Petrographic Characterization and Rare Earth Elements as Geochemical Tracers for Redox Condition of Seep Carbonates from Northwestern Black Sea

详细信息   

• 责任者：Feng Dong (Key Laboratory of Marginal Sea Geology ; Guangzhou Institute of Geochemistry ; Chinese Academy of Sciences ; Guangzhou 510640 ; China) ; Chen Duofu
• 刊名：Geoscience
• 出版年：2008
• 卷期：22(3)
• 关键词：海洋沉积物 ; deep-sea sediments ; 碳酸盐岩 ; carbonate rocks ; 黑海 ; Black Sea
• 页码：p.390-396
• 图表：7 illus., 1 table, 17 refs.
• 分类号：0200
• issnNo：ISSN1000-8527
• isbnNo：CN11-2035/P

摘要

Seep carbonate crusts described here were collected on the Romanian (RO) shelf (120 m water depth) and Ukrainian (UKR) slope (190 m water depth) of the Black Sea. X-ray diffraction investigations show that high-Mg-calcite and aragonite are the dominant minerals. Peloids and botryoidal aragonite in the carbonate crust suggest a genesis induced by bacterial metabolism at the seep sites. The content of rare earth elements (REE) of the 5% HNO₃-treated solution of the carbonates are very low(0. 068×10^-6 to 2. 817×10^-6). The shale-normalized REE patterns of RO carbonate show significantly negative Ce anomalies, while that of UKR carbonate shows no Ce anomalies, indicating that RO and UKR seep carbonates were deposited in oxic and anoxic environments, respectively.