Collaborative Research: Improved Geochronology-Based Sediment Provenance Analysis Through Physico-Mechanical Characterization of Zircon Transport

合作研究：通过锆石运移的物理机械表征改进基于地质年代学的沉积物物源分析

• 批准号: 2314016
• 负责人: Mauricio Ibanez-Mejia
• 金额: $ 26.06万
• 依托单位: University of Arizona
• 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: 2023-01-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2314016&HistoricalAwards=false
• 关键词: Collaborative; Research; Improved; Geochronology; Based

The generation and movement of sediments by wind and water currents are fundamental geologic processes that have shaped the surface of our planet for billions of years. Through these processes, material removed from higher elevation areas by weathering and erosion is mechanically transported to lower elevation regions (i.e., basins), thereby leveling topographic highs (e.g., mountains). Studying and understanding these processes in a quantitative way provides Earth Scientists with fundamental information about geography, evolution, human migration, climate, tectonics, and the development of economically important sedimentary basins. One of the most robust ways to study sediment transport in modern and ancient sedimentary systems (e.g., rivers, deserts), is by measuring the geologic ages of weathering-resistant minerals such as zircon that contain radioactive parent and daughter isotopes. By studying the age patterns of far-travelled zircons, Earth Scientists can draw linkages to potential source areas with comparable ages and reconstruct ancient sediment routing systems. Students will be trained in the research methods and a new Creative Inquiry course for undergraduates will be developed as part of the project.Studying sediment transport through age-dating of detrital minerals is not without complexities and potential biases. Although the mechanical sorting and fractionation of particles carried by tractive currents have been well-known processes in sedimentology for well over a century, our knowledge of how sediment transport affects detrital zircon populations and influences U-Pb age spectra remains critically inadequate. Using fluvial systems as natural laboratories, this project will quantify the effects that the physical characteristics of zircon, such as grain size, morphology, and accumulated radiation damage, have in systematically biasing detrital zircon age spectra during transport. This project will: 1) collect robust age and physical-properties information of detrital zircon fractionation during transport, and 2) apply methods of statistical inference to quantify the latent effects these physical characteristics have in biasing the observed age spectra. These insights will allow Earth Scientists to perform more ‘geologically informed’ inter-sample comparisons, enhancing the accuracy of tectonic reconstructions, quantitative provenance models, and sediment-transport pathways derived from detrital zircon U-Pb data. The code developed will be user friendly and available to other researchers.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.

风流和水流的沉积物产生和运动是基本的地质过程，这些过程已经塑造了我们星球的表面数十亿年。通过这些过程，通过风化和侵蚀从较高海拔地区去除的材料被机械运输到较低的海拔区域（即贝斯），从而使地形高（例如山区）升级。以定量的方式研究和理解这些过程，为地球科学家提供了有关地理，进化，人类移民，气候，构造学以及经济上重要的沉积贝斯的基本信息。研究现代和古老沉积系统（例如河流，沙漠）中沉积物运输的最强大方法之一是测量含有耐候的矿物质的地质年龄，例如包含放射性父母和女儿同位素的氧化锆。通过研究远距离锆石的年龄模式，地球科学家可以将与可比年龄的潜在源区域联系起来，并重建古代沉积物路由系统。学生将接受研究方法的培训，并将开发针对本科生的新创造性探究课程，作为项目的一部分。通过危险矿物质的年龄进行沉积物的运输并不没有复杂性和潜在的偏见。并且影响U-PB年龄光谱仍然严重不足。该项目将河流系统作为天然实验室，将量化锆石的物理特征（例如晶粒尺寸，形态和累积的辐射损伤）在运输过程中有系统偏见的碎屑锆石年龄光谱具有。该项目将：1）收集运输过程中碎屑锆石分馏的稳健年龄和物理培训信息，以及2）应用统计推断的方法来量化这些物理特征对观察到的年龄光谱的偏见。这些见解将使地球科学家能够执行更多的“地质知情”样本间比较，从而提高构造重建，定量出处模型以及从碎屑锆石U-PB数据得出的沉积物传输途径的准确性。开发的代码将是用户友好的，并将对其他研究人员提供。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响评论标准来评估诚实的支持。