Despite the numerous studies on geomaterials in Tunisia, quite a few clay varieties are not yet well defined. In fact no detailed geological, mineralogical, or geochemical characterizations of Tunisian palygorskite deposits have been carried out to date. The purpose of the present work was to study the continental Eocene clay deposit at the southern end of the Tunisian North axis, between Jebel Rheouis and Jebel Boudinar, to determine its potential as a clay reserve. Nine samples were collected from the Cherahil formation representing the lower, middle, and upper levels. The analytical results obtained using several techniques (chemical analysis, X-ray diffraction, specific surface area measurements, Fourier-Transform infrared spectroscopy, scanning electron microscopy) revealed that palygorskite is the dominant clay mineral. Dolomite and quartz are present as associated minerals. Chemical analysis of sample AR9 showed a smaller potassium content compared to other samples. Sample AR9 consists essentially of dolomite associated with palygorskite and quartz. Other samples (AR5, AR6, and AR7) collected from the same Cherahil formation contained palygorskite as the main phyllosilicate mineral (80%). The important reserve of palygorskite was found in the middle of the Cherahil formation. Dolomite and quartz associated with palygorskite reduced the length and crystallinity of the fibrous clay morphology. Analysis by scanning electron microscopy proved that the crystallinity of palygorskite was less in the lower and upper parts of the Cherahil formation. The central palygorskite deposit may be of interest for pharmaceutical (adsorbent drug) and other applications. The two other levels of Cherahil formation are mineralogically heterogeneous and considered economically less important than the middle level, which is rich in palygorskite.

中文翻译：

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始新世矿床的粘土材料（Khanguet Rheouis，突尼斯）：使用地球化学和矿物学特征进行鉴定

尽管对突尼斯的地质材料进行了大量研究，但仍有相当多的粘土品种尚未明确定义。事实上，迄今为止还没有对突尼斯坡缕石矿床进行详细的地质、矿物学或地球化学表征。本工作的目的是研究突尼斯北轴南端 Jebel Rheouis 和 Jebel Boudinar 之间的大陆始新世粘土矿床，以确定其作为粘土储量的潜力。从代表低层、中层和高层的 Cherahil 地层收集了 9 个样品。使用多种技术（化学分析、X 射线衍射、比表面积测量、傅立叶变换红外光谱、扫描电子显微镜）获得的分析结果表明，坡缕石是主要的粘土矿物。白云石和石英作为伴生矿物存在。样品 AR9 的化学分析表明，与其他样品相比，钾含量更小。样品 AR9 主要由与坡缕石和石英伴生的白云石组成。从同一 Cherahil 地层收集的其他样品（AR5、AR6 和 AR7）含有坡缕石作为主要的页硅酸盐矿物（80%）。重要的坡缕石储量发现于 Cherahil 地层中部。与坡缕石相关的白云石和石英降低了纤维粘土形态的长度和结晶度。扫描电镜分析表明，Cherahil 组下部和上部的坡缕石结晶度较低。中央坡缕石矿床可能对制药（吸附药物）和其他应用感兴趣。