Stable Isotope Constraints on Source, Contamination, and Alteration of Great Basin Igneous Rocks, and Implications for Metallogeny

ArehartCarlin型金矿床是北美最丰富和最重要的热液金矿床之一，在时间和空间上似乎与始新世的岩浆作用有关。相比之下，较早的岩浆活动似乎并没有产生类似的矿床。为了更好地了解作为这些热液系统的驱动力的上升岩浆与岩浆经过的地壳岩石之间的相互作用，将对大盆地中未改变的深成岩进行硫和氧的稳定同位素测量。这些测量将与地壳(克拉通基底、晚元古代裂谷充填沉积岩、显生宙沉积岩)和地幔物质的类似同位素测量进行比较，这些物质可能为这些火成岩提供成分。这些数据与现有的地质、地球化学和地球物理数据相结合，将被用来阐明该区域的地壳结构，了解其对巨型热液系统发育的控制。这些数据还将解决为什么同一地区不同年龄的岩浆活动显然没有像始新世那样在地壳中产生大规模的金属重新分布的问题。拟议的研究将为专注于发展矿藏研究事业的学生提供机会。由行业和政府支持的应用科学的结合将使学生接触到矿藏研究的多个方面，对于培养下一代在工业、学术界或政府任职的矿物地球科学家至关重要。对这项研究的支持将有助于维持和加强研究和教育的基础设施，包括内华达州稳定同位素实验室

EAR-0309935ArehartCarlin-type deposits are amongst the richest and most important hydrothermal gold deposits in North America and appear to be associated in time and space with Eocene magmatism. In contrast, older magmatic episodes do not appear to have generated similar deposits. To better understand the interaction of ascending magmas, which were the driving force for these hydrothermal systems, with crustal rocks through which the magmas passed, measurements of stable isotopes of sulfur and oxygen will be made of unaltered plutonic rocks in the Great Basin. These measurements will be compared to similar isotopic measurements of crustal (cratonic basement, late Proterozoic rift-filling sedimentary rocks, Phanerozoic sedimentary rocks) and mantle materials that could have provided components to these igneous rocks. These data, when combined with extant geological, geochemical and geophysical data, will then be used to elucidate the crustal architecture of the region, to understand its control on the development of giant hydrothermal systems. These data will also address the question of why magmatism of different ages but in the same region, apparently did not generate the same large-scale metal redistribution in the crust that occurred in the Eocene.The proposed research will provide opportunities to students focused on developing careers in mineral deposits research . The combination of applied science supported by both industry and government will provide students exposure to multiple aspects of mineral deposit research, and is critical in training the upcoming generation of mineral geoscientists for positions in industry, academia, or government. Support for this research will help to maintain and enhance the infrastructure for research and education, including the Nevada Stable Isotope Laboratory