Phanerozoic high-pressure eclogite and intermediate-pressure granulite facies metamorphism in the Gyeonggi Massif, South Korea: Implications for the eastward extension of the Dabie Sulu continental collision zone

摘要: Abstract Petrological analysis, zircon trace element analysis and SHRIMP U–Pb dating of retrogressed eclogite garnet granulite from Bibong, Hongseong area, SW Gyeonggi Massif, South Korea provide compelling evidence for Triassic (231.4 ± 3.3 Ma) high-pressure (HP) facies (M1) metamorphisms at a peak pressure–temperature ( P – T ) ca. 16.5–20.0 kb 775–850 °C. This was followed by isothermal decompression (ITD), with sharp decrease in pressure 20 to 10 kb slight temperature rise (M2), uplift cooling. Granitic orthogneiss surrounding the Baekdong ophiolite-related ultramafic lenticular body near Bibong records later Silurian (418 ± 8 Ma) intermediate (IHP) metamorphism prograde path conditions 13.5 kb 800 °C. K–Ar ages biotite granulites, amphibolites, granitic orthogneisses around metabasite are 208–219 Ma, recording cooling about 310 °C after Early metamorphic peak. Neoproterozoic cores that protoliths these rocks were ∼ 800 ∼ 900 Ma old, respectively, similar tectonic episodes Central Orogenic Belt China. This, HP/UHP both China Korea, is consistent regional link within Northeast Asia time Rodinia amalgamation continent–continent collision between North Blocks, an eastward extension Dabie–Sulu suture zone into area Korea.