Although cratons have long been recognized as an important part of continental tectonic processes, we still have much to learn about their structural features and their relation to the genesis of basins, sedimentary thickness distributions, fold and thrust belts and surface processes. Contributing to a better knowledge of the crustal state and configuration of the southernmost part of the Río de la Plata Craton, could shed light on the still controversial tectonic processes, which were responsible for the deformation of the southwestern margin of Gondwana during the Late Paleozoic. In particular, the deformation and uplift of the Sierras Australes, which are part of the Claromecó Basin (Buenos Aires, Argentina), would be closely related to the crustal structure of the southern limit of the Río de la Plata Craton. Therefore, it is of crucial importance to investigate the possible existence of crustal heterogeneities underneath the Claromecó Basin, the Sierras Australes and the Colorado Basin, which can be related to structural features and weakness zones that could have played a major role in the tectonic evolution of the study area. For this purpose, we developed a 3D lithospheric-scale density model integrating various data, such as geological information, global gravity models, well data (thicknesses and lithologies), seismic tomography data (Moho depth), and pre-existing 3D density models of the Colorado Basin. Our model includes layers of sediments, crystalline crust and lithospheric mantle and therefore predicts the thickness variation of the upper and lower crust in the study area and of the main sedimentary sequences infilling the basins. Moreover, by analysing the model results, we propose a tentative location of the southern limit of the Río de la Plata Craton and its possible tectonic relationship with transfer zones identified in the Atlantic platform southwards. Our results suggest that the southern boundary of the craton is located along the northernmost limit of the Colorado Basin, which is in contrast with the boundary proposed in previous works. Therefore, we propose that the Colorado Basin rifting process could have occurred along this weakness domain.

尽管克拉通长期以来一直被认为是大陆构造过程的重要组成部分，但我们仍然需要大量了解克拉通的结构特征及其与盆地成因，沉积厚度分布，褶皱和逆冲带以及地表过程的关系。有助于更好地了解普拉塔克拉通河最南端的地壳状态和构造，可以揭示仍存有争议的构造过程，这是冈古纳西南边缘在古生代晚期发生变形的原因。特别地，属于克拉罗梅科盆地（阿根廷布宜诺斯艾利斯）一部分的山脉澳大利亚山脉的变形和隆升，将与普拉塔克拉通河南端的地壳结构密切相关。因此，至关重要的是，研究克拉罗莫科盆地，山脉山脉和科罗拉多盆地之下地壳异质性的可能存在，这可能与可能在该研究的构造演化中起主要作用的结构特征和弱化带有关。区。为此，我们开发了一个3D岩石圈尺度密度模型，该模型整合了各种数据，例如地质信息，全球重力模型，井数据（厚度和岩性），地震层析成像数据（Moho深度）以及已存在的3D密度模型科罗拉多盆地。我们的模型包括沉积物层，晶体壳和岩石圈地幔，因此可以预测研究区域上，下壳的厚度变化以及盆地中主要沉积层的厚度变化。此外，通过分析模型结果，我们提出了拉普拉塔克拉通河南部边界的暂定位置及其与大西洋平台以南确定的过渡带的可能构造关系。我们的结果表明，克拉通的南边界位于科罗拉多盆地的最北端，这与先前的工作提出的边界相反。因此，我们建议科罗拉多盆地的裂谷过程可能已经沿着这个弱势域发生了。这与以前的工作提出的边界相反。因此，我们建议科罗拉多盆地的裂谷过程可能已经沿着这个弱势域发生了。这与以前的工作提出的边界相反。因此，我们建议科罗拉多盆地的裂谷过程可能已经沿着这个弱势域发生了。