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Experimental Investigation of the Isotopic Systematics of Sr During Melting in the Continental Crust Using Diamond Aggregates

利用金刚石聚集体对陆壳熔化过程中 Sr 同位素系统进行实验研究

基本信息

批准号：
9814548
负责人：
Kurt Knesel
金额：
$ 11.5万
依托单位：
University of Colorado at Boulder
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1999
资助国家：
美国
起止时间：
1999-01-01 至 2002-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9814548&HistoricalAwards=false
关键词：
Experimental Investigation Isotopic Systematics Sr

项目摘要

9814548KneselPartial melting of preexisting materials of the continental crust (anatexis) is an important process leading to long-term crustal differentiation and to the generation and evolution of evolved magmas in a number of important tectonic settings. Various isotope systems are commonly used as tracers of anatectic processes and source compositions, but the success of this approach depends on an assessment of equilibrium during partial melting in the continental crust. However, recent experimental and field investigations suggest that the assumption of isotopic equilibrium may not be valid for anatectic melts generated in some crustal environments. The objective of this project is to contribute to our understanding of the isotope systematics of Sr during dehydration melting of muscovite, biotite, and hornblende-bearing crustal assemblages. The Sr isotopic compositions of experimental partial melts segregated from their source using diamond aggregates will be measured by thermal ionization mass spectrometry. This technique provides a unique opportunity to investigate (1) the isotopic evolution of anatectic melts as a function of reaction progress and mineral stabilities and (2) mechanisms and time scales of melt-source equilibration during the generation and segregation of crustal melts.

9814548Knesel 大陆地壳预先存在的物质的部分熔融（深熔）是导致长期地壳分异以及在许多重要构造环境中演化岩浆的产生和演化的重要过程。各种同位素系统通常用作深熔过程和源成分的示踪剂，但这种方法的成功取决于对大陆地壳部分熔融过程中平衡的评估。然而，最近的实验和现场调查表明，同位素平衡的假设对于某些地壳环境中产生的深熔熔体可能无效。该项目的目的是促进我们对白云母、黑云母和角闪石地壳组合脱水熔融过程中锶同位素系统学的理解。使用金刚石聚集体从其来源中分离出来的实验部分熔体的 Sr 同位素组成将通过热电离质谱法进行测量。该技术提供了一个独特的机会来研究（1）深熔熔体的同位素演化作为反应进程和矿物稳定性的函数，以及（2）地壳熔体生成和分离过程中熔体源平衡的机制和时间尺度。