Institute of Physical Chemistry, Friedrich Schiller University Jena, Germany.
Spectrochim Acta A Mol Biomol Spectrosc. 2014 Jan 24;118:42-7. doi: 10.1016/j.saa.2013.08.059. Epub 2013 Aug 26.
The mineral composition of the Upper Cretaceous Duwi phosphorite deposits and underlying Quseir Variegated Shale from Safaga district, Red Sea Range, Egypt, was investigated by dispersive and Fourier transformed Raman spectroscopy. The only phosphorous containing mineral detected in the phosphorite deposits was carbonate fluorapatite. Often carbonate fluorapatite appears associated with calcium sulfate and seldom with calcium carbonate in the investigated samples. Iron is present in the form of goethite and pyrite in the phosphorite layer, while pyrite, marcasite and hematite were identified in the Quseir Shale samples. Also, a high amount of disordered carbon was detected in the black shale layers. The Raman results confirm the hypothesis that the formation of the phosphorites took place in a marine environment. During the formation of black shale, the redox conditions changed, with the pH reaching values of 4 or even lower. Diagenetic and weathering transformations had taken place in the phosphorite deposits, calcium sulfate and goethite being products of these types of processes.
通过分散和傅里叶变换拉曼光谱法研究了埃及红海山脉萨法加地区上白垩统杜威磷矿床和下伏 Quseir 杂色页岩的矿物成分。在磷矿床中检测到的唯一含磷矿物是碳酸盐氟磷灰石。在研究的样品中，碳酸盐氟磷灰石通常与硫酸钙有关，很少与碳酸钙有关。在磷矿层中，铁以针铁矿和黄铁矿的形式存在，而在 Quseir 页岩样品中则鉴定出黄铁矿、白铁矿和赤铁矿。此外，在黑色页岩层中还检测到大量无序碳。拉曼结果证实了磷矿形成于海洋环境的假设。在黑色页岩形成过程中，氧化还原条件发生了变化，pH 值达到 4 甚至更低。磷矿床发生了成岩和风化转化，硫酸钙和针铁矿是这些类型过程的产物。
