Dynamics and Evolution of Magma Systems: Mass Spectrometry of U and Th Isotopes in Young Volcanics

这个项目是用于年轻火山系统的U-Th-Ra同位素研究。传统上，这些测量是通过α光谱学进行的，而观察火山系统的能力受到计数技术的精度和大样本要求的限制。Lamont的新型Isolab 54质谱仪使pi能够直接测量火成岩中的230Th/232dTh比率。他们还计划用计数技术制造的质谱仪测量226Ra的丰度。使用这台新机器也可以进行RE/Os同位素测量。质谱方法提高了精度，为岩浆过程提供了更精确的时间分辨率，包括地幔的部分熔融和流体转移，地壳岩浆储层的演化，火山管道系统的动力学，以及对地球中U/Th的运输和分馏的更好理解。他们计划对四个特征鲜明的年轻火山中心进行具体的研究，包括岩浆类型、构造环境和火山风格。

This project is for U-Th-Ra isotopic studies of young volcanic systems. Traditionally, these measurements have been made by alpha spectroscopy and the ability to see into the volcanic system has been limited by the precision and large sample requirements of the counting techniques. The new Isolab 54 mass spectrometer at Lamont enable the PIs to make direct measurement of 230Th/232dTh ratios in igneous rocks. They also plan to measure 226Ra abundances with the mass spectrometer made by counting techniques. RE/Os isotope measurements should also be possible with this new machine. Enhanced precision afforded by mass spectrometric methods yields finer time resolution for magmatic processes, including partial melting and fluid transfer in the mantle, evolution of crustal magma reservoirs, and dynamics of volcanic plumbing systems, as well as better understanding of the transport and fractionation of U/Th in the Earth. They plan specific work on four well-characterized young volcanic centers, covering a spectrum of magma type, tectonic setting, and volcanic style.