Age and Lithogeochemistry of Volcanic-hosted Massive Sulfide Deposits of the Ambler District, Southern Brooks Range, Alaska

阿拉斯加南布鲁克斯山脉安布勒区火山块状硫化物矿床的年龄和岩石地球化学

• 批准号: 0208162
• 负责人: William McClelland
• 金额: $ 13.13万
• 依托单位: Regents of the University of Idaho
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2005-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0208162&HistoricalAwards=false
• 关键词: Age; Lithogeochemistry; Volcanic; hosted; Massive

McClellandEAR-0208162Modern examples of volcanic-hosted massive sulfide (VMS) deposits suggest that hydrothermal activity associated with formation of these deposits is a steady-state process. In contrast, ancient examples typically define distinct age groups and recent genetic models relate VMS mineralization to specific tectonic events such as incipient intra-arc rifting. Distinction between steady state and punctual models for VMS mineralization requires high precision geochronologic data to establish the duration of magmatism at the scale of individual deposits and to establish correlation, distinction, or migration of magmatism observed at the regional scale. The widespread occurrence of Devonian to Mississippian VMS deposits in the northern North American Cordillera provides an ideal setting to examine this issue. U-Pb geochronology and Nd-Sr isotope geochemistry combined with major, trace, and REE geochemistry of felsic and mafic rocks associated with mineralization and hydrothermal alteration will establish the age and tectonic setting of VMS mineralization in the Ambler district, southern Brooks Range, Alaska. The resulting database will serve as a basis for comparison with and evaluation of broadly age equivalent VMS deposits in the Yukon-Tanana terrane as well as sediment-hosted deposits within adjacent terranes and the Cordilleran miogeocline. The results of this project will provide valuable insight into the temporal and tectonic setting of VMS mineralization throughout the northern Cordillera. This insight will potentially lead to the generation of new genetic models for the evolution and preservation of VMS deposits in additional settings. The project will also address the long-standing question of the tectonic setting of mid-Paleozoic magmatism in the Cordillera.

McClellandear-0208162火山托管大型硫化物（VM）沉积物的现代实例表明，与这些沉积物形成相关的热液活性是一个稳态过程。相比之下，古代例子通常定义不同的年龄组，而最近的遗传模型将VMS矿化与特定的构造事件（例如起步性构造事件）相关联。 VM矿化的稳态模型与守时模型之间的区别需要高精度的地质学数据，以在单个沉积物的范围内确定岩浆症的持续时间，并在区域尺度上观察到的岩浆主义的相关性，区别或迁移。泥盆纪北部北美科迪利拉（Cordillera）的密西西比州VMS矿床的广泛发生，为研究这个问题提供了理想的环境。 U-PB地质学和ND-SR同位素地球化学以及与矿化和水热改变相关的Felsic和Mafic岩石的主要，痕量和REE地球化学将确定Ambler地区Ambler地区VMS矿化的年龄和构造设置，阿拉斯加南部布鲁克斯范围。所得的数据库将作为与育空 - 塔纳纳地座中广泛年龄的VMS矿床进行比较和评估的基础，以及相邻地形和Cordilleran miogeocline中的沉积物托管沉积物。该项目的结果将为VMS矿化的时间和构造环境提供宝贵的见解。这种见解将有可能导致在其他环境中生成新的遗传模型，以进化和保存VMS矿床。该项目还将解决Cordillera中期岩浆中期岩浆的构造环境的长期问题。