Mineralization, Differentiation, and Eruption of Highly-Evolved Rhyolites of Western North America

本课题拟采用电子探针、离子探针和傅里叶变换红外光谱对北美西部3个锡化流纹岩石英斑晶中的玻璃包裹体挥发物和Li、Be、Rb、Cs、Y、Nb、Ba、Sr、Th、Y、Mo、W、REE、Sn进行分析。这些数据将与现有的岩石学、野外关系和整个岩石地球化学信息相结合，以更好地了解演化岩浆中挥发物的富集和耗尽，以及主要、微量和矿石元素。该研究将确定高度演化的岩浆是如何分化的，将限制此类系统中岩浆挥发性成分最大浓度的准确值，并将真正的岩浆挥发性丰度与喷发风格联系起来。

This project proposes to analyze glass inclusions in quartz phenocrysts from three tin-mineralized rhyolites of western North America for volatiles and Li, Be, Rb, Cs, Y, Nb, Ba, Sr, Th, Y, Mo, W, REE's and Sn by electron microprobe, ion microprobe, and Fourier transform infrared spectroscopy. The data will be integrated with existing information on the petrology, field relations, and whole rock geochemistry to better understand the enrichment and depletion of volatiles, as well as major, trace, and ore elements in evolved magmas. The study will determine how highly-evolved magmas become differentiated, will constrain accurate values for the maximum concentrations of magmatic volatile constituents in such systems, and will relate true magmatic volatile abundances to eruptive style.