Magnetic and Radiometric Signatures of Carbonatite Complexes from the Western Reguibat Alkaline Province (West African Craton, Moroccan Sahara): Tectonic and Weathering Implications

IF 1.9 4区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

pure and applied geophysics Pub Date : 2025-03-11 DOI:10.1007/s00024-025-03693-3

Oualid El Amraoui, Mustapha Boujamaoui, Abdellah Nait Bba, Ibtissam Rezouki, Abdelmounaim Fahim, Hassane Sahbi, Mamadou Diallo, Hassan Ibouh, João Mata, Telmo M. Bento dos Santos, Nasrrddine Youbi, My Ahmed Boumehdi

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引用次数: 0

Abstract

The Western Reguibat Alkaline Province comprises rare earth elements (REE) and niobium (Nb)-bearing carbonatites complexes of different ages hosted by the peri-cratonic Ouled Dlim Massif located in the southernmost regions of the Moroccan Sahara, adjacent to the West African Craton. This alkaline province includes the Cretaceous Twihinat-Lamlaga-Lahjeyra carbonatite complexes (TC-LmC-LhC) that have intruded the Massif during the Middle Cretaceous Peri-Atlantic Alkaline Pulse. Their emplacement is argued to be controlled by tectonics, though no structural evidences were presented due to recent sediments covering them. In this study, we aim to explain their emplacement control and assess the weathering processes they underwent based on the interpretation of airborne magnetic and radiometric data. Magnetic data reveal that the TC-LmC-LhC aligns with NNE-trending magnetic lineaments, which are interpreted as dikes related to the Central Atlantic Magmatic Province. This alignment is explained by tectonic reactivation of these NNE-trending dikes by a N-trending shortening during the Lower-Middle Cretaceous, leading to opening of pull-apart structures via a strike-slip motion, creating areas of emplacement for the studied carbonatite complexes. Radiometric data indicate a widespread weathering across the entire western margin of the Ouled Dlim Massif and its associated carbonatite complexes, primarily controlled by the hydrographic network. Our findings suggest that major streams might be promising targets for REE-Nb exploration, given their potential to contain substantial amounts of placer-type REE-Nb deposits.

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西非克拉通西部Reguibat碱性省碳酸盐岩杂岩的磁辐射特征：构造和风化意义

西里盖巴碱性省由不同年龄的稀土元素（REE）和铌（Nb）碳酸盐杂岩组成，赋存于位于摩洛哥撒哈拉最南端、毗邻西非克拉通的围克拉通期奥勒德·林姆地块。该碱性省包括白垩纪Twihinat-Lamlaga-Lahjeyra碳酸盐岩杂岩（TC-LmC-LhC），这些碳酸盐岩杂岩在中白垩世大西洋沿岸碱性脉冲期间侵入地块。它们的位置被认为是由构造控制的，尽管由于最近的沉积物覆盖而没有提出结构证据。在本研究中，我们的目的是解释其就位控制和评估风化过程所经历的航空磁和辐射数据的解释。磁学资料显示，TC-LmC-LhC具有北北东向的磁线，与中大西洋岩浆省有关。这种走向可以解释为，在中白垩纪下-中白垩世，这些北北东向的岩脉因n向缩短而重新被构造激活，通过走滑运动导致拉分构造的打开，为所研究的碳酸盐岩复合体创造了侵位区域。辐射数据表明，整个西缘的奥勒德林地块及其伴生的碳酸盐岩杂岩具有广泛的风化作用，主要受水文网控制。我们的研究结果表明，主要河流可能是REE-Nb勘探的有希望的目标，因为它们可能含有大量的砂矿型REE-Nb矿床。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

pure and applied geophysics 地学-地球化学与地球物理

CiteScore

4.20

自引率

5.00%

发文量

240

审稿时长

9.8 months

期刊介绍： pure and applied geophysics (pageoph), a continuation of the journal "Geofisica pura e applicata", publishes original scientific contributions in the fields of solid Earth, atmospheric and oceanic sciences. Regular and special issues feature thought-provoking reports on active areas of current research and state-of-the-art surveys. Long running journal, founded in 1939 as Geofisica pura e applicata Publishes peer-reviewed original scientific contributions and state-of-the-art surveys in solid earth and atmospheric sciences Features thought-provoking reports on active areas of current research and is a major source for publications on tsunami research Coverage extends to research topics in oceanic sciences See Instructions for Authors on the right hand side.