Abstract The ages and durations of the stages in the Early Cretaceous commonly show discrepancies of several million years when the Geologic Time Scale (2020) from the International Commission of Stratigraphy (ICS) and recently published radio-astrochronologic data are compared. Here, we provide an astronomical time scale for the Barremian Stage and its subdivisions based on spectral analyses performed on magnetic susceptibility and calcium carbonate content series in two sections studied located in the Subbetic Domain of southeastern Spain. The sections are tied to Tethyan ammonite and calcareous nannofossil zones, allowing detailed correlations with other sections in the Subbetic Domain and other basins in the Tethyan Realm. Eccentricity cycles are observed throughout the series and can be correlated with the eccentricity cycles observed in other sections in the Subbetic Domain, showing that the results are reproducible. Based on the number of 405-kyr eccentricity cycles in the study interval, and considering uncertainties linked to variations in the sedimentation rates within an eccentricity cycle, the duration of the Barremian Stage is calculated at 4.58−0.29+0.15 Myr. From the astronomical time scale proposed here, together with recently published radio-astrochronological studies, the base of the Barremian Stage is dated at 125.98 ± 0.21 Ma and the top at 121.40 ± 0.34 Ma. The age of the Barremian/Aptian boundary differs from the ICS Geologic Time Scale 2020 by 3.6 Myr, but fits with the age of the base of magnetochron M0r recently deduced from a synthesis of radiochronologic data. The episodes of environmental change of the late Hauterivian–Barremian show an average pacing of 2.2 Myr, suggesting an orbital control on the expansion of oceanic anoxic conditions in the Tethys.

中文翻译：

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Barremian 阶段（早白垩世）的综合天体年代学及其生物地层细分

摘要 将国际地层委员会 (ICS) 的地质时间尺度 (2020) 与最近发布的射电天文年代学数据进行比较时，早白垩世阶段的年龄和持续时间通常存在数百万年的差异。在这里，我们根据对位于西班牙东南部亚贝蒂克域的两个部分中的磁化率和碳酸钙含量系列进行的光谱分析，提供了巴雷米亚阶段及其细分的天文时间尺度。这些剖面与特提斯菊石和钙质纳米化石带相关联，允许与亚贝蒂域的其他剖面和特提斯王国的其他盆地进行详细的关联。在整个系列中都观察到了偏心循环，并且可以与在亚贝蒂域其他部分中观察到的偏心循环相关联，表明结果是可重复的。根据研究区间内 405 kyr 偏心率循环的数量，并考虑到与偏心率循环内沉降速率变化相关的不确定性，巴雷米亚阶段的持续时间计算为 4.58-0.29+0.15 Myr。从这里提出的天文时间尺度以及最近发表的射电天文年代学研究来看，巴雷米亚阶段的底部日期为 125.98 ± 0.21 Ma，顶部为 121.40 ± 0.34 Ma。Barremian/Aptian 边界的年龄与 ICS Geologic Time Scale 2020 相差 3.6 Myr，但与最近从放射年代学数据的合成中推断出的磁测时 M0r 基础的年龄相吻合。晚 Hauterivian-Barremian 的环境变化事件显示平均步调为 2.2 Myr，表明对特提斯海洋缺氧条件扩张的轨道控制。