Organic Metamorphism of the Coals in the Chungnam Coalfield, Korea

摘要: The object of this study is to clarify the degree organic metamorphism in Late Triassic coal-bearing Chungnam Coalfield using vitrinite reflectance and crystallininity by X-ray diffraction analysis as rank parameters, discuss geological background coalification. R_(max) values range from 4.55% 6.48%, which indicate coals belong anthracite meta-anthracite stage ASTM classification. shows very distinct peak 25.51 25.58 2θ, indicates an average molecular repeat distance approximately 3.49Å Ovals. Integral breadth ranges 6.06 5.98. Bireflectance varied 1.79 3.35. Above mentioned characteristic features are inferred a manifestation higher temperature pressure metamorphism. begin decrease at 5.5% pattern striking contrast that European coals. tend increase with increasing values. modes do not always correspond each other progressing In unit formations, Amisan Formation most advanced coalification crystallinity. Anthracitization was took placed post-Daebo Orogeny caused thermal effects intrusion Jurassic Daebo Granite. Judging fossil plants paleomagnetic data, it formation coal deposits formed subtropical climate Korean Peninsula paleogeographically situated near horse-latitudes lower latitudes than present geographic position time.