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41.
Maya V. Oshurkova 《世界地质(英文版)》2012,15(1):1-12
The paper presents results of palynological studies of the coal-bearing Carboniferous in Central Ka-zakhstan.A quantitative dynamics of major genera of miospores reflects an overall succession of the Carbonifer-ous miospore assemblages.Viséan Serpukhovian assemblages are dominanted by Lophozonotriletes fuscatus,Ac-anthozonotriletes cristifer,A.inclusus,Punctatisporites glabratus,Crassispora ignorata,C.scrupea,Cyclobacu-lisporites trichacanthus,Lycospora breviapiculata,L.echinata and Vallatisporites decrescens.Rare Punctatis-porites bertschoguriensis,Stenozonotriletes marginellus,Vallatisporites appilicatus,Verrucosisporites scrobiculatus,Reticulatisporites cancellatus,Granulatisporites arcuatus are recorded,which are not found in assemblages from overlying sediments.Bashkirian--Moscovian assemblages are dominated by Lycospora subtriquetra,L.pusilla,Vallatisporites ciliaris,Apiculatisporis mollis,Cyclogranisporites testiculatus,Calamospora microrugosa,Schopfi-pollenites principalis,Psilohymena psiloptera,Florinites grandis and Granulatisporites piroformis miospores.Cris-tatisporites latispinus,Angulisporites didymus,Thymospora obscura and Torispora securis are also present,as well as single Apiculatisporis curvispinus,Raistrickia inordinata,Marsupipollenites retroflexus,Entylissa caperata,Potonieisporites grandis and Cordaitina sp.A similar succession of miospore assemblages is recorded in the Carboniferous deposits of Europe and North America,which allows carrying out correlations,despite an endemic characters of many species of Paleozoic miospores from the coal-bearing Carboniferous of the Kazakh-stan Province in the Euramerian Paleofloristic Region. 相似文献
42.
Vladimír Stejskal Ladislav Kašpárek Galina N. Kopylova Alexei A. Lyubushin Lumír Skalský 《Studia Geophysica et Geodaetica》2009,53(2):215-238
tWe analyse continuous measurements of groundwater level in two deep wells VS-3 and V-28 at the experimental hydro-meteorological
station situated on the NE margin of the Bohemian Massif, central Europe, characterized by the weak intraplate seismic activity.
The aim of our study is to examine the relationships between changes in the groundwater level and earthquake occurrence. Based
on the tidal and barometric response of the water level, we estimated selected elastic parameters of the observed aquifers:
the shear modulus G, the Skempton ratio B, the drained matrix compressibility β and the undrained compressibility βu. Using these parameters and assuming the homogeneous poroelastic material, we derived the sensitivity of the wells to the
crustal volume strain. During the observation period from November 1998 to December 2005 we detected in the VS-3 well two
pre-seismic steps, related to August 10, 2005 (M = 2.4) and October 25, 2005 (M = 3.3) earthquakes. Amplitudes of the recorded
precursory changes (+6 cm and +15 cm) are several times higher than the values predicted from the theoretical precursory crustal
strain and the strain sensitivity of the well. Therefore, we presume that the observed pre-seismic water level steps can be
attributed to heterogeneity of poroelastic material. We consequently propose the hypothesis of the origin of precursory events
based on the presumption of a sensitive site, at which the well is situated. 相似文献
43.
The seismic waves excited by the M
w
7.6 Olyutorskii earthquake that occurred on April 20, 2006 in the Koryak Upland gave rise to water-level changes in five
wells situated in continental areas of Kamchatka at hypocentral distances of 750–1150 km. We describe the effects due to seismic
waves, as well as the water-level anomalies for February–April 2006 before the earthquake. We used an original technique for
the processing of water-level records based on the study of barometric and tidal water-level responses in order to estimate
the volume strain in water-saturated rocks during synchronous level variations at two wells. We discuss possible mechanisms
for producing anomalous water-level changes due to elastic deformation of monitored groundwater reservoirs and to crack dilatancy
in the water-saturated rocks. 相似文献
44.
Maya P. Bhatt Toshiyuki Masuzawa Mineko Yamamoto Kevin H. Gardner 《Environmental Geology》2009,57(3):557-569
Surface water samples were collected from Langtang Lirung glacier outlet point to the Narayani river system in central Nepal
in order to investigate the role of elevation in the variation of chemistry along the drainage networks. The chemistry of
Langtang–Narayani river system was dominated by sulfide oxidation coupled with carbonate dissolution and weathering of silicate
minerals. Calcium and magnesium concentrations were relatively higher than other cations and the sum of both species strongly
correlated with alkalinity, supporting the dissolution of carbonate and dolomite as the dominant source for these ions. Aluminosilicate
minerals primarily as albite and anorthite appeared as dominant silicate minerals within the drainage basin. Bisiallitization
was the dominant type of weathering within the entire drainage system. Hydrogen ion concentration was lower in the low elevation
sites than in high elevation sites reflecting the more consumption of carbon dioxide in the low elevation sites due to enhanced
chemical weathering rates. Furthermore, major solutes like sum of base cations, silicon as well as alkalinity increased in
concentration in the lower elevation sites. All regulating factors appeared to be directly related to elevation and hence
elevation appeared to be the prime factor for the variation in chemical species along the Langtang–Narayani river system.
Toshiyuki Masuzawa: deceased. 相似文献
45.
I. A. Andreeva V. S. Antipin O. A. Bogatikov M. V. Borisov N. S. Bortnikov N. V. Vladykin V. L. Vinograd A. V. Girnis V. A. Glebovitskii L. V. Danyushevsky N. L. Dobretsov V. S. Kamenetsky L. T. Kogarenko A. M. Kozlovskyi S. P. Korikovsky A. B. Kotov M. G. Kopylova M. I. Kuz’min N. N. Laverov F. A. Letnikov B. A. Litvinovsky A. A. Marakushev M. A. Nazarov V. B. Naumov A. V. Nikiforov I. S. Puchtel Yu. M. Pushcharovsky S. V. Ruzhentsev I. D. Ryabchikov V. S. Samoilov A. V. Samsonov A. G. Simakin A. V. Sobolev A. I. Khanchuk N. P. Yushkin V. V. Yarmolyuk 《Petrology》2011,19(4):325-326
46.
We consider the flare oscillations from the active red dwarf AT Mic detected with the XMM-Newton space observatory in the soft X-ray energy range (0.2–12 keV). Following Mitra-Kraev et al. (2005a), we associate the observed oscillations with a period of ≈750 s with the excitation of a standing slow magnetoacoustic (SMA) wave in a coronal loop. The damping of flare loop SMA oscillations is shown to be governed by electron thermal conduction. We have estimated the plasma density (≈3 × 1010 cm?3) and the minimum magnetic field strength (≈100 G) in the region of flare energy release. The adopted model is consistent with the results of a spectral analysis of the soft X-ray emission. The piston mechanism is assumed to be responsible for the excitation of loop SMA oscillations. 相似文献
47.
Kopylova Yu. G. Lepokurova O. E. Tokarenko O. G. Shvartsev S. L. 《Doklady Earth Sciences》2011,436(2):284-289
This article presents the data of studies of ion-salt, microcomponent, gas, and isotopic compositions of water and the equilibrium
calculation results for the water-rock system. The Tersinskie carbonic-acid waters are shown to be genetically close to soda
waters of the Kuznetsk Basin (Kuzbass) in the zone with slowed water exchange. Taking these data into account, the concept
of formation of carbonic-acid mineral waters not connected with magmatic or volcanic activities in the region was developed.
According to this hypothesis, carbonic-acid waters are soda waters of regional occurrence, their composition being considerably
changed due to CO2 introduction from the deeper zones of the Earth’s crust along the zones of tectonic ruptures. 相似文献
48.
A rare occurrence of a crater-filling clastogenic extrusive coherent kimberlite,Victor Northwest (Ontario,Canada) 总被引:1,自引:1,他引:0
Bram I. van Straaten M. G. Kopylova J. K. Russell B. H. Scott Smith 《Bulletin of Volcanology》2011,73(8):1047-1062
Kimberlite pipes can contain significant proportions of dark and dense kimberlite that have mostly been interpreted as intrusive
coherent (hypabyssal) in origin. This study reports a well-documented occurrence of a fresh intra-crater clastogenic extrusive
coherent kimberlite that is concluded to have formed as a result of lava fountaining. This paper focuses on a dark, dense,
competent, generally crystal-rich, massive kimberlite unit within the Victor Northwest kimberlite pipe (Ontario, Canada).
Using a comprehensive volcanological and petrographic analysis of all available drill cores, it is shown that this unit has
a fresh well-crystallised coherent groundmass and is extrusive and pyroclastic in origin. The proposed clastogenic coherent
extrusive origin is based on deposit morphology, gradational contacts to enveloping pyroclastic units, as well as the presence
of remnant pyroclast outlines and angular broken olivines. This paper, and an increasing number of other studies, suggest
that fragmental extrusive coherent kimberlite in intra-crater settings may be more common than previously thought. The emplacement
history and volcanology of these pipes need to be reconsidered based on the emerging importance of this particular kimberlite
facies. 相似文献
49.
Palaeobotanical methods and geochemical techniques were used to assess plant contribution and palaeoenvironment for the Staniantsi Basin, Bulgaria. The aim was to connect palaeovegetation change and climate oscillation based on pollen and statistical analysis with organic geochemical proxies for a Late Miocene lacustrine to paludial sedimentary succession.Three samples from lignite/marl cycles were studied. The biomarker assemblage and bulk chemical data indicated that gymnosperms were not important in the palaeomire. The presence of des-A-triterpenoids, 17,21-seco-triterpenoids, hopanes, a high content of a D-ring monoaromatic hopane, and aromatized triterpenoids suggested that photochemical and microbial processes significantly contributed to the alteration of the organic matter (OM). A prolonged period of high water table and severe mechanical destruction promoted microbial activity prior to burial and enhanced decay. A geochemical appraisal of short term climate oscillation (ca. 21.7 kyr) was attempted within the limitations of the small number of samples studied. The cycles are expressed as lignite/marl-clay layers combined with cyclic changes in swamp vegetation related to cyclic changes in groundwater level and inundation of the basin. In periods of low water level (swamp phase) lignite accumulation took place. Preliminary results for selected samples suggest that the oscillation may be reflected in the content of friedelin vs. possible degradation products. The ratio of a chromatographic peak tentatively assigned as A-norfriedel-8-en-10-one to friedelin is proposed as a means of detecting short term environmental cycles, where values <1 represent the swamp phase and those >1 reflect periods of inundation. However, time-series analysis using densely sampled lignite-clay layer oscillations are needed to confirm the value of this biomarker ratio for environmental reconstruction. 相似文献
50.
T. B. Goldvarg Yu. T. Tsap Yu. G. Kopylova A. V. Stepanov 《Bulletin of the Crimean Astrophysical Observatory》2013,109(1):90-97
The fine structure of the time variations of microwave and hard X-ray emissions from the solar flare of November 5, 1992 was analyzed. On the basis of the wavelet analysis, pulsations of intensity with a period of about 6 s were revealed in both the data sets. The observed time delay between the coronal plasma emission measure maximum and the temperature maximum is consistent with the concept of chromospheric evaporation. The anticorrelation observed between the time profiles of the microwave and hard X-ray emissions and the nature of the time delays between the peaks are associated with the excitation of radial fast magneto-acoustic oscillations in the flare loop (a coronal trap). Consequences of the obtained results are discussed. 相似文献