rapakivi granites are Neoarchaean orthogneisses and Palaeo-Mesoproterozoic graphite-bearing metasedimentary rocks of granulite facies, and they are similar to those of the rapakivi granites and anorthosites exposed in South Korea and in the North China Craton. We conclude that the three massifs in the Korean Peninsula commonly record an identical Palaeo-Mesoproterozoic anorogenic magmatic event, indicating that they have a common Precambrian basement with the North China Craton.