SHRIMP Ion Microprobe Investigation of Fine-scale Sulfur Isotopic Systematics in the Creed Moat Sediments

克里德脉区是一个世界级的浅成热液贱金属硫化物矿床，与科罗拉多州的一个大型第三系破火山口群有关。由于充填克里德破火山口护城河的火山碎屑沉积物的沉积、成岩和热液历史对于了解流体、硫和金属进入区域脉状矿化的循环至关重要，因此我们建议利用SHRIMP离子微探针对护城河沉积物中的细尺度(30um)硫同位素体系进行综合研究。稳定同位素分析的微束技术提供了对成矿过程的极大洞察，因为矿物比传统的整体同位素取样和分析技术包含了更多关于其来源和随后的变质作用的信息。首席调查人员将与其他克里德项目科学家提出的大量同位素研究合作，将他们在解决湖泊和火山环境中细微规模的硫同位素变化方面的经验应用于克里德护城河沉积物。特别是，它们将侧重于记录关键沉积和成岩事件的微观硫同位素变化，以及有助于改进克里德模型的任何硫同位素变化，并将促进我们对地壳浅层环境中沉积、成岩和热液成矿过程的时间和相互作用的理解。

The Creede vein district is a world-class epithermal base metal sulfide deposit associated with a large Tertiary caldera cluster in Colorado. Because the sedimentary, diagenetic and hydrothermal history of the volcaniclastic sediments filling the Creede caldera moat is critical to understanding the cycling of fluids, sulfur and metals into the district vein mineralization, we propose a comprehensive investigation of fine-scale (30 um) sulfur isotopic systematics in the moat sediments using the SHRIMP ion microprobe. Microbeam techniques of stable isotope analysis offer great insight into mineralizing processes, because minerals contain more information concerning their origins and subsequent modifications than can be obtained by conventional bulk isotopic sampling and analytical techniques. The principal investigators will apply their experience in resolving fine-scale sulfur isotopic variations in lacustrine and volcanic environments to the Creede moat sediments, in cooperation with bulk isotopic studies proposed by other Creede project scientists. In particular, they will focus on microscopic sulfur isotope variations that record critical sedimentary and diagenetic events, as well as any contribute towards an improved Creede model, and will advance our understanding of the timing and interplay of sedimentary, diagenetic and hydrothermal ore-forming processes in shallow crustal environments.