Genetic deposit model for orogenic Au-Cu-Co-(Ni-Sb-U-REE) deposits: examples from Paleoproterozoic Finland

芬兰的古元古代火山岩中有热液型、造山型金矿床和Au-Cu-Co-（Ni-Sb-U-REE）矿床。两种存款类型在空间上密切相关，产于相同的寄主岩石和相同的构造中。古元古代造山型金矿床在芬兰和其他地方是众所周知的。尽管流体和金的来源问题仍然悬而未决，但这些矿床形成的成因模式已经很成熟。造山型金矿床与Au-Cu-Co-（Ni-Sb-U-REE）矿床的共生，提出了如何解释矿床的不同金属赋型以及后者存款类型是如何形成的问题。我们希望利用构造、岩石学、地球化学和年代学方法，对芬兰芬兰中部这两种类型的选定矿床进行调查。我们将建立矿物组合，并将它们与不同的金属含量联系起来。将制定矿物形成和构造（即含金矿脉）的相对时间表。地质年代学将为矿化过程提供一个绝对的时间框架。详细的微量元素、卤素和稳定同位素地球化学将被用作存款中流体和金属来源以及沉淀机制的替代物。后者将通过岩相学观察和结构分析来辅助。在金矿床成因模式的基础上，综合上述资料，建立金-铜-钴-（镍-锑-铀-稀土）矿床成因模式。我们期望从整体上获得变质热液矿床成因的重要新信息，这些信息可用于未来的靶向矿产勘查。

Paleoproterozoic terranes in Finland host hydrothermal, orogenic gold-only deposits and Au-Cu-Co-(Ni-Sb-U-REE) deposits. Both deposit types are closely spatially associated, occur in the same host rocks and in the same structures. Paleoproterozoic orogenic gold-only deposits are well-known form Finland and elsewhere. A genetic model for the formation of these deposits is well-developed, although the question on the source of fluids and gold remains open. The co-occurrence of orogenic gold-only deposits and Au-Cu-Co-(Ni-Sb-U-REE) deposits raises the question on how the different metal endowment of the deposits can be explained and how the latter deposit types has formed. We want to investigate selected deposits of both types in central Finland using structural, petrological, geochemical and geochronological methods. We will establish mineral assemblages and relate them to the different metal content. A scheme of relative timing of mineral formation and structures, i.e. auriferous veins, will be developed. Geochronology will yield an absolute time frame for the mineralization process. Detailed trace element, halogen and stable isotope geochemistry will be used as proxies for fluid and metal source as well as precipitation mechanisms in the deposit. The latter will be aided by petrographical observation and structural analysis. All data will be integrated in order to formulate a genetic model for the Au-Cu-Co-(Ni-Sb-U-REE) deposits on the basis of the genetic model for gold-only deposits. We expect important new information on the genesis of hydrothermal ore deposits in metamorphic terranes as a whole, which can be used in future targeted mineral exploration.