Dynamic topography of the East European craton: Shedding light upon lithospheric structure, composition and mantle dynamics     

Irina M. Artemieva   《Global and Planetary Change》2007,58(1-4):411

Most of the East European Craton lacks surface relief; however, the amplitude of topography at the top of the basement exceeds 20 km, the amplitude of topography undulations at the crustal base reaches almost 30 km with an amazing amplitude of ca. 50 km in variation in the thickness of the crystalline crust, and the amplitude of topography variations at the lithosphere–asthenosphere boundary exceeds 200 km. This paper examines the relative contributions of the crust, the subcrustal lithosphere, and the dynamic support of the sublithospheric mantle to maintain surface topography, using regional seismic data on the structure of the crystalline crust and the sedimentary cover, and thermal and large-scale P- and S-wave seismic tomography data on the structure of the lithospheric mantle. For the Precambrian lithosphere, an analysis of Vp/Vs ratio at 100, 150, 200, and 250 km depths does not show any age-dependence, suggesting that while Vp/Vs ratio can be effectively used to outline the cratonic margins, it is not sensitive to compositional variations within the cratonic lithosphere.Statistical analysis of age-dependence of velocity, density, and thermal structure of the continental crust and subcrustal lithosphere in the study area (0–62E, 45–72N) allows to link lithospheric structure with the tectonic evolution of the region since the Archean. Crustal thickness decreases systematically with age from 42–44 km in regions older than 1.6 Ga to 37–40 km in the Paleozoic–Mesoproterozoic structures, and to ca. 31 km in the Meso-Cenozoic regions. However, the isostatic contribution of the crust to the surface topography of the East European Craton is almost independent of age (ca. 4.5 km) due to an interplay of age-dependent crustal and sedimentary thicknesses and lithospheric temperatures.On the contrary, the contribution of the subcrustal lithosphere to the surface topography strongly depends on the age, being slightly positive (+ 0.3 + 0.7 km) for the regions older than 1.6 Ga and negative (− 0.5–1 km) for younger structures. This leads to age-dependent variations in the residual topography, i.e. the topography which cannot be explained by the assumed thermal and density structure of the lithosphere, and which can (at least partly) originate from the dynamic component caused by the mantle flow. Positive dynamic topography at the cratonic margins, which exceeds 2 km in the Norwegian Caledonides and in the Urals, clearly links their on-going uplift with deep mantle processes. Negative residual topography beneath the Archean-Paleoproterozoic cratons (− 1–2 km) indicates either a smaller density deficit (ca. 0.9%) in their subcrustal lithosphere than predicted by global petrologic data on mantle-derived xenoliths or the presence of a strong convective downwelling in the mantle. Such mantle downflows can effectively divert heat from the lithospheric base, leading to a long-term survival of the Archean-Paleoproterozoic lithosphere.  相似文献   

Inorganic matter in coal: Yakov E. Yudovich and Marina P. Ketris, Russian Academy of Science, Ural Division, Ekaterinburg, 2002, 422 pp. (in Russian).     

Irina Galuskina 《International Journal of Coal Geology》2004,58(4):269-270

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Runup of nonlinearly deformed waves on a coast     

I. I. Didenkulova  N. Zahibo  A. A. Kurkin  B. V. Levin  E. N. Pelinovsky  T. Soomere 《Doklady Earth Sciences》2006,411(8):1241-1243

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Impact of Air Transport on Seasonal Variations and Trends of Surface Ozone at Kislovodsk High Mountain Station     

Oksana A. Tarasova  Nicolai F. Elansky  Gennady I. Kuznetsov  Irina N. Kuznetsova  Irina A. Senik 《Journal of Atmospheric Chemistry》2003,45(3):245-259

The impact of air transport on the surface ozone variations is analyzed at Kislovodsk High Mountain Station for the period 1989–1996 on the basis of 2D back trajectories. It was shown that the contribution of photochemical and dynamical processes is different for the different seasons. In summer months the surface ozone concentration is governed by photochemical ozone production in semi polluted air from the regions of Northern Caspian, Southern Ural and Volga region. Time of the seasonal ozone maximum appearance is defined by joint influence of the processes of photochemical production and destruction in the eastern sectors and advection from Ukraine and Central Europe. The value of the seasonal minimum is determined by the processes of ozone destruction in the air coming from northeastern direction in the stable frontal zone. Distribution of sectors of the air transport changes from year to year and it can partly explain strong negative trend of the surface ozone concentration at the site.  相似文献   

Seismic anisotropy and mantle creep in young orogens   总被引：9，自引：0，他引：9  

Rolf Meissner  Walter D. Mooney  Irina Artemieva 《Geophysical Journal International》2002,149(1):1-14

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Coastal cooling/heating events: Laboratory experiments     

Natalia Demchenko  Irina Chubarenko 《Acta Geophysica》2007,55(1):56-64

We report the results of laboratory experiments on water heating/cooling, performed in 5 m long water channel with a slope. About 63 series of photos were analyzed: for 3 locations, for 3 bottom slopes (3.7, 6.7 and 12 degrees) and for different Ra numbers. It was pointed out that there exist two types of mixing characterizing different circulations in the presence of slope: gravity current and undersurface jet; the thermal bar is the region where one type of mixing is replaced by another; the highest speed and flowrate are at the break point; the flow is three-dimensional.  相似文献   

Climatological aspects of convective parameters from the NCAR/NCEP reanalysis   总被引：1，自引：0，他引：1  

Harold E. Brooks  Aaron R. Anderson  Kathrin Riemann  Irina Ebbers  Heather Flachs 《Atmospheric Research》2007,83(2-4):294-305

Annual cycles of convectively important atmospheric parameters have been computed for a variety of from the National Center for Atmospheric Research (NCAR)/National Centers for Environmental Prediction (NCEP) global reanalysis, using 7 years of reanalysis data. Regions in the central United States show stronger seasonality in combinations of thermodynamic parameters than found elsewhere in North America or Europe. As a result, there is a period of time in spring and early summer when climatological mean conditions are supportive of severe thunderstorms.The annual cycles help in understanding the large-scale processes that lead to the combination of atmospheric ingredients necessary for strong convection. This, in turn, lays groundwork for possible changes in distribution of the environments associated with possible global climate change.  相似文献   

Longitudinal Distribution of Coronal Holes During 1976–2002     

Irina A. Bilenko 《Solar physics》2004,221(2):261-282

The longitudinal distribution of coronal holes has been analyzed for the time interval 1976–2002. Coronal holes don't seem to be randomly distributed. The cluster structure has been revealed in the time—space organization of coronal hole distribution. The complexity and lifetime of clusters depend on the solar cycle phase. The comparison of active region and coronal hole cluster structures shows that some coronal hole clusters as well as active region ones occur almost simultaneously in both hemispheres, some clusters in the north or in the south hemisphere only. Some coronal hole clusters coincide with the active region clusters and some do not coincide. They reflect the large-scale solar magnetic field distribution.  相似文献   

In the footsteps of Alexander the Great: searching for the origins of ancient zooplankton on the wild steppe of Central Asia          下载免费PDF全文

Mark Williams  David J. Siveter  Vincent Perrier  Elena Mikhailova  Anna Tarasenko  Firuza Salimova  Irina A. Kim 《Geology Today》2015,31(2):68-73

Rising above the modern town of Nurata, in Navoiy Province, eastern Uzbekistan is the ancient fortress of Alexander the Great, built as part of Alexander's campaigns to subjugate the Persian‐speaking Sogdian peoples that lived in this province of the Persian Empire in the 4th Century bc . Alexander passed this way in 327 bc , marching his ancient army through this beautiful but desolate landscape, and conquering all before him. His fortress was built in a strategic place at the boundary between fertile agricultural lands and a dry and uncompromising vastness of steppe that lies to the east. From Nurata, about one hour drive by car along a road that cuts eastwards across the desert, is the sleepy town of Jo'sh. In the mountains beyond Jo'sh sits the hamlet of Kanda, a few mud‐brick houses nestling at the head of a small valley where a spring emerges miraculously from a bone‐dry landscape. Hereabouts are telltale signs of ancient marine deposits yielding graptolites from rocks of the Silurian system. And in these rocks are the fossils of tiny arthropods that mark a fundamental shift in the marine arthropod zooplankton 425 million years ago. It is these fossils that we have chased halfway across the world to the steppe of Central Asia.  相似文献   

A new species of extinct genus Lycopodites from Lower to Middle Jurassic sediments of Irkutsk coal basin (Eastern Siberia)     

Andrei O. Frolov  Irina M. Mashchuk 《世界地质(英文版)》2014,17(1):1-10

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