DIKE-HOSTED ORES OF THE BEAST DEPOSIT AND THE IMPORTANCE OF EOCENE MAGMATISM IN GOLD MINERALIZATION OF THE CARLIN TREND, NEVADA—A DISCUSSION
DIKE-HOSTED ORES OF THE BEAST DEPOSIT AND THE IMPORTANCE OF EOCENE MAGMATISM IN GOLD MINERALIZATION OF THE CARLIN TREND, NEVADA—A DISCUSSION
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野兽矿床的岩脉矿石和始新世岩浆作用在内华达州卡林趋势金矿化中的重要性——讨论
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发表时间：
2001
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通讯作者：
G. D. Langstaff
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作者：
G. D. Langstaff
Sir：Ressel et al.“S（2000 b，第1417页）的断言“始新世岩浆活动被认为是驱动热液循环的主要过程，形成了卡林走向的卡林型矿床”和结论（第1438页）“北方卡林走向的矿床应被认为与岩体有关”没有可靠的证据支持。
Ressel等人（2000年b）将卡林趋势以南700平方公里的航磁异常归因于始新世岩体，其依据是暴露的始新世岩群与航磁异常的关联以及异常内外始新世岩脉的存在。同样的推理也可以很好地支持将异常归因于侏罗纪或白垩纪的岩体。侏罗纪接触岩体（Coats，1987）和白垩纪Osgood岩体（Berger，1985）具有航磁异常（Hildenbrand和Kucks，1988）。在卡林趋势上，侏罗纪岩群出现在后贝兹，相关岩脉向北延伸（Ressel等人，2000年a）。白垩纪侵入体出现在700 km2异常的北方，白垩纪岩脉出现在卡林矿（Hofstra等人总结，1999年）。与白垩纪富铜的Mike存款有关的异常被认为是由于下伏的深成岩（Teal和Branham，1997年）。因此，没有证据表明，700平方公里的异常是由于始新世岩体，而不是侏罗纪或白垩纪之一。
“卡林趋势和内华达州北方其他地方的沉积岩容金矿床与始新世岩脉和侵入岩之间的空间和时间联系表明矿化和..之间存在遗传联系。
Sir: Ressel et al.’s (2000b, p. 1417) assertion that "Eocene magmatism is considered the major process that drove hydrothermal circulation, which formed Carlin-type deposits of the Carlin trend" and conclusion (p. 1438) that "Deposits of the northern Carlin trend should be considered pluton related" are not supported by credible evidence.
Ressel et al. (2000b) attributed the 700 km2 aeromagnetic anomaly south of the Carlin trend to an Eocene pluton, based on the association of exposed Eocene stocks with aeromagnetic anomalies and on the presence of Eocene dikes within and beyond the anomaly. The same reasoning could equally well support attribution of the anomaly to Jurassic or Cretaceous plutons. The Jurassic Contact pluton (Coats, 1987) and the Cretaceous Osgood pluton (Berger, 1985) have aeromagnetic anomalies (Hildenbrand and Kucks, 1988). On the Carlin trend, a Jurassic stock occurs at Post-Betze and related dikes extend farther north (Ressel et al., 2000a). A Cretaceous intrusion crops out in the northern part of the 700 km2 anomaly and Cretaceous dikes occur in the Carlin mine (summarized by Hofstra et al., 1999). An anomaly associated with the Cretaceous, copper-rich Mike deposit has been attributed to an underlying pluton (Teal and Branham, 1997). Thus, there is no evidence that the 700 km2 anomaly is due to an Eocene pluton rather than to a Jurassic or Cretaceous one.
"The spatial and temporal association of sedimentary rock-hosted gold deposits of the Carlin trend and elsewhere in northern Nevada with Eocene dikes and plutons argues for a genetic link between mineralization and …