Effects of weathering on in situ portable X-ray fluorescence analyses of geological outcrops: dolerite and rhyolite outcrops from the Preseli Mountains, South Wales
Effects of weathering on in situ portable X-ray fluorescence analyses of geological outcrops: dolerite and rhyolite outcrops from the Preseli Mountains, South Wales
复制标题
风化对地质露头现场便携式 X 射线荧光分析的影响：南威尔士普雷塞利山脉的辉绿岩和流纹岩露头
DOI：
10.1002/xrs.881
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发表时间：
2006
影响因子：
1.2
通讯作者：
P. Webb
中科院分区：
文献类型：
--
作者：
P. Potts;F. Bernardini;M. C. Jones;O. Williams;P. Webb
通过实验室实验研究了风化对南威尔士普雷塞利山脉辉绿岩和流纹岩样品的影响，该地区对考古文物的起源具有重要的考古学意义。便携式XRF(PXRF)分析被用来构建穿过合适岩石样品风化层的元素浓度的深度剖面。这些测量是通过顺序磨掉连续的层来进行的，每次都用PXRF测量新暴露的表面。所研究的元素包括K、Ca、Ti、Mn、Fe、Ba、Nb、Pb、Sr、Y和Zr。在辉绿岩样品中，Ca、Fe和Y在风化严重的表层中普遍亏损，而K和Pb则明显增加，后者明显增加，这可能是人为活动(含铅汽车燃料排放)的结果。流纹岩中的元素行为不太一致。根据风化表面浓度与蚀变层下相应的稳态(新鲜岩石)浓度之比，得出了每种元素的修正系数。该修正系数被评估为在测量风化表面时补偿元素差异的一种可能手段。获得了大量元素的改进数据，但需要进一步的工作才能充分评价这一程序。
Laboratory experiments were undertaken to investigate the effect of weathering on dolerite and rhyolite samples from the Preseli Mountains, South Wales, an area of archaeological significance for the provenancing of archaeological artefacts. Portable XRF (PXRF) analysis was used to construct a depth profile of elemental concentrations through the weathering layer of suitable rock samples. These measurements were made by sequentially grinding away successive layers, each time measuring the newly exposed surface by PXRF. The elements studied included K, Ca, Ti, Mn, Fe, Ba, Nb, Pb, Sr, Y and Zr. In dolerite samples, Ca, Fe and Y were generally depleted in heavily weathered surface layers,whereas K and Pb were enhanced, the latter element significantly so, probably as a result of anthropogenic activities (emissions from leaded automobile fuel). Element behaviour in rhyolites was less consistent. A correction factor was derived for each element based on the ratio of the weathered surface concentration to the corresponding steady-state (fresh rock) concentration beneath the altered layer. This correction factor was evaluated as a possible means of compensating for elemental discrepancies when measuring weathered surfaces. Improved datawere obtained for a significant number of elements, but furtherwork is required to evaluate this procedure fully.