A new view of the palaeogeography and tectonic evolution of eastern Gondwana during the late Mesozoic is emerging, driven largely by the detrital zircon record of sedimentary basins comprising the Great Australian Superbasin (GAS). The updated model suggests that a long-lived magmatic arc was present on the eastern margin of Australia, which is in stark contrast to some previous views that eastern Australia was situated well-inland of a plate boundary. However, the active magmatic arc model is derived from Late Jurassic-Cretaceous strata, with tectonic processes and sediment pathways operating in the Early Jurassic still poorly understood. The Lower Jurassic Precipice Sandstone in the Surat Basin – an important stratigraphic component of the GAS – affords an opportunity to fill such a knowledge gap. The Precipice Sandstone is also economically important due to its aquifer capacity and prospectivity for CO₂ sequestration. Previous work has hypothesized that the formation contains deposits sourced from multiple terranes, yet this has not been rigorously tested. In this study, we used detrital zircon geochronology, CA-TIMS dating, petrography, and palaeocurrent analysis to characterise the sedimentary provenance of the Precipice Sandstone and the overlying Evergreen Formation. Our analysis revealed mixed provenance with multiple source terranes within the Tasmanides. The bulk of sediment was derived from the Thomson Orogen, with a lesser contribution from the New England Orogen. We found no evidence for sediment derived from the Lachlan Orogen, despite a distinct northward palaeocurrent component. Syn-depositional volcanic material within the interval corroborates the notion of continued arc magmatism along the eastern Gondwana margin, which contributed sediment to the GAS throughout the Early Jurassic. Radiometric ages place the Precipice-Evergreen succession in the Sinemurian-Toarcian which falls within the broader Hettangian-Aalenian age range suggested by recent palynostratigraphic data and suggest diachronous deposition across the basin. Despite pronounced variations in formation thickness, the Precipice Sandstone shows relatively uniform provenance across the basin, showing little evidence for multiple depocenters.

中生代晚期冈瓦纳东部古地理和构造演化的新观点正在出现，这主要是由包括大澳大利亚超级盆地 (GAS) 在内的沉积盆地的碎屑锆石记录驱动的。更新后的模型表明，澳大利亚东部边缘存在一个长期存在的岩浆弧，这与之前的一些观点形成鲜明对比，即澳大利亚东部位于板块边界的内陆。然而，活跃的岩浆弧模型源自晚侏罗世-白垩纪地层，对早侏罗世的构造过程和沉积物路径仍知之甚少。苏拉特盆地的下侏罗统悬崖砂岩——天然气的重要地层组成部分——提供了填补这一知识空白的机会。₂封存。以前的工作假设地层包含来自多个地体的沉积物，但这还没有经过严格的测试。在这项研究中，我们使用碎屑锆石年代学、CA-TIMS 测年、岩石学和古电流分析来表征悬崖砂岩和上覆常绿组的沉积物源。我们的分析揭示了塔斯曼尼德斯内多源地体的混合来源。大部分沉积物来自汤姆森造山带，新英格兰造山带的贡献较小。我们没有发现来自拉克兰造山带的沉积物的证据，尽管有明显的北古洋流成分。该区间内的同沉积火山物质证实了沿冈瓦纳东部边缘持续的弧形岩浆作用的概念，它在整个早侏罗世为 GAS 贡献了沉积物。辐射年龄将 Precipice-Evergreen 序列置于 Sinemurian-Toarcian 中，该序列属于最近的孢粉地层数据所建议的更广泛的 Hettangian-Aalenian 年龄范围，并表明整个盆地的穿时沉积。尽管地层厚度存在显着变化，但 Precipice 砂岩在整个盆地中显示出相对均匀的物源，几乎没有证据表明存在多个沉积中心。