Constraints on genetic relationships between organic-rich black shales and Zn-Pb mineralization in the Mid-Continent Region, U.S.A.

美国中大陆地区富含有机质黑色页岩与锌铅矿化之间成因关系的制约

• 批准号: 1952088
• 负责人: Adriana Potra
• 金额: $ 39.71万
• 依托单位: University of Arkansas
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-15 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1952088&HistoricalAwards=false
• 关键词: Constraints; genetic; relationships; between; organic

Mississippi Valley-type (MVT) ores are important worldwide, especially in developing countries that are utilizing their natural resources to create jobs and develop infrastructure. The US technologic and economic interests are critically reliant on a continuation of prospecting, discovery and exploitation of new strategic ore deposits. Resources of this type necessitate investigation since they are part of our effort to ensure societal development on a sustainable Earth. Constraining the source(s) of metals in the MVT deposits is very important for a better understating of how this significant class of ores form. Understanding the mechanism can lead to modeling and predicting where they may be concentrated and may result in identification of yet-to-be-found deposits. The PI’s intent is to emphasize the education and training of economic geologists and will integrate research with an effort to enhance students’ preparation and understanding in the natural resources area. Research will also include student training in the radiogenic isotope class 100 clean lab and use of the state-of-the-art technology, including a Nu Plasma MC-ICP-MS and Thermo Scientific iCAP Q ICP-MS. The PI is using this research as a platform to contribute to ongoing outreach efforts focused on training and recruiting high-quality students of under-represented minorities of historically Black Colleges and Universities and Hispanic Serving Institutions. This project is jointly funded by the Petrology and Geochemistry Program the Established Program to Stimulate Competitive Research (EPSCoR).A genetic link between black shales and MVT ores has long been thought to exist because of (1) the presence of mature hydrocarbon and brine fluid inclusions within many MVT ores, (2) the association of the hydrothermal fluids that are linked to MVT ore formation with organic compounds and oil-like droplets, and (3) the highly radiogenic nature of the ores. Research aims to provide a better understanding of the genetic relationship between metal-rich black shales in large sedimentary basins and sulfide mineralization associated with (1) major MVT ores in carbonate sequences and (2) minor occurrences of ores in shales. A secondary goal is to better constrain the sources of metals in the MVT ores. The main hypothesis to be tested is that metal-rich black shales deposited in large sedimentary basins are the source of metals for Pb-Zn mineralization in the Mid-Continent Region of the United States. Preliminary Pb isotope and trace element data suggest that U-enriched black shales represent a potential source for radiogenic Pb to be mobilized in the ores and that different depositional environments within the larger shale body may explain the patterns of metal occurrence in the black shales and their movement into adjacent strata. Recognition and proof that these shales may be a major source of metals in ores may cause a paradigm shift of the basic concepts of how and where these deposits form. Understanding MVT deposits can also lead to enhanced knowledge about presence and relevant characteristics of metal-bearing black shales. This project is jointly funded by the Petrology and Geochemistry Program the Established Program to Stimulate Competitive Research (EPSCoR).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.

密西西比河谷型（MVT）矿石在世界范围内都很重要，特别是在利用其自然资源创造就业机会和发展基础设施的发展中国家。美国的技术和经济利益严重依赖于继续勘探、发现和开发新的战略矿床。这类资源需要调查，因为它们是我们确保在可持续地球上实现社会发展的努力的一部分。限制MVT矿床中金属的来源对于更好地理解这一重要类别的矿石是如何形成的非常重要。了解这种机制可以导致建模和预测它们可能集中在哪里，并可能导致识别尚未发现的矿床。PI的目的是强调经济地质学家的教育和培训，并将研究与努力提高学生在自然资源领域的准备和理解相结合。研究还将包括在放射性同位素100级清洁实验室和使用最先进的技术，包括Nu Plasma MC-ICP-MS和Thermo Scientific iCAP Q ICP-MS。PI正在利用这项研究作为平台，为正在进行的外展工作做出贡献，重点是培训和招募高质量的学生，代表历史上黑人学院和大学以及西班牙裔服务机构的少数民族。该项目由岩石学和地球化学计划刺激竞争研究既定计划（EPSCoR）联合资助。长期以来，人们一直认为黑色页岩和MVT矿石之间存在遗传联系，因为（1）存在成熟的碳氢化合物和盐水流体包裹体许多MVT矿石中，（2）与MVT成矿有关的热液流体与有机化合物和油滴的缔合;（3）矿石的高放射成因性质。研究的目的是更好地了解大型沉积盆地中富含金属的黑色页岩与硫化物矿化之间的成因关系，硫化物矿化与（1）碳酸盐岩序列中的主要MVT矿石和（2）页岩中的次要矿石发生有关。第二个目标是更好地限制MVT矿石中金属的来源。有待检验的主要假设是，大型沉积盆地中沉积的富含金属的黑色页岩是美国中大陆地区铅锌矿化的金属来源。初步铅同位素和微量元素数据表明，富铀黑色页岩代表放射性铅的潜在来源，以动员在矿石中，不同的沉积环境内的较大的页岩体可以解释的模式，金属赋存在黑色页岩和它们的运动到邻近地层。认识和证明这些页岩可能是矿石中金属的主要来源，可能会导致这些矿床如何以及在何处形成的基本概念的范式转变。了解MVT矿床还可以提高对含金属黑色页岩的存在和相关特征的认识。该项目由岩石学和地球化学计划共同资助，该计划旨在促进竞争性研究（EPSCoR）。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Constraining the provenance of black shales using rare earth elements and neodymium isotopes, Midcontinent United States

使用稀土元素和钕同位素限制黑色页岩的来源，美国中大陆

• DOI: 10.1130/b37264.1
• 发表时间: 2024
• 期刊: Geological Society of America Bulletin
• 影响因子: 4.9
• 作者: Morris, Noah;Potra, Adriana;Samuelsen, John R.
• 通讯作者: Samuelsen, John R.