New high-resolution ID-TIMS geochronology of zircon from tuff horizons reveals a regionally traceable temporal hiatus of ∼ 3–10 Ma in sedimentation along the contact between the Middle-Upper Jurassic Walloon Coal Measures (WCM) and the Upper Jurassic Springbok Sandstone (SS), Surat Basin, Australia. Undecompacted sedimentation rates of 15–65 m.Ma−1 in the WCM drop to apparent sedimentation rates of 0 to 7 m.Ma−1 near the WCM-SS transition, rising again to 15–51 m.Ma−1 during SS deposition. U-Pb geochronology identifies a hiatus – either a cessation in sedimentation or an erosional event defining a regional unconformity – not discernable from sedimentary features, highlighting the need for high-resolution geochronology in defining key bounding surfaces in sequence stratigraphy of intracratonic basins. Determining the exact position of lithological contacts and characterizing petrophysical properties of units below and above the WCM-SS transition are particularly important in quantifying connectivity between the gas-bearing units below with regional aquifers above the unconformity. As exploration for coal-seam and shale gas in intracratonic sedimentary basins expands globally, identification of major stratigraphic transitions through high-resolution geochronology will help assessing the economic potential and environmental vulnerabilities of such systems.

中文翻译：

---

用高精度锆石 CA-TIMS 地质年代学追踪克拉通盆地中的区域不整合面


来自凝灰岩层位的锆石的新高分辨率 ID-TIMS 地质年代学揭示了沿中上侏罗纪瓦隆煤层 （WCM） 和澳大利亚苏拉特盆地上侏罗纪跳羚砂岩 （SS） 之间的接触，沉积中存在 ∼ 3-10 马的区域可追溯时间中断。WCM 中未解实的沉降速率为 15-65 m.Ma−1，在 WCM-SS 过渡区附近下降到 0 至 7 m.Ma−1 的表观沉降速率，在 SS 沉积期间再次上升到 15-51 m.Ma−1。U-Pb 地质年代学确定了无法从沉积特征中辨别的中断——沉积停止或定义区域不整合的侵蚀事件——突出了在克拉通内盆地层序地层学中定义关键边界表面时需要高分辨率地质年代学。确定岩性接触的确切位置并表征 WCM-SS 过渡下方和上方单元的岩石物理特性，对于量化下方含气单元与不整合面上方区域含水层之间的连通性尤为重要。随着克拉通内沉积盆地中煤层和页岩气勘探的全球扩展，通过高分辨率地质年代学确定主要地层过渡将有助于评估此类系统的经济潜力和环境脆弱性。