Molasse basin is one of the best-preserved pieces of evidence of the Alpine orogeny. Molasse and flysch sequences deposited during the convergence between the Adriatic and the European continents recorded various geological processes. However, detailed provenance analysis of the foreland basin in the Western Alps is still in need of precise data for molasse strata. This paper provides new detrital zircon U–Pb geochronology results from five sandstone samples to constrain the provenance of the Molasse Basin in the Western Alps. The main populations in zircon age spectra correspond to the four tectonothermal events defined in the Alpine domain: the late Neoproterozoic to early Cambrian magmatic event, the pre-Variscan rifting event, the Variscan orogeny, and the Permian extensional event, respectively. Two magmatic zircons (100 ± 2 Ma and 130 ± 5 Ma) and one metamorphic zircon grain (116 ± 3 Ma) yield Cretaceous age. The metamorphic one was probably originated in the Internal zone. A contribution of the Valaisan unit as part of the source terrane is possible to account for the Cretaceous magmatic zircons. Comparing our results with published detrital zircon age data using multidimensional scaling, we infer that the Austroalpine unit was an essential provenance of the Western Alps Molasse Basin during the late Oligocene and the middle Miocene. During the middle Miocene, the deposition of the Molasse Basin was strongly influenced by the exhumation of the External Massifs and the propagation of the subalpine fold-and-thrust belt. Meanwhile, the French Massif Central was also possible to provide a limited proportion of the material for the basin.

莫拉塞盆地是保存最完整的高山造山运动证据之一。在亚得里亚海和欧洲大陆之间的融合过程中沉积的莫拉西和复理层序记录了各种地质过程。然而，对西部阿尔卑斯山前陆盆地的详细物源分析仍需要糖蜜地层的精确数据。本文提供了来自五个砂岩样品的碎屑锆石U-Pb年代学新结果，以约束西阿尔卑斯山莫拉斯盆地的物源。锆石年龄谱中的主要种群分别对应于高山地区定义的四个构造热事件：新元古代晚期至寒武纪早期岩浆事件，瓦里斯坎裂谷前的裂谷事件，瓦里斯卡造山运动和二叠纪伸展事件。两个岩浆锆石（100±2 Ma和130±5 Ma）和一个变质锆石晶粒（116±3 Ma）产生白垩纪。变质之一可能起源于内部区域。瓦莱桑单元作为源地层的一部分的贡献可能解释了白垩纪岩浆锆石。将我们的结果与使用多维标度法发布的碎屑锆石年龄数据进行比较，我们推断，在渐新世晚期和中新世中期，奥山岭单元是西阿尔卑斯山莫拉斯盆地的重要物证。在中新世中期，外地块的发掘和亚高山褶皱-冲断带的传播强烈影响了莫拉塞盆地的沉积。同时，法国Massif Central也有可能为盆地提供有限比例的材料。