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

了解地球的地质历史可以让我们深入了解塑造地球和经济资源分布的过程。然而，古代地质事件很难破译，因为它们的物理存在可能会因侵蚀而消失。幸运的是，在风化和侵蚀之前存在的岩石的类型和年龄（即它们的来源）的信息被编码在一些保存在沉积物和沉积岩中的矿物中。碧玺就是这样一种矿物。它是地质信息的关键储存库，因为它包含了反映其形成的岩石环境的广泛化学元素-也就是说，它编码了岩石的化学特征，类似于指纹。电气石也是一种耐化学和耐机械的矿物，当它从形成它的岩石中风化出来时，它可以变成沙粒，并与沉积物（和岩石）结合在一起。一旦它融入了原始的化学特征，电气石颗粒就会将这些特征储存数百万或数十亿年。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，通过使用新技术激光诱导击穿光谱（LIBS）和现有技术电子探针分析（EMP）整合矿物电气石的化学分析。两者都能产生原位化学指纹图谱：LIBS的优势在于它能收集所有元素及其配合物的信号，包括轻元素，并提供元素的相对组成，而EMP是一种成熟的分析技术，可用于大多数元素（除了轻元素H， Li）的高精度和精确的微米级化学数据。这项工作的一个目标是利用这些互补的技术，在广泛收集已知来源的电气石样品的基础上，开发出可靠的来源确定方法。在一个案例研究中，物源技术将应用于东南极山脉（6.5 - 4.8亿年前）的地质发展。本案例研究的目的是测试利用LIBS和EMP分析电气石在破译南极东部复杂地质历史中的有效性。这项研究有两个主要含义。首先，它将开发新的来源研究途径，利用广泛存在的矿物电气石来完善我们对地球历史的理解。一个额外的社会效益是有可能将电气石从不同的宝石矿床中区分出来，这些矿床的价格截然不同。本研究的样本、数据和技术将用于两所少数民族大学的本科生和研究生班，以培养下一代地球科学家。两所大学之间的学生交流将拓宽他们的教育和分析经验，这对今天来说是必要的。美国的全球劳动力。该研究团队包括两名女性合作pi，所有pi都是STEM学科中大量女性的导师。与行业的合作汇集了学者和行业合作伙伴，包括一家女性拥有的盈利性小企业，以及与另一所本科大学的教师合作。

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, it 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.