Processes and Rates of Compositional Zonation in Crustal Magma Bodies: Constraints From High-Precision U-Th Disequilibria

地壳岩浆体成分分带过程和速率：高精度U-Th不平衡的约束

• 批准号: 9418720
• 负责人: Wendy Bohrson
• 金额: $ 8.57万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-02-01 至 1999-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9418720&HistoricalAwards=false
• 关键词: Processes; Rates; Compositional; Zonation; Crustal

9418720 Bohrson This is a two year project to document U-Th disequilibria characteristics of pumice glass and minerals from two compositionally zoned pyroclastic deposits from the Phlegrean Fields, Italy: the Campanian Ignimbrite and the Neopolitan Yellow Tuff. High-precision thermal ionization mass spectrometry will be used to document the 230Th/232Th characteristics and U and Th concentrations (by isotope dilution) of pumice glass that represents the compositional ranges of the deposits. In addition, phenocrysts (feldspar, magnetite) from selected pumice will also be characterized. These data will be used to document processes and timescales associated with the generation of zoned crustal magma bodies using geochemical and fluid dynamical modeling. In addition, the integration of geochemical and fluid dynamical modeling represents a potentially powerful approach for understanding the development of chemical gradients in crustal magma bodies.

这是一个为期两年的项目，旨在记录意大利Phlegrean气田两个组成分区的火山碎屑沉积物（Campanian Ignimbrite和Neopolitan Yellow Tuff）中浮石玻璃和矿物的U-Th不平衡特征。高精度热电离质谱法将用于记录浮石玻璃的230Th/232Th特征和U和Th浓度（通过同位素稀释），代表沉积物的成分范围。此外，从选定的浮石中提取的斑晶（长石、磁铁矿）也将被表征。这些数据将用于利用地球化学和流体动力学建模来记录与带状地壳岩浆体产生有关的过程和时间尺度。此外，地球化学和流体动力学建模的结合为理解地壳岩浆体化学梯度的发展提供了潜在的有力途径。