| 摘要: |
| 对母液中Mg2+离子对硼掺入无机碳酸盐沉积的影响进行了研究。通过扫描电子显微镜和X射线衍射确定在Mg存在时生成的无机碳酸盐是低镁方解石。实验发现：溶液的pH值是硼进入碳酸盐的主要控制因素，低Mg2+方解石中硼的浓度从63.91 μg∙g−1（pH = 7.40 ± 0.03）增加到582.41 μg∙g−1（pH = 8.80 ± 0.03）。Mg2+离子严重影响硼进入碳酸盐中的量，在相同实验条件下，硼在低镁方解石中的含量高于无Mg2+方解石中的含量，平均为2.57倍（1.83 — 3.56倍）。这一结果表明：有Mg2+离子时，硼掺入无机碳酸盐的机制和无Mg2+离子的是不同的。Mg2+离子的存在改变了晶体的形貌。这对利用B/Ca指标恢复深海碳酸盐系统研究有重要影响。 |
| 关键词: 作用 镁离子 硼 无机碳酸盐沉积 |
| DOI：10.7515/JEE201603009 |
| CSTR：32259.14.JEE201603009 |
| 分类号: |
| 基金项目: |
| 英文基金项目:National Natural Science Foundation of China (41573013, U1407109); “Key Program” of the West Light
Foundation of Chinese Academy of Sciences (42904101) ; Natural Science Fund of Shaanxi Province (2015JM4143) |
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| The effect of Mg2+ on boron incorporation into carbonate and the influence of B/Ca proxies for the deep ocean carbonate system |
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HE Maoyong, XIAO Yingkai1,2,3
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1. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment,
Chinese Academy of Sciences, Xi’an 710061, China;2. Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China;3. Shaanxi Key Laboratory of Accelerator Mass Spectrometry
Technology and Application, Xi’an 710061, China
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| Abstract: |
| Background, aim, and scope B/Ca proxies for the deep ocean carbonate system is an important proxy to evaluate carbon sink in sea. Mg2+ is common element in sea which can effect B/Ca values of marine carbonate. Materials and methods The influence of Mg2+ in a parent solution on boron incorporation in an inorganic carbonate precipitate is studied using a different solubility method technique. The calcium carbonate precipitate is characterized by scanning electron microscopy and X-ray diffraction. The boron concentration of the samplers is analyzed by ICP-AES. Results The calcium carbonate precipitate is confirmed to be low-Mg calcite. The boron concentrations in the precipitated calcite increased from 63.91 μg∙g−1 to 582.41 μg∙g−1 when the artificial solution pH values increased from 7.40 ± 0.03 to 8.80 ± 0.03. Discussion The results show that boron uptake by low-Mg calcite is greater than boron uptake by free-Mg calcite grown under nearly identical conditions, and the boron concentration in low-Mg calcite is higher than in free-Mg calcite by 2.57 average time (from 1.83 to 3.56). This result suggests that the mechanism for borate-boron co-precipitation with Mg2+ present is different than without Mg2+ present, and the Mg2+ clearly modifies calcite crystal morphology, as identified in SEM images. Conclusions pH has a significant effect on the incorporation of boron into synthetic carbonate, and the Mg2+ also influence on boron incorporation into calcite precipitate. Recommendations and perspectives The data provide a significant scientific basis for B/Ca proxies for the deep ocean carbonate system. It is recommended that the Mg2+ would be consider when using B/Ca proxies. |
| Key words: effect magnesium ions boron precipitated inorganic carbonate |
