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Abstract The Khanguet Aicha Barremian Biota site (KABBS) has yielded five actinopterygian taxa, four of are shortly described in this paper. The fish assemblage comprises the ichthyodectiform Cladocyclus sp., indeterminate osteoglossiform, chanoidei and stem otophysan, plus an ellimmichthyiform previously described. The fish assemblage recorded in the KABBS corresponds to a mixture of mostly freshwater taxa, the osteoglossiform, with taxa that dwell in both marine and freshwater environments (Cladocyclus and the chanoidei) and a marine fish (the stem otophysan). The association of the fish specimens with both freshwater conchostracan and marine shrimp indicates that the paleoenvironment was characterized by the influence of freshwater input. The fish assemblage contains a mixture of taxa that are found along the southern margin of the Tethys and along both margins of the incipient South Atlantic Ocean. Sedimentary facies of the Sidi Aïch Formation, which encompasses the KABBS include channel intraformational clasts, cross-bedded sandstones with mud drapes, herringbone cross-bedding; and sigmoidal cross-bedding suggesting strong tidal influences. Tidal facies together with paucity of bioturbation and mixed freshwater to marine fossils indicate that sedimentation took place mainly in restricted tidal flat ponds. The clayey varved facies, which dominates the KABBS corresponds to dark organic-rich and white organic-poor laminae interpreted as cyclic rhythmites reflecting neap-spring tidal cycles interrupted by flood events. Excellent preservation biota within KABBS and like-varved facies suggest deposition in low-energy restricted environments like mixed marine and fresh-water ponds along the tidal flats of the tidal meandering channel. Organic geochemistry analysis supported the idea of rapid burial associated with short-period sub-anoxic condition. [ABSTRACT FROM AUTHOR]

Three tetrapod track assemblages from the early-middle Mesozoic of southern Tunisia are reported. The strata exposed at the Tejra 2 clay-pit near the Medenine and Rehach site, located in the vicinity of Kirchaou, contain the first tetrapod tracks found in the Triassic of Tunisia. The Middle Jurassic (early Aalenian) dinosaur tracks are reported from the Mestaoua plain near Tataouine. In the Middle Triassic outcrop of the Tejra 2 clay-pit, tridactyl tracks of small and medium-sized dinosauromorphs, were discovered. These tracks represent the oldest evidence of dinosaur-lineage elements in the Triassic deposits of Tunisia. Similar tracks have been described from the Middle Triassic of Argentina, France and Morocco. An isolated set of the manus and pes of a quadrupedal tetrapod discovered in Late Triassic Rehach tracksite is referred to a therapsid tracemaker. The Middle Jurassic deposits of the Mestaoua plain reveal small and large tridactyl theropod dinosaur tracks (Theropoda track indet. A-C). Based on comparison with the abundant record of Triassic tetrapod ichnofossils from Europe and North America, the ichnofauna described here indicates the presence of a therapsid-dinosauromorph ichnoassociation (without typical Chirotheriidae tracks) in the Middle and Late Triassic, which sheds light on the dispersal of the Middle-Upper Triassic tetrapod ichnofaunas in this part of Gondwana. The reported Middle Jurassic ichnofauna show close similarities to dinosaur track assemblages from the Lower and Middle Jurassic of northwestern Africa, North America, Europe and also southeastern Asia. Sedimentological and lithostratigraphic data of each new tracksite have been defined on published data and new observations. Taken together, these discoveries present a tantalizing window into the evolutionary history of tetrapods from the Triassic and Jurassic of southern Tunisia. Given the limited early Mesozoic tetrapod record from the region, these discoveries are of both temporal and geographic significance. [ABSTRACT FROM AUTHOR]

The “red beds” of the Triassic succession outcropping at Tejra-Medenine (southern Tunisia, Saharan Platform) have yielded rich fossil assemblages of both freshwater and brackish-marine invertebrates and vertebrates. The new discovered fauna indicates an Anisian-Lower Ladinian age for the Tejra section. Its lowermost part is considered as equivalent of Ouled Chebbi Formation, while the medium and upper parts are considered as equivalent of the Kirchaou Formation. Both sedimentological characteristics and fossil assemblages indicate the increasing marine influences within the middle part of the section and the migration of brackish and freshwater fauna into the lacustrine/playa environment at the top. The marine fauna-rich interval of the Tejra section correlates well with the well-known Myophoria -rich carbonate stratigraphic marker confirming the Middle Triassic (Ladinian) major transgression well recorded eastward in the Tunisian Jeffara basin and in Libya. The use of this Ladinian stratigraphic event in addition to the Carnian carbonate transgressive events of the Jeffara escarpment outcrops was of great help for regional lithostratigraphic correlations between the Triassic outcropping series and those currently buried in Ghadames and Berkine basins. The age of the sandstones of “Trias Argilo-Gréseux Inférieur” (TAGI) which forms the main oil and gas reservoir in the Saharan domain is attributed to the Anisian-Carnian and considered as coeval of Ouled Chebbi and Kirchaou Formations of the Dahar escarpment. An updated synthetic stratigraphic chart is proposed for the Triassic of Saharan Platform domain on the basis of the compilation of the new obtained results and the subsurface data taken from published literature. [ABSTRACT FROM AUTHOR]

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Copyright of Revue de Micropaleontologie is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: The Holocene sedimentary record of Sabkha Boujmel (SE Tunisia) is expressed by a shallowing-upward carbonate lagoon–tidal flat cycle (2.3 m thick) unconformably overlying continental silt–sandy sediment, Late Würmian in age. The sedimentary package of this cycle starts with transgressive marginal shallow marine (intertidal to subtidal) bioclastic sands grading upwards to black mudstone, rich in organic matter (T.O.C. up to 1.3%) deposited within a lagoon protected from the sea by Upper Pleistocene lithified sand spits. The uppermost part of the cycle is represented by oobioclastic carbonate sands covered with dead biodegraded microbial mats and/or reddish sands of aeolian origin deposited in intertidal to supratidal environments. The facies arrangement, particularly the spatial distribution of the ancient and the more recent microbial mats, records the progressive infilling of the lagoon as well as the progradation of the shoreline during the last 2000 years. The organic-rich facies which provide an age varying between 4130 and 6800 yr B.P. were deposited when the Boujmel lagoon started to be progressively separated from the Mediterranean Sea. The main factors controlling the facies and the thickness variation are the local topographic sea-floor irregularities most likely controlled by the inheritance morphology resulting from an important fluviatile digging that occurred during the last glacial maximum, the relative sea-level fluctuations, the hydro-isostatic rebound and the climate. [Copyright &y& Elsevier]

The various and heterogeneous nomenclatures previously proposed for the Jurassic of both central and northern Tunisia were examined and revised. In this work we propose a new lithostratigraphic chart taking into account the progress of our knowledge on the sedimentological and palaeontological (ammonites) aspects obtained during the two late decades. This chart summarizes and restores the major sedimentary and stratigraphic events (discontinuities) recorded in the Jurassic rocks. It outlines the main phases of the palaeogeographic evolution of the Tunisian atlasic domain during the Jurassic, in relation with the main controlling factor (tectonic and eustatism), which accompanied the tethyan rifting. [Copyright &y& Elsevier]

Micropalaeontological investigations of the Bouhedma Formation in the Jebel Majoura section from the southern Central Tunisian Atlas revealed four successive ostracod associations (in total 16 species of 13 genera) of higher palaeoenvironmental, and thus far limited biostratigraphic and palaeobiogeographic utility due to poor preservation. The most notable of these is a new upper Hauterivian?–Barremian non-marine Wealden-type ostracod assemblage of high diversity from the Lower Member of the Bouhedma Formation, the first one documented from the southern Central Tunisian Atlas, which consists of 9 species: Cypridea cyrtorostralis , Cypridea aff. tenuis , Cypridea aff. insulae , Cypridea sp., Theriosynoecum cf. fittoni , Vecticypris polita , Alicenula ? leguminella , as well as Klieana sp. and Fabanella sp. The subsequent two ostracod assemblages from the Lower Member are characterized by the brackish species Rehacythereis ? sp., Fabanella sp. , Ilyocypris sp., and Schuleridea ? sp. indicating transition to lagoonal environment. The subsequent ostracod assemblage from two levels of the Middle Member of the Bouhedma Formation is exclusively composed of the euryhaline marginal marine Paracypris sp., and the marine species Antepaijenborchella praealta , Protocythere cf. bedoulensis and Metacytheropteron aff. grosdidieri , reflecting a marine incursion event. The biostratigraphic utility, particularly that based on the non-marine fauna, is limited thus far but the results are consistent with an upper Hauterivian?–Barremian age previously assigned to the Bouhedma Formation from the southern Central Tunisian Atlas, facilitating its regional stratigraphic correlation with coeval series from the northern part of this palaeogeographic domain. The discovery of Tunisian Wealden-type non-marine ostracods from the southwestern margin of the Tethys (North Africa) sheds new light on the dispersal patterns and palaeobiogeography of these ostracods, their potential utility as biostratigraphic tool, as well as on the significance of the north Gondwanan continental basins and peri-Tethyan islands of the Central Tunisian Atlas for recording Early Cretaceous non-marine microfaunas and -floras. [Display omitted] • First report of an Hauerivian?–Barremian Wealden-type ostracod fauna from the southern Central Tunisian Atlas. • First documentation and inventory of non-marine to marginal marine ostracod faunas from the Bouhedma Formation (middle Lower Member) at Jebel Majoura, southern Central Tunisian Atlas. • The non-marine fauna is highly diverse and has been retrieved from a limestone using acetolysis. • Paleoenvironmental analysis of ostracod faunas documents marine incursion within the mid-to upper part of Lower Member of the Bouhedma Formation. [ABSTRACT FROM AUTHOR]

Two non-marine to marginal-marine intervals have been identified by ostracod assemblages in the mid-Cretaceous carbonate platform of the Central Tunisian Atlas, the deposits of which belong to the Orbata Formation. The first non-marine interval has been recorded within member Unit 2b of the Orbata Formation which yielded the first lower Aptian ostracod fauna composed of Alicenula ? leguminella , Vecticypris polita , Cypridea ventriosa , Perissocytheridea altesulcata sp. nov., Harbinia ? cf. sinuata , Hourcqia aff. bateke , Ovocytheridea nuda , Bythocypris ? pythagorasi sp. nov., Paracypris lusitanicus and Paracypris chekhmai sp. nov. The assemblages indicate continental to marginal-coastal environment and lower Aptian emergence of the Orbata Platform, and are interpreted as response to an earliest Aptian 3rd-order (0.5–3 myr) sea-level fall event of major amplitude. A second lowermost Albian ostracod fauna, recorded within members Unit 5b, 6 of the Orbata Formation, is composed of Candonopsis carthaginensis sp. nov., Cypridea quadrangulata , Virgatocypris kechoulaensis , Alicenula ? leguminella , Vecticypris polita , Stenestroemia mosensis , Perissocytheridea kouminiensis sp. nov., Hourcqia aff. bateke , Dolocytheridea bosquetiana , Dolocytheridea donzei sp. nov., Ovocytheridea anterocompressa , Paracypris dubertreti , Paracypris mdaouerensis , Clithrocytheridea espichelensis , Bythocypris ? multagracilis sp. nov. and Bythocypris dorsogibba sp. nov. The assemblages indicate another interval of non-marine to marginal-marine depositional settings as direct response to a prominent eustatic latest Aptian to earliest Albian sea-level fall event that enhanced the quasi-total emersion of the Central Tunisian Atlas palaeogeographic domain. Hence, the two studied faunas herein allow us to define two stratigraphic key surfaces of regional utility giving new insights into the chronostratigrahic subdivision of the Orbata carbonate platform, especially in supporting a previously neglected early Albian age of its upper part (Unit 5b, 6 and 7) and allow the regional stratigraphic correlation of these key surfaces in the Central Tunisian Atlas (CTA) domain. Accordingly, our results not only disprove the previous consideration of an uppermost Aptian–lower Albian hiatus but also implicate the necessity to redefine and review the previous palaeogeographic and tectono-sedimentary schemes of the CTA as suggested for almost fourty years. Image 1 • Ostracod assemblages from two mid-Cretaceous 'regional discontinuities' of Central Tunisian Atlas described. • 6 new mid-Cretaceous ostracod species first time described from Gondwana. • Major eustatic sea-level fall events KAp1 and KAp7 well calibrated by ostracods, charophytes, Strontium isotope and dinosaurs. • New chronostratigraphic scheme of the Central Tunisian Carbonate platform established. [ABSTRACT FROM AUTHOR]

Recent geological mapping undertaken in the Southern-Central Atlas of Tunisia led to the discovery of Jurassic ammonite-bearing series in the Jebel Bou Hedma E–W anticline structure. These series represent the Southernmost Jurassic rocks ever documented in the outcrops of the Tunisian Atlas. These series which outcrop in a transitional zone between the Southern Tunisian Atlas and the Chott basin offer a valuable benchmark for new stratigraphic correlation with the well-known Jurassic series of the North–South Axis of Central Tunisia and also with the Jurassic subsurface successions transected by petroleum wells in the study area. The preliminary investigations allowed the identification, within the most complete section outcropping in the center of the structure, of numerous useful biochronological and sedimentological markers helping in the establishment of an updated Jurassic stratigraphic framework chart of South-Western Tunisia. Additionally, the Late Jurassic succession documents syn-sedimentary features such as slumping, erosion and reworking of sediments and ammonite faunas that can be considered as strong witnesses of an important geodynamic event around the Jurassic-Cretaceous boundary. These stratigraphic and geodynamic new data make of the Jurassic of Jebel Bou Hedma a key succession for stratigraphic correlation attempt between Atlas Tunisian series and those currently buried in the Chott basin or outcropping in the Saharan platform. Furthermore, the several rich-ammonite identified horizons within the Middle and Upper Jurassic series constitute reliable time lines that can be useful for both paleogeographic and geodynamic reconstructions of this part of the North African Tethyan margin but also in the refinement of the potential migration routes for ammonite populations from the Maghrebian Southern Tethys to Arabia. [ABSTRACT FROM AUTHOR]

Abstract: Compressional events are well recognized, in the subsurface of the Sahel foreland basin in eastern Tunisia, evolving toward the Palaeogene sedimentary cover. These events are expressed by folds, inversional structures and a set of angular unconformities. The compressional events that started in the Campanian–Maastrichtian continued through the Palaeocene and attempted their paroxysm in the Lutetian–Priabonian prior to the angular toplap unconformity of the Oligocene series. On the other hand, the Oligo-Miocene series recorded tectonic quiescence events expressed by extensional tectonics. The tectonic events recorded by the Palaeogene series are well correlated to the major events recognized in eastern Algeria, especially the Atlasic event (Lutetian–Priabonian), which must be considered as a major tectonic event largely expressed in the whole Atlasic domain of North Africa. To cite this article: S. Khomsi et al., C. R. Geoscience 338 (2006). [Copyright &y& Elsevier]

Abstract: Seismic and sequence stratigraphy analyses, petroleum-well control and surface data studies of the Majoura–El Hfay region in the Central Atlas of Tunisia had led to identify and calibrate Jurassic seismic horizons. Seismic stratigraphic sections, seismic tectonics analyses, isochron and isopach mapping of Jurassic sequences show a differentiated structuring of platform and depocentre blocks limited by deep-seated NE–SW, north–south east–west and NW–SE faults intruded by Upper Triassic salt. The early salt migration seems to have started by the platform fracturing during the Lower Liassic rifting event. These movements are fossilized by thickness variations of Jurassic horizons, aggrading and retrograding onlap and toplap structures between subsiding rim-syncline gutters and high platform flanks intruded by salt pillows and domes. The salt migration is also attested by Middle and Upper Jurassic space depocentre migrations. Around the Majoura–El Hfay study blocks bounded by master faults, Triassic salt have pierced the Cretaceous and Tertiary sedimentary cover in a salt diapir extrusion and salt wall structures. To cite this article: D. Tanfous Amri et al., C. R. Geoscience 337 (2005). [Copyright &y& Elsevier]

Twenty-two ichnogenera and thirty-one ichnospecies have been recorded in the Oligocene–Miocene Numidian Formation of northern Tunisia. Heterolithic successions of thin-bedded turbidite sandstones and interchannel mudstones contain the most diverse trace fossil assemblages. Thick- to very thick-bedded structureless sandstones and conglomerates representing the fill of channel complexes contain a low-diversity trace fossil assemblage. The ichnoassemblage in the lower part of the formation (Oligocene), which includes Paleodictyon isp., Scolicia strozzii , Spirorhaphe isp., ? Cosmorhaphe isp. and Halopoa isp., can be ascribed to the Paleodictyon ichnosubfacies of the Nereites ichnofacies. The ichnoassemblage in the upper part of the formation (Miocene: Aquitanian), including Diplocraterion cf. habichi , Scolicia vertebralis and Ophiomorpha isp., is interpreted as the shallower part of the Ophiomorpha rudis ichnosubfacies of the Nereites ichnofacies. The notable switch in ichnofauna between the Oligocene and lower Miocene reflects variation in environmental and depositional conditions. The common occurrence of trace fossils of the Ophiomorpha rudis ichnosubfacies, and Diplocraterion cf. habichi in the early Miocene, indicates an increase in energy level, greater environmental disturbance and probable shallowing. This is also confirmed by a corresponding decrease in the abundance and diversity of benthic foraminifera. The integration of ichnological, sedimentological and microfossil contents has allowed the distinction of two quite distinct geographical depositional settings within the Numidian Formation. The first domain includes the Numidian succession of the Tabarka, Cap-Negro, Cap-Serrat and Bouhertma areas, which are characterised by “distal” turbidites, showing the Paleodictyon ichnosubfacies that is compatible with a lower bathyal depth in the Oligocene and an upper slope depositional environment during the early Miocene. The second domain includes the NE part of Mogod Mountain (e.g. the Ras El Korane, Jebel Gattous–Zoukar), which exhibit more proximal characteristics compatible with a probable slope canyon interpretation. The southern margin of the Kroumirie (Balta and Zouza areas) and Sejnene area shows a distal setting compared with the Ras El Korane and Jebel Gattous–Zoukar areas. It is ascribed to a mid- to upper slope depositional environment during the Oligocene to early Miocene. [ABSTRACT FROM AUTHOR]

Abstract: In Tunisia, in the platform domain, the Aptian-Albian transition is associated with a major stratigraphic gap not precisely dated, which is related to the subaerial exposure of the Aptian Orbata platform. Locally, in central Tunisia (Jebel Kebar), this gap is substituted by the sedimentary records of the Kebar Formation. This formation provided a rich association of fossil charophytes, formed by Atopochara trivolvis trivolvis, Clavator harrisii zavialensis and Sphaerochara verticillata which allows attributing it to the late Aptian–early Albian interval (most probably early Albian). In addition, a new variety, Sphaerochara verticillata var. kebariensis, is described. The charophyte assemblage shows significant biogeographic affinities with a coeval flora found in the Iberian Peninsula. The Kebar Formation was previously regarded as exclusively nonmarine, but the presence of the assemblage of charophytes and associated ostracods described rather indicates a fluctuation between margino-littoral (lagoonal) and continental environments. [Copyright &y& Elsevier]

Abstract: The analysis of calpionellid associations from jebels Amar and Jédidi sections in North-Atlasic Tunisia provides, for the first time, a precise biozonation of the Jurassic–Cretaceous transition succession. In the light of the new data obtained and considering recently published results, the age of Upper Jurassic formations is clarified, allowing correlations with the Tunisian ‘Dorsale’ and the North–South Axis successions. Within the Maghrebides'' range, sections from the external zones correlated to the Tunisian successions are quite distinctive from their equivalent in the internal zones. Both have evolved in different palaeogeographic domains related to the early structuration of the northwestern and southwestern Tethys margins. To cite this article: M. Boughdiri et al., C. R. Geoscience 338 (2006). [Copyright &y& Elsevier]