The Lajas Formation of the Neuquén Basin (Argentina) was deposited mainly during the Middle Jurassic but with a highly diachronic pattern. The exact time elapsed in the deposition of this unit remains controversial and depends on the location within the basin. Particularly in the Portada Covunco locality, north of the Huincul High, the debate on the age of the Lajas Formation persists. The age of the unit has been assigned by sequence stratigraphy, palynological, and magnetostratigraphic studies. Moreover, previous studies suggest that the Lajas Formation in this locality is composed of two depositional sequences (Sq1 and Sq2) with a change in the composition of the sandstone, indicating different areas of sedimentary supply. The new U–Pb data (LA-ICP-MS) in the detrital zircons allows us to define a maximum depositional age of approximately 163 Ma for Sq1 and 162 Ma for Sq2, suggesting a Callovian age for the Lajas Formation in the studied area. Furthermore, we propose that the provenance pattern in Sq1 was dominated by U–Pb ages of detrital zircons from the Permian–Triassic (peak at 264, 244 and 215 Ma), indicating derivation predominantly from the North Patagonian Massif magmatic units; while Sq2 shows a provenance pattern of detrital zircons associated with the uplift and exhumation of units located to the southwest margin of the basin during the end of the Middle Jurassic. Interestingly, it is not possible to rule out that the Huincul High may be related to the change in the sedimentary supply area; the probable uplift of the Huincul High has resulted in an effective physical barrier that limited sediment input from the extreme southeast during the deposition of Sq2.

内乌肯盆地（阿根廷）的拉哈斯组主要沉积在侏罗纪中期，但具有高度的历时性。该单元沉积的确切时间仍存在争议，并取决于盆地内的位置。特别是在Huincul高地以北的Portada Covunco地区，关于Lajas组时代的争论仍在继续。该单元的年龄已通过层序地层学，孢粉学和地磁学研究确定。此外，先前的研究表明，该地区的拉哈斯组由两个沉积序列（Sq1和Sq2）组成，砂岩的成分发生了变化，表明沉积物供应的区域不同。碎屑锆石中的新的U–Pb数据（LA-ICP-MS）使我们可以定义Sq1的最大沉积年龄约为163 Ma，Sq2的最大沉积年龄约为162 Ma，这表明该地区Lajas组的卡洛维纪年龄。此外，我们认为Sq1的物源模式主要是由二叠纪-三叠纪（峰值分别为264、244和215 Ma）的碎屑锆石的U–Pb年龄决定的，这表明主要来自北巴塔哥尼亚地块岩浆单元。而Sq2则显示出碎屑锆石的物源模式，与中侏罗纪末期位于盆地西南边缘的单元的抬升和掘出有关。有趣的是，不可能排除Huincul高压可能与沉积物供应区域的变化有关；