Fouillard, France
Fouillard, France

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Breuer P.,Aramco Services Company | Al-Hajri S.,Aramco Services Company | Le Herisse A.,Institut Universitaire de France | Paris F.,Rue des Jonquilles | And 3 more authors.
Revue de Micropaleontologie | Year: 2017

A rare occurrence of a rich and diverse palynological assemblage from the Tawil Formation is described from well JLMD-EW-8 in northwestern Saudi Arabia. The composition of this assemblage strongly indicates a middle Přídolí age. The assemblage encountered contains very characteristic chitinozoans, acritarchs, tasmanitids, freshwater algae, scolecodonts, eurypterid cuticle and other organic remains. Land-derived miospores are also common and two new cryptospore species (Cymbohilates jalamidensis and Gneudnaspora sordida) are herein formally described. Most taxa of taxonomic interest and useful for regional and intercontinental correlation are illustrated. The palaeogeographic distribution of this assemblage is also discussed as organic-walled microphytoplankton, chitinozoans and miospores encountered in the studied samples correlate well with similar assemblages from various Algerian, Libyan, and Ibero-armorican localities (i.e. Ibarmaghian regions). This corresponds to what is considered as a transgressive middle Přídolí event in the Algerian Sahara, with non-marine intervals bracketing this brief marine sea-level rise. This event is likely to have extended into all of north Gondwana, including Arabia, and can be correlated to the S50 Maximum Flooding Surface from the sequence stratigraphic framework defined in the Neftex Geodynamic Earth Model. © 2017 Elsevier Masson SAS.


Hints O.,Tallinn University of Technology | Paris F.,Rue des Jonquilles | Paris F.,CNRS Geosciences Laboratory of Rennes | Al-Hajri S.,Aramco Services Company
Review of Palaeobotany and Palynology | Year: 2015

This paper reports the discovery of Late Ordovician scolecodonts from the Qusaiba-1 core hole, central Saudi Arabia. The collection of about 100 relatively well preserved diagnostic jaws represents one of the richest jawed polychaete faunas from the Gondwanan realm and the first description of scolecodonts from the Arabian Peninsula. Scolecodonts were most diverse and abundant in the Quwarah Member and basal Sarah Formation, corresponding to the Ancyrochitina merga and Tanuchitina elongata chitinozoan zones (latest Katian to early Hirnantian). The polychaete assemblage contains up to 15 apparatus-based species and is dominated by the globally distributed genera Kettnerites, Oenonites and Atraktoprion, and a new genus of probable ramphoprionid affinity. Additionally, Skalenoprion and Kalloprion? are recorded, both for the first time from Gondwana. Characteristic of the assemblage is very low frequency of taxa with placognath-type jaws. Comparing the Qusaiba-1 assemblage with coeval faunas of Baltica and Laurentia revealed that northern Gondwana was more similar to mid-continent Laurentia than Baltica. High proportion of paulinitids, ramphoprionids and atraktoprionids, and scarcity of placognaths is typical of both northern Gondwana and Laurentia. The Baltic faunas, in contrast, had several endemic genera particularly among placognaths, whereas paulinitids and ramphoprionids were rare. This anomalous biogeographic pattern, diverging from that of most other fossil groups, cannot be fully explained without additional first-hand data from the Middle and early Late Ordovician of Gondwana and Laurentia. © 2014 Elsevier B.V.


Paris F.,Rue des Jonquilles | Paris F.,CNRS Geosciences Laboratory of Rennes | Verniers J.,Ghent University | Miller M.A.,IRF Group Inc. | And 3 more authors.
Review of Palaeobotany and Palynology | Year: 2015

The continuously cored Qusaiba-1 drilled in North Central Saudi Arabia penetrated successively the Qalibah, Sarah and Qasim formations. Silurian graptolites and chitinozoans from the Qusaiba Member of the Qalibah Formation were previously investigated. The present study focuses on the Upper Ordovician and lowermost Silurian parts of the core hole. Part of the sample set yielded abundant and well-preserved specimens associated with eurypterid remains, scolecodonts, acritarchs and cryptospores. Other samples from glacially derived shaly sediments contain only a few fragmented chitinozoan vesicles of Middle and Late Ordovician species indicating reworking through glacial processes. Four different chitinozoan assemblages are identified. The first recorded chitinozoan assemblage is restricted to the deepest processed sample (core 56). It contains Belonechitina cf. robusta, Hercochitina sp. A, and Spinachitina cf. kourneidaensis, and taxa also represented in the second assemblage, e.g., Fungochitina spinifera and Euconochitina species. This first assemblage, however, lacks some of the diagnostic species of the second one (e.g., Acanthochitina barbata, Tanuchitina cf. elongata) and suggests a slightly older late Katian age. The second recovered chitinozoan assemblage is documented in the upper part of the Qasim Formation (cores 49-56) and in the deeper core samples referred to the lower part of the Sarah Formation (cores 45-47 from the disrupted facies of the Sarah Sandstone Member). It contains abundant and well-preserved Armoricochitina nigerica and Ancyrochitina merga associated with e.g., Euconochitina lepta, Calpichitina lenticularis, A. barbata and Desmochitina typica. In addition to these classical components, new species have been observed. This assemblage occurring in pre-glacial as well as in glacially related strata is assigned to the late Katian-earliest Hirnantian (Ashgill). The overlying productive interval, corresponding to the Baq'a Shale Member, is less productive and sometimes virtually barren of chitinozoans. This interval yields a third assemblage mainly composed of broken specimens of Angochitina cf. curvata, C. lenticularis, Cyathochitina sp., D. typica, F. spinifera, Tanuchitina fistulosa, Euconochitina gr. lepta, and even Siphonochitina formosa. Most of these forms are interpreted as glacially reworked. The youngest assemblage is restricted to three samples (core 27), which are located very close to a Silurian gamma ray peak and above the highest evidence of glacial sediments represented by the Sarah Formation. This forth assemblage contains extremely abundant chitinozoans coexisting with a few graptolite remains and inarticulate brachiopods. This chitinozoan assemblage is dominated by Cyathochitina caputoi, which is associated with Belonechitina pseudarabiensis and subordinate numbers of Ancyrochitina and Euconochitina species. The classical Late Ordovician chitinozoan taxa are no longer present and an earliest Rhuddanian age is proposed.Carbon stable isotope (δ13Cchit.) values have been measured on picked chitinozoan vesicles from the upper part of the Quwarah Member (upper Qasim Formation) and from the basal part of the Qusaiba Member (Qalibah Formation) where they register a shift towards more negative values close to the Gamma ray peak. The timing of the Late Ordovician glaciation and correlation with Hirnantian glacial events recorded in Northern Gondwana regions are briefly discussed based on the recovered chitinozoans.Four new species, i.e., Conochitina rotundata sp. nov., Belonechitina tenuicomata sp. nov., Hercochitina multiansata sp. nov., and Calpichitina bernardae sp. nov. are described, discussed and illustrated. Biometric data are provided for Acanthochitina barbata and for Armoricochitina nigerica. © 2014 Elsevier B.V.


Le Herise A.,CNRS Oceanic Domains Laboratory | Paris F.,Rue des Jonquilles | Paris F.,CNRS Geosciences Laboratory of Rennes | Steemans P.,University of Liège
Bulletin of Geosciences | Year: 2013

Well preserved assemblages of cryptospores, chitinozoans, acritarchs, leiospheres, tasmanitids, colonies of Gloeocapsomorpha, scolecodonts and eurypterid fragments from 23 core samples of the Moussegouda core hole in the Erdi Basin, northern Chad, and from two samples from well KW-2 in Kufra Basin, South East Libya are investigated. These palynomorphs were recovered from the southernmost North African marine deposits of Late Ordovician and possibly early Silurian age. The palaeoenvironment evolves from late Hirnantian glacio-marine diamictites to silt-dominated sequences suggesting a marginal marine environment of possibly latest Hirnantian to earliest Rhuddanian age (post-elongata-pre-fragilis chitinozoan assemblages). The recovered palynomorph assemblages are compared and correlated with contemporaneous assemblages recorded in other northern Gondwana localities (Mauritania, Morocco Algeria, Libya, Africa, Saudi Arabia, Jordan), and in South Africa, in order to evaluate possible effects of the ice cap melting on palynomorph assemblages and sedimentation. Our goal is also to improve the regional biostratigraphy across the Ordovician-Silurian boundary. The composition of the recovered palynomorph assemblages, with mixed terrestrial and marine microflora, suggests that the topmost Ordovician or earliest Silurian in northern Chad and southeastern Libya, reflects nearshore conditions, with obvious fresh water influences. The lack of black shale or grey shale in the uppermost Ordovician and of "hot shale" in the lower Silurian in these areas, and their replacement by siltstones, are probably related to an isostatic readjustment that rapidly starved the marine sedimentation in the areas previously overlain by a thick ice cover during the climax of the Hirnantian glaciation. Tasmanites tzadiensis Le Herisse sp. nov. and Euconochitina moussegoudaensis Paris sp. nov., two new palynomorphs of biostratigraphical interest are described and illustrated.


Paris F.,Rue des Jonquilles | Paris F.,CNRS Geosciences Laboratory of Rennes | Miller M.A.,IRF Group Inc. | Al-Hajri S.,Aramco Services Company | Zalasiewicz J.,University of Leicester
Review of Palaeobotany and Palynology | Year: 2015

Sixty one core samples from three shallow core holes (Qusaiba-1, Baq'a-3 and Baq'a-4) penetrating the Qalibah Formation (Qusaiba Member) in the North Central Saudi Arabia were investigated. These core slabs corresponding to grey-greenish hemipelagic shale or silty-shale yield well-preserved and very abundant early Silurian chitinozoans. Most of the recorded chitinozoan assemblages are diverse and include several new species occurring with well-known species. An informal early Rhuddanian chitinozoan assemblage dominated by Cyathochitina caputoi is documented in the lowermost part of the Qusaiba Member. The six chitinozoan biozones defined above this basal assemblage range from Aeronian to Telychian. They are considered of regional value for northern Gondwana. From the lowest to the highest they are the Angochitina qusaibaensis (pro parte), Conochitina alargada, Angochitina hemeri, Angochitina macclurei, Tanuchitina obtusa and Euconochitina silurica biozones. The older regional biozones have been previously documented in Saudi Arabia whereas the two youngest ones, the eponymous index species of which were described from the subsurface of the Algerian Sahara, are documented for the first time in the Arabian Peninsula. Four subbiozones, of at least of regional application, are also defined in order to improve the precision of biostratigraphic correlation between Silurian lithostratigraphic units cropping out along the Arabian Shield and their counterparts in the subsurface of Central Saudi Arabia. Thanks to the closely spaced and to the regular sampling, the total range of several highly diagnostic forms as well as the interval of uncertainty between the successive chitinozoan biozones are better constrained. A hiatus with a duration of late Rhuddanian to early Aeronian separates the lowest informal chitinozoan assemblage from the qusaibaensis Biozone. A recent detailed study of the graptolites in the three cored holes provides independent chronostratigraphical control calibrating the previous chitinozoan-based age assignments. The qusaibaensis (pro parte), the alargada, and the hemeri chitinozoan biozones occur with the mid-Aeronian convolutus graptolite Biozone whereas the macclurei chitinozoan Biozone extends through the early Telychian guerichi and turriculatus graptolite biozones. The obtusa and the silurica chitinozoan biozones occur in an interval devoid of usable graptolites. They are referred to the mid-late Telychian as they do not contain typical Sheinwoodian species.Besides the abundant chitinozoans and acritarchs, sporadic occurrences of scolecodonts and of eurypterid cuticle fragments are also noted in the organic residues. The presence of eurypterids reflects a shallowing trend in the sedimentary record, which is consistent with the distribution of the graptolite remains (siculae and/or rhabdosomes). Indeed, graptolites are common throughout the Qusaiba Member, except in the youngest processed samples presaging the shallower environments prevalent in the Sharawra Member. The taphonomy of the chitinozoans (isolated vesicles, chain-like structures, clusters, coprolites) and their environmental context is briefly discussed.Fifteen new species are described and illustrated: Ancyrochitina alhajrii sp. nov., Ancyrochitina camilleae sp. nov., Armoricochitina crassicarinata sp. nov., Armoricochitina gengi sp. nov., Bursachitina baqaensis sp. nov., Conochitina viiuae sp. nov., Cutichitina minivelata sp. nov., Cyathochitina neolatipatagium sp. nov., Fungochitina merrelli sp. nov., Muscochitina olivieri sp. nov., Plectochitina alisawyiahensis sp. nov., Plectochitina alnaimi sp. nov., Plectochitina jaquelineae sp. nov., Plectochitina lucasi sp. nov., and Spinachitina geerti sp. nov. © 2014 Elsevier B.V.


Thusu B.,University College London | Rasul S.,University College London | Paris F.,Rue des Jonquilles | Paris F.,CNRS Geosciences Laboratory of Rennes | And 5 more authors.
Review of Palaeobotany and Palynology | Year: 2013

Latest Ordovician-earliest Silurian Tanezzuft Formation shales recovered from core material of the shallow borehole JA-2 drilled in Jebel Asba at the eastern margin of the Kufra Basin, southeastern Libya, yielded well-diversified palynomorph assemblages with transparent and brownish to yellowish vesicles and organic matter (visual kerogen Types 1 and 2) from depth interval 46.20 to 67.82. m. In addition, miospores including cryptospores, and Tasmanites sp. (". Tasmanites with nodules"), scolecodonts, and a stratigraphically significant palaeo-marker, the enigmatic, tubular organic structure Tortotubus protuberans, were also recorded frequently in most samples. Kerogen colour based on miospores (TAI <. 3) and chitinozoan reflectance indicate an immature facies for oil generation. The two uppermost samples (from 33.33. m and 46.20. m depths) and the lowermost ones (from 67.92 to 73.21. m depth) contain rare palynomorphs and other organic remains and have been partially affected by oxidation.Furthermore, palynological and palynofacies analyses were carried out on cuttings from an old well (UN-REMSA well), ca. 530. m towards the NNE from well JA-2. The composition of the organic residue is similar in both wells. However, the UN-REMSA well yields fairly numerous chitinozoans, scolecodonts and biofilms but lacks the "thread-like structures" and ". Tasmanites with nodules" observed in well JA-2.All the investigated samples in well JA-2 are dominated by a single chitinozoan species, Euconochitina moussegoudaensis Paris (in Le Hérissé et al., 2013). Based on correlation with chitinozoan-bearing strata around the Ordovician-Silurian boundary, the analysed samples from well JA-2 and from the UN-REMSA well are regarded as post-glacial, but still of either latest Hirnantian age, or at least no younger than earliest Rhuddanian. A well-diversified acritarch, miospore and cryptospore assemblage recorded in well JA-2 supports a marginal marine (nearshore) depositional environment. This assemblage is no older than earliest Rhuddanian yet the latest Hirnantian age of the assemblage cannot be completely ruled out as our current knowledge on the post-glacial, latest Hirnantian acritarch and miospore assemblages is poorly documented in North Africa. © 2013 Elsevier B.V.


Bogolepova O.K.,University of Cambridge | Gubanov A.P.,University of Cambridge | Paris F.,Rue des Jonquilles
GFF | Year: 2012

The chitinozoan Conochitina aff. emmastensis Nestor, 1982 has been identified from the Silurian Telychian Stage, Llandovery Series, of Severnaya Zemlya, the Russian Arctic. Its presence suggests an early to late Telychian age for the strata, which is in accordance with previous biostratigraphic dating based on graptolites and conodonts. © 2012 Copyright Geologiska Föreningen.

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