Collaborative Research: A New Approach to Detrital Provenance Determination: Application of Laser-Induced Breakdown Spectroscopy (LIBS) to the Tourmaline Supergroup Minerals

合作研究：碎屑来源测定的新方法：激光诱导击穿光谱 (LIBS) 在电气石超族矿物中的应用

• 批准号: 1551434
• 负责人: Barbara Dutrow
• 金额: $ 20.75万
• 依托单位: Louisiana State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-15 至 2022-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1551434&HistoricalAwards=false
• 关键词: Collaborative; Research; New; Approach; Detrital

Understanding Earth's geological history provides insight into processes that shape our planet and the distribution of economic resources. However, ancient geological events can be difficult to decipher because their physical presence may be lost to erosion. Fortunately, information on the types and ages of rocks (i.e., their provenance) that were present prior to weathering and erosion are encoded in some minerals that are preserved in sediments and sedimentary rocks. Tourmaline is one such mineral. It is a key repository of geologic information because it incorporates a wide range of chemical elements that reflect the rock environment in which it forms - that is, it encodes the chemical signature of that rock, similar to a fingerprint. Tourmaline is also a chemically and mechanically resistant mineral that, when weathered out of the rock in which it formed, can become a sand grain that is incorporated into sediments (and rocks). Once it incorporates its original chemical signature, the tourmaline grain stores that signature for millions or billions of years.This work uses a synergistic approach to decipher former geological events, their record in sediments and rocks, by integrating chemical analyses of the mineral tourmaline using the new technology Laser-Induced Breakdown Spectroscopy (LIBS) with the established technology Electron Microprobe analyses (EMP). Both yield in-situ chemical fingerprints: LIBS is advantageous because it collects signals of all elements and their complexes, including the light elements, and provides relative compositions of elements, while EMP is a mature analytical technique and is used for highly precise and accurate micrometer-scale chemical data for most elements (except light elements H, Li). One goal of this work is to use these complementary techniques to develop robust approaches to provenance determination based on an extensive collection of tourmaline samples of known provenance. The provenance techniques will be applied, in a case study, to the geologic development of the East Antarctic Mountains (650-480 million years ago). The goal of this case study is to test the efficacy of tourmaline analysis by LIBS and EMP in deciphering complex geologic history of East Antarctic. This study has two major implications. First, it will develop new avenues of provenance studies to refine our understanding of Earth history using the widespread mineral tourmaline. An additional societal benefit is the potential to differentiate tourmalines from different gem deposits that command radically different prices. Samples, data and techniques from this study will be used in both undergraduate and graduate classes at two minority-serving Universities to educate the next generation of geoscientists. A student exchange between the two universities will broaden their educational and analytical experience, necessary for today?s global workforce. This research team includes two female co-PIs and all PIs serve as mentors to a significant number of women in STEM disciplines. Collaboration with industry brings together academics and industrial partners including a woman-owned for-profit small business, in addition to collaborations with faculty at another undergraduate-focused university.

了解地球的地质历史可以深入了解塑造地球的过程和经济资源的分配。 然而，古代地质事件可能很难破译，因为它们的物理存在可能会因侵蚀而消失。幸运的是，有关风化和侵蚀之前存在的岩石类型和年龄（即其来源）的信息被编码在沉积物和沉积岩中保存的一些矿物中。 电气石就是这样一种矿物。它是地质信息的重要存储库，因为它包含了反映其形成的岩石环境的多种化学元素，也就是说，它编码了该岩石的化学特征，类似于指纹。电气石也是一种耐化学和机械性的矿物，当它从形成它的岩石中风化出来时，可以变成沙粒，融入沉积物（和岩石）中。一旦它结合了其原始的化学特征，电气石颗粒就会将该特征存储数百万或数十亿年。这项工作使用协同方法来破译以前的地质事件，它们在沉积物和岩石中的记录，通过使用矿物电气石的化学分析进行整合新技术激光诱导击穿光谱 (LIBS) 与成熟的电子微探针分析 (EMP) 技术。两者都产生原位化学指纹：LIBS 的优势在于它可以收集所有元素及其配合物（包括轻元素）的信号，并提供元素的相对组成，而 EMP 是一种成熟的分析技术，用于高精度和准确的测微计大多数元素的比例化学数据（轻元素 H、Li 除外）。这项工作的目标之一是利用这些补充技术，根据大量已知产地的电气石样品，开发可靠的产地确定方法。 在案例研究中，溯源技术将应用于东南极山脉（650-4.8 亿年前）的地质发展。本案例研究的目的是测试 LIBS 和 EMP 电气石分析在破译南极东部复杂地质历史方面的有效性。 这项研究有两个主要意义。 首先，它将开发新的来源研究途径，以利用广泛存在的矿物碧玺来加深我们对地球历史的理解。另一个社会效益是可以将碧玺与价格截然不同的不同宝石矿床区分开来。 这项研究的样本、数据和技术将用于两所少数族裔大学的本科生和研究生课程，以教育下一代地球科学家。 两所大学之间的学生交流将扩大他们的教育和分析经验，这对于当今的全球劳动力来说是必需的。该研究团队包括两名女性联合 PI，所有 PI 都是 STEM 学科中大量女性的导师。 除了与另一所以本科生为重点的大学的教师合作外，与工业界的合作还将学术界和工业合作伙伴聚集在一起，其中包括一家女性拥有的营利性小企业。