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Yoo D. G.;Park S. C.;Park K. S.;Sunwoo D.;Han H. S.
- 한국석유지질학회:학술대회논문집
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- spring
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- pp.15-21
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- 1998
Sparker profiles and sediment cores collected from the Korea Strait show a distinct pattern of stacked prograding wedges consisting of three distinct units. These wedges are interpreted as the lowstand deposits formed during glacioeustatic sea-level lowstands. Repeated sea-level falls during late Pleistocene with high sediment discharge from the paleo-Nakdong River system resulted in the formation of thick lowstand wedges.
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Lee Young joo;Huh Shik;Kwak Young hoon;Kim Hag ju;Chun Jong Hwa;Jun Sang Joon;Yoo Hai Soo
- The Korean Journal of Petroleum Geology
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- v.7 no.1_2 s.8
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- pp.35-40
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- 1999
Chemical and isotopic compositions of hydrocarbon gases were analyBed to characterize the properties of the shallow gases distributed in the southeastern part of the Ulleung Basin, offshore Korea. Sediments from the core were also analyzed to determine the characteristics and relationship to shallow gases. Hydrocarbon gases in the sediments consisted of methane (697.9-6054.4 ppm), ethane, propane, butane and hexane. The total carbon content of the sediments ranges from 1.84fe to $5.11{\%}$ and the total organic carbon content ranges from $0.29{\%} \;to\; 2.65{\%}$. High C/N ratio (>10) indicates that input of terrestrial organic matter was prevalent at the time of deposition. The methane content and stable isotopic data indicate that hydrocarbon gases from the sediments are identified to be thermogenic gas and mixture of both biogenic and thermal gases. Based on the Rock-Eval and carbon isotopic data, the level of thermal maturity of organic matter in the sediments $(Tmax<425^{\circ}C)$ is lower than that of gas. It suggests that thermal gases in the sediments migrated from the deeper sediments than the penetrated depth.
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