ABSTRACT A magnetotelluric acquisition and modelling campaign, comprising 400 full tensor soundings, was carried out in the Sub‐Andean Foothills in the area located south of Santa Cruz de la Sierra, Bolivia. The objective of the survey was to improve the imaging of the Paleozoic section and provide insight to the overall structure of the Devonian Silurian complex. The acquired data were inverted assuming both two‐dimensional and three‐dimensional dimensionality of the subsurface structure, adopting a multi‐step iterative workflow, which began applying unconstrained inversion and introduced increasing constraints determined at each following step based on the interpretation of the latest inversion results. The geological interpretation of the final inversion results allowed to better image the expected complexity in the structures, particularly highlighting several different levels of detachment, mainly in the area of Kirusillas Formation. Furthermore, an oblique sense was identified of the main tendency of N‐S deformation, related to a dextral transgressional movement that generates discrete dislocations, at a length scale of the order of a few kilometres.

中文翻译：

---

使用大地电磁学增强亚安第斯山麓地质成像。玻利维亚南部 3D 调查的案例历史

摘要 在玻利维亚圣克鲁斯德拉谢拉以南地区的亚安第斯山麓进行了大地电磁采集和建模活动，包括 400 个完整的张量测深。调查的目的是改进古生代剖面的成像，并提供对泥盆纪志留系杂岩整体结构的洞察。假设地下结构的二维和三维维度，对获取的数据进行反演，采用多步迭代工作流程，开始应用无约束反演，并根据对最新反演的解释在随后的每一步引入增加的约束结果。最终反演结果的地质解释可以更好地成像结构的预期复杂性，特别突出了几个不同级别的分离，主要是在 Kirusillas 组区域。此外，还确定了 N-S 变形的主要趋势的倾斜感，这与产生离散位错的右旋海侵运动有关，在几公里的长度尺度上。