A key event in the paleogeographic evolution of the Austral-Magallanes foreland basin was the Santonian–Maastrichtian continentalization, marked by the appearance of deltaic, fluvial and wetland sequences stacked on top of deep marine deposits. The expanding ecological niche was exploited by theropods and influenced the evolutionary history of dinosaurs. We present new detrital zircon U–Pb geochronological data across this littoral to continental depocenter, in order to provide insights of its age, geographical extension, source regions and geodynamic setting. Littoral sandstones from La Anita Formation yield Maximum Depositional Ages (MDA) between ~86–80 Ma (weighted mean ages), and ~79–78 Ma youngest zircons. Our results are in accordance with a Santonian–Campanian depositional age. The sequence continues with badlands and fluvial systems (Cerro Fortaleza and La Irene Formations), followed by meandering fluvial and lacustrine deposits (Chorrillo Formation). Transgressive marine facies topping the sequence (Calafate Formation) yield a preferred Maastrichtian 69 ± 2 Ma MDA from the youngest zircon. The provenance and tectonic analyses indicate that basin shallowing during Santonian–Campanian times was driven by advance of the orogenic front, which produced the shift from a foredeep setting to a wedge-top depozone. The unroofing of progressively deeper structural levels is registered in the basin fill, which suggests exhumation in the Basement domain during the Santonian–Maastrichtian.

Austral-Magallanes 前陆盆地古地理演化的一个关键事件是 Santonian-Maastrichtian 大陆化，其标志是堆积在深海沉积物顶部的三角洲、河流和湿地序列的出现。不断扩大的生态位被兽脚类动物利用，并影响了恐龙的进化史。我们提供了这个沿海到大陆沉积中心的新碎屑锆石 U-Pb 年代学数据，以提供对其年龄、地理延伸、源区和地球动力学环境的见解。来自 La Anita 组的沿岸砂岩产生最大沉积年龄 (MDA) 介于 ~86-80 Ma（加权平均年龄）和 ~79-78 Ma 最年轻的锆石。我们的结果与 Santonian-Campanian 沉积时代一致。该序列继续是荒地和河流系统（Cerro Fortaleza 和 La Irene Formations），然后是蜿蜒的河流和湖泊沉积物（Chorrillo Formation）。顶部序列（Calafate 组）的海侵海相从最年轻的锆石中产生了首选的 Maastrichtian 69 ± 2 Ma MDA。物源和构造分析表明，Santonian-Campanian 时期盆地变浅是由造山锋的推进驱动的，这导致了从前渊环境向楔顶沉积层的转变。在盆地填充物中记录到逐渐更深的结构层的开顶，这表明在桑托尼-马斯特里赫特时期地下室区域的挖掘。顶部序列（Calafate 组）的海侵海相从最年轻的锆石中产生了首选的 Maastrichtian 69 ± 2 Ma MDA。物源和构造分析表明，Santonian-Campanian 时期盆地变浅是由造山锋的推进驱动的，这导致了从前渊环境向楔顶沉积层的转变。在盆地填充物中记录到逐渐更深的结构层的开顶，这表明在桑托尼-马斯特里赫特时期地下室区域的挖掘。顶部序列（Calafate 组）的海侵海相从最年轻的锆石中产生了首选的 Maastrichtian 69 ± 2 Ma MDA。物源和构造分析表明，Santonian-Campanian 时期盆地变浅是由造山锋的推进驱动的，这导致了从前渊环境向楔顶沉积层的转变。在盆地填充物中记录到逐渐更深的结构层的开顶，这表明在桑托尼-马斯特里赫特时期地下室区域的挖掘。这产生了从前深环境到楔顶沉积环境的转变。在盆地填充物中记录到逐渐更深的结构层的开顶，这表明在桑托尼-马斯特里赫特时期地下室区域的挖掘。这产生了从前深环境到楔顶沉积环境的转变。在盆地填充物中记录到逐渐更深的结构层的开顶，这表明在桑托尼-马斯特里赫特时期地下室区域的挖掘。