Collaborative Research: RUI: Using K-feldspar megacryst and mineral inclusion T-X-t histories to assess batholith growth and evolution in the Tuolumne intrusive complex, CA

合作研究：RUI：利用钾长石巨晶和矿物包裹体 T-X-t 历史来评估加利福尼亚州图奥勒米侵入岩杂岩的岩基生长和演化

• 批准号: 2223332
• 负责人: Valbone Memeti
• 金额: $ 33.78万
• 依托单位: CSU Fullerton Auxiliary Services Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2223332&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; Using; feldspar

Volcanoes are well-known but poorly understood. How does magma build up beneath active volcanoes, and how long does it take to do so? What controls whether it erupts or cools deep underground to form plutons? How long does it stay molten there, and how much of it is eruptible for how long? Hundreds of millions of people live within 100 miles of active volcanoes. They are at risk of being exposed to volcanic hazards. Volcanic eruptions also affect climate and the environment. Yet decades of research have not answered some of these basic questions. This project will address these questions in the Tuolumne pluton. It is home to the spectacular rock exposures of Yosemite National Park. Uranium-lead age dates of small minerals will determine when the plutons cooled to the rocks that are exposed at the surface today. They will also reveal the duration of time that magma was present. Additionally these much smaller minerals are found included in several-inch-large potassium feldspar crystals. The chemistry of the feldspars serves like fingerprints in a crime scene. They will determine when, where and how much magma was stored 90 million years ago to feed volcanic eruptions. How sticky and hot magma was will help determine what these eruptions might have looked like. This project supports two research groups: 1) Researcher Memeti, a woman at Hispanic-serving, undergraduate-focused California State University Fullerton, and 2) Researcher Schoene at research-focused Princeton University. The team will train several graduate students in age dating and chemistry methods. Graduate students help train undergraduate students involved in different parts of the project. All students take part in all aspects of research activities including field work and publishing. Memeti will complete following activities: 1) update authored Yosemite audiotour mobile app based on this project’s results, 2) continue to organize field trips to Yosemite National Park, and 3) share research results with park rangers. 4) She will develop introductory geology labs for geology students, and 5) continue her outreach efforts on volcanic hazards at southern California public events. Schoene will teach local K-12 teachers on volcanoes and hazards in a seminar at Princeton University. This 3-yr collaborative RUI project between California State University Fullerton and Princeton University seeks to determine the time and length scales of magma bodies in magmatic arcs and their changes in composition, crystallinity, and volume over time. The study will use K-feldspar pheno- and megacrysts up to 12 cm long and megacryst-hosted mineral inclusions from the Half Dome and Cathedral Peak units of the 95-85.5 Ma Tuolumne intrusive complex in the central Sierra Nevada. K-feldspar textures and zoning will be imaged in 3D with CT scans and CL images and quantitatively analyzed with electron microprobe and laser ablation ICPMS for geochemistry. K-feldspar mineral inclusions will be measured for TIMS-TEA U-Pb zircon and titanite geochronology, SIMS Ti-in-zircon and Zr-in-titanite thermometry, and EMP and LA-ICPMS plagioclase and hornblende thermometry and chemometry (determining melt compositions). These data will be synthesized to test the hypotheses that the Tuolumne intrusive complex matured thermally during incremental construction, creating interconnected magma bodies many kilometers in length, capable of magma flow, fractionation, mixing, and likely eruption. These data will reflect on current debates about whether long-lived and large composite intrusions like the Tuolumne complex are characterized by “hot” or “cold” storage. “Cold” storage is characterized by small, rigid magma mushes that spend most of their time at temperatures near or at the solidus, limiting interaction with coeval magma bodies, only occasionally, if ever, “defrosting” by magma recharge to feed volcanic eruptions. In contrast, “hot storage” allows for dynamic inter-unit magma mixing and crystal recycling in large (10-100s of square kilometers) magma bodies at significantly higher temperatures above the solidus and lower crystallinities and at time scales of up to millions of years.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.

火山众所周知，但人们却知之甚少。岩浆如何在活火山下积聚，需要多长时间？是什么控制着它在地下深处喷发还是冷却形成岩体？它在那里保持熔化状态多久，其中有多少可以喷发多长时间？数亿人居住在距活火山 100 英里范围内。他们面临着遭受火山灾害的风险。火山喷发也会影响气候和环境。然而几十年的研究并没有回答其中一些基本问题。该项目将解决图奥勒米岩体中的这些问题。它是优胜美地国家公园壮观岩石的所在地。小矿物的铀铅年龄将决定深成体何时冷却到今天暴露在地表的岩石。他们还将揭示岩浆存在的持续时间。此外，这些小得多的矿物被发现包含在几英寸大的钾长石晶体中。长石的化学成分就像犯罪现场的指纹。他们将确定 9000 万年前为火山爆发而储存的岩浆的时间、地点和数量。岩浆的粘性和炽热程度将有助于确定这些火山喷发的样子。该项目支持两个研究小组：1) 研究员 Memeti，一位就职于专注于西班牙裔本科生的加州州立大学富勒顿分校的女性，以及 2) 研究员 Schoene，来自专注于研究的普林斯顿大学。该团队将培训几名研究生进行年龄测定和化学方法。研究生帮助培训参与项目不同部分的本科生。所有学生都参与各个方面的研究活动，包括实地工作和出版。 Memeti 将完成以下活动：1）根据该项目的结果更新编写的优胜美地音频旅游移动应用程序，2）继续组织优胜美地国家公园的实地考察，以及 3）与公园管理员分享研究成果。 4) 她将为地质学学生开发入门地质学实验室，5) 在南加州公共活动中继续开展有关火山灾害的宣传工作。 Schoene 将在普林斯顿大学举办的研讨会上向当地 K-12 教师教授火山和灾害知识。加州州立大学富勒顿分校和普林斯顿大学之间为期三年的 RUI 合作项目旨在确定岩浆弧中岩浆体的时间和长度尺度，以及它们的成分、结晶度和体积随时间的变化。该研究将使用来自内华达山脉中部 95-85.5 Ma Tuolumne 侵入复合体的 Half Dome 和 Cathedral Peak 单元的长达 12 厘米的钾长石苯型晶体和巨晶以及巨晶托管矿物包裹体。将使用 CT 扫描和 CL 图像对钾长石纹理和分区进行 3D 成像，并使用电子微探针和激光烧蚀 ICPMS 进行地球化学定量分析。将测量钾长石矿物包裹体的 TIMS-TEA U-Pb 锆石和钛矿年代学、SIMS 锆石中钛和钛矿中锆测温、EMP 和 LA-ICPMS 斜长石和角闪石测温和化学计量（确定熔​​体成分）。这些数据将被综合起来，以检验这样的假设：图奥勒米侵入岩在增量建造过程中热成熟，形成了数公里长的相互连接的岩浆体，能够进行岩浆流动、分馏、混合和可能的喷发。这些数据将反映当前关于像图奥勒米复合体这样的长期大型复合侵入体是否具有“热”或“冷”存储特征的争论。 “冷”储存的特点是小而坚硬的岩浆糊状物大部分时间都处于接近或固相线的温度，限制了与同时期岩浆体的相互作用，只有偶尔（如果有的话）通过岩浆补给“解冻”以供给火山喷发。相比之下，“热存储”允许在高于固相线的较高温度和较低结晶度下，在长达数百万年的时间尺度下，在大型（10-100平方公里）岩浆体中进行动态单元间岩浆混合和晶体回收。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。