Origins and Distribution Patterns of Seabed-derived Shallow Gas in the southwestern Coastal Area, East Sea

Title
Origins and Distribution Patterns of Seabed-derived Shallow Gas in the southwestern Coastal Area, East Sea
Author(s)
조진형; 신동혁; 정갑식; 이철구; 모태준; 이승용; 금병철; 장석
KIOST Author(s)
Cho, Jin Hyung(조진형)Shin, Dong Hyeok(신동혁)Jeong, Kap Sik(정갑식)Lee, Cheolku(이철구)Lee, Seung Yong(이승용)Kum, Byung Cheol(금병철)Jang, Seok(장석)
Alternative Author(s)
조진형; 신동혁; 정갑식; 이철구; 모태준; 이승용; 금병철; 장석
Publication Year
2017-04-07
Abstract
In the mud-belt off the southeastern coast of Korea, geophysical and geochemical survey from sedimentary layer to water column was performed to confirm the accumulation and release of hydrocarbon gases in the shallow depth of sedimentary layer. The active seepage has been observed by high-resolution (3.5 kHz) seismic profiling that occurs through up to 120 plumes from the topmost sedimentary layer. The plumes are hydro-acoustically detected in the area of 2.7 km2, from 20 to 50 m in water depth range, and found rare In deeper depth. The gas plumes are reached vertically up to 25 m from the seafloor. The gas seepage appears to be explosive enough to form craters, although pockmarks are rare. The carbon isotopes (δ13C) of gases in the sediments (-62.0 to – 39.7 ‰ PDB) are characteristically differentiated from the seawater (-59.8 to – 48.6 ‰ PDB). The gases are considered to be generated from abundant organic carbon (1.5 to 4.0%) in the sedimentary layer and mixed of small amounts of thermogenic gas which are derived from the underlying older sedimentary rocks.ayer. The active seepage has been observed by high-resolution (3.5 kHz) seismic profiling that occurs through up to 120 plumes from the topmost sedimentary layer. The plumes are hydro-acoustically detected in the area of 2.7 km2, from 20 to 50 m in water depth range, and found rare In deeper depth. The gas plumes are reached vertically up to 25 m from the seafloor. The gas seepage appears to be explosive enough to form craters, although pockmarks are rare. The carbon isotopes (δ13C) of gases in the sediments (-62.0 to – 39.7 ‰ PDB) are characteristically differentiated from the seawater (-59.8 to – 48.6 ‰ PDB). The gases are considered to be generated from abundant organic carbon (1.5 to 4.0%) in the sedimentary layer and mixed of small amounts of thermogenic gas which are derived from the underlying older sedimentary rocks.
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/24187
Bibliographic Citation
한국지구과학회 춘계학술발표회, pp.108 - 112, 2017
Publisher
한국지구과학회
Type
Conference
Language
English
Publisher
한국지구과학회
Related Researcher
Research Interests

marine geology,marine security,해양지질,해양방위

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