共查询到20条相似文献，搜索用时 140 毫秒
1.
Koroteev V. A. Chervyakovskiy V. S. Zaitseva M. V. Volchek E. N. Necheukhin V. M. 《Doklady Earth Sciences》2019,487(1):756-760
Doklady Earth Sciences - This paper reports on the first U–Pb dating of zircons from dacites of the volcanic paleo-edifice of the andesite–dacite complex of the Eastern Zone of the... 相似文献
2.
The first results on current movements are presented for the western part of the Dzhugdzhur–Stanovoi Terrane based on GPS geodesy of a geodynamic survey area of the Upper Amur region. Processing of the GPS data resulted in a vector field of the displacement rates of points of the geodynamic survey area with zones of intense deformations. It was concluded from a comprehensive analysis of geological–geophysical data and estimates of the displacement rates that the terrane is characterized by kinematic integrity and was subjected to a complex of tectonic factors related to the evolution of the eastern segment of Baikal Rift Zone in the area of transpression interaction of the Eurasian and Amur plates. 相似文献
3.
Martin J.S. Rudwick 《《幕》》2008,31(3):363-366
Bursting the Limits of Time by the distin- guished historian of geology Martin Rudwick is a massive, two-part book. The first part contains what he calls a synchronous history of what eventually became historical geology in western Europe between the time of de Sans- sure＇s epoch-making ascent of Mont Blanc in 1787 and the discovery of the Kirkdale hyaena cave by Buckland in the winter of 1821-1822, 相似文献
4.
Analysis of the degree of contamination and evolution in the last 100 years of the composition of the bed sediments of the Anllóns Basin 总被引：3，自引：2，他引：1
Rosa Devesa-Rey M. T. Barral J.-M. Jouanneau F. Díaz-Fierros 《Environmental Earth Sciences》2010,61(7):1401-1417
In this study, five cores of the Anllóns River bed sediments were analyzed in order to evaluate the downcore and downstream
variations in their chemical composition. The first step was the evaluation of the metal distribution in the bulk (<2 mm)
and fine fractions (<63 μm). The analysis revealed that most of the metals followed the same trend in both fractions, although
the fine fraction presented usually higher concentrations. However, the concentration of both fractions tended to equalize
with increasing contamination. No general increase was observed in the metal concentrations toward the surface which could
be attributed to recent anthropogenic contributions. Instead, the distributions were homogeneous or peaked at various depths
downcore. The most important historical feature was observed at the mouth of the river, at 96-cm depth, corresponding to the
end of the eighteenth century. Upcore increased metal concentrations in parallel with increased fine fraction occurred from
this depth, which were attributed to a bridge construction and consequent changes in sediment dynamics. As the metal concentrations
can be influenced by variations in texture or other sediment characteristics, the second step was to evaluate the efficiency
of several normalized indexes in the assessment of the degree of contamination, by calculating the enrichment factor (EF),
the geoaccumulation index (I
GEO) and the pollution load index (PLI). The EFs obtained were <10, thus revealing little anthropogenic inputs to the basin.
The I
GEO produced higher values when compared with the EFs. Instead of absolute EF or I
GEO absolute values, the use of cumulative probability plots allowed identifying more accurately potential outliers indicating
contamination. Only one population was identified for Zn and Pb, with a reduced number of outliers at the highest concentrations
for Pb. As shown, a more complex plot with the outliers identified at C4 and C5. Finally, the PLI allowed determining the
absence of a significant contamination in the bed sediments. The bioavailable and non-geogenic fractions contribute up to
a 90% of the total concentrations in the case of As and Cu, and showed similar (dissimilar) profiles in comparison with total
metals. Also, the quality guidelines were surpassed, so the high solubility of As, Zn, Pb and Ni in the sediments revealed
the need to monitor the bed sediment quality of the Anllóns River. 相似文献
5.
Doklady Earth Sciences - The influence of variations in fo-, fa-, en-, fs-, di-, an-, and ab-components in a high-Mg basaltic melt on the topology of the spinellide liquidus was analyzed using the... 相似文献
6.
Doklady Earth Sciences - The influence of the temperature and moisture content of the near-surface soil layer on variations of the barodeformation interaction of the boundary layer of the... 相似文献
7.
陶正章 《中国地球化学学报》1991,10(3):288-293,T003
The carat is the unit of weight for diamonds and other gemstones.It corresponds to the average weight of the seeds of a leguminous tree.What kind of tree is this?We have studied the samples from Ethiopia,Egypt,Cyprus and the United States.The tree is neither“Kuara“nor“Locust“（Robina pseudoacacia Linn.）,but rather Carob(Ceratonia Siliqua).In Ethiopia,as called by local inhabitants,“Kuara“is a species of Erythrina-E.brucei rather than E.abyssinica.As might be expected,using the seeds as a means of weighing an extremely valuable commodity is not very scientific.Before 1907,at various times and in various countries,there were at least twenty-three stan-dards for the carat ranging from 187.00mg to 215.990mg.The metric carat equal to 200mg was proposed in Paris in 1907.It was adopted in the United States on July1,1913 and now is the world-accepted standard.But in reality,the standard of the carat is still confused with respect to its usage throughout the world .This is why the author reiterates that the standard of the car-at should be integrated with the metric system. 相似文献
8.
Strong vibrations of the Earth’s crust in the frequency range of 7–9 Hz, referred to as the “voice of the sea,” have been recorded in the course of processing synchronous experimental data obtained during recording of variations in the deformation of the Earth’s crust using a shore laser strainmeter, atmosphere pressure variations using a laser nanobarograph, and hydrosphere pressure variations using a laser meter for hydrospheric pressure and wind velocity variations. The nature of these vibrations and their transformation to adjacent geospheres have been discussed. 相似文献
9.
Liu Shaofeng Li Sitian Zhuang Xinguo Jiao Yangquan Lu ZongshengChina University of Geosciences Wuhan 《《地质学报》英文版》1996,70(3):233-245
Characteristics of deformation in the thrust belt and sequence stratigraphic framework in the foreland basin, structural features of the basin margin, and the episodic thrusting are studied in this paper by combining the eastern Qilian thrust belt and the Late Triassic foreland basin on the southwestern margin of Ordos. On this basis, a geological model and a mechanical model of coupling mechanism were established for the pair of thrust belt and foreland basin, and the subsidence and deposition process of the foreland basin were simulated on given parameters. 相似文献
10.
Tishkov A. A. Tsarevskaya N. G. Novenko E. Yu. Belonovskaya E. A. 《Doklady Earth Sciences》2021,499(2):686-692
Doklady Earth Sciences - The problems of diagnostics of the beginning of agrarian development of coniferous–broad-leaved forests in northwestern European Russia and its specificity regarding... 相似文献
11.
The granitoids of the Dal’negorsk borosilicate deposit are ascribed mainly to the high-K metaluminous rocks of the calcic and alkali-calcic series. The thermo-baro-geo-chemical studies showed that they originated from melts with low contents of water (H2O < 3.5% H2O) and CO2 at 800–850°C and 65–90 MPa. The data on the average contents of elements in the rock-forming minerals and the estimated initial water content in the magma point to the absence of a genetic relation between the intrusion and boron mineralization. The granitoid magma was responsible for the skarn formation and for the mobilization and remobilization of boron under a favorable environment. The K/Ar dating (51.0 ± 10 Ma), the geochemical typification (signatures of within-plate, subduction, and collisional granitoids), and the low water content in the parental melts of the granitoids, in accordance with the scheme of the geodynamic evolution of the region, indicate their formation in the lithospheric plate sliding environment. 相似文献
12.
The catastrophic Shikotan earthquake of October 4 (5), 1994, occurred in the Pacific Ocean. Its focus was located 80 km eastward of Shikotan Island. The stress state of the Earth’s crust in this area was estimated by the method of the cataclastic analysis of the whole range of the earthquake mechanisms. The performed reconstruction of the parameters of the current stress state of the Earth’s crust and the upper mantle in the area of the Southern Kuril Islands made it possible to establish that this area is characterized, on the one hand, by the presence of extensive areas of steady behavior of the stress tensor parameters and, on the other hand, by the presence of local sections of anomalously fast changes in these parameters. 相似文献
13.
Lecai Xing Taiyi Luo Zhilong Huang Zhikuan Qian Mingzhong Zhou Hongtao He 《中国地球化学学报》2018,37(3):414-421
Global abrupt climate change from Marinoan snowball Earth to greenhouse Earth, recorded as cap carbonate overlain on diamictite, had shed the first light on Cambrian bio-radiation. The most documented cap carbonate sections are typical with comprehensive δ13C negative values and ubiquitous sedimentary structures, such as tepee-like, sheet-crack etc., which are associated with successive glacial eustatic variation caused by isostatic rebound in shallow-water facies. Here we report a deep-water basinal cap carbonate section with strong negative δ13C values in the southern margin of the Qinling Orogen, Heyu, Chengkou County, Chongqing in China, which consists of massive dolostone with abundant carbonaceous laminae. However, it lacks the sedimentary structure as mentioned above and is overlain by thin-bedded silicious shales and cherts. A K-bentonite bed was discovered within the base of cap carbonates, about 0.7 m above the top of the Marinoan diamictite. Magmatic zircons that were separated from the K-bentonite bed yield a SIMS concordia U–Pb age of 634.1 ± 1.9 Ma (1σ, MSWDCE = 0.31, ProbabilityCE = 1.000, n = 20). The age is in good agreement with previously reported TIMS U–Pb ages for the termination of Marinoan glaciation and provides a geochronological constraint for the Ediacaran successions in the Qinling Orogen. 相似文献
14.
T. N. Palechek A. V. Moiseev I. V. Gul’pa 《Stratigraphy and Geological Correlation》2016,24(4):381-406
New data on the structure, age, and composition of the tectonostratigraphic complexes of the western part of the Koryak Highland are presented. The conclusions on the sedimentation conditions are drawn and primary relations are interpreted for most complexes. New Kimmeridgian–Tithonian and Berriasian assemblages of radiolarians are established. Campanian radiolarians are found for the first time in the region. 相似文献
15.
Wang Yunliang Li Juchu Han Wenxi Wang Wangzhang Chengdu College of Geology Chengdu Sichuan Jiang Minxi 《《地质学报》英文版》1993,67(3)
This paper discusses the discrimination principles. deduction and methods for probing into the source composition of mantle-derived magma. The magmatophile (incompatible) source elements are not all optimal tracers for mantle source composition. The ratios of two strong magmatophile elements (D<1) or the ratios of two trace elements with the same D value are not controlled by the formation mode and evolution degree of a magma, but maintain the characteristics of their composition in mantle source region prior to the magma formation. The ratios are related to different mantle-crust structures and dynamics. The mantle source composition of the Emeishan Basalt series is similar to that of the South Atlantic Rio Grande Rise-Walvis Ridge Basalts and Brazil continental-margin basalts. This may indicate that these basalt series might have similar source regions and tectonic environments. 相似文献
16.
With increasing high-quality geological and geophysical data it becomes clear that seismicity of the continents is characterized by linear patterns which are closely associated with tectonic features. The aim of this paper is to give reasonable interpretation for the earthquake distribution in the contiguous continent of the United States. Seismic lines and earthquake concentrated zones are defined, which reflect the characteristics of the continental seismotectonics. Similarities and differences in seismotectonics between the continental part of China and the contiguous continent of US are analysed. It is demonstrated that the spatial distribution of earthquakes can provide the information of the active structures in the earth's crust. The authors consider that the patterns of continental seismotectonics are not only controlled by the pre—existing tectonic frameworks and the current boundary dynamic conditions, but also possibly affected by dynamic factors of global tectonics at a higher level. 相似文献
17.
Doklady Earth Sciences - 相似文献
18.
It has been shown from petrologic,geochemical,trace element and REE evidence that the gran-ite intrusions at Sikongshan,Anhui Province,can be assigned to two distinct types which are radically different in age and origin.The Precambrian gneissic granited resulted from remelting of old continental crust while the Mesozoic granites were derived ,also through remelting,from low-Rb/Sr rocks at greater depths.Granite masses at Tiantangzhai and Zhoujiawan in the Dabieshan Mountains are also dicussed. 相似文献
19.
《地质学报》1932,11(2):101-105
In opening the meeting, the chairman made the following address: "It is my agreable duty to announce and make the award of the Grabau Medal to two members of our Society, Drs. J. S. Lee and Davidson Black. "The Grabau Medal was founded in 1925 by Mr. C. Y. Wang. the then President of the Geological Society. It was so named in honor of Dr. Grabau 相似文献
20.
The Taipinghu Bridge is an important project, and the safety of rock masses of its foundation is very crucial. This article analyzes the potential causes of the deformation of the rock masses of the bridge foundation, and uses the Fast Lagrangian Analysis of Continua to analyze the geologic model. The simulating process shows that no mater in the excavating process or in the loading process the rock masses are suit for the engineering. The modeling and analyzing process can be used for reference. 相似文献