Banded iron formations (BIFs) archive the relationship between Earth’s lithosphere, hydrosphere, and atmosphere through time. However, constraints on the origin of Earth’s largest ore deposits, hosted by BIFs, are limited by the absence of direct geochronology. Without this temporal context, genetic models cannot be correlated with tectono-thermal and atmospheric drivers responsible for BIF upgrading through time. Utilizing in situ iron oxide U–Pb geochronology, we provide a direct timeline of events tracing development of all the giant BIF-hosted hematite deposits of the Hamersley Province (Pilbara Craton, Western Australia). Direct dating demonstrates that the major iron ore deposits in the region formed during 1.4 to 1.1 Ga. This is one billion to hundreds of millions of years later than previous age constraints based upon 1) the presence of hematite ore clasts in conglomerate beds deposited before ~1.84 Ga, and 2) phosphate mineral dating, which placed the onset of iron mineralization in the Province at ~2.2 to 2.0 Ga during the great oxidation event. Dating of the hematite clasts verified the occurrence of a ~2.2 to 2.0 Ga event, reflecting widespread, but now largely eroded iron mineralization occurring when the Pilbara and Kaapvaal cratons were proximal. No existing phosphate mineral dates overlap with obtained hematite dates and therefore cannot be related to hematite crystallization and ore formation. New geochronology conclusively links all major preserved hematite deposits to a far younger (1.4 to 1.1 Ga) formation period, correlated with the amalgamation of Australia following breakup of the Columbia supercontinent.

中文翻译：

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地球上最大矿床形成的十亿年转变


带状铁层（BIF）记录了地球岩石圈、水圈和大气层随时间变化的关系。然而，由于缺乏直接的地质年代学，对 BIF 所拥有的地球上最大矿床的起源的限制受到限制。如果没有这种时间背景，遗传模型就无法与负责 BIF 随着时间升级的构造热和大气驱动因素相关联。利用原位氧化铁 U-Pb 地质年代学，我们提供了直接的事件时间表，追踪哈默斯利省（西澳大利亚州皮尔巴拉克拉通）所有巨型 BIF 托管赤铁矿矿床的发育。直接测年表明，该地区的主要铁矿床形成于 1.4 至 1.1 Ga 期间。这比之前的年龄限制晚了 10 亿至数亿年，基于 1) 之前沉积的砾岩层中存在赤铁矿碎屑。 1.84 Ga，和 2) 磷酸盐矿物测年，在大氧化事件期间，该省铁矿化的开始时间约为 2.2 至 2.0 Ga。赤铁矿碎屑的年代测定证实了约 2.2 至 2.0 Ga 事件的发生，反映了皮尔巴拉克拉通和卡普瓦尔克拉通附近时发生的广泛但现在很大程度上被侵蚀的铁矿化。现有的磷酸盐矿物日期与获得的赤铁矿日期不重叠，因此不能与赤铁矿结晶和矿石形成相关。新的地质年代学最终将所有主要保存的赤铁矿矿床与更年轻（1.4至1.1 Ga）的形成时期联系起来，与哥伦比亚超大陆分裂后澳大利亚的合并相关。