LCZO -- Soil Geochemistry -- X-ray Florescence -- Luquillo Mountains -- (2010-2010)

X-ray Florescence (XRF) is a widely used non-destructive method that measures the elemental composition of materials. This technology was applied to investigate the rocks and sediments in the Luquillo Mountains / El Yunque region of Puerto Rico. Initial testing of wet and dry sediments revealed that the machine records higher elemental concentrations in dry compared to wet sediments as it seems that the water molecules interfere with the X-ray beam on wet samples. The XRF method on dried samples produced reliable results and allowed for the chemical separation of the five basic bedrock types found in the Luquillo Mountains. Of the volcanoclastic the Fajardo Formation can be distinguished from the others by its concentration of Barium (Ba) and Rubidium (Rb). The Unnamed formation was distinguished by Copper (Cu) and the Hato Puerto Formation was distinguished by Nickel (Ni) and Strontium (Sr). The Rio Blanco granodiorite is the youngest rock type of the region and was the only formation whose elemental chemistry was not distinguishable from the othersapparently because it was formed directly from the basic magma that also formed the Luquillo Mountains volcanic rocks. Recent studies have found high levels of Mercury (Hg) in Luquillo stream water. Knowing that the Luquillo region was heavily mined for Gold (Ag) and Silver (Au), the Hg used in historic mining is a possible source of the elevated Hg values. The XRF analysis indicated small quantities of Hg in some rocks but no Hg was found in the sediments and soils surrounding the historic mining sites. Therefore if Hg had been used in historic mining operations it is no longer apparent in the sediments and has presumably been removed by erosion of the site.

X射线荧光分析（XRF）是一种广泛应用于测定材料元素组成的无损检测方法。该技术被应用于调查波多黎各的洛奎洛山脉/埃尔尤恩基地区的岩石和沉积物。对湿沉积物和干沉积物的初步测试显示，机器在干沉积物中记录的元素浓度高于湿沉积物，这可能是由于水分子干扰了湿样品上的X射线束。对干燥样品进行的XRF分析产生了可靠的结果，并允许对洛奎洛山脉中发现的五种基本基岩类型进行化学分离。在火山碎屑岩中，法耶多地层可通过其钡（Ba）和铷（Rb）的浓度与其他地层区分开来。无名地层通过铜（Cu）来区分，哈托波多地层则通过镍（Ni）和锶（Sr）来区分。里奥布兰科花岗闪长岩是该地区最年轻的岩石类型，是唯一一种其元素化学成分与其他地层无法区分的岩层，这可能是由于其直接形成于同样形成洛奎洛山脉火山岩石的基本岩浆。近期研究发现，卢克伊洛溪流水中汞（Hg）含量较高。鉴于卢克伊洛地区历史上曾大量开采金（Ag）和银（Au），历史上用于采矿的汞可能是导致汞含量升高的可能来源。XRF分析表明，在某些岩石中发现了微量的汞，但在历史采矿遗址周围的沉积物和土壤中未发现汞。因此，如果历史上采矿作业中使用了汞，那么它现在在沉积物中已不再明显，可能已被遗址的侵蚀所移除。