Development and Calibration of Rutile (U-Th)/He Geo- and Thermochronometry

金红石 (U-Th)/He 地质测时法和热测时法的开发和校准

• 批准号: 0439824
• 负责人: Daniel Stockli
• 金额: $ 17.41万
• 依托单位: University of Kansas Center for Research Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-01 至 2008-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0439824&HistoricalAwards=false
• 关键词: Development; Calibration; Rutile; Th; He

(U-Th)/He dating of phosphate and silicate minerals such as apatite, zircon, monazite, and titanite has attracted considerable interest; however, U- and Th-bearing Fe- or Ti-oxides have not been systematically investigated and developed as low-T thermochronometers. A common oxide mineral is rutile (TiO2), which is present as an accessory mineral in many magmatic rocks and also occurs widely in high-grade metamorphic rocks, especially in blueschists, eclogites, and granulites. We propose to develop and calibrate rutile (U-Th)/He geo- and thermochronometry by investigating its He diffusion characteristics; we will include such factors as grain size and chemical composition. Furthermore, we will test rutile (U-Th)/He dating on fast-cooled volcanic rocks as well as more slowly-cooled sample arrays from the KTB ultra-deep borehole and an exhumed extensional fault block in the Wassuk Range, western Basin and Range province. We will also apply rutile (U-Th)/He thermochronometry to date the cooling of high-pressure metamorphic rocks from Oman. The (U-Th)/He calibration of rutile will provide a new geo- and thermochronometer that will be widely applicable, but should be especially useful for studies of high-P to ultrahigh-P samples that are notoriously difficult or impossible to date at the present. The scientific results and methodologies developed during our study will be disseminated to the geosciences community through publication of research papers and presentations at international meetings. The study will significantly impact the education of two students that will work with the PIs in the KU (U-Th)/He and TIMS laboratories, providing them the opportunity for active learning and exposing them to state-of-the-art analytical facilities and new research directions. This background will be important to the intellectual growth of the students and give them experience in working in collaborative and group/team situations.

磷酸盐和硅酸盐矿物如磷灰石、锆石、独居石和钛铁矿的（U-Th）/He定年引起了人们极大的兴趣;然而，含U和Th的铁或钛氧化物还没有被系统地研究和开发为低温热年代计。 一种常见的氧化物矿物是金红石（TiO 2），它作为副矿物存在于许多岩浆岩中，也广泛存在于高级变质岩中，特别是蓝片岩、榴辉岩和麻粒岩中。我们建议开发和校准金红石（U-Th）/他的地质和热测时通过调查其他的扩散特性，我们将包括晶粒尺寸和化学成分等因素。 此外，我们将测试金红石（U-Th）/He测年快速冷却的火山岩，以及从KTB超深钻孔和Wassuk山脉，西部盆地和山脉省的一个挖出的伸展断块的缓慢冷却的样品阵列。我们还将应用金红石（U-Th）/He热年代测定来确定阿曼高压变质岩的冷却。金红石的（U-Th）/He校准将提供一种新的地质和热时计，将被广泛应用，但应该是特别有用的高磷超高磷样品的研究是出了名的困难或不可能的日期在目前。 我们在研究过程中形成的科学成果和方法将通过发表研究论文和在国际会议上发言的方式向地球科学界传播。该研究将显著影响两名学生的教育，他们将与KU（U-Th）/He和TIMS实验室的PI一起工作，为他们提供主动学习的机会，并使他们接触到最先进的分析设施和新的研究方向。这种背景将是重要的学生的智力成长，并给他们在协作和组/团队的情况下工作的经验。