Radiometric Dating of Mississippi Valley-type Ore Deposits Utilizing U-Pb and Th-Pb for Hydrothermal Calcite and Rb-Sr for Sphalerite

利用 U-Pb 和 Th-Pb 测定热液方解石和 Rb-Sr 测定闪锌矿的辐射测年法对密西西比河谷型矿床进行放射性测年

• 批准号: 9614264
• 负责人: Joyce Brannon
• 金额: $ 19万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-01-01 至 1999-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9614264&HistoricalAwards=false
• 关键词: Radiometric; Dating; Mississippi; Valley; type

9614264 Brannon The proposed work seeks to improve on the isotopic methodology for dating ore-stage mineralization in Mississipi Valley-type (MVT) Pb-Zn deposits in order to provide necessary constraints for understanding the mechanisms of ore formation. The proposed study will concentrate on: (1) the radiometric dating of two North American MVT ore deposits (Illinois-Kentucky-Fluorspar and Pine-Point Zn-Pb deposits) for which conflicting ages of ore formation exist at the moment; (2) dating of ore-stage calcite and sphalerite from mines of the Tri-State (Missouri, Kansas, Oklahoma) MVT district; and (3) dating two Proterozoic MVT deposits in South Africa, thought to be among the oldest deposits of this type currently known. In addition to dating, the Rb-Sr and U-Th-Pb isotopic systematics will be used as tracers of the ore-forming fluids. Information on the source of fluids is necessary to assess models of ore genesis in the various localities and to construct a better genetic model for MVT's worldwide.

9614264 Brannon拟议的工作旨在改善密西西比山谷型（MVT）PB-ZN沉积物中约会矿阶段矿化的同位素方法，以提供必要的约束，以了解矿石形成的机制。 拟议的研究将集中在：（1）两个北美MVT矿床（Illinois-Kentucky-Fluorspar和Pine-point Zn-PB沉积物）的辐射测定，目前存在相互冲突的矿石形成时代； （2）从三州（密苏里州，堪萨斯州，俄克拉荷马州）MVT地区的矿石阶段方解石和闪光岩的约会； （3）在南非的两个proceroroic MVT沉积物约会，被认为是当前已知的这种最古老的沉积物之一。 除了约会外，RB-SR和U-TH-PB同位素系统将用作形成矿石液体的示踪剂。 关于流体来源的信息对于评估各个地区的矿石发生模型以及为MVT全球构建更好的遗传模型是必要的。