Kimmeridgian-Tithonian sea-level fluctuations in the Uljanovsk-Saratov Basin (Russian Platform)

Abstract The Uljanovsk-Saratov Basin, located in the southeast of the Russian Platform, presents an intriguing record of the Kimmeridgian-Tithonian sea-level fluctuations. In the Late Jurassic, this basin was a trough within the Interior Russian Sea. The data available from both outcrops and boreholes have permitted outlining a number of lithostratigraphic units and regional hiatuses in the northeastern segment of the Uljanovsk-Saratov Basin, thus permitting a precise reconstruction of transgressions/regressions and deepenings/shallowings. In total, three transgressive-regressive cycles and two deepening pulses have been established. These regionally documented changes were both related in part to global eustatic changes, and they also corresponded in part to the regional sea-level changes in some basins of Western Europe and Northern Africa, but not to those of the Arabian Platform. Differences observed between the global and regional curves as well as rapid Tithonian sea-level oscillations are explained by the influences of tectonic activity. It is hypothesized that the regional Tithonian oxygen depletion might have been a consequence from the rapid flooding of a densely vegetated land

Ammonite Faunal Dynamics Across Bio-Events During the Mid-and Late Cretaceous Along the Russian Pacific Coast

Jagt−Yazykova, E.A. 2012. Ammonite faunal dynamics across bio−events during the mid − and Late Cretaceous along th

Volgian and Santonian–Campanian radiolarian events of the Russian Arctic and Pacific Rim

Radiolarians are widely distributed in two siliceous intervals that coincide with the Tithonian–Berriasian and Santonian–Campanian boundaries in the Mesozoic of the Russian Arctic and Pacific Rim. The first level is rich in organic matter and typical of Jurassic–Cretaceous boundary strata from the Russian North European Margin (Barents−Pechora, Volga−Urals, and Siberian hydrocarbon provinces, as well as western Kamchatka). Abundant and diverse representatives of the family Parvicingulidae provide a basis for establishing the new genus Spinicingula (uppermost Middle Volgian–Lower Berriasian); another new genus, Quasicrolanium (Upper Volgian–Upper Berriasian) is also described. A Santonian– Campanian siliceous interval with radiolarians is documented from the margins of northern Asia (eastern Polar Ural, Kara Basin, Kamchatka). The Boreal genus Prunobrachium makes its first appearance at the Santonian–Campanian boundary and reaches an acme in Campanian strata. Radiolarian data can be used for basin biostratigraphy and correlation, as well as palaeogeographical interpretation of these hydrocarbon−rich facies. The Arctic and northern Pacific rims are well correlated on the basis of parvicingulids, while in Sakhalin these are absent and calibrations are based on Unitary Associations zones of the Tethys. In addition to the two new genera noted above, five new species (Parvicingula alata, Parvicingula papulata, Spinicingula ceratina, Lithostrobus borealis, and Spongurus arcticus) are erected, while 60 radiolarian species typical of the Russian Arctic and Pacific rims are illustrated

ЗАГАДКОВА БУДОВА ДЕЯКИХ СПІКУЛЬНИХ ЕЛЕМЕНТІВ ГУБОК, РАДІОЛЯРІЙ І НАНОТЕХНОЛОГІЇ

A comparison of siliceous sponge spicules with radiolarian spines and spicules from different time intervals of the Cretaceous (Albian-Cenomanian, Santonian-Campanian) and recent sediments has been carried out. Details of the structure of microspicules and radiolarian spines have been illustrated for the first time. An assumption that radiolarians may have originated from sponges is made. The potential of application of nature structures in nanotechnologies is shown.В статье проведено сравнение кремневых спикул губок со спикулами и иглами радиолярий из некоторых интервалов мела (альб-сеноман, сантон-кампан) и современных осадков. Впервые проиллюстрированы детали строения микросклер и скелетных игл радиолярий, рассмотрены структуры их сочленения. Сделано предположение о возможном происхождении радиолярий от кремневых губок, показана возможность использования природных структур при разработке нанотехнологий.Проведено порівняння крем’яних спікул губок зі спікулами і голками радіолярій з деяких інтервалів крейди (альб-сеноман, сантон-кампан) та сучасних осадків. Вперше проілюстровані деталі будови мікросклер і скелетних голок радіолярій; розглянуті структури їх зчленування. Зроблено припущення про можливе походження радіолярій від крем’яних губок. Показана можливість використання природних структур при розробці нанотехнологій