Evolution of the Kerguelen LIP: Insights from Crystal Stratigraphy & Crystal Size Distributions from Site 1137, Elan Bank

凯尔盖朗 LIP 的演化：水晶地层学的见解

• 批准号: 0452102
• 负责人: Clive Neal
• 金额: $ 16.26万
• 依托单位: University of Notre Dame
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-01 至 2008-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0452102&HistoricalAwards=false
• 关键词: Evolution; Kerguelen; LIP; Insights; Crystal

ABSTRACT (Neal - 0452102)Understanding how magmas evolve is important for knowing why volcanoes erupt. Analysis of whole-rock samples gives compositions that reflect only an average of the processes that the lava has experienced prior to eruption. Examination of individual crystals and crystal populations, however, provides better insight into the dynamics of magma evolution. This research involves researchers at the University of Notre Dame and utilizes different populations of crystals in igneous rocks (i.e., crystal size distributions) that have related nucleation and growth histories. It them combines this approach with mineral-scale compositional studies (i.e., crystal stratigraphy). This combined methodology constrains the timing and extent of differentiation processes (i.e., magma mixing, crustal contamination) that permits quantification the dynamics and timing of processes that have modified a magma body since separation from its source and can lead to identification of the source itself. The research uses samples from the Kerguelen Large Igneous Province on the Elan Bank In the Southern/South Indian Ocean to develop a new technique for reconstructing magma chamber evolution using crystal size distributions and wavelet based correlations to determine different plagioclase crystal populations in seven co-magmatic flows from Ocean Drilling Program Site 1137. Samples range in age from 107-108 Ma and encompass three distinct breaks in magmatism, which are represented by volcaniclastic interbeds. These volcaniclastic units divide the lave flow sequence into four parts. Each section will be studied from the top, middle, and base. Representative plagioclase crystals from different crystal zones will be analyzed for major, minor, and trace elements via electron microprobe, SEM, and in-situ laser ablation ICP mass spectrometry. These data will allow partition coefficients to be determined and the reconstruction of parent liquid compositions and local crystallization environments. Strontium isotope measurements will be made on a sub-set of crystals to further constrain parent magma compositions and the extent of crustal contamination. Independent estimates of crystal residence times will be obtained from the crystal size and geochemical data. Broader ImpactsBroader impacts of this proposal include education of a graduate student and involvement of a K-12 teacher and students at a school in a Hispanic dominated high school in Deming, New Mexico. This effort will expose Hispanic high school students to the excitement of geochemical and petrological research. The research also involves international collaboration with researchers at the University of Durham in the UK. Results of the work will be integrated into graduate and undergraduate teaching at the University of Notre Dame. A "crystal stratigraphy" web site will also be set up to inform the public and other researchers about the technique and its potential applications.

摘要（Neal - 0452102）了解岩浆如何演化对于了解火山喷发的原因非常重要。对全岩样本的分析得出的成分仅反映熔岩在喷发前经历的平均过程。然而，对单个晶体和晶体群的检查可以更好地了解岩浆演化的动态。这项研究涉及圣母大学的研究人员，并利用火成岩中具有相关成核和生长历史的不同晶体群（即晶体尺寸分布）。他们将这种方法与矿物规模的成分研究（即晶体地层学）结合起来。 这种组合方法限制了分化过程（即岩浆混合、地壳污染）的时间和程度，允许量化自与源头分离以来改变岩浆体的过程的动态和时间，并可以导致源头本身的识别。 该研究利用来自南/南印度洋埃兰岸凯尔盖朗大型火成岩省的样本，开发了一种重建岩浆房演化的新技术，利用晶体尺寸分布和基于小波的相关性来确定七种共岩浆中不同的斜长石晶体种群来自海洋钻探计划站点 1137 的流量。样本的年龄范围为 107-108 Ma，包含三个不同的岩浆活动断裂，分别由火山碎屑互层。 这些火山碎屑单元将熔岩流序列分为四个部分。 每个部分将从顶部、中部和底部进行研究。 将通过电子微探针、SEM 和原位激光烧蚀 ICP 质谱分析来自不同晶区的代表性斜长石晶体的主要元素、次要元素和微量元素。 这些数据将允许确定分配系数并重建母体液体成分和局部结晶环境。将对晶体的子集进行锶同位素测量，以进一步限制母岩浆成分和地壳污染程度。晶体停留时间的独立估计将根据晶体尺寸和地球化学数据获得。更广泛的影响 该提案的更广泛影响包括新墨西哥州戴明市一所西班牙裔占主导地位的高中的研究生教育以及 K-12 教师和学生的参与。 这项努力将使西班牙裔高中生体验到地球化学和岩石学研究的乐趣。该研究还涉及与英国达勒姆大学研究人员的国际合作。 这项工作的成果将被纳入圣母大学研究生和本科生的教学中。 还将建立一个“晶体地层学”网站，向公众和其他研究人员介绍该技术及其潜在应用。