Growth mechanisms and environmental implications of carbonate concretions from the ~?1.4?Ga Xiamaling Formation, North China
文献类型：期刊论文
| 作者 | An-Qi Liu1; Dong-Jie Tang1; Xiao-Ying Shi1; Li-Min Zhou; Xi-Qiang Zhou2; Mo-Han Shang1; Yang Li1; Hu-Yue Song1 |
| 刊名 | Journal of Palaeogeography
 |
| 出版日期 | 2019 |
| 卷号 | 8期号:1页码:285 |
| ISSN号 | 2524-4507 |
| 英文摘要 | Carbonate concretions provide unique records of ancient biogeochemical processes in marine sediments, and have the potential to reflect seawater chemistry indirectly. In fine-siliciclastic settings, they preferentially form in organic-rich mudstones, owing to a significant fraction of the bicarbonate required for carbonate precipitation resulted from the decomposition of organic matter in sediments. In the Member IV of the Xiamaling Formation ( ca. 1.40–1.35?Ga), North China, however, carbonate concretions occur in organic-poor green silty shales (avg. TOC?=?~?0.1?wt%). In order to elucidate the mechanism of the concretion formation and their environmental implications, a thorough study on the petrographic and geochemical compositions of the concretions and their host rocks was conducted. Macro- to microscopic fabrics, including deformed shale laminae surrounding the concretions, “cardhouse” structures of clay minerals and calcite geodes in the concretions, indicate that these concretions are of early diagenetic origin prior to the significant compaction of clay minerals. The carbon isotope compositions of the concretions (??1.7‰ to +?1.5‰) are stable and close to or slightly lower than that of the contemporaneous seawater, indicating that the bicarbonates required for the concretion formation were mainly sourced from seawater by diffusion rather than produced by methanogenesis or anoxic oxidation of methane (AOM); the rare occurrence of authigenic pyrite grains in the concretions likely indicates that bacterial sulfate reduction (BSR) did not play a significant role in their formation either. Almost all the calcite in the concretions has low Mn–Fe in nuclei but high Mn–Fe in rims with average Mn |
| 语种 | 英语 |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/99847]  |
| 专题 | 地质与地球物理研究所_中国科学院油气资源研究重点实验室 |
| 作者单位 | 1.中国地质大学 2.Institute of Geology and Geophysics, Chinese Academy of Sciences |
| 推荐引用方式 GB/T 7714 | An-Qi Liu,Dong-Jie Tang,Xiao-Ying Shi,et al. Growth mechanisms and environmental implications of carbonate concretions from the ~?1.4?Ga Xiamaling Formation, North China[J]. Journal of Palaeogeography,2019,8(1):285. |
| APA | An-Qi Liu.,Dong-Jie Tang.,Xiao-Ying Shi.,Li-Min Zhou.,Xi-Qiang Zhou.,...&Hu-Yue Song.(2019).Growth mechanisms and environmental implications of carbonate concretions from the ~?1.4?Ga Xiamaling Formation, North China.Journal of Palaeogeography,8(1),285. |
| MLA | An-Qi Liu,et al."Growth mechanisms and environmental implications of carbonate concretions from the ~?1.4?Ga Xiamaling Formation, North China".Journal of Palaeogeography 8.1(2019):285. |
入库方式： OAI收割
来源：地质与地球物理研究所
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