Development of a magmatic-hydrothermal model for the genesis of platinum-group element (PGE) deposits in porphyry and epithermal settings in the Canadian Cordillera

斑岩和浅成热液矿床传统上开采的是铜-金-钼-银，可能含有重要的铂族元素(PGE；特别是Pd和Pt)。在加拿大，不列颠哥伦比亚省拥有斑岩矿床，其中含有可能被归类为未来重要PGE资源的区域(~1-6克/吨Pd；参考文献)。1)。与传统的镁铁质-超镁铁质环境中的矿床相比，含PGe斑岩和低温热液系统在经济和环境上比大多数已知的岩浆硫化物矿床更具优势，因为露天开采方法的成本较低，而且矿石和废物具有很高的酸缓冲潜力。随着作为能源消费者的加拿大工业和公众面临越来越大的压力，要求他们实现《哥本哈根协议》设定的排放目标(到2020年比2005年减少17%)，对数百万盎司PGE的供应日益迫切，这种供应将在催化剂、氢净化交换膜、燃料存储介质和各种替代能源技术(风能、太阳能、潮汐)的组件的生产中发挥至关重要的作用。然而，PGE勘探的总体成功率很低，加拿大“传统”环境中充足的长期资源基础不太可能稳定下来。在斑岩-浅成热液环境中，对PGE的来源的了解非常差，阻碍了对可能包含或可能不包含经济浓度的金属的地质宿主环境的经济有效和成功的区分。这项拟议的研究将增加我们对非典型、非传统地质环境中PGE矿床成因的科学知识，并总体上阐明造山带中活动的地球化学和岩石学过程的不确定性，这些过程负责将矿石金属从地幔转移到地壳浅层。这项研究还将为加拿大和其他地方的矿业勘探公司提供经过实地测试的地质标准，以区分PGE贫瘠和PGE富饶的弧形地体。

Porphyry and epithermal deposits, traditionally mined for Cu-Au-Mo-Ag, may host important resources of platinum-group elements (PGE; notably Pd and Pt). In Canada, the province of B.C. hosts porphyry deposits that contain zones that may potentially be classified as significant future PGE resources (~1-6 grams/ton of Pd; Ref. 1). Compared to deposits in traditional mafic-ultramafic settings, PGE-bearing porphyry and epithermal systems are economically and environmentally preferable to most known magmatic sulfide deposits because of the lower cost of mining by open pit methods, and the high acid-buffering potential of ores and wastes. With increasing pressure on Canadian industry and the public as energy consumers to meet emissions targets set in motion under the Copenhagen Accord (17% reduction from 2005 levels by 2020), there is a growing urgency for multi-million ounce supplies of PGE that will play a vital role in the production of catalysts, exchange membranes for hydrogen purification, fuel storage media and components for a variety of alternative energy technologies (wind, solar thermal, tidal). However, the overall success rate for PGE exploration is very low, and it is unlikely that an adequate long-term resource base from "traditional" settings in Canada will stabilize. In porphyry-epithermal settings, understanding of the origin of PGE is very poor and prevents cost-effective and successful discrimination between geological host environments that may or may not contain economic concentrations of the metals. The proposed study will increase our scientific knowledge of the origin of PGE deposits in atypical, non-traditional geological environments, and in general, will elucidate uncertainties about the geochemical and petrological processes active in orogenic belts that are responsible for the transfer ore metals from the mantle to the shallow crust. The research will also provide mining exploration companies in Canada and elsewhere with field-tested geological criteria to enable discrimination between PGE-barren and PGE-fertile arc terranes.