Minor and trace element incorporation into branching coral Acropora nobilis skeleton
Minor and trace element incorporation into branching coral Acropora nobilis skeleton
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DOI：
10.1016/j.gca.2008.07.026
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发表时间：
2008-11-15
影响因子：
5
通讯作者：
Sano, Yuji
中科院分区：
文献类型：
--
作者：
Shirai, Kotaro;Kawashima, Tatsunori;Sano, Yuji
在不同的空间分辨率下分析了鹿角珊瑚骨架的化学和同位素组成，以研究元素融入骨架的机制。除轴向珊瑚的 5180 剖面外，轴向和径向珊瑚沿生长轴的化学和同位素剖面没有显示出季节性变化。对骨骼结构的详细观察表明，骨骼密度随着距尖端的距离而增加，因为二次沉淀的文石（这里称为“填充”骨骼）填充了“框架”骨骼中的孔隙空间。微观元素分析表明，填充骨架主体部分的Mg/Ca含量低于骨架骨架，而Sr/Ca和U/Ca含量高于骨架骨架。在微观尺度上，Sr/Ca和U/Ca彼此呈正相关，与Mg/Ca呈负相关，但相关性较弱。结果表明，填充骨架与相邻的框架骨架不仅在形成年代上而且在化学成分上都存在显着差异，并且整体成分受到填充/框架骨架比例的影响。为了将鹿角珊瑚骨骼用作古气候档案，需要建立环境因素与每个骨骼成分的化学成分之间的关系。 (C) 2008 Elsevier Ltd. 保留所有权利。
Chemical and isotopic compositions of the Acropora nobilis skeleton were analyzed at various spatial resolutions to investigate the mechanism by which elements are incorporated into the skeleton. Chemical and isotopic profiles along growth axes of axial and radial corallites did not show seasonal variation, with the exception of the 5180 profile of the axial corallite. Detailed observations of the skeletal structure revealed that the skeletal density increased with distance from the tip because secondarily precipitated aragonite (here called the "infilling" skeleton) filled pore spaces in the "framework" skeleton. Micro-scale element analyses revealed that main part of the infilling skeleton had lower Mg/Ca and higher Sr/Ca and U/Ca than the framework skeleton. At microscale, Sr/Ca and U/Ca were positively correlated with each other, and negatively correlated with Mg/Ca but only weakly. The results showed that the infilling skeleton differed significantly from the adjacent framework skeleton in terms of not only formation chronology but also chemical composition, and that the bulk composition was influenced by the infilling/framework skeletal ratio. In order to use the Acropora skeleton as a paleoclimate archive, the relationship between environmental factors and the chemical composition of each skeletal component needs to be established. (C) 2008 Elsevier Ltd. All rights reserved.