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Insights Into the Source of Relative Depletion and Enrichment of HFSE in Arc Lavas From High-Nb Basalts From the Sulu Arc (southern Philippines)

深入了解苏禄岛弧（菲律宾南部）高铌玄武岩弧熔岩中 HFSE 相对消耗和富集的来源

基本信息

批准号：
0001212
负责人：
Paterno Castillo
金额：
$ 13.93万
依托单位：
University of California-San Diego Scripps Inst of Oceanography
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2000
资助国家：
美国
起止时间：
2000-07-01 至 2003-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0001212&HistoricalAwards=false
关键词：
Insights Into Source Relative Depletion

项目摘要

EAR-0001212CastilloOne of the hallmark geochemical features of volcanic arc lavas is the depletion of their concentrations of high field strength elements (HFSE such as Nb, Ta, and Zr) relative to those of other trace elements. The main objective of this study is to test in the Sulu Arc models that have been proposed to explain this geochemical feature such as melting or dehydration of the subducted basaltic crust plus overlying sediments and presence of ocean island basalt source component in the mantle wedge beneath the arc. The Sulu Arc system offers a unique opportunity to constrain the origin of HFSE depletion in arc lavas because it contains basalts with variable Nb and other HFSE concentrations (i.e., from typical Nb-depleted arc basalts to rare high-Nb basalts) and the oceanic crust subducting beneath the arc system has been sampled by the Ocean Drilling Program. The investigation will employ various geochemical and isotopic tracers (e.g., REE, Nb/Ta, Ba/La, Pb/Ce, 87Sr/86Sr, 143Nd/144Nd, 206Pb/204Pb, 18O/16O) in order to fingerprint the behavior of many trace elements, particularly the HFSE, during the generation of arc lavas. Results of the study will also be useful for a general understanding of the source materials of lavas in the global arc system.

火山弧熔岩的一个显著的地球化学特征是，相对于其他微量元素，它们的高场强元素（如Nb、Ta和Zr）的浓度逐渐减少。本研究的主要目的是在苏鲁弧模型中进行测试，该模型已被提出用于解释这一地球化学特征，如俯冲玄武岩地壳和上覆沉积物的融化或脱水，以及弧下地幔楔中海洋岛玄武岩源成分的存在。苏鲁弧系统提供了一个独特的机会来限制弧熔岩中HFSE枯竭的起源，因为它包含具有可变Nb和其他HFSE浓度的玄武岩（即从典型的贫铌弧玄武岩到罕见的高铌玄武岩），并且海洋钻探计划已经对弧系统下俯冲的海洋地壳进行了采样。本次研究将采用多种地球化学和同位素示踪剂（如REE、Nb/Ta、Ba/La、Pb/Ce、87Sr/86Sr、143Nd/144Nd、206Pb/204Pb、18O/16O），对弧熔岩形成过程中多种微量元素，特别是HFSE的行为进行指纹分析。研究结果也将有助于对全球弧系熔岩源物质的全面认识。