The early Paleoproterozoic was a time of unprecedented change in Earth's climate and surface environment. The key to resolving some of the controversies surrounding the timing and causes of these changes lies with supracrustal sequences, such as the 2.45–2.22 Ga Turee Creek Group in the southern Pilbara craton, northwestern Australia. The group preserves a predominantly siliciclastic sequence; however, its precise age, tectonic setting, and postdepositional history are disputed. Although it is interpreted to have been deposited in a foreland basin setting shortly after 2.45 Ga, the oldest well-recognized deformational event, marked by northward folding and thrusting, is the 2.20–2.15 Ga Ophthalmia orogeny. Evidence for a pre-Ophthalmia fabric-forming tectonic event north of the Archean Sylvania Inlier, southeast Pilbara craton, which is marked by tight to isoclinal folding, has been largely overlooked. In this area, we report in situ U-Pb geochronology of authigenic monazite and xenotime in shale with a well-developed tectonic cleavage from the ca. 2.63 Ga Jeerinah Formation. Monazite porphyroblasts, which are locally wrapped by strain fringes aligned in a tectonic cleavage, yielded weighted mean 207Pb/206Pb ages at 2370 ± 11 Ma and 2312 ± 8 Ma, whereas xenotime, which overprints a crenulation cleavage, gave a weighted mean 207Pb/206Pb age of 2291 ± 11 Ma, constraining fabric development to between 2.31 Ga and 2.29 Ga. Our results confirm the existence of a pre-Ophthalmia deformational event in the southeastern Pilbara craton, herein referred to as the Sylvania orogeny, which is part of an ~300 m.y. interval (2.45–2.15 Ga) of northward-directed compression (“Hamersley orogenic cycle”). This orogenic cycle is marked by east-west and northwest-southeast folding, cleavage development, veining, hydrothermal gold mineralization, and isotopic resetting across the southern Pilbara craton. Our results indicate that the syn–Great Oxidation Event Turee Creek Group was deposited in one or more foreland basins after 2.45 Ga. Our results provide a new tectonostratigraphic and geodynamic framework for understanding the timing and origin of geochemical records in a key succession deposited during an interval of global environmental change.

中文翻译：

---

U-Pb测年揭示了沿皮尔巴拉南部（澳大利亚）的多个古元古代造山事件（哈默斯利造山循环），跨越大气氧合的开始

古元古代早期是地球气候和地表环境发生前所未有变化的时期。解决围绕这些变化的时间和原因的一些争议的关键在于上地壳层序，例如澳大利亚西北部皮尔巴拉克拉通南部的 2.45-2.22 Ga Turee Creek Group。该组保留了一个以硅质碎屑为主的序列；然而，它的确切年龄、构造环境和沉积后历史是有争议的。尽管它被解释为在 2.45 Ga 之后不久沉积在前陆盆地环境中，但以向北折叠和逆冲为特征的最古老的公认变形事件是 2.20-2.15 Ga Ophthalmia 造山运动。皮尔巴拉克拉通东南太古代西尔瓦尼亚内陆以北发生眼炎前构造事件的证据，以紧密到等斜折叠为特征，在很大程度上被忽视了。在该地区，我们报告了页岩中自生独居石和磷钇矿的原位 U-Pb 地质年代学，从大约 200 年开始具有发育良好的构造解理。2.63 Ga Jeerinah 组。独居石斑母细胞局部包裹在构造解理中排列的应变边缘，在 2370 ± 11 Ma 和 2312 ± 8 Ma 时产生加权平均 207Pb/206Pb 年龄，而叠印锯齿状解理的磷钇矿的加权平均年龄为 207Pb/206Pb年龄为 2291 ± 11 Ma，将织物发育限制在 2.31 Ga 和 2.29 Ga 之间。我们的结果证实了皮尔巴拉克拉通东南部存在眼炎前变形事件，本文称为 Sylvania 造山运动，它是~ 300 我的间隔 (2.45–2. 15 Ga）向北压缩（“哈默斯利造山旋回”）。这个造山旋回的特点是东西向和西北-东南向的褶皱、解理发育、脉络、热液金矿化和横跨皮尔巴拉克拉通南部的同位素重置。我们的研究结果表明，同-大氧化事件 Turee Creek 群在 2.45 Ga 之后沉积在一个或多个前陆盆地中。我们的结果为理解在一个关键序列中沉积的地球化学记录的时间和起源提供了一个新的构造地层和地球动力学框架。全球环境变化的间隔。