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Doklady Earth Sciences - This paper reports on the lithological, micropaleontological, and chronometric data (radiocarbon dating) for one of the areas of the White Sea coast. The sedimentary...  相似文献   

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1 Introduction Because clay minerals have the characteristics ofadsorption, ion exchange capability and expandingcapacity, they are highly capable of adsorbing allkinds of pollutants in waters, thus making soilspossess self-purification functions. Clay m…  相似文献   

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The results of REE leached by some organic acids with various concentrations and water/rock ratios for different durations from a mixed samples of the weathering crust of a granite in Gonghe,Guangdong,China,showed that:1)the contents of REE leached increase with increasing concentrations of the organic acids;2) the contents of REE leached by 0.01mol/L organic acids increase with increasing water/rock ration;3) the interaction between the organic acids and the samples enhances the pH value of the medium and the contents of REE leached tend to increase with decreasing pH value;and 4) compared with those leached by ammonia sulfate,the REE leached by the organic acids are characterized by a weaker negative C e anomaly,a stronger negative Eu anomaly,and lower(La/Sm)N and (Gd/Yb)N ratios,indicating that the organic acids have made contributions to the fractionation of REE in the weathering crust.  相似文献   

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The Saf’yanovka copper massive sulfide deposit is situated 10 km northeast from the town of Rezh, on the eastern slope of the Central Urals. The ore-hosting plagiorhyolite-dacitic sequence consists of tephrites and tuffites with interlayers of dark gray siliceous-carboniferous pelites and psephytes from 0.1 to 1.5 m thick. The shells of the Parathurammina tamarae L. Petrovae, 1981 foraminifer were identified in one of the lightened interlayers in the siliceous-carboniferous sequence. The samples for study were taken from the southern part of the orebody in the open-pit between prospecting lines 2 and 3, horizons 170 and 157. The inner part of the shell is composed of quartz and apatite, and the wall, by apatite with rare calcite grains. One shell contains a tacking disk allowing us to refer these foraminifers to the attached benthos typical of the shallow marine basin (sublitoral). In the Urals, the Parathurammina tamarae L. Petrovae, 1981 foraminifer is known in limestones from the Eifel-Givetian (Langurskii and Vysotinskii Horizons); the siliceous-carboniferous rocks from the ore-hosting sequence from the Saf’yanovka deposit has the same age.  相似文献   

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A series of strontium- and barium-doped alumina samples were prepared by hydrolysis, in neutral medium, starting from commercial Al2O3, SrCO3, and BaCO3 materials. The precursors thus obtained were calcined under air at 700 °C; then, the bulk and surface properties of the resulting mixed oxides were characterized by nitrogen physisorption, X-ray diffraction (XRD), hydrogen temperature-programmed reduction (H2-TPR), thermogravimetry (TGA), and differential thermal analysis (DTA). Contrary to SrCO3, an addition of BaCO3 to α-Al2O3 increases slightly the specific surface area. XRD patterns essentially reveal the characteristic reflections assigned to α-Al2O3. In agreement with TGA and XRD analysis, strontium and barium carbonates remain after calcination at 700 °C, their decomposition starting above 800 °C. Let us note that this decomposition occurs more readily on AlSr-100 than on AlBa-100 with no apparent relationship with the evolution observed on the specific surface areas. H2-TPR experiments underline a significant bulk reduction of barium and strontium carbonates taking place significantly above 900 °C with similar trend noticed during TGA regarding their thermal decomposition. However, the most relevant observation is related to a sharp enhancement of the reducibility of AlSr-y with the appearance two reduction ranges highlighting the existence of different types of interactions with strontium and the alumina substrate.  相似文献   

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New U–Pb zircon (TIMS) results allow dating of protoliths of tonalite–trondhjemite orthogneisses of the Olekma Complex in the central part of the Chara–Olekma Geoblock (Aldan Shield) to 2825 ± 3 Ma and 2994 ± 3 Ma. Together with the results of previous geochronological studies, this proves that the Olekma Complex comprises heterochronous igneous rocks intensively reworked under amphibolite facies conditions and formed during different stages of geological evolution of the Aldan Shield.  相似文献   

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Mercury is a pollutant of concern due to its toxic and bioaccumulative properties. Studies on the distribution and hazard of mercury in the environment are mainly focused on its forms, toxicity and the environment standard, and progresses and results have been achieved. But these studies in the past were concentrated on the scales of laboratory or smaller districts merely, such as a small unit of mineral area, vegetable base, paddy field, lake, etc. Multi-target regional geochemical survey carried out by China Geological Survey from the 1990s to now is a fundamental and commonweal geological survey, large-scale and systematical inquisition and research were conducted in 19 provinces (or municipalities directly under the Central Government) in the eastern overlay region of China, and the purpose is to provide the basic geochemical data for national economic construction, adjustment of industrial and agricultural structures and sustainable social development. Geochemical studies aim at investigating soils in these regions and 52 elements have been tested, producing a great amount of data at the same time. Methods: based on the data from 3061 samples of surface soil and 832 samples of deep soil from the project of multi-purpose geochemical survey in the Chengdu Basin, Sichuan, China, this paper describes the correlation relationship between Hg and other 48 elements and their spatial distribution in surface and deep soils of these areas by applying the method of linear regression and factor analysis.  相似文献   

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The geomorphology of the Lar Valley in the Northeast of Tehran, the Capital of Iran, is under the geological influence of the Central Alborz, in which the different geological formations are folded and thrust, time and again over each other by faults, creating the heights. The Damavand volcano is located to the east of Lar Valley, appearing in the heights of Alborz at the point of deviation in the structural strike of Alborz chain and along the faults during the quaternary period. The physiographic, landslide phenomenon, rock fall, valleys, water courses and alluvial fans in the Lar Valley were reviewed and studied according to aerial photographs, satellite images and field observations from the aspect of their susceptibility to the impact of faults. The results indicate that 80% of the peaks and high mountains in Lar Valley are created and influenced by the action of overthrust faults. Ninety percent of the land and rock sinking are located in the intermediate regions between the faults, and they are believed to be the results of fault impacts. Seven out of the nine cases of landslide in Lar are located on or in the margin of the faults depicting the latter’s influence. The floor ratios of eight valleys were calculated and it was determined that in addition to the impacts of faults on creating the valleys, the situation of most of these along the margins of the faults as well as seven valleys are influenced by faults. The slope of rivulets and auxiliary rivers and their angles in relation to each other and the main river were calculated. The results showed that seven rivulets were under the influence of faults. Fifty-nine percent of the alluvial fans in Lar Valley were greatly influenced by faults, whereas 49% were under their normal impact. The supposition in this study is that the results can be used to identify faults and their characteristics.  相似文献   

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《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   

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Organic matter from the Lower Paleozoic strata on the northern margin of the Tarim Basin of China contains abundant alkylcyclohexanes.The n-alkylcyclohexanes show the even(C16-C20) and odd (C17-C21) carbon number predominance and smooth distribution,and the methyl-n-alkylcycolhexanes the odd carbon number predominance(C17-C21) and smooth distribution,which may be related to their depositional environments and organic precursors.There are some differences in carbon number distribution between the two series of monocyclic alkanes and the n-alkanes marked by smooth distribution.The genetic relationship between the three series of compounds needs to be further studied.  相似文献   

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The geochemistry of sediments is primarily controlled by their provenances, and different tectonic settings have distinctive provenance characteristics and sedimentary processes. So, it is possible to discriminate provenances, depositional environments and tectonic settings in the development of a sedimentary basin with the geochemistry of the clastic rocks. The analytical results of the present paper demonstrate that sediments in the Songliao prototype basin are enriched in silica (SiO2=66.48-80.51 %), and their ΣREE are 30-130 dmes of that of chondrite with remarkable Eu anomalies. In discriminating diagrams of Eu/Eu vs eeeeeREE and (La/Yb)N vs ΣREE, most samples locate above the line Eu/ Eu=l, on the right of the line Eu/Eu/ΣREE=1 and under the line La/Yb)N/eeeeeREE=1/8, which indicates that the depositional environment of sediments in the basin was oxidizing. In addition, variations of MgO, TiO2, A12O3, FeO+Fe2O3, Na2O and CaO vs SiO2 reflect a tendency of increasing mineral maturity of sediments  相似文献   

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Uranium mining in southeastern Germany resulted in significant environmental risks. Closure of the mines and subsequent rises of water levels may result in heavy-metal and radionuclide-bearing mine waters penetrating aquifers that are used for water supply. While there are certain (geo-)technical constraints on the schedule with which flooding of the mines can proceed, this process must not result in aggravating the problem of metal release. Evaluation of the likely 'natural' geochemical situation of Königstein mine after mining has ceased, and different scenarios for the release of metals indicates that rapid flooding, albeit avoiding unnecessary aeration of the waters, is likely to result in reducing conditions and consequently low U-solubilities.  相似文献   

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Please refer to the attachment(s) for more details.  相似文献   

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