Abstract The Late Permian coal measures in the Bowen Basin, Australia, are extensively mineralized with calcite as cleat infilling and veins. This study utilised strontium and samarium‑neodymium isotope analyses as well as rare earth element and yttrium (REY) composition of vein calcites, from two boreholes in a faulted and intruded area within the Jellinbah Thrust Zone, to investigate the origin and timing of calcite precipitation. All samples showed low Sr isotopic ratios that overlapped the range typical of mantle materials, suggesting that fluids were derived from the mantle. The calcite veins in core from Dingonose 14, with two exceptions, exhibit very similar Sr isotopic ratios yet have large variations in REY patterns and a wide range in Sm–Nd ratios. These samples defined an isochron corresponding to an age of 174 ± 11 Ma, which may record the timing of fluid mobilization from the deeply buried part of the foreland basin during the Early and Middle Jurassic, prior to subsequent extension and uplift in the Late Cretaceous. This fluid event may be a response to the Gondwana supercontinent break-up during the Early-Middle Jurassic. Various thermal and chemical conditions resulted in the different REY patterns of calcite in Dingonose 14 core. Calcite veins in Summit 3 core showed extremely similar REY patterns and Sr isotopic ratios but different Sm–Nd isotopic compositions relative to Dingonose 14 core, with no Sm–Nd isochron able to be resolved. The structural geology of the Summit 3 locality is complex, having overturned beds and large veins of prismatic quartz present in addition to calcite, and potential for multiple periods of veining to have occurred. Hence the lack of Sm–Nd isotopic equilibrium for the Summit 3 samples is most likely due to multiple fluid events.

中文翻译：

---

澳大利亚鲍文盆地受 Sm Nd、Sr 同位素、稀土元素和钇约束的早中侏罗世流体事件的证据

摘要 澳大利亚鲍文盆地晚二叠世煤系广泛矿化，方解石充填物和脉。本研究利用来自杰林巴逆冲带断层侵入区的两个钻孔的锶和钐-钕同位素分析以及稀土元素和钇 (REY) 成分的静脉方解石，研究方解石沉淀的起源和时间. 所有样品都显示出低 Sr 同位素比率，与地幔材料的典型范围重叠，表明流体来自地幔。Dingonose 14 岩芯中的方解石脉，除了两个例外，表现出非常相似的 Sr 同位素比率，但 REY 模式变化很大，Sm-Nd 比率范围很广。这些样本定义了对应于 174 ± 11 Ma 年龄的等时线，这可能记录了早、中侏罗世前陆盆地深埋部分流体在晚白垩世伸展和抬升之前的流动时间。这一流体事件可能是对早-中侏罗世冈瓦纳超大陆分裂的反应。各种热和化学条件导致 Dingonose 14 核心中方解石的不同 REY 模式。Summit 3 核心的方解石脉显示出极其相似的 REY 模式和 Sr 同位素比率，但相对于 Dingonose 14 核心的 Sm-Nd 同位素组成不同，没有能够解析 Sm-Nd 等时线。Summit 3 地区的构造地质复杂，除了方解石外，还存在倾覆的床层和大的棱柱状石英脉，并且可能发生多次脉脉。