Abstract The study area is located in the N-NE region of Brazil where Precambrian rocks of the Sao Luis Cratonic Fragment and the Gurupi belt are overlain by Phanerozoic sediments of the Parnaiba and Sao Luis basins, making the assessment of the extents of these geotectonic domains difficult. One of the main objectives of the present study was to elaborate a NNW-SSE-trending, 180-km long magnetotelluric transect, aiming to identify the geotectonic domains of the study area by means of their geoelectric characteristics. The magnetotelluric (MT) technique is a geophysical method that detects the natural variations of the terrestrial electric and magnetic fields so as to investigate the geoelectric characteristics of the subsurface. By means of a MT survey for field data acquisition, calculation of impedance tensors and 2D inversion modeling, the geophysical transect and additionally an interpretive geological model were elaborated for the study area. The combined transverse electric (TE) and transverse magnetic (TM) geophysical model revealed superficial conductive (Parnaiba and Sao Luis basins and sedimentary coverings), resistive (Sao Luis Cratonic Fragment) and very resistive (Gurupi mobile belt) portions up to depths of the order of 15 km. These results attested for correlations between the Sao Luis Craton (South American Plate) and the West African Craton (African Plate), especially regarding the Gurupi Belt (in Brazil) and the Rokelide Belt (in Liberia), which are considered to be the boundaries of a triple junction related to the supercontinent Rodinia taphrogenesis. Besides presenting an unprecedented geophysical investigation along the Sao Luis Cratonic Fragment and the Gurupi Belt, this study promotes the discussion on the correlations between the Brazilian Gurupi and the African Rokelide belts for metallogenetic purposes.

中文翻译：

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横跨圣路易斯克拉通碎片、古鲁皮带和巴纳伊巴盆地的大地电磁横断面，巴西东北部

摘要 研究区位于巴西北东北地区，圣路易斯克拉通碎片和古鲁皮带的前寒武纪岩石被 Parnaiba 和圣路易斯盆地的显生宙沉积物覆盖，对这些大地构造域的范围进行了评估。难的。本研究的主要目标之一是制定一条 NNW-SSE 趋势的 180 公里长的大地电磁断面，旨在通过地电特征识别研究区的大地构造域。大地电磁（MT）技术是一种地球物理方法，它通过探测地球电场和磁场的自然变化来研究地下的地电特征。通过用于现场数据采集、阻抗张量计算和二维反演建模的 MT 测量，为研究区详细阐述了地球物理断面和解释性地质模型。组合的横向电 (TE) 和横向磁 (TM) 地球物理模型揭示了表面导电（Parnaiba 和圣路易斯盆地和沉积覆盖层）、电阻性（圣路易斯克拉通碎片）和高电阻性（古鲁皮移动带）部分直至深部15 公里的顺序。这些结果证明了圣路易斯克拉通（南美板块）和西非克拉通（非洲板块）之间的相关性，特别是关于古鲁皮带（巴西）和罗克利德带（利比里亚），它们被认为是边界与超大陆 Rodinia 渗出形成相关的三重连接。