Popov S.V.,Russian Academy of Sciences |
Rostovtseva Y.V.,Moscow State University |
Fillippova N.Y.,Russian Academy of Sciences |
Golovina L.A.,Russian Academy of Sciences |
And 10 more authors.
Paleontological Journal | Year: 2016
The Taman sections, reference for the Neogene of the Eastern Paratethys, are investigated thoroughly paleontologically and stratigraphically, with level-by-level description of four sections, correlated in detail with each other; fossil remains coming from them are examined conjointly, with uniform binding to the sections. The composition of malacofaunas and foraminifers allowed the recognition of all regional stages and substages from the Upper Chokrakian to Middle Kimmerian, their boundaries, and correlation with the Kerch stratotypes. The study of the taxonomic composition of ostracods improved the boundaries of stratigraphic ranges of particular species. The complete and continuous sequence of Karaganian–Konkian deposits has provided the data improving the volume and boundaries of the Konkian Regional Stage and showing that it is divided into three units. Investigation of these groups provided the stratigraphical basis for pioneer studies of phytoplankton; the taxonomic composition and distribution in the sections of nannoplankton, diatoms, and organic-walled phytoplankton are investigated completely for the first time; the points of penetra- tion of marine water into the basin are recognized. The most reliable tool for correlation of deposits in a semiclosed basin is distribution of “ecologically plastic” groups that are able to tolerate a wide range of salinity and variation of the gas regime, such as mollusks, benthic foraminifers, and, among phytoplankton, diatoms and dinocysts. The appearance of stratigraphically significant diatom and nannoplankton species in Konkian, Sarmatian, and Maeotian deposits allowed the comparison of intervals of their presence with the oceanic zones where these index species are provided with absolute dating. The level-by-level palynological characteristics of the beds is reported, providing the basis for reconstruction of climatic changes in this region. © 2016, Pleiades Publishing, Ltd.
Daragan-Sushchova L.A.,Karpinsky All Russia Research Geological Institute |
Petrov O.V.,Karpinsky All Russia Research Geological Institute |
Sobolev N.N.,Karpinsky All Russia Research Geological Institute |
Daragan-Sushchov Y.I.,Gramberg All Russia Instutute for the World Ocean Geology and Mineral Resources |
And 2 more authors.
Geotectonics | Year: 2015
The structure of the sedimentary cover and acoustic basement in the northeastern Russian Arctic region is analyzed. Beneath the western continuation of the North Chukchi trough and Vil’kitskii trough, a Late Caledonian (Ellesmere) folded and metamorphozed basement is discovered. It is supposed that Caledonides continue further into the Podvodnikov Basin until the Geofizikov branch. A large magnetic anomaly in the Central Arctic zone has been verified by seismostratigraphic data: the acoustic basement beneath the Mendeleev (and partially Alpha) Ridge is overlain by trapps. Wave field analysis showed that the acoustic basement of the Lomonosov Ridge has folded structure, whereas beneath the Mendeleev Ridge, the sporadic presence of a weakly folded stratum of Paleozoic platform deposits is interpreted. It is supposed that the Caledonian and Late Cimmerian fold belts in the periphery of the Arctida paleocontinent appeared as a result of collision between arctic continental masses and southern ones. After Miocene extension and block displacements identified from appearance of horsts, grabens, and transverse rises both on the shelf and in the ocean, a general subsidence took place and the present-day shelf, slope, and the deepwater part of the Arctic Ocean formed. © 2015, Pleiades Publishing, Inc.
Alekseev M.A.,Karpinsky All Russia Research Geological Institute
Paleontological Journal | Year: 2015
The taxonomic composition of Toarcian and Aalenian foraminifers of the order Verneuilinida Mikhalevich et Kaminski, 2003 from northern Siberia is revised. These foraminifer assemblages contain five genera: Eomarssonella Levina, 1972, Orientalia Bykova, 1947, Riyadhella Redmond, 1965, Verneuiliella M. Alekseev, 2014, and Plectinina gen. nov. These genera belong to Prolixoplectidae and include three previously described and eight new species. © 2015, Pleiades Publishing, Ltd.