Trace element distribution in annual stalagmite laminae mapped by micrometer-resolution X-ray fluorescence: Implications for incorporation of environmentally significant species
Trace element distribution in annual stalagmite laminae mapped by micrometer-resolution X-ray fluorescence: Implications for incorporation of environmentally significant species
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DOI：
10.1016/j.gca.2006.12.016
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发表时间：
2007-03-15
影响因子：
5
通讯作者：
Susini, Jean
中科院分区：
文献类型：
--
作者：
Borsato, Andrea;Frisia, Silvia;Susini, Jean
来自意大利东北部Grotta di Ernesto洞穴的石笋ER78显示出清晰的年度层压，与它在森林生态系统下的浅深度一致，该生态系统受秋季水渗透高峰的影响。同步辐射扫描微x射线荧光分析重元素在欧洲同步辐射设施ID22光束线和轻元素在ID21，以1-3 μ m的分辨率与离子探针分析的数据相结合，揭示了这些年度层的可见层的化学变化。一系列的元素显示出一个对称的峰值，以每个层的顶部的薄而暗的层为中心。峰浓度依次为Y、Zn、Cu、Pb、>、P、Br。这种层次结构被认为反映了这些元素的选择性运输，可能是在秋季入渗时从土壤带冲出来的有机胶体。离子探针分析表明，Na和F也增加了，H也增加了，后者反映了微孔隙度的增加。Sr在暗而薄的秋季层周围显示一个槽，这意味着它的结合可能受到与其他元素竞争的限制。Mg和S表现出不同的年变化模式，Fe则没有变化。微量金属，Br和Y在20世纪初显示出峰值丰度，这似乎反映了一个砍伐树木的时期，而不是气候异常。结果证明了同步加速器技术的高空间分辨率和低检测限的力量，以及它产生定量图的能力，使层状结构与孤立粒子或不规则不均匀性区分开来。(c) 2006爱思唯尔公司版权所有。
Stalagmite ER78, from Grotta di Ernesto cave in NE Italy displays clear annual lamination consistent with its shallow depth below a forest ecosystem subject to autumnal peaking of water infiltration. Synchrotron radiation scanning micro-X-ray fluorescence analyses of heavy elements at European Synchrotron Radiation Facility beamline ID22, and light elements at ID21, with 1-3 mu m resolution has been combined with data from ion microprobe analyses to reveal chemical variability across the visible layers of these annual laminae. A series of elements display a symmetrical peak, centered around the thin, dark layer at the top of each lamina. The peak concentration is ordered Y > Zn, Cu and Pb > P and Br. This hierarchy is thought to reflect the selectivity of transport of these elements, possibly by organic colloids flushed from the soil zone during autumn infiltration. Ion microprobe analysis indicates Na and F also increase, as does H, the latter reflecting increased microporosity. Sr displays a trough around the dark and thin autumn layer implying that its incorporation may be limited by competition with other elements. Mg and S show a different pattern of annual variation and Fe displays none. The trace metals, Br and Y display peak abundance in the early 20th century, which appears to reflect a period of tree-felling rather than a climatic anomaly. The results demonstrate the power of the high spatial resolution and low detection limits of the synchrotron technique, and its ability to produce quantitative maps that allow distinction of layered structure from that of isolated particles, or irregular inhomogeneities. (c) 2006 Elsevier Inc. All rights reserved.