The abundance and types of reef-bearing carbonate platforms reflect the evolution of Devonian climate, with conspicuous microbial-algal reefs in the warm Early and Late Devonian and sponge-coral reefs in the cooler Middle Devonian. A dolomitized Wenlock-Lower Devonian microbial-algal reef-bearing carbonate platform hosts epigenetic copper-cobalt-germanium (Cu-Co-Ge) sulfide mineralization at Ruby Creek-Bornite in the Brooks Range, Alaska. Here, we present rhenium-osmium (Re-Os) radiometric ages and molybdenum and sulfur (δ^98/95Mo = +2.04 to +5.48‰ and δ³⁴S = −28.5 to −1.8‰) isotope variations for individual Cu-Co-Fe sulfide phases along the paragenetic sequence carrollite-bornite-pyrite. In the context of a hot, extensional passive margin, greenhouse conditions in the Early Devonian favored restriction of platform-top seawater circulation and episodic reflux of oxidized brines during growth of the carbonaceous carbonate platform. Molybdenum and sulfur isotope data signal the stepwise reduction of hot brines carrying Cu during latent reflux and geothermal circulation for at least ca. 15 million years from the Early Devonian until Cu-Co sulfide mineralization ca. 379–378 million years ago (Ma) in the Frasnian, Late Devonian (weighted mean of Re-Os model ages of carrollite at 379 ± 15 Ma [n = 4]; Re-Os isochron age of bornite at 378 ± 15 Ma [n = 6]). On the basis of petrographic relationships between sulfides and solid bitumen, and the Mo and S isotope data for sulfides, we imply that the endowment in critical metals (e.g., Co, Ge, Re) in the Ruby Creek-Bornite deposit is linked to the activity of primary producers that removed trace metals from the warm Early Devonian seawater and concentrated Co, Ge, and Re in algal-bacterial organic matter in carbonate sediments.

含礁碳酸盐台地的丰度和类型反映了泥盆纪气候的演变，在温暖的早泥盆世和晚泥盆世有明显的微生物-藻类礁，在较冷的中泥盆世有海绵珊瑚礁。在阿拉斯加布鲁克斯山脉的红宝石溪-斑长岩中，白云石化的文洛克-下泥盆纪微生物-藻类礁石碳酸盐岩平台存在表观成因铜-钴-锗 (Cu-Co-Ge) 硫化物矿化。在这里，我们介绍了铼-锇 (Re-Os) 辐射年龄以及钼和硫（δ ^98/95 Mo = +2.04 至 +5.48‰ 和 δ ³⁴S = −28.5 至 −1.8‰) 沿共生序列卡罗石-斑铜矿-黄铁矿的单个 Cu-Co-Fe 硫化物相的同位素变化。在热的、伸展的被动边缘的背景下，早泥盆世的温室条件有利于限制平台顶部海水循环和碳质碳酸盐平台生长期间氧化盐水的间歇性回流。钼和硫同位素数据表明，在潜伏回流和地热循环过程中，携带 Cu 的热卤水至少会逐步减少约 10 年。从早泥盆世到 Cu-Co 硫化物矿化约 1500 万年。379-378 百万年前 (Ma) 在弗拉斯阶，晚泥盆世（卡罗石 Re-Os 模型年龄的加权平均值为 379 ± 15 Ma [ n = 4]；斑铜矿的 Re-Os 等时线年龄为 378 ± 15 Ma [ n= 6]). 根据硫化物和固体沥青之间的岩相关系，以及硫化物的 Mo 和 S 同位素数据，我们暗示 Ruby Creek-Bornite 矿床中关键金属（例如，Co、Ge、Re）的禀赋与初级生产者的活动从温暖的早泥盆世海水中去除了痕量金属，并在碳酸盐沉积物的藻类细菌有机物中浓缩了 Co、Ge 和 Re。