The degree to which fluids can dissolve and sulfidate carbonate host rocks is a critical control on the size and grade of Carlin-type Au deposits. This paper investigates the geological features that control fluid flow in the Osiris Carlin-type Au deposit, Yukon, and how fluid-rock interaction and Au endowment vary between different fluid conduits. Lithogeochemical relationships between Au, Mn, Sr, δ¹⁸C, and δ¹⁸O suggest that most ~ 3-m drill core intervals experienced limited fluid-rock interaction and contained multiple flow paths. Reconstruction of flow paths and the distribution of lithogeochemical alteration suggest that the fluids readily crossed layering and that fluids did not flow pervasively along sedimentary horizons for more than a few tens of meters in most of the deposit. Faults were only locally important fluid conduits. We argue that our findings are consistent with the previously published suggestion that the fluids preferentially exploited pre-existing vein networks formed during prior folding, and suggest that the limited distribution of Au within select host units occurs because this vein network had a high bulk permeability within these units, not because the host rocks had an especially high intergranular permeability. The vein network permeability is expected to be highest where veins are closely spaced, such as fold hinges in thick, competent carbonate units. However, areas dominated by ore-stage veins have poor Au grades relative to zones where alteration is pervasive throughout the host rock, suggesting that intergranular fluid flow promotes fluid-rock interaction more effectively than fracture- or vein-controlled flow. Fluid partitioning between fractures/veins and the wall-rock is controlled as much by the permeability of the vein network as it is by the intergranular permeability of host lithologies. Consequently, local changes in the bulk permeability of a vein or fracture network may be important controls on Au endowment in Carlin-type Au deposits. The dynamic diversion of fluids between flow paths as conduits are opened and closed through mineral dissolution and precipitation can result in significant variation in time-integrated fluid flux (TIFF) between flow paths, which may also help explain the observed patterns of alteration in the deposits.

流体溶解和硫化碳酸盐岩的程度是卡林型金矿床规模和品位的关键控制因素。本文研究了控制育空地区 Osiris Carlin 型金矿床流体流动的地质特征，以及不同流体管道之间的流体-岩石相互作用和金禀赋如何变化。^{Au、Mn、Sr、δ 18} C、δ ¹⁸之间的岩石地球化学关系O 表明大多数 ~ 3 米的钻芯层段经历了有限的流体-岩石相互作用并且包含多个流动路径。流动路径的重建和岩石地球化学蚀变的分布表明，流体很容易穿过地层，并且在大部分矿床中，流体不会沿着沉积层普遍流动超过几十米。断层只是局部重要的流体管道。我们认为我们的发现与先前发表的建议一致，即流体优先利用先前折叠过程中形成的预先存在的静脉网络，并表明 Au 在选定宿主单元内的有限分布是因为该静脉网络在内部具有高体积渗透性这些单元，不是因为主岩具有特别高的晶间渗透率。预计静脉网络渗透率在静脉间隔很近的地方最高，例如厚的、有能力的碳酸盐岩单元中的褶皱铰链。然而，相对于在整个主岩中普遍存在蚀变的区域，以成矿期脉为主的区域的 Au 品位较差，这表明晶间流体流动比裂缝或脉控制的流动更有效地促进流体-岩石相互作用。裂缝/矿脉与围岩之间的流体分配受矿脉网络渗透率的控制，正如它受宿主岩性的粒间渗透率控制一样。因此，矿脉或裂缝网络的整体渗透率的局部变化可能是卡林型金矿床中金禀赋的重要控制因素。