The Imini mining district (Morocco) hosts the largest manganese (Mn) ore deposits of North Africa (~120.000 T in 2016). The area is world recognized for hosting several epigenetic karst-type high-grade manganese deposits in a 10-15 meters thick Cenomanian-Turonian dolostone unit. These unconventional Mn oxide deposits occur along a belt of ~25-30 km in the southern foreland of the intraplate Atlasic belt of Morocco. This is due to two laterally extensive ore bodies of nearly pure pyrolusite-rich manganese ores (72-88 wt.% MnO₂) and a third discontinuous medium-grade coronadite-rich Mn ore (40–48 wt.% MnO₂)(Dekoninck et al., 2016a, b; Gutzmer et al., 2006). Our recent works allowed precise dating and geodynamic reconstructions of the ore deposit genesis. The ore depositions occurred during (i) late Cretaceous to late Paleocene (~ 92 Ma, ~ 78–82 Ma, ~ 65–67 Ma and ~58 Ma), (ii) late Eocene (c. 36 Ma), and (iii) early Burdigalian to early Serravalian probably in two pulses at c. 19–20 Ma and c. 13 Ma (Dekoninck et al., 2021, 2023). This multistage deposition coincides with three geodynamic events linked to the uplift of the Atlas. The late Cretaceous uplift of the Atlas created the required hydraulic head to sustain (1) fluid-rock interactions between O₂-poor acidic ground waters and the Triassic series source, (2) migration of the metal-rich low-temperature hydrothermal fluid from the rock source and (3) overpressure fluid in the Imini depositional site. The vanishing of Triassic series above the Imini anticline forced these hydrothermal fluids to mix with oxygenated ground and alkaline waters resident in the karst system and precipitated the Mn oxides. The N70°-oriented Atlasic tectonic structure controls the orientation of these epigenetic karst-hosted Mn deposits. The late Eocene – Early/Middle Miocene uplifts generated additional supplies and/or in-situ remobilizations of the primary late Cretaceous medium-grade ore to form the high-grade pyrolusite-rich ore.

References

Dekoninck et al. 2023 (accepted). Mineralium Deposita. Dekoninck et al. 2016. Mineralium Deposita 51, 13-23. Dekoninck et al. 2016. in: Mineral Deposits of North Africa. Springer International Publishing, Cham, pp. 575–594. Dekoninck et al. 2021. Mineralium Deposita 59, 935–956. Gutzmer et al. 2006. Economic Geology 101, 385–405.

How to cite: Dekoninck, A., Barbarand, J., Ruffet, G., Missenard, Y., Mattielli, N., Leprêtre, R., Mouttaqi, A., Saddiqi, O., Verhaert, M., and Yans, J.: How to create the highest manganese ore grade in the world? A geodynamic story in the Atlas of Morocco., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5478, https://doi.org/10.5194/egusphere-egu23-5478, 2023.

Integrating geological and 2D basin modeling of the East Beni Suef Basin, located in north-central Egypt, allows extending burial and thermal history modeling into the deeper parts of the basin, which are not explored by drilling activities thereby evaluating the hydrocarbon potential of the actual kitchen areas. In addition, this regional approach allows us not only to study the hydrocarbon generation potential of the deeper kitchen area but also the migration and accumulation history of the basin. The East Beni Suef Basin (EBSB) is an extensional rift basin, which was initiated following the opening of the NeoTethys and Atlantic oceans and the associated tectonic motion of Africa with respect to Eurasia during the Early Cretaceous. Its stratigraphy comprises five main rock units of mixed siliciclastic-carbonates ranging from the Albian to the Eocene from base to top as follows: Kharita Formation, Bahariya Formation, Abu Roash Formation, Khoman Formation, and Apollonia Formation. The Upper Cretaceous Abu Roash Formation is divided into seven members based on the siliciclastic to non-clastic ratio and includes the main petroleum system elements of the basin, where the carbonate “F” Member is the source rock, while the siliciclastic portions of the “E” and “G” members constitute the reservoir rocks. This study aims to gain insight into the geological evolution of the EBSB and to improve our understanding of its Upper Cretaceous petroleum system, in terms of burial and thermal histories, source rock maturity, and hydrocarbon generation, migration, and accumulation. Thus, an integrated geological and basin modeling workflow was employed, making use of two basin-wide seismic sections, crossing the EBSB in SW-NE and NW-SE directions, and three boreholes with well data. The interpreted 2D seismic lines served as the basis to define the geometrical and structural framework and the development of the subsequent 2D basin modeling of the basin. Modeling results indicate that the Abu Roash “F” source rock maturity ranges from the early oil window at the basin margins to the main oil window in the center. The main phase of hydrocarbon generation occurred during the Eocene after trap formation in the Late Cretaceous. Generated hydrocarbons have migrated both laterally and vertically, most likely from the central part of the basin toward the basin margins, particularly eastward to the structural traps. The model predicts low accumulation rates for the EBSB, which are caused by the ineffective sealing capacity of the overburden rocks and normal faults. In addition to the proven kitchen for the charging of the Abu Roash “E” reservoirs, an additional kitchen to the west of the basin is suggested for the Abu Roash “G” reservoirs. The results of this work can better elucidate the present-day distribution of the Upper Cretaceous accumulations in the EBSB for further successful exploration activities.

How to cite: Tawfik, A. Y., Ondrak, R., Winterleitner, G., and Mutti, M.: Integrated Workflow for Petroleum System Analysis: Application to the East Beni Suef Basin, Egypt, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8854, https://doi.org/10.5194/egusphere-egu23-8854, 2023.

The geomorphological and tectonic processes being responsible for the control of the mountain ranges geometry is feasible to be assessed through geomorphological and morphotectonic indices. Those indices are dependent on tectonic or erosional processes and other factors influencing the development of the landforms. Tectonic geomorphology applications using satellite-based remotely sensed data, such as Digital Elevation Models (DEMs), can highlight specific geomorphic features capable to provide useful information and knowledge towards the evaluation of the regional tectonic activity in mountain ranges. This study examines the Moroccan High Atlas mountain range by using morphotectonic and geomorphometric indices such as the channel steepness index, amplitude of relief index, stream length gradient index, swath profiles, local relief and hillslope mapping to determine the distribution of the tectonic activity variations. Through those indices the evaluation of the geomorphic responses to tectonics takes place by highlighting the relationships between tectonic activity, rock resistance, stream channel slope, active or recent vertical displacements. The outcomes of the geomorphometric and morphotectonic investigation highlight the presence of considerable geomorphic variations across the main fault zones featuring the orogen’s anatomy, while tectonic activity seems to be a major factor controlling and shaping the Moroccan High Atlas mountain range landscape. The methodological framework of this study could be developed into a low-cost technique for assessing seismic hazard, offering a valuable tool towards assessing disaster risk reduction activities, whereas in conjunction with other factors the georesources exploration. 

Acknowledgements

The corresponding author acknowledges the 'EXCELSIOR': ERATOSTHENES: Excellence Research Centre for Earth Surveillance and Space-Based Monitoring of the Environment H2020 Widespread Teaming project (www.excelsior2020.eu). The 'EXCELSIOR' project has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No 857510, from the Government of the Republic of Cyprus through the Directorate General for the European Programmes, Coordination and Development and the Cyprus University of Technology.

How to cite: Argyriou, A. V., Skikra, H., Amrouch, K., and Soulaimani, A.: GIS-based morphotectonic and geomorphometric assessment for the Moroccan High Atlas mountain ranges, Morocco., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12569, https://doi.org/10.5194/egusphere-egu23-12569, 2023.

The Wilson Cycle (ca. 250-300 Ma) is driven by plate tectonics, and is expressed by the opening of oceanic basins, which are subsequently closed to form orogens. Morocco has experienced several orogenic cycles: e.g., Eburnean, Pan-African, Hercynian (Variscan) and Alpine (Atlasian). The last Wilson Cycle that shaped the geology of Morocco is the Alpine Cycle (300-0 Ma). It started by the dismantlement of the Pangea Supercontinent leading to the opening of the Atlantic Ocean and the Atlas rift system. The latter was subsequently aborted and inverted into a fold-and-thrust belt during the Cenozoic, due to the opening of the South Atlantic and the convergence between Africa and Iberia-Europe. The Atlas system of NW Africa includes two intracontinental ranges, the High and Middle Atlas extending ENE-WSW and NE-SW, respectively. It is a key piece in the Pangea breakup puzzle, as its evolution captures the kinematic of the African plate during Mesozoic to Cenozoic times. Several studies have examined the structural and stratigraphic architectures of the Atlas system during the rifting phase, by removing the Alpine inversion along palinspaticly reconstructed 2D sections. However, little was done to investigate the crustal structure and the amount of crustal stretching during the Triassic to Jurassic extension. This work aims to reconstruct the pre-alpine architecture of the Atlas system and link it directly with the evolution of the crust. Our goal is to provide insights into the amount of crustal thinning that took place during the Mesozoic rifting in the Atlas domain and constrain the strain distribution within the African plate during the dismantlement of the Pangea.

Key words: Wilson cycle; Atlas system; Pangea; Break up; Inversion; Pre-Alpine cycle.

How to cite: Ankach, M., Amrouch, K., and Gouiza, M.: Reconstructing the Pre-Alpine cycle of Moroccan Atlas system before the inversion phase, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2949, https://doi.org/10.5194/egusphere-egu23-2949, 2023.

The intracontinental High Atlas Mountains are the result of multiple tectonic events, from Late Permian-Early Mesozoic Pangea breakup to Cenozoic Africa-Eurasia convergence. Prior to the Cenozoic inversion event, the South Atlas Fault Zone (SAFZ), which surrounded the High Atlas from the south, witnessed for the growth of multiple basins during the Liassic rifting in the eastern segment of the belt. The present work aims to shed light on the development of the Beni Bassia Liassic basin through two faults components of the SAFZ, the E-W J. Amalou faulted anticline (ridge) and Garn Talou fault from the South. Preliminary investigations based on the combination of field data and satellite images reveal significant results regarding the evolution of the basin. In the Beni Bassia Basin, the Ouchbis-Pleinsbachian Formation is an alternating layer of conglomerate limestones and marls, containing olistoliths over 10 meters in length, resulting from the destruction of the underlying platform of the Idikel-Sinemurian Formation. This huge breccia developed at the foot of steep faults on the southern margin of the basin, during the acceleration of the Liassic rifting. During the Cenozoic deformation and uplift of the Eastern High Atlas, bedding directions of Jurassic formations denote progressive changes from E-W in the northwestern to approximately NW-SE to N-S in the southeastern part of the basin. Similarly, the dip direction changes from dipping towards the south to dipping southwest to westward, indicating a dextral movement due to NNW-SSE regional shortening driven by the plates convergence. Other smaller-scale structures confirm dextral transpression kinematics at several places east of the High Atlas, including easterly detachments recorded in Lower Jurassic carbonates. Further investigations are planned to quantify the stress, strain and mechanisms involved in the configuration of the Liassic basin and the subsequent Cenozoic transpression.

Keywords: Eastern High Atlas, South Atlas Fault Zone, Beni Bassia Basin, Jurassic, Inversion, Transpression.

How to cite: Es-sabbar, I., Amrouch, K., Soulaimani, A., and Skikra, H.: Cenozoic inversion of the Lower Jurassic Beni Bassia Basin in the Eastern High Atlas (Morocco): effect of the right lateral transpression along the South Atlas Fault Zone (SAFZ), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2104, https://doi.org/10.5194/egusphere-egu23-2104, 2023.