EAR-PF: Quartz-in-zircon: An elastic model for quantifying depth and time scales of crystallization and exhumation of Hadean zircon

EAR-PF：锆石中的石英：用于量化冥古宙锆石结晶和折返的深度和时间尺度的弹性模型

• 批准号: 1952698
• 负责人: Joseph Gonzalez
• 金额: $ 17.4万
• 依托单位: Gonzalez, Joseph P
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1952698&HistoricalAwards=false
• 关键词: EAR; PF; Quartz; zircon; elastic

Dr. Joseph Gonzalez has been awarded an NSF EAR postdoctoral fellowship to work at the University of Pavia developing an elastic model for quartz inclusions contained in zircon to better understand Hadean (4 Ga) earth conditions. Zircon is common in crustal rocks and is the most frequently used mineral to infer ages and crystallization temperatures attained by rocks. Despite the extensive use of zircon for time and temperature determinations, there are no methods for determining the depth of zircon crystallization. The objective of this project is to develop a method to determine depth of zircon formation by investigating quartz crystals trapped as inclusions at various stages of growth in 4 Ga old Hadean zircon. Dr. Gonzalez will achieve these goals by modeling the elastic interactions between quartz inclusions and their zircon host and integrating model results with existing zircon geochronologic and thermometric determinations. The quartz-in-zircon elastic model applied to Hadean zircons from the Jack Hills province of Australia will give insights into the timing and evolution of the onset of Earth’s plate tectonics. During his tenure as an NSF Postdoctoral Fellow, Dr. Gonzalez will organize and participate in educational events hosted by the University of Pavia to explain ongoing research to the general public and prospective students. Furthermore, he will co-mentor undergraduate and graduate students and organize a dedicated website about the project, where plain language descriptions of ongoing results will be accessible to anyone interested.Elastic models of host-inclusion mineral pairs have become frequently used tools for investigating the thermobarometric conditions of inclusion entrapment during host mineral growth. However, elastic models have only been developed for elastically anisotropic inclusions (e.g. quartz) contained in elastically isotropic host minerals (e.g. garnet). In order to understand the elastic interactions between elastically anisotropic host and inclusion minerals (e.g. quartz inclusions in zircon), the reciprocal crystallographic orientation (CORs) between the host and inclusion must be incorporated. At the University of Pavia, a series of finite element models will be completed to quantify the effect of crystallographic orientation on the strain and stress between the zircon host and quartz inclusion minerals. Once the effect of orientation is known, model results can be applied to quartz inclusions contained within Jack Hills zircons to infer the crystallization depth. Single crystal X-ray diffraction will be used to obtain the crystallographic orientation and unit cell parameters of the zircon host and quartz inclusion, permitting calculation of the remnant pressure within the inclusion. Remnant pressures and crystallographic orientations can be used in finite element models and applied to 3-D X-ray tomographic models of targeted inclusions to determine the possible entrapment conditions of the quartz inclusion within the zircon host. Quartz-in-zircon results from Jack Hills zircons will be used to evaluate hypotheses that modern style plate subduction processes began under relatively cool thermal regimes in the Hadean Eon. More broadly, the quartz-in-zircon elastic model will be widely applicable to crustal rocks and can be combined with other petrologic methods to increase understanding of Earth processes. Broader impacts of this project include mentoring undergraduates and graduate students and general public outreach activities.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.

Joseph Gonzalez 博士获得了 NSF EAR 博士后奖学金，在帕维亚大学开发锆石中石英包裹体的弹性模型，以更好地了解冥古宙 (4 Ga) 地球条件。锆石在地壳岩石中很常见，也是最常见的。经常使用矿物来推断岩石的年龄和结晶温度尽管锆石广泛用于确定时间和温度，但没有方法可以确定锆石结晶的深度。该项目的目标是通过研究 4 Ga 古冥宙锆石生长各个阶段中作为夹杂物捕获的石英晶体来开发一种锆石形成深度的方法。Gonzalez 博士将通过模拟石英夹杂物之间的弹性相互作用来实现这些目标。及其锆石主体，并将模型结果与现有的锆石地质年代学和测温测定结果相结合，将石英锆石弹性模型应用于来自杰克山的冥古宙锆石。冈萨雷斯博士将深入了解地球板块构造开始的时间和演化。在担任美国国家科学基金会博士后研究员期间，冈萨雷斯博士将组织并参加帕维亚大学主办的教育活动，向澳大利亚省解释正在进行的研究。此外，他将共同指导本科生和研究生，并组织一个有关该项目的专门网站，任何感兴趣的人都可以在该网站上获得对正在进行的结果的简单语言描述。主体-包裹体矿物对的弹性模型已成为常用工具然而，弹性模型仅针对弹性各向同性宿主矿物（例如石榴石）中包含的弹性各向异性包裹体（例如石英）开发。母体和包裹体矿物（例如锆石中的石英包裹体），母体和包裹体之间的相互晶体取向（COR）必须是帕维亚大学将完成一系列有限元模型，以量化晶体取向对锆石主体和石英包裹体矿物之间的应变和应力的影响，一旦知道了取向的影响，就可以得出模型结果。应用于 Jack Hills 锆石中包含的石英包裹体以推断结晶深度，将使用单晶 X 射线衍射来获得锆石主体和石英的晶体取向和晶胞参数。夹杂物，允许计算夹杂物内的残余压力。残余压力和晶体取向可用于有限元模型，并应用于目标夹杂物的 3D X 射线断层扫描模型，以确定夹杂物内石英夹杂物可能的捕获条件。杰克山锆石中的石英锆石结果将用于评估现代板块俯冲过程是在冥古宙相对较冷的热环境下开始的假设。广泛而言，石英锆石弹性模型将广泛适用于地壳岩石，并且可以与其他岩石学方法相结合，以增进对地球过程的理解，包括指导本科生和研究生以及一般公众宣传活动。授予 NSF 的法定使命，并通过评估反映使用基金会的智力优点和更广泛的影响审查标准，被认为值得支持。

项目成果

The role of symmetry-breaking strains on quartz inclusions in anisotropic hosts: Implications for Raman elastic geobarometry

对称破缺应变对各向异性基质中石英包裹体的作用：对拉曼弹性地压测量的影响

• DOI: 10.1016/j.lithos.2022.106716
• 发表时间: 2022
• 期刊: Lithos
• 影响因子: 3.5
• 作者: Murri, M.;Gonzalez, J.P.;Mazzucchelli, M.L.;Prencipe, M.;Mihailova, B.;Angel, R.J.;Alvaro, M.
• 通讯作者: Alvaro, M.

Elastic Geobarometry for Anisotropic Inclusions in Anisotropic Host Minerals: Quartz‐in‐Zircon

各向异性宿主矿物中各向异性包裹体的弹性地压测量：石英、锆石

• DOI: 10.1029/2021jb022080
• 发表时间: 2021
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Gonzalez, Joseph P.;Mazzucchelli, Mattia L.;Angel, Ross J.;Alvaro, Matteo
• 通讯作者: Alvaro, Matteo