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401.
山东地区寒武系-奥陶系界线以往是以三叶虫和角石生物带为依据来确定,由于在界线上下几十米难以获得这类可供鉴定的大化石,这一重要年代地层界线实际上就划在三山子组b段之底。在长清区崮山镇范庄剖面上该界线确定在炒米店组之顶界,因而山东炒米店组被定义为"上寒武统最上部的一个岩石地层单位"。近年来,在长清张夏—崮山地区、青州尧王山地区和莱芜黄羊山地区,根据牙形石"Cordylodus lindstromi"准确确定的寒武系-奥陶系界线均位于炒米店组内部,分别距炒米店组顶9.05m、58.10m和4.00m。根据上述成果和岩石地层单位命名原则,炒米店组应定义为跨寒武纪与奥陶纪的岩石地层单位。 相似文献
402.
Organic Contamination of Soil and Goundwater in the Piedimont Plain of the Taihang Mountains 下载免费PDF全文
The risk of groundwater contamination following the infiltration of waste surface water, is of great interest, particularly in areas experiencing water shortage. In this study, the distribution characteristics of contaminants along the Cihe River, in the piedimont plain of the Taihang Mountains, China, was investigated by measuring the soil and water samples. The main organic contaminants detected in different media include hydrocarbons, chlorinated hydrocarbons, polycyclic aromatic hydrocarbons, and pesticides. The main contaminants found in different media are mostly derived from the river water, which can be seen from the results of waste water from the river and groundwater, from the soil samples from different depth and distance of the profiles along the river. The distribution characteristics showed that there has been a natural attenuation of the contaminants from the river during their transportation through the soils and groundwater. The sorption of organic compounds to soil organic matter is thought to be a main mechanism of natural attenuation. 相似文献
403.
Sh. K. Baltybaev G. V. Ovchinnikova V. A. Glebovitskii I. A. Alekseev I. M. Vasil’eva N. G. Risvanova 《Doklady Earth Sciences》2017,476(1):992-996
We have studied Pb isotopic systems of K-feldspar, pyrite, and pyrrhotine from gabbroids and ore of the Velimyaki Early Proterozoic massif in the northern Ladoga region in the southeastern part of the Fennoscandian Shield. The isochronous Pb–Pb age of sulfides has been determined as ~450 Ma, which corresponds to intersection of the regression line with the lead accumulation curve with μ = 10.4–10.8; the model Pb age of sulfides is close to isochronous under the condition that the composition of lead evolved from a geochemical reservoir with an age of 1.9 Ga. The isotopic parameters of the lead in sulfides and K-feldspar indicate their formation in upper crust conditions (μ = 238U/204Pb > 10). From the obtained data, it follows that the isotopic composition of lead in K-feldspar corresponds to a Proterozoic age (1890 Ma) of magmatic crystallization of the rocks in the massif, and strongly radiogenic lead sulfides testify, with the greatest probability, to the later (Caledonian) formation of sulfide ores. 相似文献
404.
Recognition of disturbances with specified morphology in time series: Part 2. Spikes on 1-s magnetograms 总被引:1,自引:0,他引:1
A. A. Soloviev S. M. Agayan A. D. Gvishiani Sh. R. Bogoutdinov A. Chulliat 《Izvestiya Physics of the Solid Earth》2012,48(5):395-409
Preliminary magnetograms contain different types of temporal anthropogenic disturbances: spikes, baseline jumps, drifts, etc. These disturbances should be identified and filtered out during the preprocessing of the preliminary records for the definitive data. As of now, at the geomagnetic observatories, such filtering is carried out manually. Most of the disturbances in the records sampled every second are spikes, which are much more abundant than those on the magnetograms sampled every minute. Another important feature of the 1-s magnetograms is the presence of a plenty of specific disturbances caused by short-period geomagnetic pulsations, which must be retained in the definitive records. Thus, creating an instrument for formalized and unified recognition of spikes on the preliminary 1-s magnetograms would largely solve the problem of labor-consuming manual preprocessing of the magnetic records. In the context of this idea, in the present paper, we focus on recognition of the spikes on the 1-s magnetograms as a key point of the problem. We describe here the new algorithm of pattern recognition, SPs, which is capable of automatically identifying the spikes on the 1-s magnetograms with a low probability of missed events and false alarms. The algorithm was verified on the real magnetic data recorded at the French observatory located on Easter Island in the Pacific. 相似文献
405.
It has been demonstrated for the first time that the Svecofennian crustal porphyric granites in the southeastern part of the Fennoscandian Shield are clearly subdivided into two age groups of 1.87 and 1.80 Ga. The representative of the first group is the Kuznechenskii Massif of porphyric granites with a U–Pb age of 1874 ± 4 Ma belongs to the group of plutons formed during the orogenic stage of Svecofennide evolution. The Borodinskii Massif with an age of 1797 ± 2 Ma is a member of the second group: these plutons were formed under tectonically stable (epiplatform) conditions. Therefore, the formation of porphyric granites occurred as the result of repeated generation of crustal magmas during multistage accretional growth of the Svecofennian crust. 相似文献
406.
通过对黑龙江省嘉荫县乌拉嘎盆地内各地层单元的岩石组合、生物化石组合与时代和沉积环境的系统研究与厘定,并与孙吴-嘉荫盆地其他断陷以及松辽盆地进行对比.研究表明:乌拉嘎盆地中、新生代划分为3个构造层5个岩石地层单元,并对其空间展布与演化进行了恢复,填制区域地质图.乌拉嘎盆地表现为明显的3期不同性质的盆地叠合演化特点,其间由... 相似文献
407.
The formation of ferromanganese concretions on continental shelves is a widespread recent biogeochemical process, which is particularly intense in the Baltic Sea. The proposed new technique for dating ferromanganese concretions is based on the equilibrium 210Pb, which is produced immediately within them due to the decay of 226Ra, which is intensely sorbed by concretions from the seawater. This method is principally different from the traditional dating of bottom sediments using nonequilibrium 210Pb, which represents a decay product of atmospheric Ra. A mathematical tool for the calculation of the concretion ages is proposed. The latter is used for calculating the ages and growth rates of ferromanganese concretions belonging to two morphological varieties. The age and average growth rates of spheroidal concretions are estimated to be 670–850 years and 0.014 mm/year, respectively. The central part of a pancake-shaped concretion is dated back to 2500–3800 years, and its calculated respective horizontal and vertical growth rates are approximately 0.028 and 0.004 mm/year. 相似文献
408.
The importance of allowance for the time-dependent effect in the kinetics at the photospheric phase during a supernova explosion has been confirmed by several independent research groups. The time-dependent effect provides a higher degree of hydrogen ionization in comparison with the steadystate solutions and strengthens the Hα line in the resulting simulated spectrum, with the intensity of the effect increasing with time. However, some researchers argue that the time-dependent ionization effect is unimportant. Its allowance leads to an insignificant strengthening of Hα in their modeling only in the first days after explosion. We have demonstrated the importance of the time-dependent effect with the models of SN 1999em as an example using the new original LEVELS software package. The role of a number of factors that can weaken the time-dependent effect has been checked. We have confirmed that the intensity of the effect is affected by the abundance of metal admixtures in the envelope, while the addition of extra levels to the model hydrogen atom weakens the time-dependent effect to a lesser degree and never removes it completely. 相似文献
409.
The paper presents results of applied medical-geographic mapping work by the Uzbek SSR Academy of Sciences in support of public health studies in Central Asian areas where water supplies are contaminated by runoff from irrigated fields. The final product of the work is a map depicting surface water quality in aggregate terms and according to indices for specific pollutants (for water quality monitoring points), which is described both in terms of its content and methods of data compilation and transformation. Translated by Elliott B. Urdang, Providence, RI 02906 from: Izvestiya vysshikh uchebnykh zavedeniy: Geodeziya i aerofotos “yemka, 1989, No. 2, pp. 166–171. 相似文献
410.
E. I. Ryzhak Sh. A. Mukhamediev S. V. Sinyukhina 《Izvestiya Physics of the Solid Earth》2016,52(6):787-802
Various geophysical processes which can lead to the origination of gravitational instability of the Rayleigh-Taylor type in layered bulk-elastic geomasses are analyzed. The analysis is based on obtained by the authors general results of theoretical study of two-layer systems of heavy bulk-elastic materials which are arbitrarily stratified over depth and occupy domains of arbitrary shape. Additionally some presented in a number of recent publications erroneous assertions related to considered issues of stability, are criticized. 相似文献