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Reconstructing the Physical and Chemical Evolution of Silicic Magma Bodies Using High Precision Isotope Analyses of Individual Volcanic Mineral Phases

利用单个火山矿物相的高精度同位素分析重建硅质岩浆体的物理和化学演化

基本信息

批准号：
9814493
负责人：
Kurt Knesel
金额：
$ 11.34万
依托单位：
University of Colorado at Boulder
依托单位国家：
美国
项目类别：
Standard 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=9814493&HistoricalAwards=false
关键词：
Reconstructing Physical Chemical Evolution Silicic

项目摘要

9814493KneselKnowledge of the mechanisms and time scales for the production and differentiation of silicic magmas is critical to our understanding of fundamental geologic problems such as the formation and growth of the Earth's continents and predicting volcanic hazards. Newly developed microsampling techniques will be used to obtain high precision Sr and Nd isotopic data from individual phenocrysts associated with two well-characterized, middle-Tertiary silicic magmatic centers in the southwestern United States. When coupled with crystal size distribution studies this information will provide greater temporal resolution of the compositional evolution of silicic magmas than obtainable in studies utilizing bulk samples alone. The first field area provides a unique opportunity to study the link between ash-flow tuffs and granitic batholiths in the Organ Mountains, southern New Mexico. The second study area, a group of well-mapped and dated lava domes in southern-central New Mexico, will allow examination of the timing and dynamics of contamination and recharge during open-system evolution of silicic magmas. Together, studies of these two localities will provide new insights into both the large- and small-scale processes operating in complex continental silicic magmatic systems.

9814493Knesel 了解硅质岩浆产生和分化的机制和时间尺度对于我们理解基本地质问题（例如地球大陆的形成和增长以及预测火山灾害）至关重要。新开发的微采样技术将用于从与美国西南部两个特征明确的中第三纪硅质岩浆中心相关的单个斑晶中获取高精度的 Sr 和 Nd 同位素数据。当与晶体尺寸分布研究相结合时，与单独使用大块样品的研究相比，该信息将提供更高的硅岩浆成分演化的时间分辨率。第一个野外区域提供了一个独特的机会来研究新墨西哥州南部器官山的灰流凝灰岩和花岗岩岩基之间的联系。第二个研究区域是新墨西哥州中南部一组地图清晰且年代悠久的熔岩穹丘，将允许检查硅质岩浆开放系统演化过程中污染和补给的时间和动态。对这两个地点的研究将为复杂的大陆硅质岩浆系统中的大型和小型过程提供新的见解。