동해에서 산출된 메탄관련 자생탄산염: 광물, 구조, 지화학적 결과

Title
동해에서 산출된 메탄관련 자생탄산염: 광물, 구조, 지화학적 결과
Alternative Title
Methane-related authigenic carbonates from the East Sea, Korea:Mineralogical, textural, and geochemical results
Author(s)
우경식; 김진경; 박장준; 현상민
KIOST Author(s)
Hyun, Sangmin(현상민)
Publication Year
2009-09-01
Abstract
Authigenic carbonates related to gas hydrates were discovered from the cores in the Ulleung Basin, East Sea. Carbonate concretions range from 3 to 6 cm in diameter, and display irregular shapes. The inside of concretions is sometimes porous and shows internal layering. Concretions are composed of aragonite or high Mg-calcite, or the combination of both. Calcite crystals are micritic and include planktonic foraminifers, diatoms, silt-sized, detrital quartz grains, and authigenic framboidal pyrites. Ultra-textural examination reveals that acicular aragonites grew as cements between micritic calcite crystals, and this suggests that micritic calcite precipitated prior to acicular aragonite. Oxygen and carbon isotopic compositions of carbonate concretions range from 2 to 5 per mil (PDB) and from -44 to -39 per mil (PDB), respectively. These depleted carbon isotopic compositions indicate that the carbon source for the formation of authigenic carbonates were gas hydrates below, and the carbonates were formed by the oxidation of methane. Relatively narrow range of carbon isotope values, compared to those of other authigenic carbonates reported elsewhere, indicates similar diagenetic environments of formation for these concretions. Distinctive clusters of stable isotope values as well as trace elemental concentrations of each concretion regardless of mineralogy imply that carbonate concretions formed in a closed-diagenetic system. Increase in Mg/Ca ratio in the semi-closed diagenetic system induced the mineralogical change from calcite to aragonite.
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/29359
Bibliographic Citation
AOGS, pp.1, 2009
Publisher
AOGS
Type
Conference
Language
English
Publisher
AOGS
Related Researcher
Research Interests

Marine environmentology,Marine environmentology,Organic chemistry,해양환경학,화학해양학,유기화학

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