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Synthesis of nickel ferrite precursors from low grade nickel matte 被引量:3
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作者 何利华 赵中伟 张有新 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第8期2422-2430,共9页
Fine nickel ferrite precursors NiFe2(C204)3·6H2O were obtained via co-precipitation method with low grade nickel matte as the raw material. Thermodynamic analysis of NiClz-FeC12-(NH4)2C204-H20 system for prec... Fine nickel ferrite precursors NiFe2(C204)3·6H2O were obtained via co-precipitation method with low grade nickel matte as the raw material. Thermodynamic analysis of NiClz-FeC12-(NH4)2C204-H20 system for precipitation identified that the theoretical optimum co-precipitation pH value is 2, and C2O2 has strong complexation with Ni2+ and Fe2+ ions. Based on these theoretical considerations, the effects of parameters on the precipitation rates and precursors size were investigated systematically. The results show that the optimum co-precipitation conditions are pH=2, temperature 45 ℃, 1.2 times theoretical amount of (NH4)2C204 dosage and 3% PEG400 addition. Under these conditions, the precipitation rates of Ni2+ and Fe2+ are both over 99.8%, with the precursors size of 1-2 urn. Furthermore, X-ray diffraction (XRD) and thermogravimetry-differential thermal analysis (TG-DTA) demonstrate that the precursors are single-phase solid solution, wherein the nickel/iron atoms are replaced by the iron/nickel atoms reciprocally. 展开更多
关键词 nickel ferrite FERRITE magnetic materials CO-PRECIPITATION low grade nickel matte
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Development of Sedimentary Environment in the Northeastern South China Sea Since the Last Glacial Stage
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作者 黄元辉 蓝东兆 《Marine Science Bulletin》 CAS 2007年第1期46-54,共9页
Core D (21°23′02″N, 116°47′13″E, water depth 405 m) was sampled from the upper slope from the northeastern South China Sea (SCS) and applied to analyze the sedimentary environmental change in this se... Core D (21°23′02″N, 116°47′13″E, water depth 405 m) was sampled from the upper slope from the northeastern South China Sea (SCS) and applied to analyze the sedimentary environmental change in this sea area since the last glacial stage. The results of grain size analysis, diatom analysis and detrital mineral analysis were well matched. We divided the core D into two layers. The surface sand layer (0 - 2 cm) consisted of residual sediments, which might be originally the sediment in the late Pleistocene and later suffered from being transformed in the post glacial transgression. The lower layer (2 - 130 cm) was quite different from the surface one, which might mainly result from a neritic sedimentary environment in the last glacial stage. Two sedimentary cycles could be detected in the core D: regression during Marine isotope stage (MIS) 4 to transgression during MIS 3 and regression during MIS 2 to transgression during the post glacial. 展开更多
关键词 DIATOM grain size sedimentary environment the last glacial stage the northeastern South China Sea
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Textural and Geochemical Characteristics of Proglacial Sediments: A Case Study in the Foreland of the Nelson Ice Cap, Antarctica 被引量:8
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作者 LIUXiaodong SUNLiguang YINXuebin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2004年第4期970-981,共12页
This paper presents a detailed study on the textural and geochemical characteristics of the proglacial sediments near the edge of modern Nelson Ice Cap, Antarctica. The grain size distributions of the proglacial sedim... This paper presents a detailed study on the textural and geochemical characteristics of the proglacial sediments near the edge of modern Nelson Ice Cap, Antarctica. The grain size distributions of the proglacial sediments are characteristic of glacigenic deposits, but very different from those of aeolian and lacustrine sediments. Moreover, the grain size distributions of the proglacial sediments are fractal with a dimension of about 2.9, and the fractal dimensions can be used as another summary statistical parameter for quantifying the relative amounts of coarse and fine materials. Correlations between the absolute element abundances of the proglacial sediments are very weak due to mineral partitioning and other effects of glacial processes, but correlations between the element/Rb ratios are statistically significant. This finding indicates that element/Rb ratios can be used to reduce or eliminate the effects of glacial processes, evaluate geochemical data and determine the sediment provenance in the foreland of Antarctic glacier. Comparisons on the element concentrations among different environments suggest that the proglacial sediments are derived predominantly from local bedrocks and appear to be natural in origin. Thus these natural sediments can be used to study chemical weathering in the proglacial foreland of modern glacier. 展开更多
关键词 proglacial sediment grain size fractal dimension element abundance chemical weathering
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Optically stimulated luminescence dating of young glacial sediments from the eastern Qinghai-Tibetan Plateau 被引量:8
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作者 ZENG Lan-hua OU Xian-jiao +1 位作者 LAI Zhong-ping ZHOU Shang-zhe 《Journal of Mountain Science》 SCIE CSCD 2016年第7期1174-1185,共12页
Poor bleaching is a significant problem for Optically Stimulated Luminescence(OSL) dating of glacial sediments. Five young glacial samples(including two modern analogues) from different depositional settings were coll... Poor bleaching is a significant problem for Optically Stimulated Luminescence(OSL) dating of glacial sediments. Five young glacial samples(including two modern analogues) from different depositional settings were collected beyond the Yingpu Glacier in the eastern Qinghai-Tibetan Plateau. De was determined using different OSL methods. The luminescence characteristics and dating results showed that the large aliquot quartz Blue Stimulated Luminescence(BSL) is more applicable than polymineral infrared stimulated luminescence(IRSL) method. Small aliquot quartz BSL results showed poor luminescence properties due to low luminescence sensitivity of quartz in this area. The dating results also indicated that glaciofluvial samples deposited close to ice margin(~40 m and ~700 m) and supraglacial debris dominated lateral moraine samples are relatively well-bleached, whereas samples from ground moraine and low terminal moraine were poorly bleached, probably due to containing subglacial and englacial debris. The residual doses of glaciofluvial and lateral moraine crest samples were below a few Gy and age overestimations were below a few hundred years. The ground moraine and low terminal moraine samples had residual doses as high as ~110 Gy, and ages were overestimated by ~15-17 ka. 展开更多
关键词 Glacial sediments Optically stimulated luminescence Quartz Residual age Qinghai-Tibetan Plateau
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Mesomechanical simulation of direct shear test on outwash deposits with granular discrete element method 被引量:6
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作者 石崇 王盛年 +2 位作者 刘琳 孟庆祥 张强 《Journal of Central South University》 SCIE EI CAS 2013年第4期1094-1102,共9页
The mechanical properties of outwash deposits which are taken as unconsolidated geo-materials with the characteristics of non-uniformity, heterogeneity and multiphase have attracted much attention in engineering. Acco... The mechanical properties of outwash deposits which are taken as unconsolidated geo-materials with the characteristics of non-uniformity, heterogeneity and multiphase have attracted much attention in engineering. According to the results of laboratory direct shear test on the remolded samples, the soil particle parameters of numerical model based on in-situ particle size cumulative curves and 3D granular discrete element method were determined. Then, numerical experiments on different lithology, stone content and gradation composition were conducted. The results show that it is not a flat surface but a shear band that yields in the sample. The curve of particle velocity vs distance from the designed shear surface of test model that is taken as a datum plane in the vertical section of sample shows in "S" shape. The shear disturbance area is about twice the maximum diameter of stone blocks. The greater the stiffness of stone is, the rougher the shear surface is. The shear strength of outwash deposits is largely controlled by lithology and stone content, and the bite force between stone blocks is the root reason of larger friction angle. It is also shown that strain hardening and low shear dilatancy occur under high confining pressure as well as possibility of shear shrinkage. But it is easy to behave shear dilatation and strain softening under low confining pressure. The relationship between particle frictional coefficient and stone content presents an approximately quadratic parabola increase. The strain energy first increases and then drops with the increase of frictional energy. The cohesion increases with soil stiffness increasing but decreases with stone stiffness increasing. Numerical results are consistent with the laboratory test results of remolded samples, which indicate that this method can be a beneficial supplement to determine the parameters of engineering deposit bodies. 展开更多
关键词 outwash deposit direct shear test granular discrete element MESOMECHANICS
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Heavy mineral stratigraphy of sediments from the southern outer shelf of the East China Sea since the last glaciation using fuzzy C-means cluster method 被引量:1
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作者 林晓彤 李巍然 +1 位作者 杜树杰 林振宏 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2010年第1期183-189,共7页
Correspondence analysis and fuzzy C-means cluster methods were used to divide the stratigraphy of heavy mineral assemblages, and the sediment sources and depositional dynamics of the environment reconstructed. The ass... Correspondence analysis and fuzzy C-means cluster methods were used to divide the stratigraphy of heavy mineral assemblages, and the sediment sources and depositional dynamics of the environment reconstructed. The assemblages were taken from marine sediments from the late Pleistocene to the Holocene in Core Q43 situated on the outer shelf of the East China Sea. Based on the variable boundaries of the mineral assemblage at 63 and 228 cmbsf (cm below sea floor), the core might have previously been divided into three sediment strata marked with units Ⅰ, Ⅱ and Ⅲ, which would be consistent with the divided sediment stratum of the core using minor element geochemistry. The downcore distribution of heavy minerals divided the sedimentary sequence into three major units, which were further subdivided into four subunits. The interval between 0 and 63 cmbsf of the core (unit Ⅰ), which spans the Holocene and the uppermost late Pleistocene, is characterized by a hornblende-epidote-pyroxene assemblage, and contains relatively a smaller amount of schistic mineral and authigenic pyrite. In comparison, the interval between 63 and 228 cmbsf (unit Ⅱ), is representative of the Last Glacial Maximum (LGM), and features a hornblende-epidote-magnetite-ilmenite assemblage containing the highest concentrations of heavy minerals and opaque minerals. However, the interval between 228 and 309 cmbsf (unit Ⅲ), which spans the subinterglacial period, is characterized by a hornblende-authigenic-pyrite-mica assemblage. Relative ratios of some heavy minerals can be used as tracers of clastic sediment sources. The lower part of the sediment core shows the highest magnetite/ilmenite ratio and relatively high hornblende/augite and hornblende/epidote ratios. The middle core shows the highest hornblende/augite and hornblende/epidote ratios, and the lowest magnetite/ilmenite ratio. The upper part exhibits a slightly higher magnetite/ilmenite ratio, and also the lowest hornblende/augite and hornblende/epidote ratios. The distribution of the mineral ratio is consistent with stratigraphic division in heavy mineral data using correspondence analysis and fuzzy C-means clustering. Variations in heavy mineral association and mineral ratio in core Q43 revealed changes in provenance and depositional environment of the southern outer shelf of the East China Sea since the late Pleistocene, well corresponding to interglacial and glacial cycles. 展开更多
关键词 the Last Glacial Period stratigraphic division heavy mineral East China Sea fuzzy C-meanscluster
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Grain Size Distribution of Soils within the Cordillera Blanca, Peru: An Indicator of Basic Mechanical Properties for Slope Stability Evaluation 被引量:2
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作者 Jan NOVOTNY Jan KLIME 《Journal of Mountain Science》 SCIE CSCD 2014年第3期563-577,共15页
This paper presents results of a study on the mechanical properties of sandy and gravely soils within the Cordillera Blanca, Peru. The soils were divided into groups according to their origin(glacial, fluvial, or debr... This paper presents results of a study on the mechanical properties of sandy and gravely soils within the Cordillera Blanca, Peru. The soils were divided into groups according to their origin(glacial, fluvial, or debris flow). The grain size distribution of forty three soil samples was used to classify the soils according to the scheme of the Unified Soil Classification System(USCS). These distributions have then been used to estimate shear strength and hydraulic properties of the soils. There are clear differences between the soils which reflect their divergent origins. The glacial soils normally fit within one of two distinctive groups according to the proportion of fines(Group A, 7%-21.5%; Group B, 21%-65%). The estimation of shear strength at constant volume friction angle and peak shear strength of the glacial sediments with low content of fines was made using published data relating to the measured shear strength characteristics of soils with similar origins and grain size distributions. The estimated values were supported by measurements of the angle of repose taken from fourteen samples from two moraines and by shear tests on samples from one locality. The results of the grain size distribution werealso used to estimate the average hydraulic conductivity using the empirical Hazen formula which results were verified by field infiltration tests at two localities. 展开更多
关键词 MORAINES Grain size distribution SHEARSTRENGTH Hydraulic conductivity Cordillera Blanca Peru
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Sedimentary evolution since the late Last Deglaciation in the western North Yellow Sea 被引量:4
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作者 LI Yan LI Anchun HUANG Peng 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2012年第1期152-162,共11页
To decipher the sedimentary evolution and environmental changes since the late Last Deglaciation, two gravity cores were analyzed from the western North Yellow Sea (NYS). The two cores (B-L44 and B-U35) were sampled f... To decipher the sedimentary evolution and environmental changes since the late Last Deglaciation, two gravity cores were analyzed from the western North Yellow Sea (NYS). The two cores (B-L44 and B-U35) were sampled for grain size, clay minerals, detrital minerals, and 14C dating. They are comparable in lithofaies, and the observed succession was divided into four depositional units based on lithology and mineral assemblages, which recorded the postglacial transgression. Depositional unit 4 (DU 4) (before 11.5 ka) was characterized with enrichment in sand, and was interpreted as nearshore deposits in shallow water during the Younger Dryas Event. DU 3 (11.5-9.6 ka) displayed a fining-upward succession composed of sediments from local rivers, such as the Huanghe (Yellow) River, and from coastal erosion, which clearly were related to the Early Holocene transgression. Stable muddy deposition (DU 2) in NYS began to form at about 9.6 ka, which received direct supply of fine materials from the Shandong subaqueous clinoform. It is believed that the Yellow Sea circulation system played a major role in controlling the formation of fine sediment deposition in DU 1 (after 6.4 ka) after the sea level maximum. 展开更多
关键词 sedimentary evolution sea level change last Late Deglaciation North Yellow Sea
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Permeability and Sedimentation Characteristics of Pleistocene Fluvio-glacial Deposits in the Dadu River Valley,Southwest China 被引量:1
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作者 TU Guo-xiang HUANG Run-qiu +1 位作者 DENG Hui LI Yan-rong 《Journal of Mountain Science》 SCIE CSCD 2013年第3期482-493,共12页
There exist many fluvio-glacial deposits in the valley of Dadu River, Southwest China, which dates back to the Pleistocene. As some of the deposits are located within the seasonal water fluctuation zone of reservoirs,... There exist many fluvio-glacial deposits in the valley of Dadu River, Southwest China, which dates back to the Pleistocene. As some of the deposits are located within the seasonal water fluctuation zone of reservoirs, the seepage of groundwater acts as one of the key factors influencing their stability. Investigation into the sediment properties and permeability is, therefore, crucial for evaluating the sediment stability. In this study, in-situ permeability and sieving tests have been carried out to determine grain size distribution, correlations of permeability and hydraulic gradients, and relations between permeability and sedimentation properties. Test results indicate that the deposits are composed mostly of sands, gravels, cobbles and boulders, and the percentage of fines is less than 5%. The sediments have high densities, low porosities and natural moisture contents. At low hydraulic gradients, the seepage velocity obeys the Darcy's law, while a non- Darcy permeability is observed with hydraulic gradient exceeding a certain value (about 0.5 - 0.7). The linear permeability coefficient ranges from 0.003 to 0.009 cm/s. Seepage failure occurs above a threshold between 1.1 and 1.5. The test data fit well with the non-linear permeability equations suggested by Forchheimer and Izbash. The non-Darcy permeability proves to be in accordance with the seepage equation suggested by Izbash with the power 'm' of about 0.6 - 0.7. The characteristic grain sizes of the studied deposits are found in a narrow range between 0.024 and o.o31 mm, which is much lowerthan the effective grain size (dlo). 展开更多
关键词 Fluvio-glacial deposits Grain sizedistribution Linear and non-linear permeability Seepage failure
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Sedimentary response to volcanic activity in the Okinawa Trough since the last deglaciation 被引量:2
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作者 蒋富清 李安春 李铁刚 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2010年第1期171-182,共12页
To investigate the relationship between volcanic activity and sediment record on regional and temporal scales,158 surface sediment samples were collected from the East China Sea Shelf to the northern Okinawa Trough (O... To investigate the relationship between volcanic activity and sediment record on regional and temporal scales,158 surface sediment samples were collected from the East China Sea Shelf to the northern Okinawa Trough (OT),and two cores recovered in the northern and southern OT,respectively.Mineralogy,grain-size,and geochemical analyses of those samples show that:1) volcanic glass,volcanic-type pyroxene,hypersthenes,and magnetite increase in sediment influenced by volcanic activity;2) sediment grain sizes (and also silt content) increase in ash layers;and 3) the contents of Na2O and Zr are higher,while terrigenous elements,e.g.,TFe2O3 and K2O,and biogenous compositions,e.g.,CaO and Sr,are relatively lower in ash layers than those of non-ash layers.The distribution of volcanic ash has three distinguishing characteristics:1) volcanic ash is more abundant in the northern and central OT than the southern OT;2) volcanic ash increases from continental shelf to the trough;3) the sediment during the last 12 000 a suggests stronger volcanic events than during 15 000-12 000 a.The eruptive locations,frequency,and volume of calderas are among the most important factors controlling the distributions of volcanic ash.In addition,the main Kuroshio warm current that extends northward probably impeded the diffusion of volcanic ash to the west and south in the OT.However,a southward current probably carried some volcanic ash toward southern OT. 展开更多
关键词 SEDIMENT ash layer last deglaciation Okinawa Trough
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New findings concerning the Pleistocene Glaciation of the Leh Basin,Ladakh(34°03'N/77°38'E)
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作者 Hermann Achenbach 《Journal of Mountain Science》 SCIE CSCD 2010年第4期367-374,共8页
Like for most parts of High Asia,researches concerning the Pleistocene landscape evolution of the Leh Basin(34°03' N/77°38' E) have also left contradictions.To push this topic,three up to now unexplo... Like for most parts of High Asia,researches concerning the Pleistocene landscape evolution of the Leh Basin(34°03' N/77°38' E) have also left contradictions.To push this topic,three up to now unexplored Ladakh Range tributaries of the Leh Basin(Stagmo-,Arzu-and Nang-Valley) have been investigated.U-shaped profiles,transfluence passes,moraine mantled and glacially rounded peaks and ridges,roches moutonnées,glacial flank polishings and ground moraines document the former glaciation of the study area.The ice fillings of these tributaries reached a minimum thickness up to 540 m.Even at the valley outlets and on the orographic right side of the Leh Basin,the glaciation was more than 350 m thick.Based on these empirically extracted results,theoretical snow line considerations lead to the conclusion that the whole Leh Basin was filled up by a former Indus-Valley glacier.An ice injection limited to the nourishment areas of the Ladakh Range valleys could not have caused the reconstructed ice cover(down to 3236 m a.s.l.),which is proved by extended ground moraine complexes.Only an Indus ice stream network(most likely during the LGP),nourished by inflowing glaciers of the Ladakh-and Stok Range,explains the widespread existence of the glacial sediments at the outlets of the investigated valleys. 展开更多
关键词 Glacial-geomorphology Formerglaciation Last glacial period Equilibrium linealtitude High Asia
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Physico-chemical Characteristics and Environmental Significance of Snow Deposition on Haxilegen Glacier No.51 in Tian Shan,China 被引量:2
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作者 DONG Zhiwen LI Zhongqin +2 位作者 ZHANG Mingjun WANG Feiteng WU Lihua 《Journal of Mountain Science》 SCIE CSCD 2011年第3期484-494,共11页
Snow chemistry on the glaciers of alpine regions is a good indicator of atmospheric environmental change.We examine snow chemistry in three snowpits at different altitudes on the Haxilegen Glacier No.51,in the Kuitun ... Snow chemistry on the glaciers of alpine regions is a good indicator of atmospheric environmental change.We examine snow chemistry in three snowpits at different altitudes on the Haxilegen Glacier No.51,in the Kuitun River source,Tian Shan,China,during July-September 2004 to 2007.We use correlation analysis,factor analysis and sea-salt tracing methods to examine the characteristics and sources of major ions and mineral dust particles in the snow.Results show that mineral dust particles and major ions in the snow pits vary seasonally.During the Asian dust period in springtime,the concentration of mineral dust particles and major ions deposited in snow is high,while the concentration is relatively low during the non-dust period of summer and autumn.This may be caused by dust storm activity in central Asia.The order of major ionic concentrations in the snow packs was determined to be Ca2+ > SO42-> NH4+ > NO3-> Cl-> Na+ > Mg2+ > K+.Ca2+ was the dominant cation;SO42- was the dominant anion.We find,with the exception of NO3-,that the variabilities of ionic concentrations are highly correlated.Results show that the glacier region was significantly affected by dust activity and anthropogenic source.The major ions,especially Na+,originate from dust sources of central Asia and from the Ocean,transported by the westerly winds. 展开更多
关键词 Snow chemistry Mineral dust Environmental significance Haxilegen glacier No. 51 Tian Shan
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Degradation of Soils in the Lowland of Kur-Araz
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作者 E. A. Gurbanov S. A. Ganiyeva 《Journal of Agricultural Science and Technology(A)》 2011年第2X期249-254,共6页
The research works were carried out for determination of the washout, types, sorts and level of the development reasons of degradation with the purpose of preparation of the measures of fight against degradation in th... The research works were carried out for determination of the washout, types, sorts and level of the development reasons of degradation with the purpose of preparation of the measures of fight against degradation in the soils in 2005-2009 in the lowland of Kur-Araz. The investigations were fulfilled by using of geographical and stasionar methods. It is revealed that 333.6 thous, ha of the soils of the lowland of Kur-Araz have been exposed to erosion. 97.4 thousand ha of them have been exposed to rainstorm erosion, 127.1 thous, have been exposed to irrigative and 122.1 thous, ha to wind erosion. The most dangerous of them are considered irrigative erosion. Under the influence of erosion process in deposited over the length of furrow, deposits the changes happened in maintenance of humus and nutritions elements. In dependence on slope and water expenditure on 1 ha 2.23-14.86 t of soil are leached. As a result of out wash from 1 ha of soil 55.88-304.59 kg of humus, 4.06-20.80 kg of nitrogen, 4.57-26.55 of phosphorus and 57.40-372.99 of potassium are lost. The soil is exposed to degradation and as a result a process of desertification begins. On the basis of the quantitative an intensity of soil outwash the possible losses of dry matter including humus and main elements of nutrition of plants as a result of erosion, their deposit with the water way, are calculated, too. 展开更多
关键词 Irrigative erosion erosion degradation wind erosion defination capacity removal of humus.
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Suspended sediment dynamics in the meltwater of Chhota Shigri glacier, Chandra basin, Lahaul-Spiti valley, India
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作者 Virendra Bahadur SINGH AL.RAMANATHAN 《Journal of Mountain Science》 SCIE CSCD 2018年第1期68-81,共14页
Present study shows suspended sediment dynamics in the meltwater of Chhota Shigri glacier,Himachal Pradesh,India for different melt seasons during the period 2011-2014.Maximum suspended sediment concentration in the m... Present study shows suspended sediment dynamics in the meltwater of Chhota Shigri glacier,Himachal Pradesh,India for different melt seasons during the period 2011-2014.Maximum suspended sediment concentration in the meltwater was found during the month of July 2011,2012 and 2014 constituting to 55.2%,48.3% and 46.9%,respectively.Whereas in 2013,maximum suspended sediment concentration was observed in August accounting for46.1% of the total.On the other hand,maximum suspended sediment load was monitored in the month of July 2011,2012 and 2014 constituting 59.5%,63% and 55.7% of the total,respectively.Whereas in2013,maximum suspended sediment load was observed in the month of August accounting for 49.8% of the total suspended sediment load.Annual distribution of suspended sediment concentration(SSC)and suspended sediment load(SSL)in the Chhota Shigri glacier shows higher value of SSC and SSL during the study period 2012 and 2013,which may be due to the presence of high glacial runoff and negative mass balance of the studied area during these time periods.Marked diurnal variation has been observed in the SSC of meltwater.Strong correlation was observed between SSC and SSL with discharge.On the other hand,SSC and SSL also showed strong exponential correlation with air temperature of the studied area.Sediment yield from the catchment of Chhota Shigri glacier is high during the peak melt season(July and August)and low during the late melt season(September and October).The average value of erosion rate for Chhota Shigri glacier basin during the study period 2011-2014 was calculated to be 1.1mm/yr,which is lower than the average erosion rate of other Himalayan glaciers such as Rakiot,Chorabari and Gangotri glaciers,which may be caused by its geological setting containing high erosion resistant rocks such as granite,granite gneiss and porphyritic granite. 展开更多
关键词 Suspended sediment concentration Hysteresis Sediment yield Erosion rate Western Himalaya Chhota Shigri glacier
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Post-sedimentary Transformation of Lateral Moraines——the Tributary Tongue Basins of the Kvíárjkull(Iceland)
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作者 Lasafam Iturrizaga 《Journal of Mountain Science》 SCIE CSCD 2008年第1期1-16,共16页
The Kvíárjokull,a southern outlet glacier of the Vatnajokull,is confined in the mountain foreland by lateral moraines measuring a height of up to 150 m. Each of the lateral moraines shows considerable breach... The Kvíárjokull,a southern outlet glacier of the Vatnajokull,is confined in the mountain foreland by lateral moraines measuring a height of up to 150 m. Each of the lateral moraines shows considerable breaches with deviations of the main moraine ridges. The paper discusses the possible origins of these modifications of the lateral moraines as result of: 1) ice overlappings during glacier advances and subsequent breaches of the lateral moraine,2) bifurcations of the Kvíárjokull glacier tongue triggered by the preglacial relief conditions and the prehistorical moraine landscape leading to afflux conditions,3) drainage of ice-marginal glacier lakes and 4. volcanic activities,such as lava flows and volcanic-induced jokulhlaups. A historic-genetic model of the formation of the lateral moraines is presented considering the breaches in the lateral moraines as result from glacier bifurcations and therefore as former tributary tongue basins. Such breaches in the lateral moraines are also common landscape features at glaciers outside of Iceland and are from wider importance for the paleoreconstruction of former glacier stages. The knowledge of their development is essential for an adequate relative age classification of individual moraine ridges. In regard to the origin of the debris supply areas of the large-sized Kvíárjokull moraines,the resedimentation of prehistoric till deposits by younger glacier advances plays a role in the formation of the lateral moraines apart from englacial and supraglacial sediment transfer processes. 展开更多
关键词 lateral moraines tributary tongue basin glacier bifurcation glacier lake outburst Kvíárjokull
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Paleo-fluvial sedimentation on the outer shelf of the East China Sea during the last glacial maximum 被引量:1
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作者 王中波 杨守业 +3 位作者 张志珣 蓝先洪 顾兆峰 张训华 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2013年第4期886-894,共9页
Evidence from lithology, foraminiferal assemblages, and high-resolution X-ray fluorescence scanning data of core SFK-1 indicates tidally influenced paleo-fluvial sedimentation during the last glacial maximum (LGM) on ... Evidence from lithology, foraminiferal assemblages, and high-resolution X-ray fluorescence scanning data of core SFK-1 indicates tidally influenced paleo-fluvial sedimentation during the last glacial maximum (LGM) on the outer shelf of the East China Sea. The paleo-fluvial deposits consist of river channel facies and estuarine incised-valley-filling facies. Different reflections on the seismic profile across core SFK-1 suggest that the river channels shifted and overlapped. River channel deposition formed early in the LGM when sea level fell and the estuary extended to the outer shelf. Channel sediments are yellowish- brown in color and rich in foraminifera and shell fragments owing to the strong tidal influence. Following the LGM, the paleo-river mouth retreated and regressive deposition of estuarine and incised-valley-filling facies with an erosion base occurred. The river channel facies and estuarine incised-valley-filling facies have clearly different sedimentary characteristics and provenances. The depositional environment of the paleo-river system on the wide shelf was reconstructed from the foraminiferal assemblages, CaCO3 content and Ca/Ti ratio. The main results of this study provide further substantial constraints on the recognition of late Quaternary stratigraphy and land-sea interactions on the ECS shelf. 展开更多
关键词 outer shelf East China Sea LGM (last glacial maximum) paleo-river channel fluvial deposition PALEOENVIRONMENT
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The grain-size characteristics of Quaternary deposits at Xingshan near Siping in Jilin province, China
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作者 Maxwell A Boateng 《Global Geology》 2006年第1期30-39,48,共11页
This research paper analyses the grain-size characteristics of the Quaternary deposits at Xingshan near Siping, Jilin province in China by employing graphic measures to study the grain size distribution and its mode o... This research paper analyses the grain-size characteristics of the Quaternary deposits at Xingshan near Siping, Jilin province in China by employing graphic measures to study the grain size distribution and its mode of transport and deposition. The Quaternary deposits at Xingshan lie unconformable on Cretaceous rocks made of siltstone, mudstone and sandstone. The average grain size is between 8.06 to 8.55Φ (0.002 6 ~0.003 7 mm). The Quaternary deposits at Xingshan mainly compose of very fine silt to clay. The compositions of the grade are clay 63% and silt 37%. The clay size components are weathered debris transported and deposited by flowing water from the SE highlands or hills to the low lying NW Xingshan plains whereas the silty components accumulated by aoelian process. The Quaternary deposits at Xingshan accumulated in the middle and late Pleistocene interglacial periods from (459.12~39.03) ka to (88.92~7.56) ka. The standard deviation ranged from 0.96 to 1.36Φ, indicating that the sediments are moderately to poorly sorted, Coefficient of skewness ranged from 0.16~0.31 with an average skewness of 0.218, (Positively skewed towards fine). Kurtosis values (0.84~1.05) from the grain size distribution and visual inspection of the frequency curves indicate platykurtic to mesokurtic curves and unimodal to bimodal grain-size distribution. The type of deposit formation is sand dune and the source is at a distal from its provenance. 展开更多
关键词 grain-size characteristics Xingshan Quaternary deposits Pleistocene interglacial period
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Palaeoclimatic evolution recorded by multidicipline in sediments in gahai lake, qaidam basin since late last deglacial
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作者 Chen Zhong Ma Haizhou +4 位作者 Cao Guangchao Zhang Xiying Zhou Dujun Yao Yuan Yang Guangshu 《High Technology Letters》 EI CAS 2010年第3期324-330,共7页
Based on the analyses of Loss-on-Ignition (LOI), carbonate content and sediment characteristics, this paper reconstructs the climatic and environmental evolution of the Gahai lake area since the late Last Deglacial ... Based on the analyses of Loss-on-Ignition (LOI), carbonate content and sediment characteristics, this paper reconstructs the climatic and environmental evolution of the Gahai lake area since the late Last Deglacial Period. The results cover the late Last Deglacial Period and the Holocene. The climate was very unstable and rather arid during the late Last Deglacial Period. The Holocene can be divided into three periods: the early Holocene (11360-8240 cal aB. P. ), which was dry but unstable and featured rising temperatures, the mid-Holocene (8240-3200 cal aB. P. ), which was warm and wet and the late Holocene ( since 3200 cal aBP), which was cold and dry. Results also show a warm-wet event around 1500 cal aB. P. 展开更多
关键词 Gahai Lake late Last Deglaciation HOLOCENE PALAEOCLIMATE
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再谈"冰镇"——兼论冷藏义词语的同音假借与殊途同归
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作者 王健 《汉语史学报》 2023年第1期231-239,共9页
"冰镇"的成词受到"镇"自身词义的制约,与"镇"的压制义密切相关."冰镇"就是"以冰镇之",符合冷饮的制作方式."冰沉"则是受到了"冰浸""冰渍""冰沁&... "冰镇"的成词受到"镇"自身词义的制约,与"镇"的压制义密切相关."冰镇"就是"以冰镇之",符合冷饮的制作方式."冰沉"则是受到了"冰浸""冰渍""冰沁"等同步构词的影响."冰镇"与"冰沉"属于词义演变过程中的"殊途同归"现象. 展开更多
关键词 冰镇 冰沉 冷藏 同步构词
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Late Quaternary glacial chronology on the eastern slope of Gongga Mountain,eastern Tibetan Plateau,China 被引量:11
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作者 WANG Jie PAN BaoTian +3 位作者 ZHANG GuoLiang CUI Hang CAO Bo GENG HaoPeng 《Science China Earth Sciences》 SCIE EI CAS 2013年第3期354-365,共12页
The Gongga Mountain is the largest area of modern glaciation in the Hengduan Mountains and,with a summit elevation of 7556 m,is the highest mountain on the eastern margin of the Tibetan Plateau.During the Quaternary g... The Gongga Mountain is the largest area of modern glaciation in the Hengduan Mountains and,with a summit elevation of 7556 m,is the highest mountain on the eastern margin of the Tibetan Plateau.During the Quaternary glacial-interglacial cycles the Gongga Mountain was extensively and repeatedly glaciated,and glacial landforms and outwash deposits from multiple glaciations are well-preserved in valleys,in basins,and on piedmonts.To constrain the glacial chronology of the eastern slope of Gongga Mountain,sample sites were selected based on the distribution and weathering of glacial tills,relationships among glacial deposits,and soil development on moraines.Dating of the tills and glaciofluvial deposits was undertaken with electron spin resonance(ESR) and optically stimulated luminescence(OSL).The ages of the glacial deposits can be divided into four clusters:2.2±0.5,11.9±0.6,35.9±2.7-58.0±6.3 and 119.2±15.9-194.2±32.8 ka.Five glacial advances in this region have been identified,which are equivalent in age to the Little Ice Age(LIA),Neoglaciation,marine oxygen isotope stage(MIS) 2,mid-MIS3,and MIS6.The largest local last glacial maximum(LGML) occurred on Gongga Mountain during mid-MIS3,characterized by a cold-humid climate,rather than the global Last Glacial Maximum(LGMG) of MIS2.The Gongga,Nanmenguangou(NMGG) and Yajiageng Glaciations occurred during the late part of the last glacial cycle,the middle of the last glacial cycle and the penultimate glacial cycle,respectively.On the basis of geomorphological,sedimentological,and compositional characteristics,landforms of the Moxi Platform and terraces can be grouped by facies and geochronology.In combination with the dating results,this analysis indicates the basal part of the Moxi Platform between Xinxin and the Moxi Hotel is correlative with the till of the Nanguanmen Glaciation(mid-MIS3).This basal unit has occasional lenses of glaciofluvial sandy gravel and lacustrine sediments.The remainder of the Moxi Platform and the terraces beside the platform are glaciofluvial deposits occasionally mixed with debris flow deposits and range in age from MIS3 to Holocene. 展开更多
关键词 ESR dating glacial chronology Gongga Mountain Moxi Platform OSL dating
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