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Eco-biostratigraphic advances in late Quaternary geochronology and palaeoclimate : the marginal Gulf of Mexico analogue

Antonarakou Assimina, Kontakiotis George, Karageorgis Aristomenis P., Besiou Eva, Zarkogiannis Stergios, Drinia Hara, Mortyn Graham P., Tripsanas Efthymis

Geological Quarterly

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2019

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Vol. 63, No. 1

178--191

EN

This study combines high-resolution planktonic foraminiferal eco-biostratigraphy and palaeoclimatic data from the high-sedimentation-rate core J PC-26 from the northwestern margin of the Gulf of Mexico (GoM). The eco-biozones recognized (GOMPFE1-12) being correlated with published Mg/Ca-based sea surface temperatures. This updated palaeoclimatic and stratigraphic reference record facilitates correlations with the Greenland ice core events and their climatic relationships, and also provides a solid stratigraphic framework for correlations with other palaeoclimatic and palaeoceanographic records in the circum-GOM/Caribbean region. This multidisciplinary approach underlines the utility of supporting conventional dating methodologies with different constraints, and further reveals a powerful tool for reliably correlating marine records between comparable deep-sea marginal settings and coeval sequences of this region.

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Integrated stratigraphy of the reference sections for the Callovian-Oxfordian boundary in European Russia

Kiselev D., Rogov M., Glinskikh L., Guzhikov A., Pimenov M., Mikhailov A., Dzyuba O., Matveev A., Tesakova E.

Volumina Jurassica

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2013

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Vol. 11, no. 1

59–-96

EN

The most complete succession of the Callovian-Oxfordian boundary recorded in European Russia is the Dubki section, where the authors have carried out integrated paleontological and magnetostratigraphical studies. A continuous sequence of the West-European biostratigraphic units in the interval from the Lamberti to the Cordatum Zones is present in this section, and 10 ammonite biohorizons have been recognized. Additional data concerning nannofossil assemblages, foraminifers, ostracods, belemnoids and the paleomagnetic polarity for the Dubki section are also presented. The Callovian-Oxfordian boundary, marked by FAD of the genus Cardioceras, is placed at the base of the scarburgense biohorizon. The paleontological richness and continuity of the succession make the Dubki section a possible GSSP candidate for the Callovian/Oxfordian boundary. Correlation of the Dubki ammonite succession with those of the other GSSP candidates, Redcliff Point and Thuoux, is proposed. Other sections studied in Russia have yielded some additional observations on the Callovian-Oxfordian boundary beds. Although in the Dubki section the praemartini biohorizon is not found, its existence is proved, however, in Orenburg region (Khanskaya Gora). In the Datchovskaya section (Northern Caucasus) the paucicostatum biohorizon is characterized by an unusual combination of Subtethyan and Boreal ammonites, including Kosmoceras, which is not typical of the paucicostatum biohorizon outside the Northern Caucasus.

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Facies and integrated stratigraphy of the Upper Turonian (Upper Cretaceous) Grossberg Formation south of Regensburg (Bavaria, southern Germany)

Niebuhr B., Richardt N., Wilmsen M.

Acta Geologica Polonica

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2012

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Vol. 62, no. 4

595-615

EN

The Upper Turonian Grossberg Formation of the Regensburg area (Danubian Cretaceous Group, Bavaria, southern Germany) has a mean thickness of 20-25 m and consists of sandy bioclastic calcarenites and calcareous sandstones which are rich in bryozoans, serpulids and bivalves (oysters, rudists, inoceramids). Eight facies types have been recognized that characterize deposition on a southward dipping homoclinal ramp: the inner ramp sub-environment was characterized by high-energy sandwave deposits (sandy bioclastic rud- and grainstones, bioclastic sandstones) with sheltered inter-shoal areas. In mid-ramp settings, bioturbated, glauconitic, calcareous sand- and siltstones as well as bioturbated, bioclastic wacke- and packstones predominate. The carbonate grain association of the Grossberg Formation describes a temperate bryomol facies with indicators of warm-water influences. An inferred surplus of land-derived nutrients resulted in eutrophic conditions and favoured the heterozoan communities of the Grossberg Ramp. Carbon stable isotope geochemistry cannot significantly contribute to the stratigraphic calibration of the Grossberg Formation due to the depleted and trendless bulk-rock [delta^13]C values, probably resulting from a shallow-water aquafacies with depleted [delta^13]C DIC values and low [delta^13]C values of syndepositional and early diagenetic carbonate phases. However, strongly enriched skeletal calcite [delta^13]C values support a correlation of the Grossberg Formation with the mid-Late Turonian positive Hitch Wood isotope event (Hyphantoceras Event of northern Germany). This interpretation is supported by biostratigraphic data and a range from the Mytiloides striatoconcentricus Zone into the lower My. scupini Zone is indicated by inoceramid bivalves. Both the base and top of the Grossberg Formation are characterized by unconformities. Sequence boundary SB Tu 4 at the base is a major regional erosion surface (erosional truncation of the underlying Kagerhoh Formation in the Regensburg area, fluvial incision at the base of the Seugast Member of the Roding Formation in the Bodenwohr area towards the north and northeast). It is suggested that this unconformity corresponds to a major sea-level drop recognized in many other Cretaceous basins below the Hitch Wood or Hyphantoceras Event. The transgression and highstand of the Grossberg Formation is concomitant to the deposition of the fluvial Seugast Member and the onlap of the marginal-marine. Veldensteiner Sandstein. onto the Frankische Alb. The unconformity at the top of the Grossberg Formation (late Late Turonian SB Tu 5) is indicated by a ferruginous firm-/ hardground and an underlying zone of strongly depleted [delta^13]C values. The abrupt superposition by deeper marine marls of the lower Hellkofen Formation (uppermost Turonian.Lower Coniacian) may be connected with inversion tectonics at the southwestern margin of the Bohemian Massif.

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Occurrence and significance of Cenomanian belemnites in the lower Danubian Cretaceous Group (Bavaria, southern Germany)

Wilmsen M., Niebuhr B., Chellouche P.

Acta Geologica Polonica

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2010

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Vol. 60, no. 2

231-241

EN

The belemnite records of the lower Danubian Cretaceous Group (DCG, northeastern Bavaria, southern Germany) are compiled, taxonomically described and placed within the new integrated stratigraphic framework of the group. Three specimens from the lower Regensburg Formation (Saal Member) south of Regensburg can be assigned to Neohibolites cf. ultimus (d'Orbigny) and are dated as late Early Cenomanian (Mantelliceras dixoni Zone). Eight specimens represent Praeactinocamax plenus (Blainville) and occur in an event (plenus Event) in the lower Eibrunn Formation (Regensburg area) or basal Regensburg Formation (Roding area in the Bodenwohrer Senke). Biostratigraphy and carbon stable isotopes suggest that the belemnite horizon with P. plenus in the DCG has strictly the same chronostratigraphic position (mid-Late Cenomanian, middle Metoicoceras geslinianum Zone) as elsewhere in Central and NW Europe. The lithostratigraphic units of the lower Danubian Cretaceous Group (i.e., the Regensburg and Ebirunn formations), however, are characterized by a pronounced diachronism based on their time-transgressive (i.e., onlapping) deposition during the Cenomanian.Early Turonian transgression. The distribution of P. plenus around the Mid-European Island can be easily explained by migration around the positive area without the necessity of a marine strait across the Bohemian Massif.

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Jurassic Chronostratigraphic Database and the TimeScale Creator Visualization System

Ogg J., Przybylski P.

Volumina Jurassica

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2009

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Vol. 7, no. 1

175-179

EN

A joint project of the International Commission on Stratigraphy (ICS) and CHRONOS database program is to provide detailed global and regional “reference” scales of Earth history. Such scales integrate biostratigraphy (zones, datums for marine and terrestrial realms), sea-level (curves, sequences), geochemistry (trends, events), magnetic polarity chrons and astronomical cycles. The current Jurassic scale contains over 1000 events and zones correlated to Tethyan and Boreal ammonite zones with approximate numerical ages from Geologic Time Scale 2004 (Gradstein et al. 2004). This public database will be progressively enhanced through the efforts of the Jurassic Subcommission of the ICS and by other stratigraphic and regional experts. On-screen display and production of usertailored time-scale charts is provided by the TimeScale Creator, a Java package freely available from the ICS Subcommission for Stratigraphic Information or the TS-Creator websites (http://stratigraphy.science.purdue.edu or www.tscreator.org). After specifying the time interval and vertical scale, a user selects a subset of stratigraphic columns and trends. In addition to screen views and a scalable-vector graphics (SVG) file for importation into popular graphics programs, the on-screen display also has “hot-curser-points” to open windows providing additional information on events, zones and boundaries. The database and visualization package are envisioned as a convenient reference tool, chart-production assistant, and a window into the geologic history of our planet.

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The Triassic/Jurassic boundary beds of the Karwendel Syncline (Austria) - initial report of a new GSSP candidate for the base of the Jurassic

von Hillebrandt A., Krystyn L., Kuerschner W.

Volumina Jurassica

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2006

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Vol. 4, no. 1

287-288

EN

The northwestern part of the Northern Calcareous Alps (NCA) is famous for its fully marine and complete Triassic/Jurassic transition beds formed in an intraplatform through of the western Tethys called as Eiberg Basin (Krystyn et al. 2005). A classic boundary section (Kendlbachgraben) with a relatively rich Rhaetian invertebrate fauna is known since 150 years but with the handicap of a 15 m gap between the last Triassic (Choristoceras marshi) and the first Jurassic ammonite (Psiloceras calliphyllum). A wealth of macro- and microfaunistic information has since been added (Golebiowski 1990) favouring a TJB directly on top of the Koessen Formation (Eiberg Member), just above the disappearance of many Triassic fossil groups (ammonoids, conodonts, brachiopods). New palynological and isotopic research in the area (Kuerschner et al. in press) now points to a boundary located 6 m higher within the Tiefengraben Member (or Grenzmergel) of the lower Kendlbach Formation where along with a distinct δ ¹ ³C shift the appearance of Cerebropollenites thiergatii marks the onset of Jurassic palynomorphs (Fig. 1). Another drastic negative C isotope excursion occurs at the top of the Koessen Formation concomitant with the disappearance of Triassic macrofauna, and both isotopic events can be recognized in boundary sections in England, Greenland and Nevada. The Triassic/Jurassic boundary (TJB) beds of the Karwendel Syncline (northern Tyrol) are well exposed at many places, easily correlatable by palynology (Fig. 1) and show a thicker (about 20 m), lithologically different, marl-dominated Tiefengraben Member with reddish clays ("Schattwald beds" auct.) at the base. They are richer and more diverse in micro- and macrofauna, and they contain an ammonite horizon around 7 m above the Koessen top with a new psiloceratid ammonite unknown from Europe and the Tethys realm. Based on its less intended suture line, the involute conch (umbilical width 40%) and juvenile tubercles (Knötchenstadium) the species is close to the South American earliest psiloceratid P. tilmanni but differs in a subtriangular cross-section. The new "Liassic" ammonite layer corresponds closely to the turnover in the Forminifera and to the onset of "Jurassic" ostracods (e.g. Cytherelloidea pulchella) as well as palynomorphs, with C. thiergatii as a first order correlation tool to marginal marine and continental basins. Bivalves in the basal Grenzmergel may bridge the present macrofaunal gap down to the Koessen Formation top but have still to be evaluated; a nannoplankton analysis is already under way. The investigated sections provide an important new insight in the nature of the physical and biological changes occurring around the boundary with rapidly changing palynomorph associations that point to several short-termed climatic oscillations. In which way they have affected the environmental conditions across the TJB and have controlled the stratigraphic ranges of biomarkers will be an important issue of the ongoing studies. Irrespective of any extinction scenario we see the fossil and geochemical record of the Karwendel Syncline as a major improvement of our knowledge of this time interval and as justified reason to introduce there a section as GSSP candidate for the Triassic/Jurassic boundary.

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Dubki (Saratov region, Russia), the reference section for the Callovian/Oxfordian boundary

Kiselev D., Rogov M., Guzhikov A., Pimenov M., Tesakova E., Dzyuba O.

Volumina Jurassica

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2006

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Vol. 4, no. 1

177-179

EN

Efforts in the choosing of GSSP for the Cl/Ox boundary have led to distinction of some available sections with good succession of the ammonite faunal horizons in the vicinities of Saratov. One of the primary criteria for GSSP proposal is the good traceability across the world, and hence, the study of reference section (especially in the region with mixed faunas) in the terms of integral stratigraphy. Additional importance of the investigation of the reference sections for the Cl/Ox boundary is connected with wide distribution of the condensed facies and gaps perhaps due to the suggested sharp changes in climate of the Northern Hemisphere. Few variants of the infrasubzonal units for the Cl/Ox transitional beds of the Russian Platform were suggested recently. Here we are using the scheme of Kiselev and Rogov (2005). The Dubki section is located few kilometers north from Saratov and originally was a temporary quarry for the nearby road-building. Recently this section and/or ammonites from this section were briefly described by Mitta (Keupp & Mitta 2004) and by the present authors (Rogov & Egorov 2003). In addition, this section has recently been proposed as possible candidate for the Cl/Ox GSSP (Kiselev & Rogov 2004). Precise ammonite sampling permits establishing a succession of faunal horizons close to that of Northwest Europe (Fig. 1). Inclined boundaries between some horizons in the figure mean short transitional span, where index species (or both morphologies in lineage) co-occur. Only ranges of the few, most important taxa are shown. Strong Tethyan influence is fixed in the mojarowskii and baccatum horizons, while Boreal cardioceratids dominate in the other intervals. Among the Belemnitida two main groups are recorded. Belemnotheutids are generally scarce; they range from Henrici to Praecordatum subzones. Belemnitids are typically of Tethyan origin (Hibolithes). Boreal forms are common only in two restricted levels. Ostracods are numerous and diverse. However, they show wide oscillations in these two characters through the section, possibly reflecting sea-level changes. Remarkably, Infacythere dulcis is replaced by Nophrecythere oxfordiana at the Cl/Ox boundary as determined by ammonite biostratigraphy. Quite exceptionally, some levels in the studied section provided good samples for magnetostratigraphic studies across the Cl/Ox boundary. Lamberti Zone is chiefly characterized by normal polarity, whereas Mariae and Cordatum zones show dominant reverse polarity, corresponding to polarity structure of the M-35-M37 Chrons (Ogg 2004).

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A multi-proxy study of the Kimmeridgian/Volgian boundary beds in the Gorodischi section (Middle Volga area, Russia), the lectostratotype of the Volgian Stage

Rogov M., Schepetova E., Ustinova M., Price G., Guzhikov A., Pimenov M., Dzyuba O.

Volumina Jurassica

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2006

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Vol. 4, no. 1

208-210

EN

The Gorodischi section is one of the most famous and well-studied sections among the Russian Jurassic. This section was chosen as lectostratotype of the Volgian Stage by Gerasimov & Mikhailov (1966). Following by the proposals of Cope (1996) regarding the acceptance of secondary standards, Zakharov (2003) suggested Gorodischi as Secondary Stratotype Section and Point for the Volgian Stage. In spite of the small thickness of Volgian rocks, recent studies show an absence of biostratigraphically significant gaps within the whole Volgian Stage (Kiselev & Rogov 2005). The ammonite succession consists of a mixture of Subboreal, Boreal and Submediterranean taxa, with an alternation of the dominant groups through the section, providing a highly accurate correlation of the Lower Volgian with the Tithonian Stage and Arctic Volgian. The succession of Neochetoceras has particular significance for the correlation of the Kimmeridgian/Volgian and Kimmeridgian/Tithonian boundaries, which is also marked by disappearance of aulacostephanids. Among the belemnites Boreal and Subboreal taxa are predominate with exception of the neoburgense horizon, rich in small Hibolithes. Nannofossil samples were collected from only part of the section, but changes in calcareous nannofossils permit the identification of the Boreal Zones N16-N17 (Fig. 1). Both sedimentologic, isotopic and petromagnetic data reflect rapid sea level fluctuation during the Kimmeridgian-Volgian transition. The character of the oscillations of the saturation remanent magnetization (Jrs) and growth of magnetic susceptibility after heating the rocks up to 500°C in air (dk) allows the recognition of three successive zones (I-III). The alternation of the light and dark clays reflects irregularities in the nannofossil versus organic matter abundance. Numerous features of the short gaps could be traced by the ammonite accumulations, sometimes associated with zonal phosphate nodules and in few cases by numerous belemnites. The frequency of condensed levels increases significantly from Kimmeridgian into the Volgian, simultaneously with a gradual coarsening of the terrigenous matter. The character of sedimentation as a whole reflects slow input of terrigenous rocks and oscillations in productivity of calcareous nannoplankton, controlled by climate change and eustasy. The changes in lithology testify to progressive shallowing of the sea basin and increasing of the sensitivity of sedimentation against sea level changes.