Oxygen Isotope Studies of the Sources of Basaltic Volcanism: A Reevaluation Using Laser Fluorination of Phenocrysts

Stolper氧同位素比值对玄武岩地幔源区的化学和同位素不均一性的成因提供了重要的制约。 传统的测量全岩标本和玻璃通常显着的影响，样品蚀变和同位素分馏过程中的岩浆过程。 P.I.s建议使用激光扫描技术对来自弧相关熔岩的斑晶（主要是橄榄石）中的氧同位素变化进行全面调查。 迄今为止的结果表明，激光衍射技术提供了一个准确和精确的手段来分析橄榄石和其他斑晶中的18 O/16 O比值。 这项工作将包括调查与弧有关的熔岩，重点是玄武岩弧后熔岩，可以提供有关俯冲带上方地幔“楔”的信息。

9628142 Stolper Oxygen isotope ratios can provide important constraint on the origins of chemical and isotopic heterogeneity in the mantle sources of basaltic lavas. Conventional measurements of whole-rock specimens and glasses are typically significantly influenced by the effect of sample alteration and isotopic fractionation during magmatic processes. The P.I.s propose to use laser fluorination techniques to undertake a comprehensive survey of oxygen isotope variations in phenocrysts (primarily olivine) from arc-related lavas. Results thus far indicate that laser fluorination technique provides an accurate and precise means of analyzing 18O/16O ratios in olivine and other phenocrysts. The work will involve a survey of arc-related lavas, emphasizing basaltic back-arc lavas that can provide information on the mantle "wedge" above subduction zones.