Abstract The Oulad Dlim Massif, located west of the Archean part of the Reguibat Rise of the West African Craton, has an areal extent close to 36,000 km2. Despite its tectonic importance, as it may have been the main indenter during the late Paleozoic Laurentia-Gondwana collision that formed supercontinent Pangea, this region has remained unstudied for a long time. Based on previous research done by Spanish geologists before 1965, the pioneering work done by Rjimati and Zemmouri (2002 and personal communication) between 2000 and 2010, and new fieldwork conducted after 2010 in collaboration with Moroccan exploration geologists, we carried out a massif-wide study that includes sensitive high-resolution ion mass spectrometry (SHRIMP) zircon U Pb geochronology, modern petrography, geochemistry, and isotope geology. Here we present these results and discuss their interpretation in the context of other circum-Atlantic orogens and terranes. The Oulad Dlim Massifs is composed of an Archean terrain divided by an NNE-SSW trending Ediacaran (Pan-African) intracontinental rift marked by a voluminous bimodal mafic-felsic magmatism, and a Silurian-Devonian belt in the west. The massif is affected by an intense shear deformation that likely marks its main assembly. Deformed and undeformed Silurian-Devonian granites indicate that such deformation was active at ≈420 Ma, declined at ≈410 Ma, and ended at ≈404 Ma. The whole massif is metamorphosed. The metamorphism is especially intense in the Ediacaran Adrar Suttuf Metamafic Complex, i.e., the rift-related mafic magmatic rocks, which have a crystallization age of 603 ± 1 Ma and probable metamorphic age of 570 Ma to 550 Ma. There is also evidence of a later thermal event, likely related to the formation of the Silurian-Devonian belt, that reset the Rb Sr system of the Ediacaran leucogranites to ≈ 420 Ma and metamorphosed them in the greenschist facies. We have also found an enigmatic strip of Late Carboniferous rocks in the Silurian-Devonian belt, and evidence indicating that the latest structures and low-grade metamorphism affecting the Silurian-Devonian granites likely were of this age. Therefore, we suggest that off-shore and west of the Silurian-Devonian belt, underneath the Cenozoic cover and on the continental shelf there may be more evidence for Late Carboniferous deformation equivalent to the eastern North America Alleghanian Orogen, which, like this, would have resulted from the Laurentia-Gondwana collision during the Late Carboniferous.

中文翻译：

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Oulad Dlim 地块的太古代至晚古生代建筑，是与劳伦西亚碰撞期间冈瓦纳大陆的主要压痕

摘要 Oulad Dlim 地块位于西非克拉通 Reguibat 隆起太古代部分以西，面积接近 36,000 平方公里。尽管它在构造上很重要，因为它可能是晚古生代劳伦大陆-冈瓦纳大陆碰撞形成超大陆盘古的主要压痕，但该地区长期以来一直未被研究。根据西班牙地质学家在 1965 年之前所做的前期研究，Rjimati 和 Zemmouri（2002 年和个人交流）在 2000 年至 2010 年期间所做的开创性工作，以及 2010 年之后与摩洛哥勘探地质学家合作进行的新田野工作，我们进行了一个地块范围的包括灵敏高分辨率离子质谱 (SHRIMP) 锆石 U Pb 年代学、现代岩石学、地球化学和同位素地质学的研究。在这里，我们展示了这些结果，并在其他环大西洋造山带和地体的背景下讨论了它们的解释。Oulad Dlim 地块由太古宙地形组成，由 NNE-SSW 走向的埃迪卡拉纪（泛非）大陆裂谷分隔，以大量双峰基性-长英质岩浆作用为标志，西部是志留纪-泥盆纪带。地块受到强烈剪切变形的影响，这可能标志着其主要组件。变形和未变形的志留系-泥盆纪花岗岩表明这种变形在 ≈420 Ma 时活跃，在 ≈410 Ma 时下降，并在 ≈404 Ma 时结束。整个地块都变形了。变质作用在 Ediacaran Adrar Suttuf Metamafic Complex 中尤为强烈，即与裂谷相关的基性岩浆岩，其结晶年龄为 603±1 Ma，可能的变质年龄为 570 Ma 至 550 Ma。还有证据表明，可能与志留纪-泥盆纪带的形成有关的后来的热事件将埃迪卡拉纪白花岗岩的 Rb Sr 系统重置为 ≈ 420 Ma，并使它们在绿片岩相中变质。我们还在志留纪-泥盆纪带发现了一条神秘的晚石炭世岩石带，有证据表明影响志留纪-泥盆纪花岗岩的最新构造和低变质作用很可能属于这个时代。因此，我们认为，在志留纪-泥盆纪带的近海和西部，新生代覆盖之下和大陆架上，可能有更多的证据表明晚石炭世变形相当于北美东部阿勒格汉造山带，像这样，