Andò Sergio, Bersani Danilo, Vignola Pietro, Garzanti Eduardo
University of Milano-Bicocca, Department of Geological Sciences and Geotechnologies, Piazza della Scienza 4, 20126 Milano, Italy.
Spectrochim Acta A Mol Biomol Spectrosc. 2009 Aug;73(3):450-5. doi: 10.1016/j.saa.2008.11.005. Epub 2008 Nov 17.
Raman spectroscopy represents a new way to obtain detailed comprehensive information on heavy-mineral assemblages. In this work are presented several examples from major Alpine (Po River) and Himalayan (Ganga and Brahmaputra Rivers) fluvio-deltaic sands. Our attention was focused on the chemical properties of garnet, which is a widespread mineral in orogenic sediments, easy to be identified, and relatively stable during both equatorial weathering and intrastratal dissolution. Garnet grains were studied in different samples representative of various depositional environments (fluvial bar, fluvial levee, shoreface, beach berm, eolian dune), in order to investigate specifically the hydraulic behaviour of grains with different density in different hydrodynamic conditions. Raman spectra and semi-quantitative analysis of Raman shifts allowed us to rapidly determine the distribution of garnet types in each sample in order to obtain chemical composition, to calculate the density of each garnet, and finally to infer their respective provenance. This manuscript presents one possible application of the "MIRAGEM" method described by Bersani et al. in this volume. References, data sets and details on the analytical routine are widely explained in the above mentioned work.
拉曼光谱法是一种获取重矿物组合详细综合信息的新方法。在这项工作中，展示了来自主要的阿尔卑斯山（波河）和喜马拉雅山（恒河和雅鲁藏布江）河流三角洲砂的几个例子。我们的注意力集中在石榴石的化学性质上，石榴石是造山带沉积物中一种广泛分布的矿物，易于识别，并且在赤道风化和层内溶解过程中相对稳定。对代表各种沉积环境（河漫滩、河漫滩堤、滨面、海滩护堤、风成沙丘）的不同样品中的石榴石颗粒进行了研究，以便具体研究不同密度的颗粒在不同水动力条件下的水力行为。拉曼光谱和拉曼位移的半定量分析使我们能够快速确定每个样品中石榴石类型的分布，从而获得化学成分，计算每种石榴石的密度，并最终推断它们各自的物源。本手稿展示了Bersani等人在本卷中描述的“MIRAGEM”方法的一种可能应用。参考文献、数据集和分析程序的详细信息在上述工作中有广泛解释。
