Genetic model of the Sedex-type stratiform Tizi-n-Isdid manganese deposit hosted in lower Cambrian series (High Atlas, Morocco)

IF 2.2 4区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of African Earth Sciences Pub Date : 2025-09-18 DOI:10.1016/j.jafrearsci.2025.105853

Imad Aflla , Augustin Dekoninck , Mustapha Souhassou , Marieme Jabbour , Moha Ikenne

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引用次数: 0

Abstract

The Tizi-n-Isdid manganese deposit is located between the Central Anti-Atlas and the Ounein High Atlas in Morocco. and represents a significant occurrence of stratiform manganese mineralization with low to medium Mn ore grades ranging from 8 to 32 wt% Mn. In this study, we examine the geological framework alongside the mineralogy and geochemistry of the Tizi-n-Isdid manganese mineralization to provide insights into the interplay between Mn accumulation mechanism during sedimentation, hydrothermal processes, and post-depositional transformations. The Tizi-n-Isdid mineralization is hosted by reddish-brown claystones occurring at the base of the Taroudant Group in the Tabia member, below the Tamjout dolomite. The new stratigraphic framework supports a Lower Cambrian age for the Mn mineralization, estimated at between 529 and 541 Ma. Braunite is the dominant ore-forming mineral alongside piemontite, hollandite, neltnerie, pyrolusite, jacobsite, rhodochrosite and kutnohorite. The gangue consists of claystone fragments, calcite, quartz, and minor barite. The mineralization extends over 6 km in a north-south direction, exhibiting a stratiform and lenticular shape. Three main mineralization facies are identified: massive (F1), banded (dominant) (F2), and brecciated (F3), with thicknesses ranging from a few centimeters to a maximum of 3 m. Geochemical analyses support a hydrothermal Sedex-type origin for the deposit, characterized by exhalative Mn-rich sediments. The Fe/Mn ratios and trace elements indicate that the mineralizing fluids were likely associated with syn-sedimentary hydrothermal activity, possibly linked to rift-related fault systems rather than direct volcanic influence. The deposit has undergone slight metamorphism, as evidenced by the transformation of primary braunite into secondary braunite and piémontite. This model can be applied to other stratiform Mn deposits occurring in the Ouarzazate Manganese Field.

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摩洛哥高阿特拉斯下寒武统sedex型层状Tizi-n-Isdid锰矿床成因模式

Tizi-n-Isdid锰矿位于摩洛哥中部Anti-Atlas和Ounein High Atlas之间。具有明显的层状锰矿化，低至中锰矿品位在8%至32%之间。在本研究中，我们考察了Tizi-n-Isdid锰矿化的地质格架以及矿物学和地球化学，以深入了解沉积、热液过程和沉积后转化过程中锰的富集机制之间的相互作用。Tizi-n-Isdid矿化是由位于塔比亚段Taroudant群底部Tamjout白云岩下方的红褐色粘土岩所赋存。新的地层格架支持下寒武统锰成矿年龄，估计在529 ~ 541 Ma之间。与斑铁矿、荷兰矿、软锰矿、软锰矿、黄锰矿、菱锰矿、钾锰矿并列的是白锰矿。脉石由粘土碎屑、方解石、石英和少量重晶石组成。矿化沿南北方向延伸约6公里，呈层状和透镜状。确定了3种主要成矿相：块状（F1）、带状（F2）和角砾岩（F3），厚度从几厘米到最大3米不等。地球化学分析支持该矿床的热液sedex型成因，其特征是富锰的呼出性沉积物。铁锰比和微量元素表明，矿化流体可能与同沉积热液活动有关，可能与裂谷相关的断裂系统有关，而不是直接受到火山的影响。矿床经历了轻微的变质作用，主要表现为原生砂质岩向次生砂质岩和松质岩的转变。该模型可应用于瓦尔扎扎特锰矿田其他层状锰矿床。

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来源期刊

Journal of African Earth Sciences 地学-地球科学综合

CiteScore

4.70

自引率

4.30%

发文量

240

审稿时长

12 months

期刊介绍： The Journal of African Earth Sciences sees itself as the prime geological journal for all aspects of the Earth Sciences about the African plate. Papers dealing with peripheral areas are welcome if they demonstrate a tight link with Africa. The Journal publishes high quality, peer-reviewed scientific papers. It is devoted primarily to research papers but short communications relating to new developments of broad interest, reviews and book reviews will also be considered. Papers must have international appeal and should present work of more regional than local significance and dealing with well identified and justified scientific questions. Specialised technical papers, analytical or exploration reports must be avoided. Papers on applied geology should preferably be linked to such core disciplines and must be addressed to a more general geoscientific audience.