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.

火山是众所周知的，但知之甚少。岩浆是如何在活火山下积聚起来的，这需要多长时间？是什么控制着它是喷发还是冷却到地下深处形成深圳湾？它在那里保持熔融状态多久，有多少可以喷发多久？数以亿计的人生活在离活火山100英里的范围内。他们面临着遭受火山灾害的危险。火山爆发也会影响气候和环境。然而，几十年的研究并没有回答这些基本问题。本项目将解决Tuolumne岩体中的这些问题。它是约塞米蒂国家公园壮观的岩石暴露的所在地。小矿物的铀铅年龄将决定深圳湾何时冷却到今天暴露在地表的岩石。它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。晶石的化学成分就像犯罪现场的指纹。它们将确定9000万年前火山喷发时岩浆的储存时间、地点和数量。岩浆的粘性和热度将有助于确定这些喷发可能是什么样子。该项目支持两个研究小组：1）Memeti研究员，一位在西班牙裔服务的女性，以本科生为重点的加州州立大学富勒顿，2）研究员Schoene在以研究为重点的普林斯顿大学。该小组将培训几名研究生的年龄和化学方法。研究生帮助培训参与项目不同部分的本科生。所有学生参加研究活动的各个方面，包括实地考察和出版。Memeti将完成以下活动：1）根据本项目的结果更新编写的约塞米蒂有声旅游移动的应用程序，2）继续组织约塞米蒂国家公园的实地考察，3）与公园管理员分享研究成果。4)她将为地质学学生开发介绍性的地质学实验室，并在南加州公共活动中继续她对火山危险的宣传工作。舍恩将在普林斯顿大学的一个研讨会上教授当地K-12教师火山和危险。加州州立大学富勒顿和普林斯顿大学之间的这个为期3年的合作RUI项目旨在确定岩浆弧中岩浆体的时间和长度尺度及其随时间的成分，结晶度和体积变化。该研究将使用来自内华达州中部Sierra的95-85.5 Ma Tuolumne侵入杂岩的Half Dome和Cathedral Peak单元的长达12 cm的钾长石斑晶和巨晶以及巨晶托管矿物包裹体。利用CT扫描和CL图像对钾长石结构和分带进行三维成像，并利用电子探针和激光烧蚀ICPMS进行定量地球化学分析。将测量钾长石矿物包裹体，用于TIMS-TEA锆石和钛铁矿的U-Pb年代学、西姆斯锆石中钛和钛铁矿中锆的温度测定、EMP和LA-ICPMS斜长石和角闪石的温度测定和化学测定（确定熔体成分）。这些数据将被合成，以测试的假设，Tuolumne侵入杂岩热成熟过程中的增量建设，创造互连的岩浆体许多公里长，能够岩浆流动，分馏，混合，并可能喷发。这些数据将反映目前的辩论是否长寿和大型复合侵入体，如图奥勒米复杂的特点是“热”或“冷”存储。“冷”储存的特点是小而坚硬的岩浆泥，大部分时间都处于接近或接近固相线的温度，限制了与同时代岩浆体的相互作用，只有偶尔，如果有的话，“被”岩浆补给以供给火山爆发。与此相反，“热储存”允许大规模的动态单元间岩浆混合和晶体再循环（10- 100平方公里）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进行评估，被认为值得支持的搜索.