Collaborative Research: 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：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: 2223333
• 负责人: Blair Schoene
• 金额: $ 38.57万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Continuing 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=2223333&HistoricalAwards=false
• 关键词: Collaborative; Research; Using; feldspar; megacryst

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。岩浆如何在活火山下建立，然后需要多长时间？是什么控制它爆发或冷却地下以形成李子？它在那里融化了多长时间，其中有多少可破坏多长时间？数亿人居住在100英里的活火山中。他们有暴露于火山危害的风险。火山喷发也会影响气候和环境。然而，数十年的研究尚未回答这些基本问题。该项目将在Tuolumne Pluton中解决这些问题。它是优胜美地国家公园壮观的岩石暴露的家园。小型矿物质的铀铅年龄将确定何时将岩石冷却到今天暴露在表面的岩石上。他们还将揭示岩浆存在的时间。此外，这些较小的矿物质被发现包括在几英寸的大钾长石晶体中。长石的化学反应在犯罪现场类似于指纹。他们将确定9000万年前存储了何时，何地和多少岩浆来喂火山喷发。多么粘稠和热岩浆将有助于确定这些喷发的外观。该项目支持两个研究小组：1）研究员Memeti，是西班牙裔，专注于本科的加利福尼亚州立大学富勒顿的一名女性，以及2）以研究为重点的普林斯顿大学的研究员Schoene。该团队将培训几名以年龄约会和化学方法的研究生。研究生帮助培训参与项目不同部分的本科生。所有学生都参与研究活动的各个方面，包括现场工作和出版。 Memeti将完成以下活动：1）根据该项目的结果，更新撰写的优胜美地Audiotour移动应用程序，2）继续组织前往优胜美地国家公园的实地考察，3）与公园游骑兵共享研究结果。 4）她将为地质学生开发简介地质实验室，5）继续她在南加州公共活动的火山危害方面的宣传工作。 Schoene将在普林斯顿大学的一家开创性的开创性的火山和危险上教当地的K-12老师。加利福尼亚州立大学富勒顿和普林斯顿大学之间的这个3年合作RUI项目旨在确定岩浆弧体中岩浆体的时间和长度尺度及其在构图，结晶度和随时间的变化方面的变化。该研究将使用长达12厘米长的k-feldspar势和巨型晶体，并从内华达州中部的95-85.5 ma tuolumne侵入式复合物的半圆顶和大教堂峰单元中获得巨型晶体的矿物质夹杂物。 K-Feldspar纹理和分区将在3D中使用CT扫描和CL图像成像，并用电子微探针和激光消融ICPM定量分析用于地球化学。 K-feldspar矿物质夹杂物将用于TIMS-TEA U-PB锆石和钛，地球人数，SIMS TI-In-In-In-In-In-In-In-In-In-In-In-In-In-In-In-In-In-In-In-In-In-In-Intanite温度计，以及EMP和LA-ICPMS Plagioclase和Hornblende Plagioclase和Hornblende Pllenblende温度计和化学仪（确定融化融化融合组合）。这些数据将被合成，以测试Tuolumne侵入性复合物在增量构造过程中热成熟的假设，从而产生了长度许多公里的相互联系的岩浆体，能够岩浆流量，分级，混合和可能的喷发。这些数据将反映有关当前关于长寿和大型复合入侵（例如Tuolumne Complex）是否以“热”或“冷”存储为特征的辩论。 “冷”储存的特征是刚性的岩浆肌肉小，大部分时间都花在附近或处于固相的温度下，从而限制了与岩浆体的相互作用，但只有偶尔（如果有的话），玛格玛补给的“除霜”以供应火山爆发。相比之下，“热储存”允许在大型（10-100千公里公里）的岩浆体中进行动态的单位岩浆混合和晶体回收，其温度明显高于Solidus，较低的结晶率，并且在时间尺度上，最多数百万年的时间尺度上，NSF的法定任务和稳定的构成了诚实的良好态度，这表明了诚实的构成良好的构成诚实的依据。