Collaborative Research: Halogen Behavior In the Pluton-To-Volcanic Arc System

合作研究：岩体到火山弧系统中的卤素行为

• 批准号: 2211242
• 负责人: Jaime Barnes
• 金额: $ 14.96万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-15 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2211242&HistoricalAwards=false
• 关键词: Collaborative; Research; Halogen; Behavior; Pluton

Halogen elements (fluorine, chlorine, bromine, and iodine) are abundant, highly reactive elements in the atmosphere, oceans, and lithosphere. Halogens within Earth’s crust can affect magmatic properties and carry elements to form economic mineral deposits. Within volcanic arc systems, halogen elements are carried to depth by subducting crust and can travel within melts through the overriding crust and out at volcanoes. Estimates of halogen inputs at subduction zones and outputs through volcanic gases show a deficit that suggest a portion of halogens are trapped deep within the Earth. There are multiple possible reservoirs to host halogens that are not well characterized because they are too difficult to access and sample. One example is the magmatic system under volcanoes where concentrations of halogens in subsurface magma chambers and erupted volcanic rocks are not well known. This team will measure the full halogen suite in intrusive plutonic rocks and extrusive volcanic rocks from the same ancient arc system now exposed in the Sierra Nevada, California. This will allow them to address key open questions including: whether halogens are enriched in the plutonic magma chamber or erupted volcanic rock; where halogens are hosted within the rocks; and what impact halogens have on magmatic processes and mineral deposits at volcanic arcs. Through this research, the principal investigators and graduate students will design an undergraduate mineralogy and petrology class with accessibility, equity, and inclusion principles and engage in undergraduate students in research and safe, inclusive field experiences. A subset of the samples used for this study come from an historic collection. These samples will be digitized using 3D technology and created into an educational resource hosted on the Virtual Microscope public website.Halogen movement and reservoirs within the deep Earth are highly uncertain due to the lack of data from key reservoirs, namely, the fore-arc, deeply subducted slab residues, subcontinental mantle, and – the focus of this study – continental crust. Given halogen incompatibility in the mantle and affinity towards more evolved melts, continental crust is a potentially important reservoir; however, bulk rock compositions of plutonic and volcanic arc rocks are relegated to a handful of studies. This research will characterize the full halogen (Fl, Cl, Br, I) composition and behavior within an arc magmatic system by analyzing a suite of spatially-related plutonic and volcanic rocks that share similar chemical composition and age from the Sierra Nevada Arc. Specifically, this team will measure bulk rock halogen (Cl, F, Br, I) concentrations, in-situ mineral concentrations (F, Cl), and O and H-isotopes on a suite of geochemically well-characterized samples. This sample suite will be used to 1) determine whether halogens are concentrated in the plutonic or volcanic section within a single arc system, 2) identify where halogens are hosted (i.e., in minerals or other sites), and 3) assess the role of halogens in magmatic processes during the formation of continental crust. In order to interpret the role of processes, such as assimilation and hydrothermal alteration, on halogen behavior, they also propose to analyze a complimentary suite that includes lower crustal xenoliths, host wall rocks (e.g., schists, marbles), hydrothermally altered rocks and associated veins, and more mafic lithologies (e.g., gabbros) to strengthen our interpretations. The dataset will significantly contribute to what is known of bulk rock halogen compositions for continental arc crust, and be used with major element, trace element, and isotopic compositions to evaluate the impact of primary magmatic processes (e.g., crustal assimilation, fractional crystallization) on the halogen record and interpret overall halogen systematics through the arc magmatic system.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

卤素元素（氟，氯，溴和碘）在大气，海洋和岩石圈中是丰富的，高反应性的元素。地壳内的卤素会影响磁性特性并携带元素形成经济矿藏。在火山弧系统中，卤素元素通过俯冲构成外壳，并可以在熔体内穿过覆盖的外壳和在火山上传播。俯冲带和通过火山气体输出的卤素输入的估计表明，防御表明一部分卤素被困在地球深处。有多种可能的储层可以容纳卤素，这些卤素没有很好地表征，因为它们难以访问和采样。一个例子是火山下的岩浆系统，在地下岩浆腔和爆发的火山岩中的卤素浓度尚不清楚。该团队将在现在在加利福尼亚州内华达州山脉的同一古老的弧度系统中衡量整个卤素套房和富裕的岩石岩石和挤出的火山岩。这将使他们能够解决关键的开放问题，包括：卤素是在岩岩腔室中富集还是爆发的火山岩；卤素在岩石中托管的地方；以及卤素对火山弧的岩浆过程和矿藏的影响。通过这项研究，主要研究人员和研究生将设计具有可访问性，公平性和包容性原则的本科矿物学和岩石学课程，并从事研究和安全，包容性的现场经验的本科生。该研究使用的样本的一个子集来自历史悠久的收藏。这些样品将使用3D技术进行数字化，并将其创建为虚拟显微镜公共网站上的教育资源。由于缺乏关键储层的数据，即高度不确定地球内的Halogen运动和储层，即前Aarc，深层俯冲的Slab Slab slab slab slab slab slab slab slab slab slab，subcontinental subcontinental and cocrust and cob cob cob cob cob cob cob cob cob cob cob cob cob cob cob，鉴于地幔中的卤素不相容性和对更具进化的熔体的亲和力，连续地壳是潜在的重要储层。然而，岩石和火山弧岩的散装岩石组成与少数研究有关。这项研究将通过分析一套与空间相关的岩石和火山岩相似的卤素（FL，CL，BR，I）组成和行为的整体卤素（FL，CL，BR，I），它们具有相似的化学成分和来自内华达山脉弧的化学成分和年龄。具体而言，该团队将在一组地球化学良好的样品套件上测量大量岩石卤素（CL，F，BR，I）浓度，原位矿物质浓度（F，Cl）和O和H-同位素。该样品套件将用于1）确定卤素是否集中在单个弧系统内的岩石或火山截面中，2）确定卤素托管的位置（即，在矿物或其他地点），3）评估卤素在岩浆过程中的作用。为了解释工艺的作用，例如同化和水热改变，对卤素行为的作用，他们还建议分析一个免费的套件，其中包括较低的地壳异种石，宿主壁岩石，宿主壁岩石（例如，片岩，大理石），水热岩石和相关的静脉和相关的静脉和更多的Mafic Mafic lithology（例如，Gulthology）（例如，Glithology（例如，gabbros）。该数据集将显着有助于对连续弧壳的散装岩石卤素组成，并与主要元素，痕量元素和同位素组成一起评估主要岩浆过程的影响使用基金会的知识分子优点和更广泛的影响审查标准，通过评估被认为是宝贵的支持。