Pr. BENDELLA Mohamed
1)- Madani Benyoucef, Adán Pérez-García ; Bendella, Mohamed., Francisco Ortega, Romain Vullo ; Imad Bouchemla ; Bruno Ferré., (2022). The “mid”-Cretaceous (Lower Cenomanian) Continental Vertebrates of Gara Samani, Algeria. Sedimentological Framework and Palaeodiversity. Front. Earth Sci. 10:927059. doi: 10.3389/feart.2022.927059.
BELKHEDIM Salim
Experiences related to scientific research:
Papers
1-BELKHEDIM, S., MUNNECKE, A., BENAAOUME, H., MATTHIAS, L. C., NEMRA, A.,
BENHAMOU, M., (2025a) Lateral facies heterogeneity and carbonate productivity changes during the Lower Jurassic of the Traras Mountains (NW Algeria): local versus regional controls. Facies 71(1), 1-23.
DOI: https://doi.org/10.1007/s10347-024-00691-0 (DAAD funding), IF; 1.8
Abstract
Lateral facies heterogeneity and carbonate production perturbation within peri-Tethyan platforms were widespread phe nomena during the Early Jurassic. These variations were either controlled by local factors affecting small areas or by processes prevailing on a global scale. Three geological sections are investigated in Lower Jurassic outcrops in the Traras Mountains, northwest Algeria, from synrift-settings to disentangle the influence of local and global factors. The detailed sedimentological study reveals 11 facies types, grouped into four facies associations ranging from alluvial fan to outer ramp setting. Whereas thickness variation and lateral facies distribution are mainly controlled on a regional scale by synsedimentary tectonics, resulting from the spreading of the Tethys, the irregular topography inherited from the palaeo alluvial fan topography of the underlying Beni Menir Formation seems to be the main control on a local scale. This irregular topography which coexisted in very close proximity to the studied carbonate deposits provided a significant amount of siliciclastic input, partially disturbing carbonate production. The local erosion of this detrital material during the initial early Pliensbachian transgression, combined with other local factors such as a low rate of accommodation space renewal and high-energy conditions, resulted in the absence of the otherwise prevalent Lithiotis fauna in the studied sector. Siliciclastic input perturbating carbonate production during the late Pliensbachian to early Toarcian could instead have been induced by a global warming event that increased continental weathering at the global scale during the Pl/To bound ary or T-OAE associated with storm intensification. Alternatively, in view of the lack of solid biostratigraphic attribution, high terrigenous input could also have been induced from a cooling event leading to a sea-level fall during the latest Pliensbachian (Emaciatum Zone) and/or the lowermost Toarcian (latest Tenuicostatum Zone). In addition to tectonics, this eustatic sea-level fall could also explain the absence of shallow carbonate production in the Traras Mountains during these periods. In the future, a multidisciplinary basin-scale approach may resolve these uncertainties related to the lack of biostratigraphic dating, thus helping to identify the key factor influencing the perturbation of carbonate production
Keys words; Jurassic Algeria · Traras Mountains · Facies analysis · Synsedimentary tectonics
Climate change · Eustatic sea-level change
ISSN: 0172-9179
EISSN: 1612-4820
2- SADJI, R., MUNNECKE, A., SANTANTONIO M., RAMDANE N., NEMRA A., BELKHEDIM, S (2025) Growth and demise episodes of a Middle-Late Jurassic carbonate platform (Ouarsenis Mountains, northwestern Algeria). International Journal of Earth Sciences. DOI: https://doi.org/10.1007/s00531-025-02531-0. IF, 1.8
Abstract The Middle-Late Jurassic carbonate succession from the Ouarsenis Mountains (NW Algeria) is characterized by shallow water to pelagic deposits. During this time span the carbonate platform underwent successive periods of growth and demise of carbonate production within different depositional environments. These phases have been correlated to previously published carbon curves from the Ouarsenis Mountains, seawater temperatures, local tectonics and the global standard sea-level curve. The Callovian deposits indicate a lagoonal environment with oligotrophic conditions documenting a healthy carbonate plat form in the Tiaret sector, and a storm-dominated environment in the Tissemsilt sector. The transition to the middle Oxfordian is characterized by a mixture of products of the benthic and pelagic factories, representing the drowning succession phase developed under eutrophic conditions. The appearance of the Ammonitico Rosso can be ascribed to the middle Oxfordian. Increase of detrital input during the late Oxfordian hampered the carbonate production efficiency, consequently this time span represents a period of carbonate production demise, which is concomitant with a negative carbon excursion, mirrored by marl-limestone alternations. This period of carbonate production demise persisted until the Bimammatum Zone. The Kimmeridgian represents another period of carbonate growth documenting inner to mid ramp environments in the Tiaret sector, whereas micritic limestones with Saccocoma and pelagic foraminifera in the Tissemsilt sector were deposited in an open marine environment. This period is accompanied by a minor positive excursion. The lower Tithonian displays another phase of carbonate production demise, mirrored by a lithofacies change, while stable carbon isotopes show the lowest values.
Keys words;
Carbonate platform · Carbonate production demise · Shallow · Pelagic · Ammonitico Rosso · Carbon
ISSN: 1437-3254
EISSN: 1437-3262
3- BELKHEDIM, S., EBERLI, G.P., MATTHIAS, L.C., SADJI, R., NEMRA, A., BENHAMOU, M.,
MUNNECKE, A., (2024a) Microbial micritic cementation in deep time: Implications for early marine lithification and paleoenvironmental reconstruction. Sedimentary Geology 471, 106727.
DOI: https://Doi.org/10.1016/j.sedgeo.2024.106727 (DAAD funding), IF, 2.9
Abstract;
Early micritic cementation is important to reconstruct paleoenvironments of sedimentary gaps. However, due to their scarcity in ancient records, their initial mineralogy (low-magnesium calcite (LMC), high-magnesium calcite (HMC), aragonite), as well as their origin (biotic or abiotic) and paleoenvironments are still controversial. Herein, based on fluorescence microscopy (FL), cathodoluminescence microscopy (CL), and microdrilling carbon and oxygen isotope analyses, we investigate well developed micritic cements in lower Pliensbachian limestones from the Traras Mountains, northwestern Algeria. Evidence for a microbiological influence in the formation of these cements is given by their irregular morphology, the presence of clotted micropeloidal structures, as well as their bright fluorescence under FL. Together, they reflect precipitation of the micritic cements under microbial control via active and/or passive mechanisms, in the presence of organic matter. Their orange luminescence and low δ18O signals suggest their initial precipitation by sea-water as HMC before being recrystallized into LMC within the meteoric and/or burial realm. These micritic cements, including anisopachous and meniscus like cements, are thought to be precipitated within the marine phreatic zone, as they are associated mainly with isopachous fibrous cements, which is in contrast to their widespread attribution as typical and indicative fabrics of the marine vadose zone. In addition, it has been shown that crystalline cements are developed always upon the early micritic envelopes and micritic cements. These observations, which are in line with recent studies conducted on modern deposits, confirm that preservation of marine microbial cements in deep time is crucial not only for early grain stabilization, but also serving as a foundation for the subsequent crystal growth..
Keys words; Early micritic cementation Initial mineralogy Microbial control Organic matter Marine phreatic Grain stabilization Crystal growth.
ISSN: 0037-0738
EISSN: 1879-096
NEMRA, , JUGURTHA, T., KNAUST, D., BENDELLA, M., BELKHEDIM, S., OUALI
MEHADJI, A (2023) Middle Miocene trace fossils from the Tenes area (NW Algeria) and their paleoenvironmental implications. Palaeobiodiversity and paleoenvironments 104, 327–362.
DOI: https://doi.org/10.1007/s12549-023-00594-y. IF, 1.4
Abstract
The Miocene succession (Allala River Sandstones and Tenes Blue Marls Formation) that crops out in the Tenes area, situated in the northeast of the Lower Chelif Basin in NW-Algeria, contains a low-diversity assemblage of trace fossils. Fifteen (15) ichnogenera were identified: Arenicolites, Beaconites, Cylindrichnus, Diplocraterion, Macaronichnus, Ophiomorpha, Palaeophycus, Parahaentzschelinia, Planolites, Rosselia, Skolithos, Taenidium, Teichichnus, Thalassinoides and Zoophycos. Ethologically, these ichnogenera chiefly display dwelling and feeding activities. The presence of thick, deep-tier, scattered, mainly vertical dwelling burrows attributed to the Skolithos ichnofacies indicates high energy conditions, normal oxygenation and soft substrate. Moreover, elements of the Cruziana ichnofacies show more varied behavioural strategies and higher inchnodiversity with the dominance of horizontal burrows of deposit-feeders. This ichnological study supports the palaeoenvironmental interpretation based on sedimentological analysis of a wave-dominated siliciclastic platform (backshore to offshore), allowing a more precise zonation of the shoreface zone (middle/upper and lower shoreface). In addition, this study allows evaluation of variable degrees of storm influence in response to the contrasting palaeogeomorphology of the coastline.
Keys words; Ichnology, Tenes, Lower Chelif Basin, Shallow-marine, Storm influence
ISSN: 1867-1594
EISSN: 1867-1608
- SADJI, , MUNNECKE, A., BENHAMOU, M., BELKHEDIM, S., Ramdan, N (2021)
Reconstructions of Late Jurassic temperatures for the southern margin of the Tethys, based on O values of belemnites from the Ouarsenis Mountains, north-western Algeria. Palaeogeography Palaeoclimatology Palaeoecology. 566, 110224.
DOI: https://doi.org/10.1016/j.palaeo.2021.110224. IF, 2.7
Abstract;
This study presents the first record of stable carbon and oxygen isotopes of well-preserved belemnites and bulk sediment from the Upper Jurassic pelagic carbonates of the Ouarsenis Mountains (northwestern Algeria), which were deposited at the southern margin of the Tethys Ocean. Cathodoluminescence and scanning electron microscopy was used to eliminate potentially diagenetically altered specimens (brachiopods, aptychi, and some belemnites). Ultimately, 55 belemnite specimens were used to reconstruct water temperatures for the Middle Oxfordian to the Early Tithonian. Their δ¹⁸O₍carb₎ values ranged from 0.35‰ to 3.88‰, suggesting warm and mostly stable temperature conditions during the Late Jurassic. Using a δ¹⁸O₍sea₎ value of 0‰ for the tropical palaeolatitude of 15–20°N, the δ¹⁸O₍carb₎ values of the well-preserved belemnite rostra translate into average temperatures of 27.8 °C in the Middle Oxfordian (Gregoryceras transversarium Zone), 27.0 to 27.5 °C in the Late Oxfordian (Epipeltoceras bimammatum and Idoceras planula zones, respectively), 26.2 °C in the Early Kimmeridgian, and 27.3 °C in the Early Tithonian (Hybonoticeras hybonotum Zone).
ISSN: 0031-0182 EISSN: 1872-616X
- BELKHEDIM, , JAROCHOWSKA, E., BENHAMOU, M., NEMRA, A., RADOUANE, S.,
MUNNECKE, A (2019 a) Interplay of autogenic and allogenic processes on the formation of shallow carbonate cycles in synrift setting (Lower Pliensbachian, Traras Mountains, NW Algeria). Journal of Sedimentary Research. 89(8), 784-807.
DOI: https://doi.org/10.2110/jsr.2019.33. IF, 2.4
ABSTRACT:
Meter-scale shallowing-upward cycles are recorded in many carbonate successions around the world. It is often difficult to recognize whether they represent autocycles, formed through intrinsic controls, or allocycles, resulting from orbital forcing or tectonic movements, or both. Here, we review the criteria used in the identification of the two types of cyclicity and apply them to two newly described lower Pliensbachian outcrops in the Traras Mountains, northwestern Algeria. Throughout the investigation of six sections, the deposits are suggested to have formed in intertidal–supratidal to shallow subtidal environments on a tropical ramp in the Western Tethys. In this area, shallowing-upward small-scale peritidal and subtidal cycles have been shown to be, and are assumed to be, ordered. The carbon isotope data mirror the recorded cycles and indicate different lengths of subaerial exposures. These cycles, in a developed within synrift setting, have been interpreted as produced mainly by autocyclic processes, but interacting with allocyclic factors. Peritidal cycles are thought to be generated by progradation of intertidal and supratidal flats into lagoonal sediments, while subtidal cycles are interpreted to have been controlled by lateral migration of shoals. The impact of the minor fluctuations of eustatic sea level is weakly marked, and only long subaerial exposure can reveal the contribution of these fluctuations to the formation of the recorded cycles. Tectonic movements resulting from spreading of the Tethys are interpreted to have controlled cycle distribution and thickness at a regional scale. However, synsedimentary tectonic features are rare in the studied area; this suggests that sediment transport would control the thickness and duration of cycles instead of the rate at which accommodation was created
Key words; Lower Jurassic, shallowing upward cycles, autogenic processes, allogenic processes, peritidal cycles, subtidal cycles.
ISSN; 15271404,
EISSN; 1938-3681
- NEMRA, , OUALI MEHADJI, A., MUNNECKE, A., BELKHEDIM, S., AND BELKEBIR, L
(2019) Carbonate concretions in Miocene mudrocks in NW Algeria: types, geochemistry, and origins: Facies, 65 (2), 17.
DOI: https://doi.org/10.1007/s10347-019-0559-2. IF, 1.8
ABSTRACT:
Meter-scale shallowing-upward cycles are recorded in many carbonate successions around the world. It is often difficult to recognize whether they represent autocycles, formed through intrinsic controls, or allocycles, resulting from orbital forcing or tectonic movements, or both. Here, we review the criteria used in the identification of the two types of cyclicity and apply them to two newly described lower Pliensbachian outcrops in the Traras Mountains, northwestern Algeria. Throughout the investigation of six sections, the deposits are suggested to have formed in intertidal–supratidal to shallow subtidal environments on a tropical ramp in the Western Tethys. In this area, shallowing-upward small-scale peritidal and subtidal cycles have been shown to be, and are assumed to be, ordered. The carbon isotope data mirror the recorded cycles and indicate different lengths of subaerial exposures. These cycles, in a developed within synrift setting, have been interpreted as produced mainly by autocyclic processes, but interacting with allocyclic factors. Peritidal cycles are thought to be generated by progradation of intertidal and supratidal flats into lagoonal sediments, while subtidal cycles are interpreted to have been controlled by lateral migration of shoals. The impact of the minor fluctuations of eustatic sea level is weakly marked, and only long subaerial exposure can reveal the contribution of these fluctuations to the formation of the recorded cycles. Tectonic movements resulting from spreading of the Tethys are interpreted to have controlled cycle distribution and thickness at a regional scale. However, synsedimentary tectonic features are rare in the studied area; this suggests that sediment transport would control the thickness and duration of cycles instead of the rate at which accommodation was created
Key words; Carbonates concretions, Nodular limestone, Synsedimentary instability, Methanogenesis, Tenes, Algeria, Lower Chelif Basin
ISSN: 0172-9179
EISSN: 1612-4820
- BELKHEDIM, , MUNNECKE, A., BENHAMOU, M., NEMRA, A., SADJI, R (2019b)
Challenging asymmetric cements as indicators of vadose diagenesis: ―Pseudo-gravitational cements from the lower Pliensbachian of the Traras Mountains in NW Algeria: Facies, 65(2), 12. DOI: https://doi.org/10.1007/s10347-019-0554-7. IF, 1.8
Abstract Asymmetric, pendant cements are considered good indicators for early lithification in the vadose zone. In the present study, asymmetric cements are recorded in thin-sections of a Lower Jurassic limestone from the Traras Mountains (northwest Algeria). Geopetal fabrics, however, indicate that these seemingly “pendant cements” are, in some places, oriented upwards, i.e., they have grown in the opposite direction from that expected, or they grew from grains towards the pore centers. These observations disprove their origin as gravitational cements precipitated from pendant water droplets on the undersides of grains as in the vadose zone. In contrast, a formation in the marine phreatic zone seems more probable. Under high-energy conditions, and after an early lithification stage with isopachous cements in the subtidal zone, strong tidally driven hori zontal pore-water flow allowed sufficient seawater to pass through the slightly cemented but still highly permeable rock. Those grain sides, which were oriented towards the pore center, where faster flowing water prevailed, were more exposed to CaCO3-supersaturated percolating seawater and therefore the cements precipitated here show their greatest thickness. In relatively more protected areas around the margins of the pores, asymmetric cements are rarely developed. The resulting rock exhibits an unusual, heterogeneous cementation with preferential centripetal nucleation areas.
Key words; Geopetal fabrics · Horizontal permeability · Phreatic zone · Early lithification
Centripetal nucleation
ISSN: 0172-9179
EISSN: 1612-4820
DRAOUI Abdelmalik
Les articles
The Lower Cretaceous “Continental Intercalaire” around Tidikelt (Central Sahara, Algeria): Sedimentology, palaeontology and ichnology
Abdelmalik Draoui , Mohamed Bendella , Bruno Ferr´e , Miloud Benhamou , Moussa Ben Abdelkrim , Madani Benyoucef
https://doi.org/10.1016/j.jafrearsci.2021.104396
Abstract
The Lower Cretaceous strata are exposed over a large surface in the northern part of the Ahnet basin. They consist of transgressive, horizontal formations overlying the folded Palaeozoic formations by angular unconformity across the Tidikelt region. The present study addresses the respective lithostratigraphical units of the “Continental Intercalaire” succession and their subsequent palaeo-environment in the Tidikelt area using a trace fossil analysis combined with sedimentological and palaeontologic data. The lithological and sedimentological features of the study sections recognised eleven sub-units organised within four lithological units: the Lower Clay Unit of Barremian-Neocomian age consisting of three Sub-units (Akablie Sandstone, Sidi Mahmoud Clays and Pebbly Sands); the Quartzite Sandstones Unit referred to a Late Barremian-Early Aptian age; the Middle Clay- Sandstone Unit consisting of a thick deposit of Early Aptian-Albian age, divided into five Sub-units (Tit Sandstones, In Salah Sand-Clay, In Salah Sandstone, Foum El Bouib Sandstone, and Sandstone-Clay); and the Upper Clay Unit comprising the Oued Taleh Sand and the El-Golea Clays Sub-units. Vertebrate remains all evidence a Late Albian-Early Cenomanian age for the top part of the Continental Intercalary. Ichnologic data analysis documents lower diversity of the invertebrate trace fossils: only ten ichnotaxa are recorded so far and grouped in five ichnoassemblages. Fuvial-lacustrine ichnoassemblage represents a continental ichnofacies of a fluvial-lacustrine environment: Mermia, Scoyenia and Skolithos ichnofacies. Fluvial Ichnoassemblage of the Quartzite Sandstone Unit is represented by insect trace fossils typical of the Coprinisphaera ichnofacies. Fluvio-marginal ichnoassemblage corresponds to a tidal-influenced, fluvial deposit transgressive on Unit B, represented by Skolithos and Psilonichnus ichnofacies. Lower shoreface ichnoassemblage shows the upper part of Unit C, documented by horizontal trace fossils such as Thalassinoides and vertical root traces, all supporting a lower shoreface environment in a semi-arid climate interlined by well-oxygenated episode with nutrient-rich conditions and vegetation dominance. Near to shoreface ichnoassemblage coincides with the upper unit D of coastal deposits with fluvial-tidal influence at the base (Oued Taleh Sands) associated with Scoyenia and Skolithos trace fossils and lagoon deposit of the El-Golea Clays Sub-units.
Keywords: Lower cretaceous “Continental intercalaire” Tidikelt Ahnet basin Trace fossils Vertebrate
Multiple trackways from the Cenomanian Djoua series, in In Amenas region (southeastern Algeria), represent the first ichnological evidence of gregarious behavior in Cretaceous sauropods from Africa
Mansour Zaagane, Adrian P. Hunb, Mohamed Bendella, Spencer G. Lucas, Abdelmalik Draoui and Ommar Mouzti
https://doi.org/10.1080/08912963.2023.2269173
Abstract
For the first time, a complete study of sauropod trackways has been carried out in the lower part of the Djoua series in the In Amenas region (southeastern Algeria). Several locomotion tracks have been discovered in this area. In the present work, we report the discovery of sauropod tracks exposed on a bedding surface of the Lower Formation attributed to the early Cenomanian that we assign to cf. Brontopodus isp. The tracks are located in two different areas approximately 2 km apart and are oriented N00° and N330° at the first and second sites, respectively. These tracks were formed when dinosaurs crossed an emergent or lightly submerged river plain. At the second site, trackways show several tracks generated by sauropods. They are sub-parallel in orientation and provide the first ichnological evidence of gregarious behavior in Cretaceous sauropods in Africa.
Keywords: In Amenas; southeastern Algeria; Djoua series; Cenomanian; sauropod trackways; gregarious behavior
Trace fossil assemblages from the Lower Devonian (Lochkovian‑Emsian) of the Touat area (Reggane Basin, Algerian Sahara) and their palaeoenvironmental significance
Abdelmalik Draoui · Mohamed Bendella · Bruno Ferré · Mostapha Benzina · Mansour Zaagane · Khaldia Ziouit · Abdelouafi Boutadaraa · Ahmed Boutadaraa · Abderraouf Salah
https://doi.org/10.1007/s12549-024-00602-9
Abstract
Mixed siliciclastic-carbonate deposits of Lower Devonian (Lochkovian-Emsian) age are exposed in the northeastern part of the Reggane Basin (Touat region). Based on lithological, sedimentological and palaeontological data, these deposits are subdivided into four distinct lithological units: Unit A characterises the Silurian-Devonian transitional zone; Unit B consists of a thick succession of Lochkovian-Pragian age, whereas Units C and D both document Emsian deposits. The studied section exhibits low to moderate ichnodiversity consisting of 14 ichnotaxa: Arenicolites isp., Chondrites isp., Curvolithus multiplex, Lockeia siliquaria, Monomorphichnus isp., Neonereites bisserialis, Neonereites uniserialis, Ophiomorpha isp., Palaeophycus isp., Planolites isp., Psilonichnus upsilon, Skolithos linearis, S. verticalis, and Thalassinoides isp. Both Curvolithus multiplex and Psilonichnus upsilon are documented for the first time from Palaeozoic deposits of the Saharan platform. These ichnofaunas are commonly ascribed to the Skolithos and Cruziana ichnofacies. Five distinct ichnoassemblages (Ichnoassemblages A to E) were defined, reflecting palaeoenvironmental changes from the foreshore to upper offshore zones, with frequent storm influence. Ichnofabric analysis of the section studied reveals six levels with different bioturbation intensities showing different palaeoecological conditions in various environmental settings (Monospecific Planolites, Lower combined Skolithos-Arenicolites, Combined Skolithos-Thalassinoides, Monospecific Skolithos, and Upper combined Skolithos-Arenicolites and Reburrowed Chondrites ichnofabrics). The vertical evolution of these deposits displays the successive deepening and shallowing trends recorded during the Lower Devonian in this area.
Keywords Lower Devonian · Touat · Reggane Basin · Ichnoassemblage · Palaeoenvironment · Ichnofabric
Soft-sediment deformation structures of tide origin: A case study from the late Miocene Tafna Basin (NW Algeria)
Mostapha Benzinaa , Abdelmalik Draoui , Hakim Hebib , Małgorzata Pisarska-Jamroży
https://doi.org/10.1016/j.pgeola.2024.12.001
Abstract
Typical liquefaction-induced soft-sediment deformation structures were recognised in the Neogene-age tide-dominated estuarine sedimentary succession Bled El Trayfa in the Tafna basin (NW Algeria). Although NW Algeria was tectonically active during late Neogene, we suggest that another trigger mechanism that is not re-lated to earthquakes is responsible for the liquefaction phenomenon and the development of soft-sediment de-formation structures in the area. The sedimentary succession called the Bled El Trayfa exhibits tidal rhythmites, heterolithic beddings, bi-directional cross-laminae, and tidal bore couplets deposited in tidal flats within the intertidal environment. A tidal bore, defined as upstream-propagating hydraulic jumps associated with the flood tide in estuarine rivers, is proposed as the main trigger mechanism responsible for the liquefaction phenomenon and the development of soft-sediment deformation structures. This suggestion was made on a set of observed arguments: firstly, the presence of draping massive sand underlain by erosional surfaces indicating scouring by upstream-propagating bores, followed by a very rapid deposition in a tide-dominated estuarine from the inter-tidal environment and secondly, the formation of distinctive (typical) soft-sediment deformation structures, characterised by convoluted and folded structure like flow rolls along with associated dewatering structures. Alongside flow rolls as typical and dominant soft-sediment deformation structures, the succession also includes load casts, recumbent folds, water-escape structures, convolute laminations, ball-and-pillow structures, and flame structures. Even though the relationship between the tidal bore and sediment deformation structures has been proved in some current researches, the Bled El Trayfa succession was considered among the rare areas where this relationship was identified as the origin of SSDSs in ancient rock record.
Keywords: Soft-sediment deformation structures, Liquefaction, Tide, Tidal bore, Tafna Basin
Diverse Lophoctenium burrows from the Upper Devonian (Famennian V and VI) of Algeria
Olev Vinn ,Mohamed Bendella ,Mansour Zaagane , Abdelmalik Draoui , Radouane Sadji , OmmarMouzti
https://doi.org/10.1016/j.pgeola.2023.12.001
Abstract
Three ichnospecies of Lophoctenium (L. comosum, L. richteri and L. cf. haudimmineri) are reported from the Upper Devonian Argiles de Marhouma Formation (southwestern Algeria) for the first time. This formation contains a diverse assemblage of trace fossils belonging to the Nereites ichnofacies. We describe three ichnospecies of Lophoctenium that correspond to three different feeding strategies among the diverse ichnofauna of the Argiles de Marhouma Formation. The strategy of L. comosum evidences food-rich sediments as it maximises the amount of collected food per foraged distance. The strategy of L. richteri is probably most efficient for feeding in slightly less nutrient rich sediment, but gives the opportunity to discover more prolific feeding sites by moving on longer distances. The strategy with a straight central burrow and probes on both sides of the main burrow with long interspaces (L. cf. haudimmineri) was presumably used in the least food rich sediment. It seems that the Lophoctenium was widespread in the Devonian, but restricted to seas surrounding Gondwana.
Keywords: Trace fossils, Ichnofossils, Algeria, Devonian
Dissolution as the origin of soft-sediment deformation structures in the
Upper Cretaceous of the Noumerat area (Oued Mya Basin, Algerian Sahara)
Mostapha Benzina, Abdelmalik Draoui, Małgorzata Pisarska-Jamroży, Hocine Guerradi , Hakim Hebib , Safa Maache
https://doi.org/10.1016/j.pgeola.2025.101134
Abstract
This study presents the first evidence of soft-sediment deformation structures (SSDS) within Upper Cretaceous lagoonal deposits of the Noumerat area, formed as a result of dissolution processes. Sulphates, particularly anhydrite, are well known for their susceptibility to karstification, with dissolution commonly reported as the origin of collapse breccia. However, this research introduces not only as the origin of breccia but also as a trigger for a variety of SSDS. These deformation features are primarily associated with the dissolution of anhydrite in Noumerat sedimentary succession, located on the Mzab Plateau in the Northern Algerian Sahara. As the anhydrite dissolved, the overlying claystones subsided into collapse troughs, accompanied by lateral sliding, forming distorted structures such as dome-like folds, water-escape structures, and slump structures. Furthermore, the presence of faults and cracks within the anhydrite layers significantly accelerated dissolution, promoting the formation of breccia fragments within the karst system. This underscores the chemical instability and rapid dissolution of anhydrite. The presence of secondary gypsum-bearing claystones, along with evidence of unconformity, and unconformities further supports this interpretation.
Keywords: Soft-sediment deformation structures, Lagoonal deposits, Anhydrite, Dissolution, Cretaceous, Noumerat, Sahara.
Soft-sediment deformation structures of storm origin from the upper
Miocene of the Tafna Basin (NW Algeria)
Mostapha Benzina, Hakim Hebib, Małgorzata Pisarska-Jamroży, Abdelmalik Draoui,
Khaldia Ziouit
DOI: 10.1127/njgpa/1255
Abstract
A wide variety of liquefaction-induced soft-sediment deformation structures were recognised in Neogene-age shallow marine sedimentary successions in Sikkak area (NW Algeria). Although NW Algeria was tectonically active during late Neogene, we suggest the trigger mechanisms that is not related to earthquakes is responsible for the liquefaction phenomenon and the development of soft-sediment deformation structures in the area. Here, the action of storm waves has been proposed as the main trigger mechanism responsible for the liquefaction phenomenon and development of soft-sediment deformation structures such as pseudonodules, pipe, dyke, cusp, dome and water-escape structures. This trigger mechanism was proposed because soft-sediment deformation structures were exclusively reported from an interval showing tempestite deposits with hummocky cross-stratification. Moreover, the field investigation revealed the fining-upward storm deposit lithofacies referring to shallow marine environment, as there were no signs of the other triggers evidence and arguments in terms of earthquake, tsunamis, tide mechanisms, breaking wave, rapid aggradation among others, excluding their influence. The presence of some specific fauna, which require high energy such Skolithos ichnofacies and the dominance of Ammonia genus are in favour of the suggested trigger in the current study.
Keywords: Soft-sediment deformation structures; liquefaction; storm; tempestite; Tafna Basin
Some Tortonian ostracods from the Oued Bir Moka section (Tafna Basin, NW Algeria)
Abdelhakim BENKHEDDA , Francesco SCIUTO, Mostapha BENZINA , Abdelmalik DRAOUI, Hakim HEBIB
https://doi.org/10.1016/j.revmic.2025.100866
Abstract
Ostracod species, some new, others little known, belonging to the family Trachyleberididae are described, figured and commented in this paper. The specimens come from Tortonian sediments outcropping along a stratigraphic section located in the Tafna Basin (NW Algeria).
Keywords: Tafna Basin, NW Algeria, Tortonian, Ostracoda, New species
SADJI Radouane
Growth and demise episodes of a Middle-Late Jurassic carbonate platform (Ouarsenis Mountains, northwestern Algeria)
Radouane Sadji, Axel Munnecke, Massimo Santantonio, Nabil Ramdane, Abdelkerim Nemra, Salim Belkhedim
Journal: International Journal of Earth Sciences- 2025-
DOI: 10.1007/s00531-025-02531-0
Impact factor: 2.0
Abstract
The Middle-Late Jurassic carbonate succession from the Ouarsenis Mountains (NW Algeria) is characterized by shallow-water to pelagic deposits. During this time span the carbonate platform underwent successive periods of growth and demise of carbonate production within different depositional environments. These phases have been correlated to previously published carbon curves from the Ouarsenis Mountains, seawater temperatures, local tectonics and the global standard sea-level curve. The Callovian deposits indicate a lagoonal environment with oligotrophic conditions documenting a healthy carbonate platform in the Tiaret sector, and storm-dominated environment in the Tissemsilt sector. The transition to the middle Oxfordian is characterized by a mixture of products of the benthic and pelagic factories, representing the drowning succession phase developed under eutrophic conditions. The appearance of the Ammonitico Rosso can be ascribed to the middle Oxfordian. Increase of detrital input during the late Oxfordian hampered the carbonate production efficiency, consequently this time span represents a period of carbonate production demise, which is concomitant with a negative carbon excursion, mirrored by marl-limestone alternation. This period of carbonate production demise persisted until the Bimammatum Zone. The Kimmeridgian represents another period of carbonate growth representing inner to mid ramp environments in the Tiaret sector, whereas micritic limestone with Saccocoma and pelagic foraminifera in the Tissemsilt sector were deposited in an open marine environment. This period is accompanied by a minor positive excursion. The lower Tithonian displays another phase of carbonate production demise, mirrored by a lithofacies change, while stable carbon isotopes show the lowest values.
Keywords: Carbonate platform, Carbonate production demise, Shallow, Pelagic, Ammonitico Rosso, Carbon.
Late Jurassic temperatures for the southern Tethyan margin based on belemnites δ18O from the Ouarsenis Mountains, northwestern Algeria.
Sadji Radouane, Munnecke Axel, Benhamou Miloud, Alberti Matthias, Belkhedim Salim, Ramdane Nabil
Journal: Palaeogeography, Palaeoclimatology, Palaeoecology: -2021
DOI: 10.1016/j.palaeo.2021.110224
Impact Factor: 2.7
Abstract
This study presents the first record of stable carbon and oxygen isotopes of well-preserved belemnites and bulk sediment from the Upper Jurassic pelagic carbonates of the Ouarsenis Mountains (northwestern Algeria), which were deposited at the southern margin of the Tethys ocean. Cathodoluminescence and scanning electron microscopy was used to eliminate potentially diagenetically altered specimens (brachiopods, aptychi, and some belemnites). Ultimately, 55 belemnite specimens were used to reconstruct water temperatures for the Middle Oxfordian to the Early Tithonian. Their d18O values ranged from 0.35‰ to 3.88‰, suggesting warm and mostly stable temperature conditions during the Late Jurassic. Using a δ18Ocarb value of 0‰ for the tropical palaeolatitude of 15–20 N, the δ18Ocarb sea values of the well-preserved belemnite rostra translate into average temperatures of 27.8 °C in the Middle Oxfordian (Gregoryceras transversarium Zone), 27.0 to 27.5 C in the Late Oxfordian (Epipeltoceras bimmamatum and Idoceras planula zones, respectively), 26.2 °C in the Early Kimmeridgian, and 27.3 °C in the Early Tithonian (Hybonoticeras hybonotum Zone).
Key words: Stable isotopes, Bulk sediment, Tropical palaeolatitude, Palaeoclimate, Pelagic carbonates
BOUALEM Noureddine
HADJOU Fatiha
- Bendella