Origin of a Dolomite-Related Jade Deposit at Chuncheon, Korea

摘要: The Chuncheon nephrite deposit in Korea is among the largest jade deposits worldwide. hosted Precambrian dolomitic marble and amphibole schist that were intruded by posttectonic (Late Triassic) granite. Carbonates have oxygen carbon isotope compositions range of –0.1 to +18.2 per mil –4.3 +0.9 mil, –0.4 +3.5 –9.9 –4.7 respectively. These data are agreement with decarbonation processes driven fluid infiltration forming from temperature 330° 430°C. Stable silicates homogeneous extremely depleted 18 O D; tremolite has δ = –7.9 D –118 –105 mil; diopside –13.6 –11.5 three samples grossular –4.4, +10.4, +11.5 clinochlore –9.5 –9.0 –103 –94 two talc veins –7.7 –7.3 –86 –90 mil. Quartz nearby schists also variable +0.5 –8.4 –0.6 respectively, not isotopic equilibrium. It suggested formation this postdated metamorphism country rocks. distinctly negative values indicate infiltrated was mainly meteoric origin its circulation most likely related intrusion Model calculations demonstrate fluid/rock ratios high, both hydrogen buffered phase, X CO 2 phase very low during formation. conditions contrast spatially associated serpentinites (e.g., Fengtien deposit, Taiwan). Such formed regional their host serpentinite.