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1.
《西北地质》2004,37(3):F003-F003
名次期刊名称影响因子总被引频次即年指标基金论文比来源文献量1冰川冻土 2 .42 6 6740 .41 2 0 .87 1 362地理学报 2 .30 1 1 2 0 4 0 .2 62 0 .98843地质学报 2 .1 33 935 0 .397 0 .84634地理科学进展 1 .2 4 5 2 76 0 .1 490 .93 745岩石学报 1 .1 97 71 1 0 .2 81 0 .91 646地理科学 1 .0 2 0 5 87 0 .1 0 4 0 .841 357地质论评 0 .82 1 85 0 0 .2 5 0 0 .75 848极地研究 0 .80 6 1 2 5 0 .1 43 0 .74359地层学杂志 0 .780 31 1 0 .1 0 7 0 .86 5 61 0矿床地质 0 .769392 0 .32 7 0 .895 21 1古地理学报 0 .75 992 0 .1 490 .60 4 71 2…  相似文献   

2.
名次期刊名称总被引频次影响因子即年指标基金论文比来源文献量1地理学报 1 2 0 4 2 .30 1 0 .2 62 0 .98842地质学报 935 2 .1 33 0 .397 0 .84633地质论评 85 0 0 .82 1 0 .2 5 0 0 .75 844岩石学报 71 1 1 .1 97 0 .2 81 0 .91 645冰川冻土 6742 .42 6 0 .41 2 0 .87 1 366沉积学报 62 2 0 .75 1 0 .0 86 0 .681 1 67地理科学 5 87 1 .0 2 0 0 .1 0 4 0 .841 358地理研究 5 5 90 .41 80 .2 780 .98909地质科学 5 1 80 .6890 .1 5 5 0 .745 81 0矿床地质 392 0 .7690 .32 7 0 .895 21 1山地学报 377 0 .5 2 80 .0 75 0 .77 1 341 2海洋地…  相似文献   

3.
《西北地质》2004,37(2):F003-F003
(据中国科学技术信息研究所,2 0 0 3年1 2月)名次期刊名称总被引频次影响因子即年指标基金论文比来源文献量1地理学报1 2 0 4 2 .30 1 0 .2 62 0 .98842地质学报935 2 .1 33 0 .397 0 .84633地质论评850 0 .82 1 0 .2 50 0 .75 844岩石学报71 1 1 .1 97 0 .2 81 0 .91 645冰川冻土674 2 .42 6 0 .41 2 0 .87 1 366沉积学报62 2 0 .751 0 .0 86 0 .681 1 67地理科学587 1 .0 2 0 0 .1 0 4 0 .841 358地理研究5590 .41 80 .2 780 .98909地质科学51 80 .6890 .1 55 0 .74 581 0矿床地质392 0 .7690 .32 7 0 .89521 1山地学报377 0 .52 80 .0 75…  相似文献   

4.
INTRoDUCTION'Therearemanyproblemsofenvironmentalgeoscience.Theirfactorsofaffectionareverycomp1icated.Theyareal-mostfromtheearth,othercelestialbodiesandthebiosphere,especiallythefactorsofhumanaction.Becausethedevelop-mentofgeologicalenvironmentwillnotstop,theactionsofslopeandcatastrophesappearuninterruptedly,andenviron-mentdeterioratesfast.BAS1CTHEoRIESANDDEDUCTIONSoFPR1NC1PLESBiomathematicianVerhulstrevisedMalthusmode1andproposedthatarestrictingtermwasadded.ItisorY'=ap(t)[1…  相似文献   

5.
产　品　名　称 进口量(ｔ)进口额(万美元 )出口量(ｔ)出口额(万美元 )1、化学矿 1 6883 0 0 .71 1 0 43 .44 5 2 795 0 0 .0　 3 0 5 1 8.0 8　其中 :未焙烧的黄铁矿 6.0 0 .5 44 92 0 .95 7.3 6　　　焙烧黄铁矿 1 3 6.0 5 .0 66972 .0 1 8.80　　　天然或未精练的硫磺 1 5 86777.6741 9.962 73 7.5 3 7.3 2　　　未研磨磷灰石 1 .2 0 .1 61 0 882 0 5 .3 43 44.46　　　已研磨磷灰石 2 9.5 4.7964 0 0 0 6.1 2 664 .74　　　天然硫酸钡 (重晶石 ) 2 5 7.1 1 2 .0 0 83 2 2 64 .3 3 1 79.76　　　天然硼砂及精矿 5 1 1 9.92 3 7.2 5 3 3 6…  相似文献   

6.
企业名称 产　　　　量本月 (ｔ)　累计 (ｔ)　累计为去年同期 ( % )重点磷矿企业合计　 3931 57.0　 33560 4 1 .0　 1 1 0 .89　　荆襄磷化学工业公司 37932 .0 53372 6.0 1 33.0 0　　贵州开磷集团公司 1 90 52 9.0 1 5471 1 1 .0 93.79　　贵州瓮福矿肥基地 82 0 0 0 .0 62 5349.0 1 81 .1 6　　云南磷化学集团公司 82 696.0 649855.0 1 0 3.1 0重点硫铁矿企业合计 1 55335.0 1 3642 1 4.0 94.63　　广东云浮硫铁矿企业集团公司 1 2 2 556.0 1 1 0 32 83.0 91 .0 5　　山西阳泉硫铁矿工业公司 32 779.0 2 60 932 .0 1 1 3.53青海盐湖集…  相似文献   

7.
名次期刊名称影响因子名次期刊名称总被引频次1地质学报 1 .81 6 1地理学报 8472地理学报 1 .492地质论评 82 33冰川冻土 1 .4693地质学报 75 34地质论评 1 .2 4 94岩石学报 5 5 15矿床地质 1 .0 4 7 5地质科学 4416岩石学报 1 .0 35 6冰川冻土 4327地理研究 0 .975 7沉积学报 42 08古地理学报 0 .95 3 8地理研究 41 59地理科学进展 0 .8889矿床地质 32 21 0山地学报 0 .80 91 0地理科学 2 961 1地质科学 0 .791 1 1海洋地质与第四纪地质 2 811 2高校地质学报 0 .691 1 2山地学报 2 781 3岩石矿物学杂志 0 .5 64 1 3地质科技情报 2 2 41 4岩…  相似文献   

8.
1IntroductionTheTarimBasin ,NWChina,istheonlybasininChinawherenotonlymarine ,butalsoter restrialindustrialoilandgaspoolsaredeveloped .TheterrestrialoilandgaspoolshavebeenfoundintheKuchedepressioninthenorthernpartofthebasinanditsfrontupliftarea (Fig .1) .ThesourcerocksoftheterrestrialoilandgaspoolsareTriassicandJurassiclacustrinemudstonesandswampcoals.ThebiomarkersfromthesaturatedfractionsofTriassicandJurassicterrestrialsourcerocksandFig .1 .LocationofTriassicandJurassicterrestrialsource…  相似文献   

9.
(据中国科学技术信息研究所 ,2 0 0 2年 1 2月 )名次期刊名称影响因子名次期刊名称总被引频次1地质学报 1 . 81 6 1地理学报 8472地理学报 1 . 492地质论评 82 33冰川冻土 1 . 4693地质学报 75 34地质论评 1 . 2 4 94岩石学报 5 5 15矿床地质 1 . 0 4 7 5地质科学 4416岩石学报 1 . 0 35 6冰川冻土 4327地理研究 0 . 975 7沉积学报 42 08古地理学报 0 . 95 3 8地理研究 41 59地理科学进展 0 . 8889矿床地质 32 21 0山地学报 0 . 80 91 0地理科学 2 961 1地质科学 0 . 791 1 1海洋地质与第四纪地质 2 811 2高校地质学报 0 . 691 1 2山地学报 …  相似文献   

10.
1IntroductionFormationwaterisanimportantmediumforhydrocarbongenerationandmigration .Thelong termcontactofformationwaterswithoilandgasmustleavesomeorganiccomponentsintheforma tionwaters.Ofcourse,thechemicalcompositionofformationwater (i.e.,oilfieldwater)iscloselyrelatedtotheformationofoilandgasreservoirs (Collins,1 975) .Since 1 970smanyscholarsbothathomeandabroadhavecenteredonthestudyofthecharacteristicsofformationwatersthemselves(Collins,1 975;LiuChongxi,1 988;HuangFutangetal.,1 993 ;GaoX…  相似文献   

11.
Environmental geochemistry plays an important role in understanding the distribution of major cations (Ca2+, Mg2+, Na+, K+) in Helwan catchment, south Cairo, Egypt. Evaluation of soil mechanical erosion rate, depletion rate, exchangeable rates of base cations and sodium adsorption ratios are essential for understanding soil degradation problems in the representative Helwan catchment. Soil erosion is a natural process. It often becomes a problem when human activity causes it to occur much faster than under natural conditions. The results of the mechanical erosion rate of soil and the exchangeable rates of base cations are 1845 and 80.3 kg ha−1 yr−1, respectively. The high intensity of the mechanical erosion rate is probably attributed to the high specific surface area of the studied type of Vertisol, intensive application of fertilizer and industrial activities. Mechanical erosion of soil, exchangeable rate of base cations and the depletion rate of base cations are almost inexhaustible sources of sodium, and all these increase the problem of sodic soils and may affect plant productivity in Helwan catchment.  相似文献   

12.
In natural river systems, the chemical and isotopic composition of stream- and ground waters are mainly controlled by the geology and water-rock interactions. The leaching of major cations from soils has been recognized as a possible consequence of acidic deposition from atmosphere for over 30 years. Moreover, in agricultural areas, the application of physiological acid fertilizers and nitrogen fertilizers in the ammonia form may enhance the cation leaching through the soil profile into ground- and surface waters. This origin of leached cations has been studied on two small and adjacent agricultural catchments in Brittany, western France. The study catchments are drained by two first-order streams, and mainly covered with cambisoils, issued from the alteration and weathering of a granodiorite basement. Precipitations, soil water- and NH4 acetate-leachates, separated minerals, and stream waters have been investigated. Chemical element ratios, such as Ba/Sr, Na/Sr and Ca/Sr ratios, as well as Sr isotopic ratios are used to constrain the relative contribution from potential sources of stream water elements.Based on Sr isotopic ratio and element concentration, soil water- and NH4 acetate leaching indicates (1) a dominant manure/slurry contribution in the top soil, representing a cation concentrated pool, with low 87Sr/86Sr ratios; (2) in subsoils, mineral dissolution is enhanced by fertilizer application, becoming the unique source of cations in the saprolite. The relatively high weathering rates encountered implies significant sources of cations which are not accessory minerals, but rather plagioclase and biotite dissolution.Stream water has a very different isotopic and chemical composition compared to soil water leaching suggesting that stream water chemistry is dominated by elements issued from mineral and rock weathering. Agriculture, by applications of chemical and organic fertilizers, can influence the export of major base cations, such as Na+. Plagioclase dissolution, rather than anthropogenically controlled soil water, seems to be the dominant source of Na+ in streams. However, Ca2+ in streams is mostly derived from slurries and manures deposited on top soils, and transferred into the soil ion-exchange pool and stream waters. Less than 10% of Na+, 5-40% of Sr2+ and 20-100% of Ca2+ found in streams can be directly derived from the application of organic fertilizers.  相似文献   

13.
《Applied Geochemistry》1993,8(3):273-283
A new model for base cation release due to chemical weathering of soil minerals has been developed based on transition state theory, and included in the integrated soil chemistry model PROFILE. The data required for model application can be operationally determined on soil samples, making the model generally applicable and independent of any type of calibration. The model considers the contribution to the weathering rate from 12 groups of the most common primary and secondary minerals of soils, reacting in separate reactions with H+-ion, H2O, CO2 and organic acids expressed as dissolved organic carbon (DOC). The weathering rate sub-model couples the effects of dissolved Al and base cations on the reaction mechanisms. The model takes into account changes in soil temperature, different chemical conditions, the effect of vegetation interactions with the soil and N transformations. The kinetic coefficients and reaction orders are based on a complete re-evaluation of weathering data available in the literature, and additional kinetic data determined by the authors.Data from 23 different independent determinations of the field weathering rate from 15 sites in Scandinavia, Central Europe and North America were compiled and used to verify the model. The model is capable of estimating the release rate of base cations due to chemical weathering from information on soil mineralogy, texture and geochemical properties of the order of ±20% of the rate determined by independent methods. The results indicate that small amounts of dark minerals like epidote and hornblende, and the plagioclase content, largely determine the field weathering rate.  相似文献   

14.
Chemical weathering rates and erosionrates of granitic till in northern Sweden have beenestimated. The present-day chemical weathering rate iscompared with the long-term average weathering ratesince the last deglaciation approximately 8,700 yearsago. Also, the present-day release rates of major andtrace elements due to chemical weathering are comparedwith the mobility of these elements in a spodosolprofile as shown by soil water samples from the vadozezone. The estimation of the past weathering rate isbased on elemental depletion trends in a soil profile(typic haplocryod), whereas the present weatheringrate is based on elemental input/output budgets in asmall catchment (9.4 km2). The long-term averagechemical erosion rate, expressed as the sum of majorelement oxides (SiO2, Al2O3, CaO,Fe2O3, K2O, MgO, MnO, Na2O,P2O5, TiO2), was estimated to be4.9 gm-2 yr-1. The long-term base cation(Ca2+, Mg2+, Na+, K+) depletionwas 0.325 keq ha-1 yr-1. The currentchemical erosion rate was estimated to be2.43.0 g -2 yr-1, which is at least an order ofmagnitude higher than the rate of physical erosion,and the base cation flux due to chemical weathering is0.356–0.553~keq ha-1 yr-1. However,0.074 keq ha-1 yr-1 of this flux may be related tocation exchange processes induced by atmospheric inputof acid rain. There is no evidence for any recentlyincreased weathering rate of silicates in this area.The inputs of Cd, Cu, Ni and Zn exceed the outputs,and hence, these elements are currently accumulatingin the soil.There is a distinct seasonal variation in thechemical composition of the soil water. Results fromthe soil water samples show that Na, followed by Siand S (Cl was not measured), are the most mobileelements in the spodosol profile between the E-horizonand the C-horizon, and that Al and Fe were the leastmobile elements. However, there is no simplerelationship between the mobility of an element in thespodosol profile and the current release rate due toweathering of that element. This fact may haveimplications for the validity of the comparisonbetween the past and present weathering rates asperformed in this study.  相似文献   

15.
A simple, unifying approach to classifying quantitatively the susceptibility of catchment soils and surface waters to acidification is suggested. In areas subject to a strong maritime influence, such as the UK and substantial parts of NW Europe, wherever soil mineral weathering rates are low and soils are unfertilised, atmospherically derived base cations of maritime origins have a greater effect than those derived from biogeochemical weathering on the exchangeable soil base cations. This is directly reflected in the relative base cation concentrations of the associated drainage waters, which become increasingly Na-dominated. Using 10 sub-catchments of the River Dee in north-eastern Scotland, it is shown here that the extent of Na dominance, the ratio of Na+ to ΣNa++Ca2++Mg2+, at any point in a river provides a quantitative index of the upstream weathering rate and thus of the susceptibility of the river concerned to acidification under diverse flow conditions. Data from a further 58 sub-catchments from the same river system, and from 4 other catchments from around Scotland, were used to validate this theory.  相似文献   

16.
The results of experimental studies of ion exchange properties of Co-bearing ferromanganese crusts in the Magellan Seamounts (Pacific Ocean) are discussed. Maximum reactivity in reactions with the participation of manganese minerals (Fe-vernadite, vernadite) is typical of Na+, K+, and Ca2+ cations, whereas minimum activity is recorded for cations Pb2+ and Co2+. The exchange complex of ore minerals in crusts is composed of Na+, K+, Ca2+, Mg2+, and Mn2+ cations. The exchange capacity of manganese minerals increases from the alkali metal cations to rare and heavy metal cations. Peculiarities of the affiliation of Co2+, Mn2+, and Mg2+ cations in manganese minerals of crusts are discussed. In manganese minerals, Co occurs as Co2+ and Co3+ cations. Metal cations in manganese minerals occur in different chemical forms: sorbed (Na+, K+, Ca2+, Mn2+, Co2+, Cu2+, Zn2+, Cd2+, and Pb2+); sorbed and chemically bound (Mg2+, Ni2+, Y3+, La3+, and Mo6+); and only chemically bound (Co3+). It is shown that the age of crust, its preservation time in the air-dry state, and type of host substrate do not affect the ion exchange indicators of manganese minerals. It has been established that alkali metal cations are characterized by completely reversible equivalent sorption, whereas heavy metal cations are sorbed by a complex mechanism: equivalent ion exchange for all metal cations; superequivalent, partly reversible sorption for Ba2+, Pb2+, Co2+, and Cu2+ cations, relative to exchange cations of manganese minerals. The obtained results refine the role of ion exchange processes during the hydrogenic formation of Co-bearing ferromanganese crusts.  相似文献   

17.
The detailed hydro-chemical study of meltwater draining from Khangri glacier Arunachal Pradesh has been carried out to evaluate the major ion chemistry and weathering processes in the drainage basin. The investigative results shows that the meltwater is almost neutral to slightly acidic in nature with Mg–HCO3-dominated hydro-chemical facies. In glacial meltwater, Ca+?2 is the most dominated cation followed by Mg+2, Na+, and K+, while HCO3? is the most dominant anion followed by SO42?, NO3?, and Cl?. The dominant cations such as Ca+2 and Mg+2 show a good relation with the minerals abundance of the rocks. Calcite (CaCO3) and biotite [K(Mg,Fe)3AlSi3O10(F,OH)2] are the most abundant minerals in the deformed carbonate-rich metasedimentary rocks near to the snout with some K feldspar (KAlSi3O8) and quartz (SiO2). This suggests Ca+2 have definitely entered into the water due to the dissolution of calcite and Ca feldspar (CaAl2Si2O8), while one of the source of Mg+2 is biotite. Na feldspar (NaAlSi3O8) has contributed towards the availability of sodium ion, while potassium ion is derived from the chemical weathering of K feldspar and biotite. The chemical weathering is the foremost mechanism controlling the hydro-chemistry of the Khangri glacier because of the least anthropogenic interferences. The mineralogy of surrounding rocks is studied to understand better, the rock–water interaction processes, and their contribution towards ionic concentration of meltwater. The meltwater discharge and individual ion flux of the catchment area have also been calculated, to determine the ionic denudation rate for the ablation season. The high elemental ratio of (Ca?+?Mg)/(Na?+?K) (7.91?±?0.39 mg/l) and low elemental ratio of (Na?+?K)/total cations (0.11?±?0.004) indicate that the chemical composition of meltwater is mainly controlled by carbonate weathering and moderately by silicate weathering. The scatter plot result between (Ca?+?Mg) and total cations confirms that carbonate weathering is a major source of dissolved ions in Khangri glacier meltwater. In addition, the statistical analysis was also used to determine the correlation between physical parameters of glacier meltwater which controlled the solute dynamics.  相似文献   

18.
《Chemical Geology》2007,236(3-4):199-216
The chemical characteristics of freshwaters draining the silicate rocks in the northern part of Okinawa Island were studied to understand solute generation processes, and to determine rates of chemical weathering and CO2 consumption. It was observed that the water chemistry is highly influenced by marine aerosols, contributing more than 60% of total solute. Significant positive correlations observed for chloride versus dissolved silica and chloride versus bicarbonate suggest a strong influence of evapotranspiration on the seasonality of solute concentration. It was also found that chemical weathering has been highly advanced in which the dominant kaolinite minerals are being gibbsitized. Carbonic acid was found to be the major chemical weathering agent, releasing greater than 80% of weathering-derived dissolved cations and silica while the remaining portion was attributed to weathering by sulfuric acid generated via oxidation of pyrite contained in the rocks. The flux of basic cations, weathering-derived silica and CO2 consumption were relatively high due to favourable climatic condition, topography and high rate of mechanical erosion. Silicate weathering rates for basic cations were estimated to be 6.7–9.7 ton km− 2 y− 1. Carbon dioxide consumed by silicate weathering was 334–471 kmol km− 2 y− 1 which was slightly higher than that consumed by carbonate weathering. In general, divalent cations (Mg and Ca) and bicarbonate alkalinity derived from carbonate dissolution were higher than those from silicate weathering. As a consequence, the evolution of chemical species in the freshwaters of northern area of Okinawa Island to a large extent could be explained by mixing of two components, characterized by waters with Na+ and Cl− as predominant species and waters enriched with Ca2+ and HCO3−.  相似文献   

19.
Ectomycorrhiza-forming fungi (EMF) alter the nutrient-acquisition capabilities of vascular plants, and may play an important role in mineral weathering and the partitioning of products of weathering in soils under nutrient-limited conditions. In this study, we isolated the weathering function of Suillus tomentosus in liquid-cultures with biotite micas incubated at room temperature. We hypothesized that the fungus would accelerate weathering by hyphal attachment to biotite surfaces and transmission of nutrient cations via direct exchange into the fungal biomass. We combined a mass-balance approach with scanning electron microscopy (SEM) and atomic force microscopy (AFM) to estimate weathering rates and study dissolution features on biotite surfaces. Weathering of biotite flakes was about 2-3 orders of magnitude faster in shaken liquid-cultures with fungus compared to shaken controls without fungus, but with added inorganic acids. Adding fungus in nonshaken cultures caused a higher dissolution rate than in inorganic pH controls without fungus, but it was not significantly faster than organic pH controls without fungus. The K+, Mg2+ and Fe2+ from biotite were preferentially partitioned into fungal biomass in the shaken cultures, while in the nonshaken cultures, K+ and Mg2+ was lost from biomass and Fe2+ bioaccumulated much less. Fungal hyphae attached to biotite surfaces, but no significant surface changes were detected by SEM. When cultures were shaken, the AFM images of basal planes appeared to be rougher and had abundant dissolution channels, but such channel development was minor in nonshaken conditions. Even under shaken conditions the channels only accounted for only 1/100 of the total dissolution rate of 2.7 × 10−10 mol of biotite m−2 s−1. The results suggest that fungal weathering predominantly occurred not by attachment and direct transfer of nutrients via hyphae, but because of the acidification of the bulk liquid by organic acids, fungal respiration (CO2), and complexation of cations which accelerated dissolution of biotite. Results further suggest that both carbohydrate source (abundant here) and a host with which nutrients are exchanged (missing here) may be required for EMF to exert an important weathering effect in soils. Unsaturated conditions and physical dispersal of nutrient-rich minerals in soils may also confer a benefit for hyphal growth and attachment, and promote the attachment-mediated weathering which has been observed elsewhere on soil mineral surfaces.  相似文献   

20.
The spatial variability of long-term chemical weathering in a small watershed was examined to determine the effect of landscape position and vegetation. We sampled soils from forty-five soil pits within an 11.8-hectare watershed at the Hubbard Brook Experimental Forest, New Hampshire. The soil parent material is a relatively homogeneous glacial till deposited ∼14,000 years ago and is derived predominantly from granodiorite and pelitic schist. Conifers are abundant in the upper third of the watershed while the remaining portion is dominated by hardwoods. The average long-term chemical weathering rate in the watershed, calculated by the loss of base cations integrated over the soil profile, is 35 meq m−2 yr−1—similar to rates in other ∼10 to 15 ka old soils developed on granitic till in temperate climates. The present-day loss of base cations from the watershed, calculated by watershed mass balance, exceeds the long-term weathering rate, suggesting that the pool of exchangeable base cations in the soil is being diminished. Despite the homogeneity of the soil parent material in the watershed, long-term weathering rates decrease by a factor of two over a 260 m decrease in elevation. Estimated weathering rates of plagioclase, potassium feldspar and apatite are greater in the upper part of the watershed where conifers are abundant and glacial till is thin. The intra-watershed variability across this small area demonstrates the need for extensive sampling to obtain accurate watershed-wide estimates of long-term weathering rates.  相似文献   

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