High Precision U-, Th-Disequilibrium Analyses by Thermal Ionization Mass Spectrometry

该奖项是为了表彰加州大学洛杉矶分校凯克同位素地球化学中心利用高精度热电离质谱法进行的铀、钍不平衡分析的一年发展。所要求的资金将主要支持现阶段急需的人员，以制定Th同位素分析方案，并执行和解释新的双扇区质谱仪的第一代分析。利用同位素分析，pi将评估爱达荷州月球陨石坑和加利福尼亚州皮斯加陨石坑熔岩场岩浆过程的时间和化学演化。这两个场都被解释为是从经历了地壳同化的岩浆房喷发出来的，尽管前者是硅质物质，后者是基性物质。然后，他们将研究来自美国西部不同构造环境的精选熔岩的配对Th-Pb同位素系统，以用于表征岩石圈（地壳和地幔）与软流圈成分对岩浆作用的影响。

This award is for a year of development of U-, Th-disequilibrium analyses utilizing high precision thermal ionization mass spectrometry in the Keck Center for Isotope Geochemistry at UCLA. The requested funds will largely support personnel critically needed at this stage to develop protocols for the Th isotope analyses, and to perform and interpret the first generation of analyses on the new dual sector mass spectrometer. Using Th isotopic analyses, the PIs will evaluate the temporal and chemical evolution of magma processes for the lava fields of Craters of the Moon, Idaho, and Pisgah crater, California. Both fields have been interpreted as erupting from magma chambers which have undergone crustal assimilation, albeit of silicic material in the case of the former and mafic material in the case of the later. They will then investigate paired Th-Pb isotope systematics of selected lavas from diverse tectonic settings in the western U.S. for their utility in characterizing lithospheric (crust and Mantle) versus asthenospheric components to magmagenesis.