Chemical and isotopic compositions of authigenic carbonates from bottom sediments of Northwest Pacific marginal seas ...

• Main Authors: Astakhova, N V, Sorochinskaya, A V
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 1999
• Subjects: Box corer; Gravity corer; Dredge; Multiple investigations; MultiCorer; Gravity corer Kiel type; AN_1993; LV27/GREGORY; Akademik A Nesmeyanov; Akademik M.A. Lavrentyev; Archive of Ocean Data ARCOD; Carbonic acid; okhotsk sea
• Online Access: https://dx.doi.org/10.1594/pangaea.775328; https://doi.pangaea.de/10.1594/PANGAEA.775328

The paper presents data on authigenic carbonate distribution in Holocene - Upper Pleistocene deposits of the Okhotsk, Japan, East China, Philippine and South China Seas. Description of carbonate samples, their chemical and isotope compositions are given. Chemical analysis of the samples indicates that almost all authigenic carbonates are composed of calcite or magnesian calcite; and only in one case, of siderite. Oxygen isotopic composition (d18O) ranges from +37.7 to +26.1 per mil (SMOW); it is, probably, connected with different temperatures of carbonate formation. A distinct geographic regularity is traced. Decrease in d18O values is observed from the cold Okhotsk Sea to the warm South China Sea. A very wide range of carbon isotopic composition (d13C from -42 to +3.8 per mil) indicates different sources of carbonic acid required for formation of these carbonates. As a basis for carbon isotopic composition we can distinguish three sources of carbonic acid in the studied sediments: microbiological methane ... : Supplement to: Astakhova, N V; Sorochinskaya, A V (1999): Authigenic carbonates in Upper Pleistocene - Holocene deposits of marginal seas, Northwest Pacific. Tikhookeanskaya Geologiya (Pacific Geology), 18(1), 41-49 ...