Articles de revues : « Oxfordium »

1

Gröschke, Manfred, et Annette Kossler. « Reineckeiidae of Late Caliovian/Early Oxfordian age from northern Chile ». Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 211, n^o 1-2 (29 janvier 1999) : 31–48. http://dx.doi.org/10.1127/njgpa/211/1999/31.

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Riegraf, Wolfgang. « Planktonic Foraminifers and Radiolarians from Callovian to Oxfordian (Jurassic) Deposits of Southern Germany ». Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 176, n^o 1 (22 décembre 1987) : 91–103. http://dx.doi.org/10.1127/njgpa/176/1987/91.

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Gawlick, Hans-Jürgen, et Hisashi Suzuki. « Stratigraphy of the Strubberg Formation in the Northern Calcareous Alps (Callovian-Oxfordian) ». Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 211, n^o 3 (23 avril 1999) : 233–62. http://dx.doi.org/10.1127/njgpa/211/1999/233.

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Helm, Carsten, Markus Reuter et Immo Schülke. « Die Korallenfauna des Korallenooliths (Oxfordium, Oberjura, NW-Deutschland) : Zusammensetzung, Stratigraphie und regionale Verbreitung ». Paläontologische Zeitschrift 77, n^o 1 (avril 2003) : 77–94. http://dx.doi.org/10.1007/bf03004561.

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Krautter, Manfred. « Gregoryceras aus dem Weißen Jura alpha (Oxfordium) vom "Lochen" bei Balingen (Schwäbische Alb, Baden-Württemberg) ». Jahresberichte und Mitteilungen des Oberrheinischen Geologischen Vereins 76 (5 avril 1994) : 325–34. http://dx.doi.org/10.1127/jm//76/1994/325.

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Krautter, Manfred. « Gregoryceras aus dem Weißen Jura alpha (Oxfordium) vom "Lochen" bei Balingen (Schwäbische Alb, Baden-Württemberg) ». Jahresberichte und Mitteilungen des Oberrheinischen Geologischen Vereins 76 (5 avril 1994) : 325–34. http://dx.doi.org/10.1127/jmogv/76/1994/325.

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Krautter, Manfred. « Gregoryceras aus dem Weißen Jura alpha (Oxfordium) vom "Lochen" bei Balingen (Schwäbische Alb, Baden-Württemberg) ». Jahresberichte und Mitteilungen des Oberrheinischen Geologischen Vereins 76 (5 avril 1994) : 325–34. http://dx.doi.org/10.1127/jm/76/1994/325.

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Helm, Carsten, et Immo Schülke. « Crustaceen-Koprolithen aus dem Korallenoolith (Oxfordium, Niedersächsisches Becken, NW-Deutschland) (Crustacean coprolites trom the Korallenoolith Formation (Lower Saxony Basin, Oxtordian, NW Germany)) ». Neues Jahrbuch für Geologie und Paläontologie - Monatshefte 2004, n^o 8 (20 août 2004) : 496–512. http://dx.doi.org/10.1127/njgpm/2004/2004/496.

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Gawlick, Hans-Jürgen, Wolfgang Janauschek, Sigrid Missoni, Volker Diersche et Heinrich Zankl. « Facies, stratigraghy and component analysis of polymict mass-flow deposits in Jurassic cherty sediments (Callovian - Oxfordian) of the Büchsenkopf in the Nationalpark Berchtesgaden and their significance for the tectonic and paleogeographic interpretation of the Berchtesgaden Calcareous Alps (Germany) ». Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 228, n^o 2 (28 mai 2003) : 275–304. http://dx.doi.org/10.1127/njgpa/228/2003/275.

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Melendez, Guillermo. « Oxfordian ». Geobios 27 (décembre 1994) : 761–65. http://dx.doi.org/10.1016/s0016-6995(94)80243-2.

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Zhabina, Natalia. « Correlation of the eastern segment of Tethyan Upper Jyrassic reef barrier and adjacent facies (Carpathian-Crimean-Caucasian area) ». Geology and Geochemistry of Combustible Minerals 1-2, n^o 193-194 (2024) : 95–112. http://dx.doi.org/10.15407/ggcm2024.193-194.095.

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The spread of the Oxfordian-Valanginian facial belts of the carbonate shelf is traced on the territory of the eastern segment of Tethyan Upper Jurassic reef barrier by the results of own research and analysis of the published data. It is based on the scheme of distribution of the standard facial belts (D. Wilson, 1980). Complex correlation of the reefogenic and related deposits is done on the basis of comparison of the litofacial and micropaleontological composition. Standard biozonal scheme by Tintinnida and correlative associations of the Foraminifera are used. Most complete reefogenic deposits are presented in the West Ukrainian (Stryi Jurassic deep), where reefal, reef-front and back-reef facies are distributed. They are overlap by the deposits of the open shelf. This carbonate complex is significantly eroded to the East and represented only by Oxfordian back-reef facies on the Kovel ledge and by biohermic belt in the Belarus Brest cavity. In the Pieniny Klippen Belt in the Ukrainian Carpathians, the fragments of the Oxfordian-Valanginian pelagic facies of carbonate shelf are distributed. In the deep basement of the Ukrainian Transcarpathians, the Upper Tithonian, Berriassian and Valanginian deposits of open shelf are presented. To the West, the similar Oxfordian-Valanginian facies of the carbonate shelf are spread out on the adjacent territory of Poland, but they are mostly eroded. Reef belt is represented only by Oxfordian bioherms on the Polish Lowland. Oxfordian and Kimmeridgian back-reef facies and Tithonian-Berriassian deposits are more widespread. Reef-front facies are represented only by the Oxfordian. These deposits are overlaped by the Berriassian–Valanginian open shelf sedimens. In the Polish Carpathian Pieniny Klippen Belt and Tatra Mts, the fragments of the Oxfordian–Valanginian pelagic deposits of carbonate shelf are presented. In the Flysch Carpathians, Tithonian-Berriassian reefal limestone and Oxfordian and Tithonian reef-front facies also are presented. Upper Jurassic reefogenic belt spread on the south-east in Predobrogian deep, where it is very eroded and overlaped by Lower Cretaceous rocks. Reefal facies is represented only by Middle Oxfordian – Lower Kimmeridgian biohermes. Back-reef facies of the Middle Oxfordian – Lower Kimmeridgian and Upper Tithonian – Lower Berriassian are present. Kimmeridgian and Tithonian lagoone-evaporite facies are the most spread. Reef-front facies are represented by the Oxfordian – Lower Kimmeridgian and Upper Tithonian. In the Crimean Orogen, Upper Jurassic reef barrier is represented by destroyed and insufficiently studied sections, because of that the complete regularity of facial directions is not found. Oxfordian – Lower Kimmeridgian and Upper Tithonian – Lower Berriassian reefal facies, as well as Lower Oxfordian, Upper Kimmeridgian – Lower Berriassian facies are presented. In Greater Caucasus, the Upper Jurassic – Lower Cretaceous carbonate complex is completed with the Oxfordian and Tithonian reefal facies and Oxfordian-Tithonian back-reef facies and evaporates, as well as by the Oxfordian-Valanginian pelagic deposits. These sections are fragmental, and the complete regularity of facial directions is not found. So, the eastern segment of Tethyan Upper Jurassic reefogenic complex is spread trough the regions of Carpathian Foredeep, Predobrogean deep, orogens of Carpathians, Crimea and Greater Caucasus. In the orogene structures, this complex is presented fragmentarily, and in the Polish Lowland and Predobrugean deep, it is very eroded. In the Stryi Jurassic deep, the complete complex of reef barrier is presented, and regularity of facial directions are determined. All specified facial belts in these regions are characterized by the similar lithologic composition, as well as by the same associations of Foraminifera and Tintinnida. This made it possible to implement the stratigraphic correlation of the lithofacies formations of the carbonate complex.

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Djeric, Nevenka, et Marija Vuletic. « Radiolarian assemblage from radiolarites of the Krs Gradac section (SW Serbia) : On the way to a better reconstruction of the Middle-Late Jurassic geodynamic history of the Inner Dinarides ». Annales g?ologiques de la Peninsule balkanique, n^o 00 (2023) : 10. http://dx.doi.org/10.2298/gabp231028010d.

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The type section of the Gonje Formation (Krs Gradac, Sjenica area) is characterized by an abundance of radiolarian tests, which, however, are gene - rally recrystallized and poorly preserved. This paper focuses on the age of radiolarite sequence below the series with intercalated turbidites and mass transport deposits. The Callovian/Oxfordian (?early Oxfordian) moderately preserved radiolarian assemblage was determined from the higher part of the radiolaritic sequence without mass transport deposits. The new biostratigraphic age is consistent with the previously published data of the authors and reveals that the radiolaritic sequence without mass transport deposits of the Gonje Formation was deposited between the Bathonian and Oxfordian. The biostratigraphic age of this part of the Gonje Formation evidence that the Ljubis Basin underwent in Late Oxfordian to earliest Tithonian times a phase of starvation with reduced sediment supply or production. The reasons for this starvation are discussed.

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Gabdullin, R. R., N. V. Badulina, E. A. Bakai, E. V. Rubtsova, A. Yu Yurchenko, E. V. Karpova, A. V. Ivanov et al. « COMPOSITION AND ORIGIN OF CALLOVIAN-OXFORDIAN DEPOSITS OF THE SUDAK BAY (CRIMEA) ». Moscow University Bulletin. Series 4. Geology, n^o 3 (28 juin 2018) : 25–40. http://dx.doi.org/10.33623/0579-9406-2018-3-25-40.

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Composition and origin of Callovian–Oxfordian deposits of the Sudak Bay based upon generalizations of our own results and analysis of published and unpublished data were specified. A botanic feature for geological prospecting of Oxfordian limestones was used for the first time.

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Stancliffe, R. P. W. « Dinoflagellate cysts from the Oxfordian (Upper Jurassic) of Skye, Scotland and Southern Dorset, England ». Journal of Micropalaeontology 10, n^o 2 (1 décembre 1991) : 185–202. http://dx.doi.org/10.1144/jm.10.2.185.

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Abstract. Ten sediment samples from Upper Oxfordian strata of Skye and six from the uppermost Lower Oxfordian of southern Dorset were processed for palynomorphs. Of the dinoflagellate cysts recognized, the genus Furzidinium and species F. sentum, Cleistosphaeridium sarmentum and Prolixosphaeridium floccum are described for the first time. The new combination Polygonium bavarica is proposed and Cleistosphaeridium ehrenbergii is retained.

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Wilkinson, Ian P. « <i>Eripleura,</i> ; a new genus of ostracod from the Upper Jurassic of England and its relationship with <i>Procytheropteron</i> ; Ljubimova ». Journal of Micropalaeontology 6, n^o 1 (1 mai 1987) : 111–16. http://dx.doi.org/10.1144/jm.6.1.111.

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Abstract. A new genus of cytherurid ostracod, Eripleura, with the type species E. eleanorae sp. nov. from the Upper Oxfordian (? rosenkrantzi Zone) and Lower Kimmeridgian (baylei Zone) of southern England is described and compared with Procytheropteron. Two further species are described for the first time, Eripleura obliquicosta from the Lower Kimmeridgian cymodoce Zone, and Procytheropteron? elongatum from the Upper Oxfordian tenuiserratum Zone.

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Starzyk, Natalia. « The oldest species of the genusLaeviprosopon (Decapoda : Brachyura : Prosopidae) from the Oxfordian of Poland ». Acta Zoologica Cracoviensia 63, n^o 1 (30 juin 2020) : 9–13. http://dx.doi.org/10.3409/azc.63.02.

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Till now the genus Laeviprosopon has comprised 12 species aged from the Late Jurassic to the end of the Early Cretaceous. Recently a new species was found in the Oxfordian locality of Polish Jura Chain, Laeviprosopon musialiki n. sp., described herein. Representatives of the genus Laeviprosopon are very rare in the Oxfordian localities of southern Poland. Laeviprosopon musialiki n. sp. is the oldest member of the genus.

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BARSKI, Marcin. « Dinoflagellate cyst assemblages across the Oxfordian/Kimmeridgian boundary (Upper Jurassic) at Flodigarry, Staffin Bay, Isle of Skye, Scotland – a proposed GSSP for the base of the Kimmeridgian ». Volumina Jurassica XV, n^o 1 (6 septembre 2018) : 51–62. http://dx.doi.org/10.5604/01.3001.0012.4594.

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Examination of seven ammonite-calibrated palynological samples across the Oxfordian/Kimmeridgian boundary in the Flodigarry sections at Staffin Bay, Isle of Skye, northern Scotland, has revealed dinoflagellate cyst assemblages in general terms in line with previous contributions. The sparse occurrence of Emmetrocysta sarjeantii, Perisseiasphaeridium pannosum and Senoniasphaera jurassica slightly above the proposed Oxfordian/Kimmeridgian boundary may be used as a palynological approximation of the base of the Kimmeridgian. The high abundance of tests resembling modern zygnemataceous chlorophycean alga Spirogyra in two samples above the Oxfordian/Kimmeridgian boundary horizon is probably associated with increased eutrophication and possible association with ‟green tides”. This bloom is proposed as a palynofloral proxy event for the boundary in the Flodigarry section. According to previous studies, various eutrophication events may have a correlation potential in Subboreal Europe.

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Marinov, Vladimir, Alexander Alifirov, Alexander Kudamanov et Varvara Bumagina. « CALLOVEAN AND UPPER JURASSIC CONSTRUCTION ON EM-EKOVSKOE FIELD (WESTERN SIBERIA) ». Interexpo GEO-Siberia 2, n^o 1 (2019) : 87–94. http://dx.doi.org/10.33764/2618-981x-2019-2-1-87-94.

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The results of litho-bio-stratigraphic studies of Callovian and Upper Jurassic of the Em-Ega oil field (Western Siberia) are presented. The formation of sediments took place in the sea basin and had a pulsating character. Episodes of sediment accumulation were replaced by periods of a sharp shortage of terrigenous material. The main stages of the arrival of terrigenous material were Callovian, Middle and Late Oxfordian, Early Kimmeridgian and Middle and Late Volgian. In Early Oxfordian, Late Kimmeridgian, Early Volgian deposits did not accumulate.

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Croisé, Jean, Gerhard Mayer et Rémi De La Vaissière. « Determination of the in situ hydraulic parameters of the Callovo–Oxfordian clay rock in a long-term hydraulic interference testing at Andra's Underground Research Laboratory (CMHM) ». Safety of Nuclear Waste Disposal 2 (6 septembre 2023) : 49–50. http://dx.doi.org/10.5194/sand-2-49-2023.

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Abstract. Between 2009 and 2015, Andra has conducted a unique long-term hydraulic interference test in two parallel boreholes 1 m apart from each other and air core drilled in the undisturbed Oxfordian Clay rock at Andra's Underground Research Laboratory (CMHM) in Bure, France. The experimental set-up consisted of six test intervals positioned along the parallel boreholes drilled from a drift located within the Callovo–Oxfordian clay at around 500 m b.g.l. (below ground level). The 20 m boreholes were oriented around 30∘ downwards. The pressure sensors linked to six intervals of 1 m length each allowed for continuous pressure measurement over 6 years and a slanted borehole for the observation of rock displacements (see Fig. 1). Additionally, flow rates were measured during water injection tests that lasted weeks or months. This extensive set of hydraulic data allowed, for the first time, a precise determination of the in situ Callovo–Oxfordian clay rock permeability and anisotropy and its specific storage at the metre to decametre scale. It was achieved based on an automated calibration, using a 3D flow model and explicitly considering all the relevant hydraulic elements acting on the flow system (such as rock mass, borehole disturbed zone and sealing elements) and the drift acting as a steady sink due to the underground ventilation (see Fig. 2). The history matching was performed on the transient pressure measurements. The obtained numerical calibration results were in close agreement with the hydraulic parameter values of the Callovo–Oxfordian clay determined at a smaller scale (single borehole tests and rock core samples in the laboratory), therefore demonstrating the reliability of the very low permeability of the Callovo–Oxfordian clay at the metre to decametre scale. Furthermore, the modelling illustrated the impact of the measurement set-up and its details on the observed hydraulic behaviour. The analysis methodology and the main findings will be presented.

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Schudack, U., et M. E. Schudack. « Ostracods from the Upper Jurassic (Oxfordian-Tithonian) of southern Germany ». Journal of Micropalaeontology 19, n^o 2 (1 décembre 2000) : 97–112. http://dx.doi.org/10.1144/jm.19.2.97.

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Abstract. At present the ostracod faunas from the Upper Jurassic of southern Germany are incompletely known due to the absence of detailed studies. This preliminary systematic investigation has yielded 46 species from 25 genera, of which 23 species are left in open nomenclature, while 4 are new species: Bythoceratina (Praebythoceratina) danuvensis, Nemoceratina (Pariceratina) urlichsi, Pokornyopsis punctata and Quasihermanites spiralus. Diversity increases through the late Jurassic with 16 species in the Oxfordian, 19 species in the Kimmeridgian, and 23 species in the Tithonian. Endemism is lowest in the Oxfordian, while highest in the Kimmeridgian.

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Delahoyde, Michael, Richard Malim, Mark Anderson et Hank Whittemore. « Recent Publications in Oxfordian Studies ». Rocky Mountain Review of Language and Literature 60, n^o 2 (2006) : 52. http://dx.doi.org/10.2307/4143858.

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Piasecki, Stefan, Michael Larsen, Jens Therkelsen et Henrik Vosgerau. « Jurassic dinoflagellate cyst stratigraphy of Hold with Hope, North-East Greenland ». Geological Survey of Denmark and Greenland (GEUS) Bulletin 5 (1 novembre 2004) : 73–88. http://dx.doi.org/10.34194/geusb.v5.4808.

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Dinoflagellate cysts of the Middle–Upper Jurassic succession on northern Hold with Hope have been studied in order to establish a biostratigraphic framework and to date the succession. The Pelion Formation is characterised by abundant Chytroeisphaeridia hyalina and Sentusidinium spp., with some Ctenidodinium thulium and Paragonyaulacysta retiphragmata in the lower part. Mendicodinium groenlandicum appears higher in the formation followed by Trichodinium scarburghense in the upper part. The succeeding Payer Dal Formation contains Scriniodinium crystallinum, Rigaudella aemula and Leptodinium subtile in the lower part and Dingodinium jurassicum and Prolixosphaeridium granulosum in the uppermost part. The Bernbjerg Formation contains abundant Sirmiodinium grossii and Gonyaulacysta jurassica. Adnatospahaeridium sp., Cribroperidinium granuligerum, Glossodinium cf. dimorphum and Scriniodinium irregulare appear in the lower part of the formation, followed by Avellodinium spp. in the highest part. The dinoflagellate cyst assemblages in the Pelion Formation indicate an Early–Late Callovian age (C. apertum – P. athleta Chronozones). This is supported by ammonites in the lower part of the formation, which refer to the C. apertum and P. koenigi Chronozones. A significant hiatus, from Late Callovian to Middle Oxfordian, is present between the Pelion Formation and the overlying Payer Dal Formation. The age of the Payer Dal Formation is Middle Oxfordian to earliest Late Oxfordian (C. tenuiserratum – A. glosense Chronozones). The Payer Dal Formation is conformably overlain by the Bernbjerg Formation of Late Oxfordian to possibly earliest Kimmeridgian age (A. glosense – P. baylei Chronozones). The A. glosense Chronozone is also documented by abundant ammonites in the lowermost part of the formation.

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Marinov, V. A., A. S. Alifirov, V. A. Bumagina, A. E. Igolnikov, A. I. Kudamanov, E. B. Avramenko, M. A. Grishchenko et M. D. Smyshlyaeva. « STRATIGRAPHY AND FORMATION CONDITIONS OF CALLOVIAN AND UPPER JURASSIC DEPOSITS OF THE CENTRAL PART OF THE KAZYM-KONDA REGION (WEST SIBERIA) ». Geology and mineral resources of Siberia, n^o 2 (2021) : 3–16. http://dx.doi.org/10.20403/2078-0575-2021-2-3-16.

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The results of stratigraphic and facies studies of the Callovian and Upper Jurassic of the Kazym-Konda facies region (West Siberia) are presented. The sequence of subdivisions of the boreal zonal standard is established. The section is composed of rocks with predominantly shallow marine genesis; their composition depended on sedimentation cyclicity and sea level fluctuations. The highest incoming rates of sedimentary material were associated with transgressive episodes in the Callovian, Middle Oxfordian and Middle Volgian. Stratigraphic breaks and periods of deficient sedimentation in the Late Oxfordian, Kimmeridgian, Early Volgian and Late Volgian correspond to regressive episodes in the section.

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Lorin, Sébastien, Philippe Courville, Pierre-Yves Collin, Jacques Thierry et Anthony Tort. « Settlement down again patterns of a carbonated platform following up a sedimentary crisis : example of the middle-late Jurassic boundary in the southeastern part of the Paris Basin ». Bulletin de la Société Géologique de France 175, n^o 3 (1 mai 2004) : 289–302. http://dx.doi.org/10.2113/175.3.289.

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Abstract Following a sedimentary crisis which begins in the late Lower Callovian and spans all the early Oxfordian, the settlement down patterns of a platform with carbonated sedimentation are analysed in a southeastern area of the Paris Basin (fig. 1). Ten lithostratigraphic units (reefal formations, associated bioclastic facies and marly distal lateral facies ; fig. 2) are defined (fig. 3). New ammonite and brachiopod faunas, collected in situ, allow to date accurately the sedimentary units with a precision matching an ammonite subzone of the standard bio-chronostratigraphic scale (fig. 4) of the middle-late Oxfordian (from the Parandieri Subzone, at the base of the Transversarium Zone, to the Planula Subzone, at the top of the Planula Zone). The sedimentologic analysis coupled with the study of the benthic and pelagic faunal communities allow to define twelve type-facies (tabl. I and II). Regrouped into three associations, these characterise depositional environments which occur in succession, following three platform models (fig. 5). As witnesses of the evolution of the accomodation/sedimentation ratio, the resulting time succession of sedimentary bodies shows a depositional dynamics organised into three sequence tracks (fig. 5 and 6) : – a retrogradation phase is characterised by a moderately deep and open platform, dominated by low energy and marly sedimentation, which ranges from the Middle Oxfordian (Plicatilis Zone and Transversarium Zone) to the lowermost late Oxfordian (Bifurcatus Zone) ; – during the late Oxfordian (Bimammatum Zone, from the Semimammatum Subzone to the Bimammatum Subzone) an aggradation phase corresponds to the installation of three successive shallow platforms with contrasted morphology. Indicating the re-initiation of carbonated production, these platforms are well limited and represent high energy shallows with reef buildings, which lateraly grade into dismantling bioclastic faciès, then secondly and more laterally again into low energy and medium deep marly facies ; – the upper part of the late Oxfordian (Hauffianum Subzone, in the uppermost Bimammatum Zone, and Planula Zone) shows the wide extent of a low energy and morphologically very little contrasted distal platform. This one has a high potential of carbonated production characterised by bioclastic, oolitic and micritic facies which illustrate a progradation phase ; such a phase proceeds in the early Kimmeridgian. The collected data and the corresponding phenomenons pointed out on this area of the southeastern border of the Paris Basin are discussed and replaced in the general framework of the sedimentary, biologic, palaeogeographic and palaeoclimatic events henceforth recognised at the middle-late Jurassic boundary on the peri-Tethyan intracratonic domains of western Europe. The demise of the carbonate production seems to be correlated with a global cooling of both marine waters and atmosphere, which is considered as a limiting factor. During the Middle Oxfordian, the re-initiation of carbonate production with the developement of reef buildings should correspond to a large scale warming of the marine waters still observed elswhere on the Russian Platform, in the North Sea and in the Paris Basin. However, the geographic distribution and the chronologic succession of the facies and deduced palaeoenvironments is probably equally related to a synsedimentary tectonic activity which operates as a favorable factor at both a local and regional scale.

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Morales, Chloé, Pierre Pellenard, Benoit Vincent, Franck Smektala, Fleur Daniau et Philippe Landrein. « Stratigraphic Modelling of the Lower/Middle Oxfordian (Upper Jurassic) Outer Ramp Deposits from the NE Paris Basin (France) ». Geosciences 12, n^o 10 (10 octobre 2022) : 375. http://dx.doi.org/10.3390/geosciences12100375.

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We investigate herein the lateral and vertical lithological heterogeneities of the Lower/Middle Oxfordian deposits (“Terrain à Chailles” and “Marnes des Eparges” formations) in the north-eastern Paris Basin. This new detailed stratigraphic framework documents the evolution at high resolution of an outer ramp based on regional correlations in order to constrain the evolution of petrological properties between the clayey “Argiles de la Woëvre” Formation and the more calcareous “Marnes et Calcaires à Coraux de Foug Formation. The “Argiles de la Woëvre” Formation is targeted for the deep storage of nuclear waste in north-eastern France. Nine wells are correlated over the “Zone of Interest for Further Research” (ZIRA), defined by the French agency for radioactive waste management (Andra), with a resolution of 0.5–1.0 m. The architecture and the age control of these formations have been refined, revealing that the “Terrain à Chailles” Formation is characterised by a regular slightly inclined sedimentation gently deeping in the SW direction and shows a lithological evolution from silty claystones to an increased occurrence of its calcareous content towards the top (Lower Oxfordian, uppermost mariae and cordatum ammonite zones). The above “Marnes des Eparges” Formation, characterised by claystone limestone alternations, is assigned to the Middle Oxfordian (plicatilis ammonite zone), deposited during a slightly enhanced subsidence phase in the SE part of the basin and documented and associated with onlaps geometries on the more proximal areas. However, this change in geometry does not affect petrological properties over ZIRA, as this is not accompanied by lithological changes. The environmental factors controlling petrological heterogeneities over ZIRA are also discussed. The stepwise increase in the carbonate content and the decrease in the detrital content towards the Lower to Middle Oxfordian deposits was likely triggered by a climate change towards drier conditions, modulated by sea level changes on a ramp morphology. A major condensation phase encompassing most of the Lower Oxfordian cordatum ammonite zone is also highlighted. The occurrence of a maximum regressive surface associated with gentle slope topography is a probable trigger for condensation. Changes in geometries are, however, associated with the activity of the Metz Fault, which potentially had an influence on the subsidence rates of the basin at that time.

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Matyja, Bronisław A., Andrzej Wierzbowski et John K. Wright. « The Sub-Boreal/Boreal ammonite succession at the Oxfordian/Kimmeridgian boundary at Flodigarry, Staffin Bay (Isle of Skye), Scotland ». Transactions of the Royal Society of Edinburgh : Earth Sciences 96, n^o 4 (décembre 2005) : 387–405. http://dx.doi.org/10.1017/s026359330000136x.

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ABSTRACTThis paper describes extensive new collections of ammonites made bed-by-bed across the Oxfordian/Kimmeridgian boundary sequence in the Flodigarry sections at Staffin Bay on the Isle of Skye. The ammonites belong to the Sub-Boreal family Aulacostephanidae and the Boreal family Cardioceratidae, enabling recognition of both the current standard Sub-Boreal and Boreal ammonite zonations. In consequence, it is possible to make a close correlation of these two zonal schemes through the interval studied in Skye. The research has provided new palaeontological data at levels of precision that justify the proposal of the section at Staffin as the site of a potential Global Boundary Stratotype Section and Point (GSSP) for the Oxfordian/Kimmeridgian boundary.The traditional Oxfordian/Kimmeridgian boundary placed at the Pseudocordata/Baylei zonal boundary of the Sub-Boreal zonal scheme corresponds precisely to the Rosenkrantzi/Bauhini zonal boundary of the Boreal zonal scheme. This level is characterised by the appearance of the first Pictonia (Pictonia flodigarriensis sp. nov.) together with first Prorasenia, replacing an older assemblage of Ringsteadia–Microbiplices (Sub-Boreal). It is also characterised by the first occurrence of small-sized Amoeboceras (Plasmatites) spp., as well as large Amoeboceras schulginae Mesezhnikov (Boreal). An alternative level that may be considered as a potential GSSP is the boundary between the Bauhini Zone and the Kitchini Zone of the Boreal zonal scheme, characterised by first occurrence of Amoeboceras (Amoebites) of the A. bayi group. This level corresponds to the Planula/Galar subzonal boundary of the Sub-Mediterranean zonal scheme, and lies close to the currently accepted Oxfordian/Kimmeridgian boundary in the Sub-Mediterranean Province.

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Abbink, O. A., J. H. A. Van Konijnenburg-Van Cittert, C. J. Van der Zwan et H. Visscher. « A sporomorph ecogroup model for the Northwest European Jurassic - Lower Cretaceous II : Application to an exploration well from the Dutch North Sea ». Netherlands Journal of Geosciences - Geologie en Mijnbouw 83, n^o 2 (juin 2004) : 81–91. http://dx.doi.org/10.1017/s0016774600020059.

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AbstractJurassic shallow marine to non-marine depositional sequences are among the most important economic targets in the North Sea. Detailed, ‘high resolution’ stratigraphy of these sequences has become a necessity in both predictive geological exploration models as well as in production reservoir models. In these paralic sequences, palynomorphs are the most abundant (micro) fossil group. Palynology is increasingly challenged to improve the biostratigraphic control, and to support the sequence stratigraphical framework. Based on a recently developed, conceptual Sporomorph EcoGroup model, the quantitative distribution patterns of terrestrial palynomorphs are grouped in six Sporomorph EcoGroups (SEGs), viz. Upland, Lowland, River, Pioneer, Coastal, and Tidally-influenced SEG. Application of the SEG model to data from a marginal marine, uppermost Callovian - Middle Oxfordian section of NAM well F17-4 from the southern part of the Central North Sea Graben allows the recognition of sea-level fluctuations and climate changes. A marked palaeoclimatic shift occurred in the earliest Middle Oxfordian. The relatively cool-subtropical, humid climate changed into a warmer, subtropical-tropical, drier climate. The sea-level reconstructions based on the SEG model are validated against a latest Callovian - Earliest Oxfordian depositional sequence.

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Walley, C. D. « Depositional history of southern Tunisia and northwestern Libya in Mid and Late Jurassic time ». Geological Magazine 122, n^o 3 (mai 1985) : 233–47. http://dx.doi.org/10.1017/s0016756800031447.

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AbstractThe good exposures of virtually undeformed Callovian and Oxfordian strata along the Djeffara escarpment of southern Tunisia and northwestern Libya have allowed analysis of regional depositional history during this time.A number of lithostratigraphic problems are considered. In Tunisia, the Foum Tatahouine Formation is subdivided into members and in Libya some of the stratigraphic issues are clarified. A correlation between the two sequences is proposed. The widely claimed aeolian origin for the Libyan Chameau Mort Sandstone is rejected.The depositional patterns of the Callovian and Oxfordian strata are described in the context of Mid and Late Jurassic sedimentation in the eastern Ghadames basin of the African craton. After a regressive Bathonian sequence, transgressive conditions commenced in Early Callovian time. In a series of continental–marine cycles, this transgressive sequence culminated in widespread shallow, restricted-marine micritic deposition. A regression in Late Callovian time resulted in emergence marked by a thin but widespread calcrete horizon. In Mid? Oxfordian time a renewed transgression brought in open marine, high-energy, shallow-water carbonates. Later, regressive conditions returned, leading to increasing restriction, and latest Jurassic time saw the first signs of the fluvio-deltaic deposition that was to dominate the region in Early Cretaceous time.

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Descostes, M., V. Blin, F. Bazer-Bachi, P. Meier, B. Grenut, J. Radwan, M. L. Schlegel, S. Buschaert, D. Coelho et E. Tevissen. « Diffusion of anionic species in Callovo-Oxfordian argillites and Oxfordian limestones (Meuse/Haute–Marne, France) ». Applied Geochemistry 23, n^o 4 (avril 2008) : 655–77. http://dx.doi.org/10.1016/j.apgeochem.2007.11.003.

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Stepanov, I. A., A. Yu Kazansky, D. N. Kiselev, L. R. Kosareva, M. A. Rogov, E. M. Tesakova, E. V. Shchepetova et Ya A. Shurupova. « Potencial of rock-magnetic methods in paleoecological reconstructions : case study of Mikhailovtsement reference section (Ryazan region) ». Moscow University Bulletin. Series 4. Geology, n^o 2 (28 avril 2019) : 30–38. http://dx.doi.org/10.33623/0579-9406-2019-2-30-38.

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On the basis of detailed, combined rock-magnetic, lithological, and micropaleontological study of the Mikhailovtsement section of the Moscow syneclise (Ryazan region), the fluctuations in Central Russian Sea level in Callovian–Early Oxfordian were reconstructed. According to the variations of rock-magnetic parameters over the section, seven rock-magnetic intervals were established which correspond to different stages of basin evolution. These stages are compared with sea level fluctuations established on the basis of changes in the lithology of rocks and the ostracod complexes. In general, the nature of sea level change in Callovian–Oxfordian, revealed by combination of the methods during the study of Mikhailovtsement section coincides with global trend.

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PELLENARD, P., S. NOMADE, L. MARTIRE, F. DE OLIVEIRA RAMALHO, F. MONNA et H. GUILLOU. « The first 40Ar–39Ar date from Oxfordian ammonite-calibrated volcanic layers (bentonites) as a tie-point for the Late Jurassic ». Geological Magazine 150, n^o 6 (19 août 2013) : 1136–42. http://dx.doi.org/10.1017/s0016756813000605.

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AbstractEight volcanic ash layers, linked to large explosive events caused by subduction-related volcanism from the Vardar Ocean back-arc, interbedded with marine limestones and cherts, have been identified in the Rosso Ammonitico Veronese Formation (northeastern Italy). The thickest ash layer, attributed to the Gregoryceras transversarium ammonite Biozone (Oxfordian Stage), yields a precise and reliable 40Ar–39Ar date of 156.1 ± 0.89 Ma, which is in better agreement with GTS2004 boundaries than with the current GTS2012. This first biostratigraphically well-constrained Oxfordian date is proposed as a new radiometric tie-point to improve the Geologic Time Scale for the Late Jurassic, where ammonite-calibrated radiometric dates are particularly scarce.

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De La Fuente, M. S., et M. Iturralde-Vinent. « A new pleurodiran turtle from the Jagua Formation (Oxfordian) of western Cuba ». Journal of Paleontology 75, n^o 4 (juillet 2001) : 860–69. http://dx.doi.org/10.1017/s0022336000016954.

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The oldest Jurassic marine pleurodire is reported from the Jagua Formation in western Cuba. These remains are from levels of middle and late Oxfordian age. This turtle represents a new genus and species, Caribemys oxfordiensis. A phylogenetic hypothesis is proposed, whereby Caribemys is considered to be the sister group of Notoemys Cattoi and Freiberg, 1961, plus the Eupleurodira Gaffney and Meylan, 1988. The occurrence of Caribemys oxfordiensis n. gen. and sp. in the Jagua Formation along with plesiosauroids, pliosauroids, ophthalmosaurian ichthyosaurs, and metriorhynchid crocodiles, strongly suggests that during the Oxfordian a marine seaway was present in the Caribbean, connecting the western Tethys with the Pacific Ocean.

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Gömöri, György. « Glosszák egy oxfordi rovásírás-ábécé történetéhez ». Magyar Nyelv 119, n^o 2 (25 juillet 2023) : 251–54. http://dx.doi.org/10.18349/magyarnyelv.2023.2.251.

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Ez a tanulmány egy újonnan felfedezett oxfordi kéziratot ismertet, amit William Poole (New College, Oxford) talált a Lincoln College archívumában. A Thomas Marshall kollégiumigazgató kötetében található rovásírás-ábécé szerzője Harsányi Nagy Jakab brandenburgi diplomata, és ez minden valószínűség szerint 1678-ból származik. Szerző szerint ez lehetett az alapja George Hickes oxfordi tudós 1703ؘ–1705-ben közzétett rovásírás-táblázatának.

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Hrbek, Jan. « The systematics and paleobiogeographic significance of Sub-Boreal and Boreal ammonites (Aulacostephanidae and Cardioceratidae) from the Upper Jurassic of the Bohemian Massif ». Geologica Carpathica 65, n^o 5 (1 octobre 2014) : 378–89. http://dx.doi.org/10.2478/geoca-2014-0026.

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Abstract Upper Jurassic marine deposits are either rarely preserved due to erosion or buried under younger sediments in the Bohemian Massif. However, fossil assemblages from a few successions exposed in northern Bohemia and Saxony and preserved in museum collections document the regional composition of macro-invertebrate assemblages and thus provide unique insights into broad-scale distribution and migration pathways of ammonites during the Late Jurassic. In this paper, we focus on the systematic revision of ammonites from the Upper Oxfordian and Lower Kimmeridgian deposits of northern Bohemia and Saxony. The ammonites belong to two families (Aulacostephanidae and Cardioceratidae) of high paleobiogeographic and stratigraphic significance. Six genera belong to the family Aulacostephanidae (Prorasenia, Rasenia, Eurasenia, Rasenioides, Aulacostephanus, Aulacostephanoides) and one genus belongs to the family Cardioceratidae (Amoeboceras). They show that the Upper Jurassic deposits of the northern Bohemian Massif belong to the Upper Oxfordian and Lower Kimmeridgian and paleobiogeographically correspond to the German-Polish ammonite branch with the geographical extent from the Polish Jura Chain to the Swabian and Franconian Alb. Therefore, the occurrences of ammonites described here imply that migration pathway connecting the Polish Jura Chain with habitats in southern Germany was located during the Late Oxfordian and Early Kimmeridgian in the Bohemian Massif.

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Foffa, Davide, Mark T. Young et Stephen L. Brusatte. « Evidence of macrophagous teleosaurid crocodylomorphs in the Corallian Group (Oxfordian, Late Jurassic) of the UK ». PeerJ 3 (17 décembre 2015) : e1497. http://dx.doi.org/10.7717/peerj.1497.

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Teleosaurids were a group of semi-aquatic crocodylomorphs with a fossil record that spanned the Jurassic Period. In the UK, abundant specimens are known from the Oxford Clay Formation (OCF, Callovian to lower Oxfordian), but are very rare in the Kimmeridge Clay Formation (KCF, Kimmeridgian to lower Tithonian), despite their abundance in some contemporaneous deposits in continental Europe. Unfortunately, due to the paucity of material from the intermediate ‘Corallian Gap’ (middle to upper Oxfordian), we lack an understanding of how and why teleosaurid taxic abundance and diversity declined from the OCF to the KCF. The recognition of an incomplete teleosaurid lower jaw from the Corallian of Weymouth (Dorset, UK) begins to rectify this. The vertically oriented dentition, blunt tooth apices, intense enamel ornamentation that shifts to an anastomosed pattern apically, and deep reception pits on the dentary unambiguously demonstrates the affinity of this specimen with an unnamed sub-clade of macrophagous/durophagous teleosaurids (‘Steneosaurus’obtusidens+Machimosaurus). The high symphyseal tooth count allows us to exclude the specimen fromM. hugiiandM. mosae, but in absence of more diagnostic material we cannot unambiguously assign DORCM G.3939 to a more specific level. Nevertheless, this specimen represents the first mandibular material referable to Teleosauridae from the poorly sampled middle-upper Oxfordian time-span in the UK.

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Juárez, M. T., M. L. Osete, G. Meléndez et W. Lowrie. « Oxfordian magnetostratigraphy in the Iberian Range ». Geophysical Research Letters 22, n^o 21 (1 novembre 1995) : 2889–92. http://dx.doi.org/10.1029/95gl02848.

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Belmokhtar, Malik, Pierre Delage, Siavash Ghabezloo, Anh-Minh Tang, Hamza Menaceur et Nathalie Conil. « Poroelasticity of the Callovo–Oxfordian Claystone ». Rock Mechanics and Rock Engineering 50, n^o 4 (25 novembre 2016) : 871–89. http://dx.doi.org/10.1007/s00603-016-1137-3.

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Pereira, Ricardo, Monique Feist et Ana C. Azerêdo. « New charophytes from the Upper Jurassic of the Lusitanian Basin (Portugal) ». Journal of Micropalaeontology 22, n^o 2 (1 novembre 2003) : 113–26. http://dx.doi.org/10.1144/jm.22.2.113.

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Abstract. In the Lusitanian Basin (west-central Portugal), Upper Jurassic (Oxfordian) sediments were investigated in order to identify palaeontological assemblages of charophytes. Systematic studies were undertaken on specimens obtained from four field sections (Pedrógão, Vale de Ventos, Memória and Valverde). These studies revealed the presence of new forms of Porocharaceae (Porochara pedunculata n. sp) and of forms previously unknown in this region (Auerbachichara cf. saidakovskyi), as well as P. raskyae, P. minima, P. fusca, P. sulcata, P. kimmeridgensis, Aclistochara longiformis and Porochara sp. Comparison of the charophyte palaeofloras recognized in all of the studied sections has allowed the definition of three different assemblages which, coupled with other data, help to correlate these successions of Early (?) to Middle (Late?) Oxfordian age.

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WIERZBOWSKI, Andrzej, Bronisław A. MATYJA et John WRIGHT. « Notes on the evolution of the ammonite families Aulacostephanidae and Cardioceratidae and the stratigraphy of the uppermost Oxfordian and lowermost Kimmeridgian in the Staffin Bay sections (Isle of Skye, Northern Scotland) ». Volumina Jurassica XV, n^o 1 (10 août 2018) : 27–50. http://dx.doi.org/10.5604/01.3001.0012.2437.

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Detailed study of all the ammonite collections gathered by the authors in the Staffin Bay sections has resulted in minor changes in the distribution of ammonite taxa, and slight modification of the position of the Oxfordian/Kimmeridgian boundary. Most significant is the discovery of Pictonia (Triozites) cf. seminudata which results in the placing of the stage boundary 0.16 m below the level formerly proposed. This study discusses the evolution of the Subboreal family Aulacostephanidae, and the Boreal family Cardioceratidae, indicating changes in the patterns of individual development in the evolution of both families in terms of heterochrony. The Oxfordian/ Kimmeridgian boundary interval shows major morphological changes in both ammonite families which were released from phylogenetic constraints by heterochrony, closely related to changes in environmental conditions.

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Cecca, Fabrizio, Berengere Savary, Annachiara Bartolini, Juergen Remane et Fabrice Cordey. « The Middle Jurassic-Lower Cretaceous Rosso Ammonitico succession of Monte Inici (Trapanese Domain, western Sicily) ; sedimentology, biostratigraphy and isotope stratigraphy ». Bulletin de la Société Géologique de France 172, n^o 5 (1 septembre 2001) : 647–59. http://dx.doi.org/10.2113/172.5.647.

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Abstract The pelagic Jurassic successions of the Trapani region of western Sicily are dominated by the characteristic Tethyan Rosso Ammonitico lithofacies. In order to revise the stratigraphy (sedimentology, microbiofacies, ammonite and calpionellid biostratigraphy, isotope stratigraphy) and to define a reference section, a well exposed succession of Rosso Ammonitico, spanning the Callovian-Upper Berriasian interval, has been selected in the eastern sector of Monte Inici, Trapani province. A sedimentological study has enabled us to distinguish three subfacies within the Rosso Ammonitico: nodular, pseudo-nodular, and intraclastic nodular subfacies. The two latter subfacies are characterized by the presence of intraclasts produced largely by mechanical abrasion, that suggest a formation by hydrodynamic processes. Increasing hydrodynamic energy is inferred from Lower Kimmeridgian to Upper Berriasian deposits. The vertical evolution of the microfacies shows the greatest skeletal diversity in the Middle Oxfordian, coinciding with a peak of delta 13 C. Ammonites are abundant in the Middle Oxfordian-Lower Kimmeridgian, where several ammonite zones have been recognized. With the aid of calpionellids we have been able to identify the Jurassic-Cretaceous boundary and to recognize high frequency biostratigraphic intervals in the Berriasian, that can be correlated throughout palaoetethys. The delta 13 C curve shows a marked positive peak at the base of the section (Lower to Middle Callovian) and a second, composite, positive excursion in the Middle-Upper Oxfordian. From the base of the Kimmeridgian, delta 13 C values slowly decrease, remaining low in the Berriasian. Oxygen isotope values exclude late burial diagenetic overprinting and the carbon peaks are interpreted as reflecting carbon cycle perturbations due to high biological productivity that may mirror global palaeoenvironmental variations. The Middle Oxfordian peak coincides with the highest skeletal diversity, with the first occurrence of the nodular facies, and with the onset of cherty limestones (lateral equivalents of radiolarites) in the southern sector of Monte Inici, and in localities to the west and north. The heteropy between Rosso Ammonitico and radiolarites s.l. suggests that sedimentation was controlled by local palaeotopography.

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Al-Suwaidi, Ahmed S., et Sabah K. Aziz. « Sequence stratigraphy of Oxfordian and Kimmeridgian shelf carbonate reservoirs, offshore Abu Dhabi ». GeoArabia 7, n^o 1 (1 janvier 2002) : 31–44. http://dx.doi.org/10.2113/geoarabia070131.

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ABSTRACT Carbonate reservoirs on the eastern flank of the Oxfordian-Kimmeridgian intrashelf basin in offshore Abu Dhabi had received little attention until commercial oil accumulations in structural traps were discovered in the late 1980s and early 1990s. In order to clarify the geometric and chronostratigraphic relationships of the Oxfordian-Kimmeridgian reservoirs, a multidisciplinary study (seismic, lithobiofacies, geochemistry, strontium isotope dating, and well-log data) was used to develop a sequence stratigraphic model. After deposition of the Callovian upper Araej Formation, a differentiated carbonate platform was established in the early Oxfordian in offshore and western onshore Abu Dhabi. Tectonic subsidence coupled with sea-level fluctuations controlled the geometry, deposition, and distribution of the lithofacies. These ranged from organic-rich, limy mudstones in the basinal area, to porous and permeable bioclastic packstones, grainstones, and dolomites in shallow waters on the eastern flank of the intrashelf basin. The upper Kimmeridgian Arab-D Member of the Arab Formation overlies the basinal deposits. Three third-order Depositional Sequences were identified in the offshore area. They are named according to their contained Maximum Flooding Surface; a fourth sequence is an intermediate unnamed Depositional Wedge. Depositional Sequence Jurassic 50 is of Oxfordian age and was deposited during transgressive and highstand periods. The lower Kimmeridgian Depositional Sequence Jurassic 60 is a well-defined lowstand system tract overlain by short-lived transgressive and highstand system tracts. Overlying Depositional Sequence Jurassic 60 is the Depositional Wedge. Finally, Depositional Sequence Jurassic 70 consists of transgressive and highstand system tracts developed on an undifferentiated platform that had localized depressions in the west. The best reservoir developments are in highstand bioclastic packstones and grainstones below the type-1 sequence boundaries that cap Depositional Sequences Jurassic 50 and Jurassic 60. The reservoir units have porosities greater than 20 percent and permeabilities of more than 1,000 milliDarcies. The basinal facies of Depositional Sequence Jurassic 50 have the best source-rock potential in the intrashelf basin.

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LEFORT, APOLLINE, YANN HAUTEVELLE, BERNARD LATHUILIÈRE et VINCENT HUAULT. « Molecular organic geochemistry of a proposed stratotype for the Oxfordian/Kimmeridgian boundary (Isle of Skye, Scotland) ». Geological Magazine 149, n^o 5 (7 février 2012) : 857–74. http://dx.doi.org/10.1017/s0016756811001117.

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AbstractThe composition of the soluble organic matter of the Oxfordian–Kimmeridgian Flodigarry Shale Member (Isle of Skye, Scotland) is presented for the first time. A continuous succession of silty clays and nodular limestone beds is exposed on a rocky shore to the north of Staffin Bay. This succession is proposed as a potential stratotype of the boundary between the Oxfordian and Kimmeridgian stages. This paper points out the exceptional preservation and very low thermal degradation of the organic matter. Indeed, the molecular composition is characterized by the abundance of unsaturated biomarkers (hopenes and diasterenes) as well as undamaged bioterpenoids (ferruginol and sugiol). The abundance of long-chainn-alkanes characterized by an odd-over-even predominance reveals a dominant continental contribution. This is also attested to by the relatively high amounts of plant biomarkers (e.g. ferruginol, sugiol, cadalene and retene), which suggest a palaeovegetation largely composed of pinophytes, especially Cupressaceae, Taxodiaceae and Cheirolepidiaceae, on the nearest emerged lands. The water column of the depositional environment was oxic in its upper part and rather dysoxic in its lower part. The composition of the organic matter does not significantly change along the Flodigarry Shale Member. In other words, no evolutionary events or drastic change in palaeoenvironments can be deduced from the molecular content of these sedimentary rocks, and it does not allow us to support a precise location for the Oxfordian/Kimmeridgian boundary in the succession.

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Gasparini, Zulma, et Manuel A. Iturralde-Vinent. « The Cuban Oxfordian herpetofauna in the Caribbean Seaway ». Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 240, n^o 3 (8 septembre 2006) : 343–71. http://dx.doi.org/10.1127/njgpa/240/2006/343.

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Basha, Sa'd H. S. « Callovian-Oxfordian foraminifera and ostracodes from northwestern Jordan ». Neues Jahrbuch für Geologie und Paläontologie - Monatshefte 1997, n^o 10 (10 janvier 1997) : 585–95. http://dx.doi.org/10.1127/njgpm/1997/1997/585.

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Wyn ap Gwilym Hughes, G. « Calcimicrobe tubules in uppermost Jurassic Arab-A carbonates of Saudi Arabia ». GeoArabia 15, n^o 1 (1 janvier 2010) : 17–26. http://dx.doi.org/10.2113/geoarabia150117.

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ABSTRACT Uppermost Jurassic carbonates from the Arab-A Member of the Arab Formation in the subsurface of eastern Saudi Arabia reveal hollow, intertwined, locally bifurcating, microtubules consisting of a chain-like, uniserial series of inaperturate, stacked, concavo-convex crescentic chambers tentatively assigned to Gahkumella sp. Previously confined to the Oxfordian of North America, and possibly the Lower Cretaceous of Oman, this is believed to be the first observation of such forms in uppermost Jurassic carbonates. The carbonates consist of a lower, transgressive, ooid-foraminiferal lithofacies and an upper, regressive, stromatolite-ostracod lithofacies of which the microtubules are developed in the latter. Comparison of these structures with fossil and Recent cyanobacterial microborings and Oxfordian calcimicrobial tube-like forms suggests probable cyanobacterial affinity. Despite their very limited stratigraphic extent, they may contribute to improving mouldic microporosity of the Arab-A carbonate reservoir.

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Ewin, Timothy A. M., et Ben Thuy. « Brittle stars from the British Oxford Clay : unexpected ophiuroid diversity on Jurassic sublittoral mud bottoms ». Journal of Paleontology 91, n^o 4 (3 avril 2017) : 781–98. http://dx.doi.org/10.1017/jpa.2016.162.

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AbstractThree new ophiuran species, Enakomusium whymanae n. sp., Aspidophiura? seren n. sp., and Ophiotitanos smithi n. sp., and an unnamed specimen assignable to the genus Dermocoma are described from the Callovian to Oxfordian Oxford Clay Formation of Great Britain. These determinations are based on new finds and a critical reassessment of historic specimens. The Oxford Clay ophiuroids represent two loose assemblages, one from the middle Callovian Peterborough Member and the other from the lower Oxfordian Weymouth Member. Both assemblages accord well with coeval midshelf mud bottom ophiuroid communities in terms of taxonomic composition and relative abundance of taxa. The British Oxford Clay ophiuroids are particularly significant as they are one of the rare instances where multiple species are represented, almost exclusively, by exceptionally preserved articulated skeletons. This provides an important window into the understanding of mid-Upper Jurassic ophiuroid paleobiology.

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Novikov, I. A., A. A. Razumovskiy, Yu V. Yashunskiy, A. A. Alexandrov, E. A. Molkova et P. P. Fedorov. « (Fe-Ca-Al)-phosphate mineralization enriched with rare earth elements in the sediments of the middle Jurassic paleovalley (Shankinka Occurrence, Moscow Region, central part of the Russian Plate) ». Литология и полезные ископаемые, n^o 2 (6 juillet 2024) : 223–44. http://dx.doi.org/10.31857/s0024497x24020051.

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A new occurrence of phosphate mineralization – named Shankinka – has been explored in the mouth of the Fed’kovskaya river in the Ruza District of the Moscow region, of which, the most common mineral phases include delvauxite, mitridatite, fluorapatite and crandallite. It has been established that all the Fe-Ca-Al phosphates occurrences in the region are associated with the Bajocian-Bathonian paleovalleys embedded in the Carboniferous rocks and partially filled with Callovian sediments. The structural features of the phosphatization zone as well as its enrichment with Co, Ni, Zn, Cu, and REE indicate a possible link between the Oxfordian organic-rich sediment and phosphate mineralization. It can be assumed that epigenetic phosphate mineralization was a result of the seepage of phosphorus-rich pore waters released from the Oxfordian organic-rich sediment into the underlying Callovian permeable rocks rich in iron minerals.

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Larsen, Michael, et Finn Surlyk. « Shelf-edge delta and slope deposition in the Upper Callovian – Middle Oxfordian Olympen Formation, East Greenland ». Geological Survey of Denmark and Greenland (GEUS) Bulletin 1 (28 octobre 2003) : 931–48. http://dx.doi.org/10.34194/geusb.v1.4695.

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The Upper Bajocian – Upper Volgian succession of the Jameson Land Basin in East Greenland forms an overall transgressive–regressive cycle. The Upper Callovian – Middle Oxfordian Olympen Formation represents the first regressive deposits after maximum flooding in the Middle to early Late Callovian. The formation was deposited during two southwards progradational phases separated by a major drowning event in the Early Oxfordian. The first phase was marked by incoming of massive slope and base-of-slope sand (Athene Member), but the delta front and top did not reach the area of present-day exposure. The second phase was initiated by deposition of a thick mud succession (Hades Member) indicating that the delta had shifted far to the north during the drowning event. Southwards progradation of the delta was heralded by gully erosion and the deposition of lenticular bodies of massive slope sand; on this occasion, medium- and largescale cross-bedded sand of the delta front and top (Zeus Member) reached the area. The boundary between Middle–Upper Callovian mudstones in the upper part of the underlying Fossilbjerget Formation and the Upper Callovian Athene Member sandstones formed at the turn-around point between sea-level rise and fall. The Athene Member sandstones are interpreted as an undifferentiated falling stage – lowstand systems tract and span a sequence boundary. The top of the Athene Member is the basinal correlative of the transgressive surface. The basal few metres of the overlying Hades Member mudstones represent the transgressive systems tract and a level with organic-rich mudstones is interpreted to represent the maximum flooding zone. The remainder of the Hades Member and the slope sandstones are assigned to the highstand systems tract. The succeeding cross-bedded delta front sandstones of the Zeus Member are placed in the falling stage systems tract and their sharp base is interpreted as a marine regressive surface of erosion. Comparison of this history with published sea-level curves suggests that the short term changes may be eustatic in origin including the Middle Callovian maximum flooding (K. jason – lower P. athleta Chronozones), Late Callovian regression (P. athleta – Q. lamberti Chronozones), latest Callovian – Early Oxfordian flooding (Q. mariae – C. cordatum Chronozones) and late Early – Middle Oxfordian regression (C. densiplicatum Chronozone).

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Zhabina, N. M. « COMPLEX BIOSTRATIGRAPHIC SCHEME OF THE JURASSIC DEPOSITS OF THE PIENNINE ZONE OF THE UKRAINIAN CARPATHIANS ». Geological Journal, n^o 3 (8 octobre 2021) : 48–73. http://dx.doi.org/10.30836/igs.1025-6814.2021.3.228194.

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The article summarizes the results of the study of paleontology and biostratigraphy of the Jurassic of the Piennine Zone of the Ukrainian Carpathians by domestic and foreign researchers. For the first time, a summary paleontological description of these sediments is presented, taking into account numerous published data on identified macro- and mictofossils. A correlation biozonal scale has been created, as well as complex biostratigraphic schemes for each Jurassic series of its region in accordance with the International Stratigraphic Scale (2020). Because the stratigraphic sequence was disturbed by disjunctive dislocations, these schemes were developed by analysis of fragmentary sections. At present, three series of the Jurassic are determined by ammonites, belemnites, pelecypods, brachiopods, the Lower and Upper series are also dated by dinocysts, the Upper also by foraminifera and tintinnids. The stages and standard zones of the modern international scale are determined by ammonites: Liasicus of the Gettangian; Bucklandi, Obtusum, Raricostatum of the Sinemurian; Jamesoni, Emaciatum of the Pliensbachian; Tenuicostatum, Serpentinum, Bifrons, Thouarcense of the Toarcien; Opalinum, Murchisonae, Bradfordensis, Concavum of the Aalenian; Propinquans, Humpriesianum, Parkinsoni of the Bajocian; Zigzag, Aurigerus, Subcontractus, Bremeri, Retrocostatum of the Bathonian; Athletа of the Callovian; Plicatilis і Bifurcates of the Oxfordian; Divisum, Acanticum і Cavouri of the Kimmeridgian. Continuous dinocyst zonation is traced in the Upper Jurassic – Fibrata Аcme (Upper Oxfordian), Parvula Acme, Moluccana і Borzai (Kimmerigian), Pulla, Tithonica, Malmica, Semiradiata (Lower Tithonian) and all standard tintinnide zones of Tithonian — Chitinoidella (підзони Dobeni і Boneti), Praetintinnopsella, Crassicollaria. The boundaries of the stages from the Gettangiean to the Oxfordian are not determined. The boundaries between the Lower and Upper Oxfordian as well as between the Kimmeridgian substages are determined by ammonites as well as the boundary between the Kimmeridgian and Tithonian is determined by dinocysts, and the boundary between the Jurassic and Cretaceous is determined by tintinnids (corresponds to the boundary between the zones Crassicollaria of Tithonian and Calpionella of Berriassian). Stratigraphic unconformities were revealed by the macro- and mictofossils: the regional erosion on the boundary between the Aalenian and Bajocian as well as in Early Callovian, and short gap on the boundary between the Lower and Upper Bajocian.

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Delage, P., H. Menaceur, A. M. Tang et J. Talandier. « Suction effects in deep Callovo-Oxfordian claystone ». Géotechnique Letters 4, n^o 4 (29 septembre 2014) : 267–71. http://dx.doi.org/10.1680/geolett.14.00062.

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