EAGER: Collaborative Research: Dating mineralization in a Carlin-type gold deposit: A test of the Fe-oxide (U-Th)/He chronometer

内华达州北部的卡林型金矿(CTGD)是美国大部分黄金生产的来源，因此具有重要的经济意义；然而，它们的地质来源尚不清楚。不同的成矿模式将金矿化与可能发生在不同时期的不同地质事件联系在一起，包括岩浆活动或地下水流体通过地壳中更深的含金单元的循环。由于CTGDS中缺乏易测年的矿物，确定金矿化发生的时间历来具有挑战性。其结果是，由于缺乏对这些矿床如何以及何时形成的了解，有效的勘探受到了阻碍。在这项研究中，一种新的测年方法将被提炼和测试。如果能够更确切地知道CTGD建造的年龄，金矿化可能与同时发生的更广泛的地质过程相关联。这些知识将使科学家和探险家更容易发现新的矿床。现有的地质年代学数据表明，卡林型矿化在空间和时间上与始新世席卷内华达州的西南岩浆作用大致重叠。地质年代学和热年代学数据对于确定岩浆作用和成矿作用在个别矿床重叠的直接证据至关重要。事实上，新的计时工具可以极大地扩展导致CTGD形成的遗传过程的知识。到目前为止，还没有一种直接的方法来确定CTDG的成矿日期。最近的研究已经探索了(U-Th)/He计时器在铁氧化物中的应用，但这种计时器还没有在矿床中进行系统的测试。这项拟议的研究有两个主要目标：测试铁氧化物(U-Th)/He计时器测定热液流体流动的可行性，并使用该方法确定内华达州一个CTGD的热液活动年龄。

The Carlin-type gold deposits (CTGDs) of northern Nevada are the source of most of the gold production in the United States and are thus of major economic importance; however, their geologic origin is uncertain. Various models for deposit formation relate the gold mineralization to different geologic events which likely occurred at different times, including magmatic activity, or circulation of groundwater-derived fluids through deeper gold-bearing units in the crust. Because of the lack of easily dateable minerals in CTGDs, it has historically been challenging to determine when gold mineralization occurred. The result is that effective exploration is hampered by the lack of knowledge about how and when these deposits formed. In this study, a new method of dating these deposits will be refined and tested. If the ages of CTGD formation could be more definitively known, gold mineralization could be correlated to broader geologic processes that were occurring at the same time. This knowledge would enable scientists and explorers to more easily discover new deposits.Available geochronological data suggest that Carlin-type mineralization broadly overlapped in space and time with the southwest sweep of Eocene magmatism through Nevada. Geo- and thermochronologic datasets are critical to identify direct evidence that magmatism and ore formation overlapped at individual deposits. Indeed, new chronometric tools could greatly expand knowledge of the genetic processes that lead to CTGD formation. No straightforward method currently exists to date CTDG mineralization. Recent studies have explored the use of the (U-Th)/He chronometer for Fe-oxides, but this chronometer has not been systematically tested in ore deposits. The proposed research has two major goals: to test feasibility of the Fe-oxide (U-Th)/He chronometer to date hydrothermal fluid flow, and to use this method to determine the age of hydrothermal activity in a CTGD in Nevada.