Extensional and flexural basins can evolve through multiple stages under the same plate tectonic regime over tens of millions of years. The Cretaceous tectonic evolution of the Colombian Andes is characterized by shifts between contractional and extensional tectonics. The upper plate response to these changes is recorded in the Cretaceous sedimentary rocks along the Western, Central, and Eastern cordilleras, and their adjacent basins, including the Upper Magdalena hinterland basin. We integrated field observations, petrography, geochronology, and thermochronology in the Cretaceous sedimentary units in the southern Upper Magdalena Basin and in the adjacent crystalline basement to decipher the provenance of these units and the exhumation patterns of the source areas. These results suggest that the source areas were exhumed between the Late Jurassic to Early Cretaceous, which may have resulted from the combination of Jurassic contraction and the Early Cretaceous extension. Between ∼120 and 100 Ma, a major stage of crustal extension is recorded in the Caballos Formation. Subsequently, between ∼100 and 80 Ma, sedimentation in the Villeta Group marks the end of the extension and the onset of contraction. This contractional phase was characterized by minor rock uplift within the basin. Basin modification continued between 80 and 65 Ma, involving two successive contractional stages that changed the sedimentary patterns, leading to the burial of a previously exhumed horst block and the appearance of new source areas. These major changes in source areas and sedimentary systems are the result of deformation episodes during prolonged extensional and contractional phases. This geologic evolution highlights the stages that characterize extensional to contractional settings.

中文翻译：

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上马格达莱纳盆地的源-汇地质年代学和热年代学研究揭示了哥伦比亚安第斯山脉白垩纪的伸展和收缩阶段

在同一板块构造体制下，伸展盆地和弯曲盆地可以在数千万年的时间里经历多个阶段的演化。哥伦比亚安第斯山脉白垩纪构造演化的特点是收缩构造和伸展构造之间的转换。上部板块对这些变化的响应记录在沿西部、中部和东部山脉及其邻近盆地（包括上马格达莱纳腹地盆地）的白垩纪沉积岩中。我们综合了上马格达莱纳盆地南部白垩纪沉积单元和邻近结晶基底的现场观测、岩相学、地质年代学和热年代学，以破译这些单元的物源和源区的折返模式。这些结果表明，源区在晚侏罗世至早白垩世之间被挖掘出来，这可能是侏罗纪收缩和早白垩世伸展共同作用的结果。在大约 120 到 100 Ma 之间，卡瓦略斯地层记录了地壳伸展的主要阶段。随后，约 100 至 80 Ma 之间，Villeta 群的沉积标志着伸展运动的结束和收缩的开始。这一收缩阶段的特点是盆地内岩石轻微隆起。盆地改造在 80 Ma 至 65 Ma 之间持续进行，涉及两个连续的收缩阶段，改变了沉积模式，导致先前挖掘出的地垒块被埋藏，并出现了新的源区。源区和沉积系统的这些重大变化是长期伸展和收缩阶段变形事件的结果。这种地质演化突出了从扩张到收缩环境的特征阶段。