Iron oxide-copper–gold (IOCG) deposit genesis is often genetically linked to magmatism due to temporal association between granite and mineralization and participation of magma-derived components. In the Carajás Mineral Province, NW Brazil, a set of ca. 2.6–2.5 Ga IOCG deposits has been interpreted to be genetically linked to contemporary granite, which are located along the Cinzento Shear Zone, in the northern part of the province. Despite the apparent temporal correlation, the understanding of ca. 2.5 Ga ages as magmatic may be misleading, since ca. 2.6–2.5 Ga reset ages have been previously reported for deformed and hydrothermally altered granites crystallized at ca. 2.74 Ga. We studied the morphology, texture, and composition of 2.74–2.73 Ga, 2.68 Ga, 2.64–2.62 Ga, and 2.59–2.55 Ga zircons from variably deformed and metasomatized granites located along the Cinzento Shear Zone. Our study reveals re-equilibrated magmatic, deformed, and newly grown zircon domains with compositional changes (Ta, U, Y, and LREE enrichment relative to chondrite) that inconsistently follow textural patterns. The overprint arises from diffusion–reaction, coupled-dissolution-reprecipitation processes, and alteration of metamict zircons, likely aided by alkaline (Na–K-rich) and F-Cl-rich hydrothermal fluids that circulated regionally in the Carajás Province. Such processes account for disturbances and resetting of the U-Th-Pb isotopic system in zircon; therefore, the geochronological record in granites from our study can be associated with the first (ca. 2.72–2.68 Ga) and the second (ca. 2.6–2.5 Ga) IOCG-forming hydrothermal events rather than to igneous crystallization. In this context, we rule out a temporal link between granitic magmatism and the IOCG deposits at Carajás.

由于花岗岩和矿化之间的时间关联以及岩浆衍生成分的参与，氧化铁铜金（IOCG）矿床的成因通常与岩浆作用有关。在巴西西北部的卡拉加斯矿产省，一组约。2.6–2.5 Ga IOCG 矿床被解释为与位于该省北部辛森托剪切带沿线的当代花岗岩有遗传联系。尽管存在明显的时间相关性，但对大约的理解。2.5 Ga年龄作为岩浆可能会产生误导，因为大约。之前曾报道过约 2.6-2.5 Ga 结晶的变形和热液蚀变花岗岩的重置年龄。2.74 Ga。我们研究了位于辛森托剪切带的不同变形和交代花岗岩中的 2.74–2.73 Ga、2.68 Ga、2.64–2.62 Ga 和 2.59–2.55 Ga 锆石的形态、结构和成分。我们的研究揭示了重新平衡的岩浆、变形和新生长的锆石域，其成分变化（Ta、U、Y 和 LREE 相对于球粒陨石的富集）与结构模式不一致。叠印是由扩散反应、耦合溶解再沉淀过程以及变晶锆石蚀变产生的，可能是在卡拉加斯省局部循环的碱性（富含 Na-K）和富含 F-Cl 的热液流体的帮助下形成的。这些过程解释了锆石中 U-Th-Pb 同位素系统的扰动和重置；因此，我们研究中的花岗岩地质年代记录可能与第一次（约2.72-2.68 Ga）和第二次（约2.6-2.5 Ga）IOCG形成热液事件有关，而不是与火成岩结晶有关。在这种情况下，我们排除了卡拉加斯花岗岩岩浆作用与 IOCG 矿床之间的时间联系。