Regional Variability in Aleutian Primitive Magmas and Implications for Processes in the Mantle Wedge: Proposal for an Ion Probe Study

阿留申原始岩浆的区域变化及其对地幔楔过程的影响：离子探针研究的建议

• 批准号: 9419240
• 负责人: Gene Yogodzinski
• 金额: $ 7.5万
• 依托单位: Dickinson College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-01-01 至 1998-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9419240&HistoricalAwards=false
• 关键词: Regional; Variability; Aleutian; Primitive; Magmas

9419240 Yogodzinski An ion microprobe and isotopic study of Aleutian high Mg# silicates (phenocrysts, xenocrysts, xenoliths, glass inclusions, volcanic rocks) is proposed here. The aim of this study is to understand the regional importance of the various primitive Aleutian melt types, and to infer the predominant mixing, melting, and reaction processes that occur in the Aleutian mantle wedge. The approach is to use the trace element and isotopic characteristics of thigh Mg# minerals as tracers of mantle wedge processes. There has been a recent re-emphasis on primary calc-alkaline andesitic magmas in subduction related magmatic arcs, with high Mg#'s, and high Ni and Cr contents, consistent with equilibration with mantle olivine and spinel. The presence of these lavas in arcs raises once again the question of the bulk composition of crust formed by subduction-related magmatism. This study will address this broad issue by defining more clearly the various primitive melts which are represented in the Aleutian arc, and by providing an improved basis for identifying the predominant processes which occur in the Aleutian mantle wedge.

小行星9419240 本文对阿留申高镁硅酸盐（斑晶、捕虏晶、捕虏体、玻璃包裹体、火山岩）进行了离子探针和同位素研究。 本研究的目的是了解各种原始阿留申熔体类型的区域重要性，并推断主要的混合，熔融和反应过程中发生的阿留申地幔楔。 利用镁矿物的微量元素和同位素特征作为地幔楔作用的示踪剂。 最近重新强调俯冲相关岩浆弧中的原生钙碱性安山质岩浆，具有高Mg#、高Ni和Cr含量，与地幔橄榄石和尖晶石平衡一致。 这些岩浆在弧中的存在再次提出了由俯冲相关的岩浆作用形成的地壳的整体组成的问题。 这项研究将解决这个广泛的问题，更清楚地定义了各种原始熔体中所代表的阿留申弧，并提供了一个改进的基础，以确定发生在阿留申地幔楔的主要过程。