【摘要】 流体活动是沉积盆地内最活跃的地质营力,与盆地内油气的生成、运移和成藏关系密切,精确确定流体活动历史一直是具有挑战性和前沿性的研究方向.前期对流体活动历史的研究主要依附于流体包裹体分析,该方法很难完整恢复盆地经历的所有流体事件,更无法确定流体事件活动年代.方解石是盆地流体的直接产物,对其开展年代学研究可以准确揭示盆地流体活动历史,然而目前较为成熟的同位素稀释法方解石U-Pb等时线定年成功率较低、耗时较长.近些年研发成功的方解石激光原位U-Pb定年技术可以精确确定U含量低至10×10^-9的方解石的年代,具有空间分辨率高、测试效率高的优势.该技术已成功确定多个含油气盆地流体活动历史,显示其在盆地流体研究领域具有光明的应用前景.在详细的微观鉴定和成岩观察基础上,选取不同期次的方解石样品开展方解石激光原位U-Pb定年分析,并结合C-O同位素、微量元素研究,查明盆地流体特征及其演化历史,将是未来盆地流体研究领域的重要发展方向.更多还原

【Abstract】 Basin fluid is the most active geological agent in sedimentary basins,having a close relationship with the generation,migration and accumulation of hydrocarbon resources.Accurate determination of fluid flow history has been a challenging and frontier research topic.In general,the previous studies of basin fluids mainly rely on the analysis of fluid inclusions,which is difficult to successfully reconstruct the events of basin fluids.More seriously,this method is unable to determine the timing of fluid flow events.Authigenic calcite is the direct product of basin fluids.Thus,accurate dating of authigenic calcite provides a new approach to determine the history of fluid flow events.In the field of calcite geochronology,the most widely used dating method was the isotope dilution U-Pb dating approach.However,this approach is time-consuming,and has a low success rate.In recent years,laser ablation technology has greatly facilitated U-Pb dating of accessory minerals（including calcite）because of its high spatial resolution and rapid data acquisition.It has been confirmed that the newly-developed in-situ U-Pb dating method is able to accurately determine the age of calcite with U content less than 10×10^-9.This method has successfully reconstructed the history of fluid flow events in the sedimentary basins,suggesting that it has a good application prospect in the field of basin fluid geochronology.In the future,it can be expected that the application of in-situ U-Pb dating of calcite together with C-O isotope and rare earth element analysis will be a significant development direction in the field of basin fluid studies.It is worth noting that the determination of stage of authigenic calcite through systematic microscopic identification and diagenetic observation is the premise of application success.更多还原