This study evaluates the geothermal history of Palaeozoic sedimentary rocks from the easternmost part of the Variscan external zone in the NE Czech Republic. The objective was to investigate the geothermal history of pre-Variscan Palaeozoic carbonates in the study area, and to assess its relationship with that of the overlying Variscan flysch. In the study area, the Palaeozoic succession occurs at the surface or is overlain by Miocene sediments of the Carpathian Foredeep. Palaeozoic nappes and the main Variscan overthrust have been documented in the subsurface at the deep Potstat-1borehole. Vitrinite reflectance measurements on 38 samples from the Potstat-1 well and 19 samples from nearby surface outcrops and shallow boreholes were available. A 2D thermal model was created using PetroMod and the thermal maturity evolution was modelled by EASY%Ro. The thermal model was constructed based on interpretations of two NW-SE seismic profiles (lines 5/83 and 5/84) oriented perpendicular to the main Variscan thrusts. The results were calibrated using measured vitrinite reflectance and were adjusted with 1D models from three shallow boreholes. At the Potstat-1 borehole, modelled maximum palaeo-temperatures of the Variscan flysch (Moravice Formation) ranged from 310°C at a depth of 7.3 km (the top of the preserved succession) to 395°C at the base of the succession, resulting in thermal maturities of >4%Rr. Peak maturation occurred prior to the end of Variscan thrusting. Modelling suggests that the basal heat flow for these thrust units reached a maximum value of 63 mW/m2 at 325 Ma. In addition, the modelling suggests that the maturity of the Palaeozoic carbonates was controlled by the thickness of the overlying Variscan flysch nappes. Maximum palaeo-temperatures for the Palaeozoic carbonates ranged from 265°C at the top of the interval (at a depth of 7.1 km) to 290°C at the base, resulting in a maturity of 3.8 to >4%Rr which is within the dry gas window. The study suggests that basal heat flows in the original (pre-thrust) Early Carboniferous sedimentary basin were slightly higher than those in the post-thrust location for the Variscan flysch nappes. This should be taken into account when evaluating the petroleum system in the South Moravian oil province (SW Czech Republic) where a complete sedimentary sequence has not been preserved.

中文翻译：

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东瓦里斯坎褶皱带（捷克共和国）的二维盆地建模：推力对热成熟模式的影响

本研究评估了捷克共和国东北部 Variscan 外部区域最东端的古生代沉积岩的地热历史。目的是调查研究区前瓦里斯坎古生代碳酸盐岩的地热历史，并评估其与上覆瓦里斯坎复理石的关系。在研究区，古生代序列发生在地表或被喀尔巴阡前渊的中新世沉积物覆盖。古生代推覆层和主要的 Variscan 逆冲断层已被记录在 Potstat-1 深钻孔的地下。对来自 Potstat-1 井的 38 个样品和来自附近地表露头和浅钻孔的 19 个样品进行了镜质体反射测量。使用 PetroMod 创建 2D 热模型，并使用 EASY%Ro 对热成熟度演化进行建模。热模型是基于对垂直于主要 Variscan 推力方向的两个 NW-SE 地震剖面（线 5/83 和 5/84）的解释而构建的。使用测量的镜质体反射率校准结果，并使用来自三个浅钻孔的一维模型进行调整。在 Potstat-1 钻孔中，模拟的 Variscan 复理石（Moravice 地层）的最高古温度范围从 7.3 公里深度（保留层序的顶部）的 310°C 到层序底部的 395°C，导致 >4%Rr 的热成熟度。峰值成熟发生在 Variscan 推进结束之前。建模表明，这些推力装置的基础热流在 325 Ma 时达到最大值 63 mW/m2。此外，该模型表明，古生代碳酸盐岩的成熟度受上覆 Variscan 复理石推覆层的厚度控制。古生界碳酸盐岩的最高古温度范围为区间顶部（7.1 公里深度）的 265°C 至底部的 290°C，导致成熟度为 3.8 至 >4%Rr，在干气窗。该研究表明，原始（前冲断）早石炭世沉积盆地的基础热流略高于瓦里斯坎复理石推覆的后冲断位置的基础热流。在评估尚未保存完整沉积层序的南摩拉维亚石油省（捷克共和国西南）的石油系统时，应考虑到这一点。古生界碳酸盐岩的最高古温度范围为区间顶部（7.1 公里深度）的 265°C 至底部的 290°C，导致成熟度为 3.8 至 >4%Rr，在干气窗。该研究表明，原始（前冲断）早石炭世沉积盆地的基础热流略高于瓦里斯坎复理石推覆的后冲断位置的基础热流。在评估尚未保存完整沉积层序的南摩拉维亚石油省（捷克共和国西南）的石油系统时，应考虑到这一点。古生界碳酸盐岩的最高古温度范围为区间顶部（7.1 公里深度）的 265°C 至底部的 290°C，导致成熟度为 3.8 至 >4%Rr，在干气窗。该研究表明，原始（前冲断）早石炭世沉积盆地的基础热流略高于瓦里斯坎复理石推覆的后冲断位置的基础热流。在评估尚未保存完整沉积层序的南摩拉维亚石油省（捷克共和国西南）的石油系统时，应考虑到这一点。该研究表明，原始（前冲断）早石炭世沉积盆地的基础热流略高于瓦里斯坎复理石推覆的后冲断位置的基础热流。在评估尚未保存完整沉积层序的南摩拉维亚石油省（捷克共和国西南）的石油系统时，应考虑到这一点。该研究表明，原始（前冲断）早石炭世沉积盆地的基础热流略高于瓦里斯坎复理石推覆的后冲断位置的基础热流。在评估尚未保存完整沉积层序的南摩拉维亚石油省（捷克共和国西南）的石油系统时，应考虑到这一点。