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Реконструирована палеогеография Западной Сибири в мелу. Приведены и детально описаны па-леогеографические карты для отдельных веков мелового периода, которые отражают основные этапы формирования Западно-Сибирского осадочного бассейна. Представленный авторами набор карт пост-роен исходя из модели лавинного бокового заполнения в волжско-барремское время относительно глу-боководного морского бассейна в регрессивный этап крупного седиментационного цикла. Реконструи-рован рельеф и распределение внешних источников сноса терригенного материала. Палеогеография, мел, клиноформы, лавинная седиментация, Западно-Сибирский осадочный бассейн. For paleogeographic reconstruction of the West Siberian basin during the Cretaceous we used a set of pa-leogeographic maps, which were compiled for the main epochs of the Cretaceous period. The paleogeographic maps presented in this study suggest progradational fi lling of the deep basin with avalanche-type sedimentation during Volgian-Barremian regression. The paleorelief and provenance of terrigenous sediments were reconstructed. Paleogeography, Cretaceous, clinoforms, avalanch-type sedimentation, West Siberian sedimentary basin ВВЕДЕНИЕ Ранее была рассмотрена палеогеография юры [Конторович и др., 2013]. Юрский комплекс отло-жений Западной Сибири уникально обогащен, особенно породы волжского века (баженовская свита) органическим веществом и являлся главным генератором нефти и газа в Западно-Сибирском бассейне. В перекрывающем его меловом осадочном комплексе сформированы основные резервуары, содержа-щие значительную часть ресурсов нефти и газа этого уникального осадочного бассейна. При формиро-вании залежей углеводородов в меловом комплексе решающую роль играли процессы вертикальной миграции. Палеогеография мелового периода предопределила распределение в разрезе мела проницае-мых комплексов и флюидоупоров и в значительной степени их качество. Настоящая работа посвящена палеогеографии мелового периода. Юрский период в истории Земли закончился крупной (глобальной) трансгрессией. К концу волж-ского века на территории Западно-Сибирского осадочного бассейна сформировался глубоководный эпиконтинентальный морской бассейн. Максимальные глубины этого моря, по разным оценкам, дости-гали от 400 до 800 м

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The results of this study were used to identify a reversed polarity magnetozone, referred to as M17r, in Berriasian sections of the Nordvik Peninsula (northern East Siberia) within the normal polarity magnetozone (M18n) from previous studies. The new magnetozone embraces the Volgian–Ryazanian boundary (Chetaites chetae/C. sibiricus zonal boundary). It was also found that the former magnetozone M17r at Nordvik, which includes the C. sibiricus/Hectoroceras kochi zonal boundary should correspond to magnetozone M16r. Using magnetostratigraphic and biostratigraphic criteria proves that the Boreal C. sibiricus Zone is correlated with at least the major part of the Tethyan Tirnovella occitanica Zone, and the Boreal H. kochi Zone is correlated with the lower part of the Malbosiceras paramimounum Subzone of the Tethyan Fauriella boissieri Zone.

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Paleogeographic reconstruction of the West Siberian basin during the Jurassic is based on a variety of criteria used to evaluate the depositional environments (paleontological, sedimentological, geochemical, etc.). Extensive geochemical data on the hydrocarbon biomarkers in bitumen from organic matter are first used to constrain the depositional setting of this large region over a span of about 45 Myr. The study provides a detailed description of paleogeographic maps compiled for the main epochs of the Jurassic period with the reconstruction of paleorelief and differentiation of potential external and internal sources of terrigenous material. The paleogeographic reconstructions of the basin are considered with implications for the formation of regional seals and reservoir units. A special emphasis is given to interpretation of organic matter type and depositional setting of the major oil and gas source rocks. The study infers a paleogeographic control on the stratigraphic and areal distribution of hydrocarbon accumulations in the basin.

The reality of the global‐scale sedimentation breaks remains controversial. A compilation of data on the Jurassic–Cretaceous unconformities in a number of regions with different tectonic settings and character of sedimentation, where new or updated stratigraphic frameworks are established, permits their correlation. Unconformities from three large reference regions, including North America, the Gulf of Mexico, and Western Europe, were also considered. The unconformities, which encompass the Jurassic‐Cretaceous, the Lower–Upper Cretaceous and the Cretaceous–Palaeogene transitions are of global extent. Other remarkable unconformities traced within many regions at the base of the Jurassic and at the Santonian–Campanian transition are not known from reference regions. A correlation of the Jurassic–Cretaceous global‐scale sedimentation breaks and eustatic curves is quite uncertain. Therefore, definition of global sequences will not be possible until eustatic changes are clarified. Activity of mantle plumes is among the likely causes of the documented unconformities.

We show the present state of the set of parallel zonal scales for the Siberian Jurassic, based on various fossil groups, and the principles of their construction. We discuss the significance of Siberian biostratigraphic scales for the Boreal zonal standard of the Jurassic units. The stratotype region for this standard must have a typical Boreal (Arctic rather than mixed) fauna. A possible candidate is Siberia (and the Arctic biochorema), which is located in the center of the Panboreal Superrealm, where the set of interrelated scales for various fossil groups is the most complete. The set of parallel zonal scales for the Siberian Jurassic is efficient for the subdivision and correlation of Jurassic units in various Arctic regions (Barents Sea shelf, northeastern Russia, Arctic Alaska, Arctic Canada).