МЕТОДЫ РАЗРАБОТКИ ЗОНАЛЬНОЙ СТРАТИГРАФИЧЕСКОЙ СХЕМЫ ВЕРХНЕГО МЕЛА ЗАПАДНОЙ СИБИРИ ПО ФОРАМИНИФЕРАМ

• Main Authors: ПОДОБИНА ВЕРА МИХАЙЛОВНА, КСЕНЕВА ТАТЬЯНА ГЕОРГИЕВНА
• Format: Text
• Language: unknown
• Published: Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования «Национальный исследовательский Томский государственный университет» 2015
• Subjects: ФОРАМИНИФЕРЫ,FORAMINIFERA,БИОСТРАТИГРАФИЯ,BIOSTRATIGRAPHY,ВЕРХНИЙ МЕЛ,UPPER CRETACEOUS,ЗАПАДНАЯ СИБИРЬ,WESTERN SIBERIA; Arctic; Foraminifera*; North Atlantic; Siberia
• Online Access: http://cyberleninka.ru/article/n/metody-razrabotki-zonalnoy-stratigraficheskoy-shemy-verhnego-mela-zapadnoy-sibiri-po-foraminiferam; http://cyberleninka.ru/article_covers/16455496.png

Обобщены исследования фораминифер с использованием пяти методов для расчленения, корреляции и определения возраста 12 фораминиферовых зон верхнего мела Западной Сибири (метод комплексов, филогении отдельных семейств и родов, ритмостратоны, палеогеографические и палеозоогеографические построения). Five methods previously developed by the present author were applied for zoning and correlating the Cretaceous to Paleogene deposits of Western Siberia. These investigations were based on foraminifera as one of the most widely occurring and rapidly evolving organisms. The first method includes the establishment of zonal foraminiferal assemblages and determination of index species. The second method is the creation of phylogenetic schemes for the most common foraminiferal families in Western Siberia: Hap-lophragmoididae, Haplophragmiidae, Textulariidae, Ataxophragmiidae. The third method is the rhythmostratons establishment. During the Late Cretaceous, benthic foraminifera were predominantly developing in the West Siberian basin. They sensitively reacted to the slightest changes in physico-geographical and bionomic environmental conditions and thus are valuable indices of these changes. On the basis of peculiarities of the averaged quantitative distribution of foraminifera in the central part of Western Siberia, the generalized faunal curve (GFC) was constructed, which responds to transgressive and regressive cycles in the basin development and the tectonic regime of the territory. Three clear-cut rhythms are distinguished on the GFC representing three large rhythmostratons (regional horizons). The qualitative characteristics of foraminifera along the upper Cretaceous section demonstrate the taxa changes at the level of orders and families, which are usually similar in the composition within separate rhythmothems. Horizons or their parts subordinated to rhythmothems are slightly different in lithology and characterized by a definite generic composition of foraminifera. In the hierarchy of the rhythmo-stratigraphic stratons, they may be referred to such subdivisions as rhythmoterms. The local biostrat-igraphic (foraminiferal) zones distinguishable by the species complexes are named rhythmoliths. The fourth method, viz. paleogeo-graphic, consists in revealing different facies on the region territory, which differ in lithological characteristics of rocks, systematic composition and aspect of foraminifera in the assemblage. The fifth method includes paleozoogeographic investigations. During the Late Cretaceous Epoch, three paleobiogeographic belts were retraced: circumpolar Arctic, Boreal and Tethyan. Each belt contains two paleozoogeographic realms. For example, in the aquatory of the Arctic circumpolar belt there are two realms: Arctic and North-Atlantic, with two associations of benthic foraminifera and one type of planktonic forms. In the Boreal belt, benthic and planktonic foraminifers are also distributed, which differ from Arctic forms by a wide variety and abundance. The investigations carried out in the upper Cretaceous deposits of Western Siberia resulted in establishing 12 foraminiferal zones, which correlate with separate sub-stages of the general stratigraphic scale.