排序方式： 共有15条查询结果，搜索用时 62 毫秒
1.
A detailed hydrogeological zoning of the central part of the Minusinsk artesian basin is performed. Local basins confined to smaller plicated structures, as well as hydrogeological massifs of local scale, are recognized within large block structures. Direction of subsurface streams and their role in the formation of groundwater resources and composition are discussed. Forecast resources of fresh groundwater are estimated for every recognized structure. 相似文献
2.
3.
4.
E. V. Bezrukova A. A. Shchetnikov M. I. Kuzmin O. G. Sharova N. V. Kulagina P. P. Letunova E. V. Ivanov M. A. Kraynov E. V. Kerber I. A. Filinov O. V. Levina 《Doklady Earth Sciences》2016,468(1):527-531
This paper considers the results of comprehensive lithological, biostratigraphic, and geochemical investigation of sediments in Khara-Nur Lake (Eastern Sayan Mountains) situated in the area of the greatest Holocene eruptions in the Central Asia Region. The age of the basal sediment layer is estimated at 6881 ± 53 years. The local natural environment and climate have undergone great changes since that time. The Holocene volcanic events did not exert a catastrophic impact on the regional landscape, but they caused dramatic changes in the local vegetation. The well-defined correlation of the regional events with the well-known records of the natural environment in the Northern Hemisphere is indicative of the decisive influence of global atmospheric circulation on restructuring the landscape and climate system in the Zhom-Bolok Region in the Middle–Late Holocene. 相似文献
5.
V. N. Pazukhin E. I. Kulagina S. V. Nikolaeva N. N. Kochetova V. A. Konovalova 《Stratigraphy and Geological Correlation》2010,18(3):269-289
The paper describes a Serpukhovian Stage section, exposed along the Ural River near the village of Verkhnyaya Kardailovka
(Bashkortostan). The section is uniquely complete and is proposed as a GSSP candidate for the base of the Serpukhovian. The
Upper Visean and Serpukhovian beds are represented by relatively deep facies, which contain ammonoids, conodonts, ostracods,
foraminifers, and other fossils. The section is described bed-by-bed and subdivided into zones based on four faunal groups.
The lower boundary of the Serpukhovian is placed at the base of the Lochriea ziegleri conodont zone. The stratigraphic units are correlated with synchronous beds of the East European Platform, the Donets Basin,
Western Europe, Central Asia, and North America. 相似文献
6.
E.V. Sklyarov E.P. Solotchina E.G. Vologina N.V. Ignatova O.P. Izokh N.V. Kulagina O.A. Sklyarova P.A. Solotchin V.N. Stolpovskaya N.N. Ukhova V.S. Fedorovskii O.M. Khlystov 《Russian Geology and Geophysics》2010,51(3):237-258
We present results of a complex study of evaporite sediments from one of the small saline lakes with carbonate sedimentation in the Ol’khon area and substantiate their high significance for paleoclimatic reconstructions. The mineral composition of the bottom sediments was studied by XRD analysis, IR spectroscopy, scanning electron microscopy, elemental analysis (SR-XFA), etc. By decomposition of the complex XRD profiles of carbonate minerals into individual peaks by Pearson VII function, we identified carbonate phases in each sample and determined their proportions. A high-resolution carbonate record has been obtained for the first time for the lacustrine sediments. It bears the information about the stratigraphic distribution of Mg-calcites (a continuous series of structurally disordered low- to high-Mg calcites, up to Ca-dolomites), in which the amount and proportions of phases with different Mg contents are controlled by Mg/Ca, salinity, and total alkalinity of the lake water changing depending on the climatic cycles and lake level fluctuations. Comparison of the carbonate record for the Holocene section dated by the radiocarbon (14C) method with results of lithological, diatom, and palynological analyses, data on stable isotopes (δ18O and δ13C), and the distribution of some geochemical indicators of climatic changes permitted the reconstruction of the intricate evolution of the Lake Tsagan-Tyrm basin, which was controlled by the regional climate from the Atlantic period to the present time. The directed change in various characteristics of essentially carbonate sediments evidences that the Ol’khon regional climate has become more arid in recent 6.5 kyr. Moreover, drastic frequent changes of climate and, correspondingly, the Lake Tsagan-Tyrm water level in different periods of its existence have been revealed. The widespread saline and brackish lakes in southern East Siberia, Mongolia, and North China and the highly informative (in terms of paleoclimate and paleolimnology) carbonate sediments might help to recognize the general tendencies of paleoclimate changes and local fluctuations in Central Asia. 相似文献
7.
8.
B. C. Richards S. V. Nikolaeva E. I. Kulagina A. S. Alekseev E. N. Gorozhanina V. M. Gorozhanin V. A. Konovalova N. V. Goreva M. M. Joachimski Y. A. Gatovsky 《Stratigraphy and Geological Correlation》2017,25(7):697-758
The Verkhnyaya Kardailovka section is one of the best candidates for the GSSP (Global Stratotype Section and Point) at the base of the Stage (Mississippian). For boundary definition, the first appearance of the conodont Lochriea ziegleri Nemirovskaya, Perret et Meischner, 1994 in the lineage Lochriea nodosa (Bischoff, 1957)?L. ziegleri is used. L. ziegleri appears in the Venevian Substage somewhat below the base of the Serpukhovian in the Moscow Basin. The position of the FAD of L. ziegleri within the Hypergoniatites?Ferganoceras Genozone is confirmed and lies between 19.53 and 19.63 m above the section’s base. Before 2010, deep-water stylonodular limestone containing the boundary in unnamed formation C at Kardailovka was well exposed but only 3 m of Viséan strata cropped out immediately below. Recent trenching exposed another 10 m of underlying Viséan carbonates in formation C and older Viséan siliciclastics and volcanics in unnamed formation B. The contact between formation B and underlying crinoidal limestones in unnamed formation A representing the middle Viséan Zhukovian (Tulian) regional Substage was excavated. The boundary succession, situated in the Magnitogorsk tectonic zone above the Devonian Magnitogorsk arc and Mississippian magmatic and sedimentary rift succession, was deposited west of the Kazakhstanian continent during closure of the Ural Ocean. In the lower part of the section, Viséan tuffaceous siliciclastics and volcanics of formation B record rapid deepening after deposition of neritic middle Viséan crinoid lime grainstone of formation A and subsequent subaerial exposure. The overlying condensed upper Viséan to Serpukhovian succession in formation C comprises deep-water limestone deposited in a sediment-starved basin recording minor turbidite influx and carbonate-mound development. The δ13Ccarb plot shows a positive shift of 1‰ V-PDB (from +2 to +3‰) between 17.0 and 17.75 m (3.05 and 1.97 m below FAD L. ziegleri). The δ18Oapatite graph displays a prominent upward shift from 19.9 to 21.1‰ V-SMOW (at 19.15 to 19.51 m) in the nodosa Zone below FAD of Lochriea ziegleri. 相似文献
9.
10.
S.G. Arzhannikov S.V. Alekseev A.V. Glyzin N.V. Kulagina N.V. Ignatova L.A. Orlova 《Russian Geology and Geophysics》2010,51(2):163-175
The Late Quaternary history of climate and deposition environments in the western Todzha basin has been reconstructed from the respective lacustrine and fluvial deposits. Data from sedimentary sections have provided clues to the causes and timing of sudden deposition changes, including those associated with Holocene tectonic activity in the Taskyl fault. Especially informative are permafrost, diatom, spore-pollen, and tree-ring data from a section at the Merzly Yar locality where frozen ground has preserved the pristine rhythmic pattern of sediments. The Merzly Yar section stores a record of dramatic consequences of large earthquakes generated by the fault which produced a large damlake. The revealed pattern of discontinuous limnic deposition, with prominent tree markers and syngenetic ice wedges, places exact constraints on the stratigraphy of the section and allows its correlation with Holocene climate events within the intervals of fossil soils and vegetation. 相似文献