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1

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.

2

The problem of establishing the Tithonian Stage in Western Siberia

Podobina V., Gabysheva E., Tatyanin G.

Volumina Jurassica

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2006

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Vol. 4, no. 1

205-206

EN

In 1996 the Volgian Stage was withdrawn from the General Stratigraphic Scale and replaced with the Tithonian Stage by the Resolution of the Interdepartmental Stratigraphical Committee of Russia. However, this did not solve the problem of correlation between the Volgian and Tithonian stages. The problem of identifying and mapping the Tithonian Stage within the Boreal deposits becomes unresolved. On this basis the Volgian Stage was retained in the West Siberian Stratigraphical Scale as the terminal Jurassic Stage, owing to the impossibility of the application of the new standard directly to the Boreal sections. The difficulties in comparison between the Regional Scale and the Standard one arise not only for the ammonite zones, but also in correlating the West Siberian foraminiferal zones. Numerous boreholes penetrating Western Siberia and combined studies on core samples enable tracing the continuous sequence of the Volgian foraminiferal zones and beds. The foraminiferal sequence traced through the Nyarginskian type section in the southeast of Western Siberia may serve as an example. There, in the Upper Kimmeridgian – Lower Volgian deposits, the f-beds with the Pseudolamarkina sp. Assemblage were established. The Middle Volgian Spiroplectammina vicinalis-Dorothia tortuosa F-zone was divided into two subzones: the lower Spiroplectammina vicinalis-Saracenaria pravoslavlevi subzone and the upper Dorothia tortuosa subzone The Upper Volgian deposits enclose the Ammodiscus veteranus-Evolutinella volossatovi F-zone. At the Jurassic/Cretaceous boundary, the taxonomy of benthic Foraminifera is essentially different. The phylogenetic succession of numerous foraminiferal genera during the Volgian Age indicates the integrity of the Volgian Stage. A number of genera are characteristic only for the Volgian. Benthic Foraminifera forming the basis for establishing the Upper Jurassic assemblages, and the Volgian ones in particular, showed a wide distribution in the Late Jurassic marine basins of the Boreal belt: Northern Europe (Russia and Poland), Northeast Asia, Northern America (Northern and Northwest Canada, Northern Alaska), islands of the Arctic Region and shelves of northern seas. This wide distribution of the Volgian Foraminifera resulted from the Late Jurassic transgression. The Boreal and Tethyan foraminiferal assemblages differ essentially each other in their taxonomy, which result in significant difficulties in correlation between the Volgian and Tithonian deposits of Boreal and Tethyan belts, respectively. Besides, the distinctive feature of all provinces of the Boreal belt is the absence of planktonic foraminifers or their insignificant development. The direct correlation of the Volgian assemblages is possible only within the Boreal belt, basing on the taxonomical analysis of foraminiferal assemblages and the presence of the species of correlation value. The correlation of the Volgian-Tithonian deposits of the Boreal and Tethyan belts is feasible only at the level of Lower-Middle Volgian substages and the Tithonian. We suppose that at present it is impossible to find direct counterparts of the Upper Volgian Substage.

3

Problems on the Middle Oxfordian biostratigraphy of Western Siberia

Podobina V., Polkovnikova E., Tatyanin G.

Volumina Jurassica

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2006

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Vol. 4, no. 1

206-207

EN

The knowledge of biostratigraphy of the Middle Oxfordian part of the section of the Verkhnevasyuganskiy Subhorizon although quite good is insufficient for solving all the problems of dating, detailed correlation, and identification of sandy beds of the substantial oil-and-gas bearing deposits complex in the new borehole sections. Another cluster of problems includes the detailed subdivision of two Middle Oxfordian ammonite zones (a-zones) of Western Siberia and their correlation with the coeval Plicatilis Zone of the Submediterranean zonal scheme. At present, two a-zones are distinguished in the Middle Oxfordian of Western Siberia: the lower zone with the Cardioceras densiplicatum and the upper zone with Cardioceras tenuiserratum. Two parts are distinguished in the Cardioceras densiplicatum Zone corresponding to the Cardioceras vertebrale and Cardioceras maltonense subzones. The upper zone is not subdivided, and it is based on the appearance of ammonites of the subgenus Cawtoniceras. Foraminifera are of exceptional biostratigraphical importance when the material from cores is considered where ammonoid finds are generally rare. The Middle Oxfordian sedimentary complex of Western Siberia contains foraminiferal assemblages of two f-zones: Ammodiscus thomsi-Tolypammina svetlanae and Trochammina oxfordiana. The former includes several isochronous beds recognized in different areas of the region. In the circum-polar Urals, L. G. Dain distinguished beds with Ammodiscus thomsi, Tolypammina svetlanae. In western areas, V. I. Levina distinguished beds with Ammodiscus cheradospira (=Ammodiscus aff. pseudoinfimus (=Ammodiscus thomsi) and Eomarssonella paraconica. In the southern area, V. F. Kozyreva recognized beds with Ammodiscus ex gr. pseudoinfimus (=Ammodiscus thomsi) and Trochammina oxfordiana. In the central and southern districts, beds with Trochammina oxfordiana and with Glomospirella galinae were established by G. M. Tatyanin. The geographical range of the Ammodiscus thomsi-Tolypammina svetlanae Zone covers: Western Siberia, the Preuralian, Yamal-Tyumen, Kazym-Konda, Froly-Tambey, Pur-Vasyugan facies districts (the Danilovskoye, Abalak, Vasyugan, Maurynya formations). In the Yenisey-Khatanga depression N. V. Sharovskaya distinguished beds with Trochammina oxfordiana, Lenticulina memorabilissima, now this is the Trochammina oxfordiana Zone (its top correspond to the Ammodiscus thomsi - Tolypammina svetlanae Zone). The range of the Trochammina oxfordiana Zone covers: Western Siberia, the Khatanga and Taz-Kheta facies districts, Central Siberia, the Paksa facies district (Sigovoe Formation). The analysis on the available findings of the Middle Oxfordian ammonites in the south-east of Western Siberia may offer a key to reconciling the combined macro- and microfauna finds with the ammonite scale, and refining the lower and upper boundaries of the Middle Oxfordian foraminiferal associations. This could make possible tracing and comparing the changes in the systematic composition of the foraminiferal assemblages within two Middle Oxfordian ammonite zones which include the sections of the oil-and-gas bearing horizons.

4

Jurassic Chronostratigraphic Charts and a Display Interface. 1. Hettangian through Aalenian. 2. Bajocian through Tithonian

Przybylski P., Ogg J.

Volumina Jurassica

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2006

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Vol. 4, no. 1

199-199

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. These summarize our current consensus on the inter-calibration of events, their relationships to international divisions of geologic time and their estimated numerical ages. An initial Phanerozoic database (about 9000 events and zones in April 2006) includes definitions of geologic stages, major zonations and markers of all significant fossil groups, primary and secondary magnetic polarity scales, and other stratigraphic information. Annotations on each entry include source, reliability, selected taxonomic notes, inter-calibrations, and methods of interpolating numerical age. This database will be enhanced through the efforts of the subcommissions of the ICS and other stratigraphic and regional experts. A primary source for the Jurassic was the extensive “Mesozoic and Cenozoic Sequence Chronostratigraphic Framework of European Basins” chart series of inter-calibrated bio-, magneto-, chemoand sequence stratigraphy (Hardenbol et al. 1998) which had been calibrated to the geologic time scales of 1995. We recalibrated all these chronostratigraphic and sequence stratigraphy events to Geologic Time Scale 2004 (Gradstein et al. 2004) and included selected post-1995 biostratigraphic schemes, marker events and geochemistry correlated to Tethyan and Boreal ammonite zones. On-screen display and production of user-tailored time-scale charts is provided by the Time-Scale Creator, a JAVA package available from the ICS/CHRONOS websites (www.stratigraphy.org or www.chronos.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 (e.g., Adobe Illustrator), the on-screen display 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. We present sample output for the Jurassic portion as a pair of large-format charts: Hettangian-Aalenian by Ogg and Przybylski, and an accompanying poster for Bajocian-Tithonian by Przybylski and Ogg.

5

Palynostratigraphy of the Poozerje Glaciation (Vistulian) in Belarus

Yelovicheva Y., Sanko A.

Kwartalnik Geologiczny

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1999

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Vol. 43, Nr 2

203-212

EN

A palynological examination was applied to sediments of the last glaciation (Poozerie, Vistulian) in Belarus. Accompanied by geologic setting of deposits, as well as radiocarbon and thermoluminescence dating, the Poozerie sequence could be ascribed to three substages, i.e. Kulakovo, Dvina and Naroch. The Kulakovo substage (early Poozerie) corresponds to the oxygen isotope stage 5d-a, and comprises the West Dvina megastage with the short Black Shore interstage and the megainterstage (two stages of Mirogotshi and Sloboda, and three interstages of Chericov, Suraz and Polotsk). The Dvina substage (Pleniglacial), corresponding to the oxygen isotope stages 4 and 3, consists of the Mezin and Orsha megastages and the separating megainterstage with three middle Poozerie interstages (Turov, Shapurovo and Borisov) and two stages (Rogachevo and Michalinovo). The Naroch substage (oxygen isotope stage 2) represents the Late Glacial. There are several interstages during the Poozerie Glaciation: Chericov (Amersfoort), Suraz (Brörup), Polotsk (Odderade), Turov (Moershoofd), Shapurovo (Hengelo) and Borisov (Denekamp).

PL

Na podstawie metod palinologicznych przedstawiono podział stratygraficzny osadów ostatniego zlodowacenia (poozierskiego, wisły) na Białorusi. Badania prowadzono równolegle z badaniami geologicznymi oraz datowaniem osadów metodami radiowęgla i termoluminescencji. Wyróżniono trzy podpoziomy: kułakowski, dźwiński i naroczski. Podpoziom kułakowski, odpowiadający stadium izotopów tlenu 5d-a, składa się z megastadiału zachodniodżwińskiego i megainterstadiału (w skład którego wchodzą stadiały mirogoski i slobodski) oraz trzech interstadiałów (czerikowskiego, surażskiego i połockiego). Podpoziom dźwiński (pleniglacjał, studia izotopowe 4 i 3) zawiera dwa megastadiały (mezyński i orszański), miedzy którymi jest megainterstadiał z trzema interstadiałami (turowskim, szapurowskim i borysowskim) i dwoma stadiałami (rogaczewskim i michalinowskim). Najmłodszy podpoziom, naroczski odpowiada późnemu glacjałowi zlodowacenia poozierskiego (stadium izotopowemu 2). Odpowiednikiem interstadiału czeńkowskiego jest amersfoort, suraźskiego-brörup, połockiego - odderade, turowskiego - moershooft, szapurowskiego hengelo i borysowskiego - denekamp.