Hyperextended margins are very heterogeneous along the entire length of the margin, so the definition of tectonic domains made exclusively from 2D seismic sections presents serious limitations. In this work we present an approach of the 3D crustal-scale structure of the West Iberia margin (WIM) by modelling eight lithospheric sections, using seismic, wells and gravity data. The continuous nature of gravity data allowed us to propose a new map of tectonic domains within the WIM. Maps of total horizontal (THD) and vertical gradients (dZ) of Bouguer anomaly have been calculated and compared with other criteria such as the crustal structure and thinning factor. This comparative analysis has been carried out on a section proposed as a model for the Western Iberian Margin (Tugend et al. in Tectonics, 2014; Cadenas et al. in Tectonics 37:758–785, 2018), and on four 2 + 1/2D gravimetric models transversal to the margin. The results point out a significant variation in the absolute values of Bouguer anomaly, thinning factor and crustal structure along the margin and, therefore, of the position of the different domain boundaries. Clear patterns that correlating the Bouguer anomaly signal and its derivatives to the tectonic domain are evidenced. Most significantly, the necking-zone and its transition to the hyperextended domain are characterized by high values of the THD of the Bouguer anomaly. The observed patterns in Bouguer anomaly and its derivatives provide a solid constraint for mapping the boundaries between different tectonic domains along the margin, even in those areas where limited deep seismic information could lead to uncertain interpretations. The results of this work can also inform on the general kinematics of the WIM.

超扩展边缘在边缘的整个长度上非常不均匀，因此仅由2D地震剖面构成的构造域的定义存在严重的局限性。在这项工作中，我们通过使用地震，井和重力数据对八个岩石圈剖面进行建模，提出了西伊比利亚边缘（WIM）的3D地壳尺度结构的方法。重力数据的连续性使我们能够在WIM内提出新的构造域图。已经计算了布格异常的总水平（THD）和垂直梯度（dZ）的图，并将其与其他标准（例如地壳结构和稀疏因子）进行了比较。这项比较分析是在作为伊比利亚西部边缘模型建议的部分上进行的（Tugend等，Tectonics，2014； Cadenas等，Tectonics 37：758-785，2018），在四个2 + 1 / 2D重力模型上，这些模型横向于边界。结果表明，沿边界的布格异常，变薄因子和地壳结构的绝对值的绝对值存在显着变化，因此，不同区域边界的位置也存在显着变化。证实了将布格异常信号及其衍生物与构造域相关联的清晰模式。最重要的是，颈缩区及其向超延伸域的过渡的特征在于布格异常的THD值较高。在布格异常及其导数中观察到的模式为沿边缘绘制不同构造域之间的边界提供了坚实的约束，即使在那些有限的深层地震信息可能导致不确定的解释的地区也是如此。