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[1] The Daebo Orogeny is a major orogenic event in Korea that affected the Early to Middle Jurassic Daedong Supergroup. Our investigation of the Nampo Group (part of the supergroup) in the Chungnam Basin reveals the occurrence of two phases of shortening. The majority of the Nampo Group and a basement slab were folded and displaced toward the WNW along the Ocheon thrust during the first phase (Middle Jurassic -early Late Jurassic). Field relationships suggest a ramp-flat geometry for the Ocheon thrust. Mechanical stratigraphy within the slice is consistent with a detachment fold model. Geometric modeling suggests 5.5 km and 3.3 km as the minimum amount of shortening accommodated by the Ocheon thrust and its slice for the ramp slopes of 15°and 30°, respectively. The second phase (late Late Jurassic) was a N-S shortening which produced roughly E-W-trending reverse faults and folds to form a dome-and-basin structure. These shortening events occurred over the entire Chungnam Basin, and coincide in orientation and timing with those reported from the Ogcheon Belt and the Gyeonggi massif. The first and second phases of the Daebo Orogeny are respectively correlated with the shortening in eastern China and the sinistral transpression along the Tan-Lu Fault, both belonging to the early Yanshanian movement. Subsequently in the Early Cretaceous, a regional extension commenced over Korea and eastern China. These remarkable correlations suggest that two stages of crustal thickening occurred throughout the eastern Asia during the Middle to Late Jurassic, followed by regional thinning in the Early Cretaceous.

Waterborne fluorinated anionic polyurethane dispersions (FAPUDs) were synthesized from tris(6-isocyanatohexyl) isocyanurate, N-ethyl-N-2-hydroxyethyl-perfluorooctanesulfonamide, poly(oxytetramethylene glycol) (PTMG), dimethylolpropionic acid (DMPA), hexamethylene diisocyanate, 1,4-butanediol, and two different neutralizing agents (triethylamine and sodium carbonate). Waterborne polyurethane dispersions (PUDs) were synthesized from isophorone diisocyanate, PTMG, DMPA, and ethylenediamine as chain extenders. The particle size of the FAPUDs, based on the fluorine content and degree of neutralization (DN), was measured with dynamic light scattering. So that the surface modification and morphology variations of the PUDs through the addition of the FAPUDs could be observed, the surface energy and thermal properties of the blending films [fluorine PUD mixtures (FPMs)] were measured with contact-angle analysis and differential scanning calorimetry. The particle size of the FAPUDs increased as the fluorine content in the FAPUDs increased and decreased as the DN increased. The surface energy of the FPM films made from the blending of the FAPUD T series (neutralization with triethylamine) gradually decreased above the critical fluorine concentration (0.02797 wt %). However, for the blending of the FAPUD 25Na series (neutralization with sodium carbonate), the surface energy increased above the critical fluorine concentration (0.02797 wt %) because of the increase in Na salts. The FAPUDs showed the native thermal behavior of the fluorine. However, the thermal properties of the blending films were like those of pure PUDs. This showed that the morphology of the PUDs was rarely unchanged when the FAPUDs were added.

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One of critical boundaries in Korea is the boundary between the Taebaeksan Basin and the Ogcheon metamorphic belt. We performed field mapping and geochronological/geochemical analyses in the Jecheon-Maepo areas. In the Bonghwajae section, the "Yamisan unit" (761 ± 3 Ma) belonging to the Ogcheon Supergroup occurs eastward beyond previous limit of Ogcheon metamorphic belt. Farther east, the post-Cambrian "Soyari unit" of uncertain affinity occurs. The Soyari unit borders a typical sequence of Taebaeksan Basin to the east in Maepo. We suggest that the boundary between the Ogcheon metamorphic belt and the Taebaeksan Basin is more than 20 km wide zone. Occurrence of the "Danri window" shows that the Ogcheon Supergroup sequence overlies the Joseon Supergroup unit along a decollement in the Jecheon-Maepo areas. The decollements and NW-to NNW-trending structures resulted from NE-or ENE-directed shortening probably during the Songrim Orogeny (Indosinian). We consider two alternative models for the origin/structural relationship between the Taebaeksan Basin and the Ogcheon metamorphic belt. In one plate model, the Taebaeksan Basin had formed close to the Ogcheon metamorphic belt. In two plate model, the Taebaeksan Basin had formed in the North China Block, and was transported hundreds kilometers southward along a continental transform fault.