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1.
Cecilie Bjørlykke 《GeoJournal》1996,39(2):221-227
This paper analyses the meeting between the international petroleum industry and two local communities. The building of an oil terminal in a local community is both a major event, and a generator of processes on the local level. Three different angles is used to enlighten these processes; categorised as as place, people and mind. The place analysis consentrates on the effects on population and workforce development, the people analysis look at the institutional and planning processes, and the mind analysis the effects on the feeling of local identification. The paper demonstrates that local factors are of crucial importance even for the international petroleum industry. 相似文献
2.
Partitioning and Hydrolysis of Nb and Ta and Their Implications with Regard to Mineralization 总被引：4，自引：0，他引：4
K2NbOF5 · H2O and K2TaF7 were prepared through melting Nb2O5 and Ta2O5 respectively with KHF2 · 2H2O, followed by recrystallizing. The hydrolysis properties of K2NbOF5 and K2TaF7 were determined again by using a rapidly quench vessel. As temperature (from 250 to 550 °C) and pressure (from 500 to 1500
bars) increase, the degree of hydrolysis of both K2NbOF5 and K2TaF7 will increase. Nb- and Ta-fluorine complex compounds are instable in supercritical aqueous fluids. The degree of hydrolysis
of both K2NbOF5 and K2TaF7 decreases with increasing concentration of HF, independent of the concentration of NaF.
The partition coefficients of Nb and Ta between granitic melt and fluid phase are less than 0.15, i.e., most of Nb and Ta
are left in granitic melt. The partition coefficient of Ta is more dependent on the concentration of HF than that of Nb. The
significance of hydrolysis in Nb- and Ta- mineralization is also discussed in the present paper. 相似文献
3.
Dong WANG Shaoming PAN Jichun WU Qingping ZHU Chang LIU 《中国地球化学学报》2006,25(B08):168-169
In the history, the Yellow River nurtured Chinese civilization. It is respected as the ＂ancestor of the four large rivers in China＂ and praised as ＂the mother river of China＂. At the same time, the Yellow River is regarded as ＂the misery of China＂ and considered as the most complex river hard to control in the world. Today, the Yellow River is also one large river greatly influenced by human activities in the world. The safety of the Yellow River, particularly flood control, is always the most important issue for governing and developing the country. Great achievements have been made after many years of efforts for controlling the Yellow River. However, since the nineties of 20 century, some new problems occurred, such as sharp reduction of flux to sea, dry rivercourse, worsen environment, etc. Rapidly shrinking riverbed and two-level perched stream are disadvantageous to flood safety especially. The new concepts and new practices are urgently needed to control the river. Therefore, the Yellow River Conservancy Committee of Ministry of Water Resources had continuously carded out flow and sediment diversion each year from 2002 to 2005. To timely probe into the new issues produced after flow and sediment diversion, and in order to deepen the understanding of rules for the Yellow River＇s water and sediment and provide reference and experience to the researchers for other large rivers, five hydrologic and hydraulic characteristics of the Yellow River, such as lack of water, much of sediment, different resources of water and sediment, inconsistency between water and sediment and frequency of sink switching and route changing, are described. Flow and sediment diversion of the Yellow River is also reviewed. Under flow and sediment diversion, 相似文献
4.
David W. Dyrssen 《Aquatic Geochemistry》1999,5(1):59-73
The following determinations in the Norwegian fjord Framvaren and the Black Sea have been compared: carbon-14, carbon-13, alkalinity, total dissolved inorganic carbon, sulfide, tritium (HTO), trace metals, silica, ammonium and phosphate. The historical development of the two anoxic basins is quite different. The carbon-14 age of the total inorganic dissolved carbonate in the deep water is 2000 years in the Black Sea, but only 1600 in Framvaren. The fresh water supply and composition are different. The rivers entering the Black Sea have a high alkalinity, but the river input and runoff to Framvaren has a very low alkalinity. The alkalinity, carbonate and sulfide concentrations in the anoxic waters below the chemoclines are much higher in Framvaren. This is mainly an effect of the different surface to volume ratios. The difference in carbon-13 (-8 for the Black Sea deep water, -19 in the Framvaren bottom water) is mainly due to the smaller imprint of the decomposition of organic matter on the Black Sea deep water.The concentration of trace metals in the particulate form are about the same in the deep water. About 76% of the molybdate in seawater is lost in the sulfidic water of Framvaren, and about 82–96% of the molybdate carried into the Black Sea by the Bosporus undercurrent is lost in the deep water. The relation between silica, ammonium and phosphate can be understood if part of the ammonium is being removed by denitrification, a process that most likely has been going on for thousands of years. 相似文献
5.
V. S. Urusov N. A. Gromalova S. V. Vyatkin V. S. Rusakov V. V. Maltsev N. N. Eremin 《Moscow University Geology Bulletin》2011,66(2):102-107
Data on the structural and valence distribution of Cr and Fe in chrysoberyl and in alexandrite, its gem variety, are given.
It is shown that the Cr3+ line in the natural Ural and Tanzania samples is the strongest in the M1 site and for the synthetic stones, in the M2 site.
During the annealing of the alexandrite crystals, Cr3+ passes from the smaller M1 site into the larger M2 site. The M?ssbauer spectroscopy quantitatively determined the distribution
of different valence Fe ions. The various proportions of both Fe2+ and Fe3+ ions isomorphically entering the octahedral sites in the BeAl2O4 crystal structure were established. 相似文献
6.
Fred T. Mackenzie Andreas J. Andersson Rolf S. Arvidson Michael W. Guidry Abraham Lerman 《Applied Geochemistry》2011
Epochs of changing atmospheric CO2 and seawater CO2–carbonic acid system chemistry and acidification have occurred during the Phanerozoic at various time scales. On the longer geologic time scale, as sea level rose and fell and continental free board decreased and increased, respectively, the riverine fluxes of Ca, Mg, DIC, and total alkalinity to the coastal ocean varied and helped regulate the C chemistry of seawater, but nevertheless there were major epochs of ocean acidification (OA). On the shorter glacial–interglacial time scale from the Last Glacial Maximum (LGM) to late preindustrial time, riverine fluxes of DIC, total alkalinity, and N and P nutrients increased and along with rising sea level, atmospheric PCO2 and temperature led, among other changes, to a slightly deceasing pH of coastal and open ocean waters, and to increasing net ecosystem calcification and decreasing net heterotrophy in coastal ocean waters. From late preindustrial time to the present and projected into the 21st century, human activities, such as fossil fuel and land-use emissions of CO2 to the atmosphere, increasing application of N and P nutrient subsidies and combustion N to the landscape, and sewage discharges of C, N, P have led, and will continue to lead, to significant modifications of coastal ocean waters. The changes include a rapid decline in pH and carbonate saturation state (modern problem of ocean acidification), a shift toward dissolution of carbonate substrates exceeding production, potentially leading to the “demise” of the coral reefs, reversal of the direction of the sea-to-air flux of CO2 and enhanced biological production and burial of organic C, a small sink of anthropogenic CO2, accompanied by a continuous trend toward increasing autotrophy in coastal waters. 相似文献
7.
Wang Zhiping 《《地质学报》英文版》1989,63(2):103-114
China is rich in Middle and Carboniferous fossil corals. The coral faunas in different regions have varying characteristics and can be divided into distinct assemblages. The coral fauna in South China is dominated by the order Caninida and contains numerous endemic elements; that in North China has a lot of Middle Carboniferous corals which are monotonous in species, with Late Carboniferous solitary corals being predominant. The coral fauna in Junggar mainly contains large bi-zoned solitary caninids, while that in southern Khingan is similar to that in South China due to the presence of abundant tri-zoned compound corals. In northern Tibet the coral fauna is also similar to that in South China, but in southern Tibet it is of a cold-water type. Therefore, the Middle and Late Carboniferous coral geography of China can be divided into the Tethys, Boreal and Gondwana Realms. 相似文献
8.
The spectral reflectance features of rocks and minerals are correlated with their composition,col-or,grain size and surface state.Different wall rocks,altered rocks and ores have their spectral reflectance features,which are very helpful for the explanation of remote sensing data and searching for mineral deposits by remote sensing.After the treatment of spectrum data and searching for mineral deposits by remote sensing.After the treatment of spectrum data of rocks and ores and physical and chemical parameters in the mathematical statistics,we analyzed the laboratorial spectrum dataand put forward better wave bands(520-590,650-710,730-760,770-860,1560-1760,2200 and 2300-2400nm) for distinguishing rocks and ores. 相似文献
9.
Bromine is a microelement present in waters, both in inorganic and in a wide range of organic compounds, though at lower concentrations. Typically, concentrations of organobromine compounds in waters are several orders of magnitude lower than of bromides. Two issues are addressed in the paper: the influence of bromides on the quality of treated waters and organobromines as contaminants of natural waters. Bromide presence in treated water gives rise to formation of potentially mutagenic disinfection by-products (DBPs). Registered amounts of DBPs in potable waters, exceeding the admissible levels, and the published data on DBPs in waters used for leisure and recreation activities, clearly indicate the health risk. Major sources are identified and registered concentrations of EDB, DBCB, methyl bromide, bromacil and PBDEs in the aquatic environment are summarized. The effects of bromide on DBPs formation and numerous examples of organobromine contamination of the aquatic environment indicate that the presence of bromides and organobromine compounds in the aquatic environment will have to be given more consideration, for several reasons. Firstly, larger amounts of bromide are present in saline and contaminated waters and the proportion of such waters being handled is increasing. Similarly, the processes of water purification, treatment and disinfection are now playing a major role. Secondly, emissions from manufacturing of bromine-containing materials growing, due to, inter alia, intensive development of the electronic industry and the plastic manufacturing sector. Thirdly, bromine compounds are also used as medicine ingredients. There is now a growing awareness of the presence of pharmaceuticals in the aquatic environment. Fourth, low bromide concentrations in hypergene zones may be modified in the future, partly because of the climate changes, which may give rise to difficulties with water treatment systems.Water quality standards having relevance to water used for consumption are based only on the best-known (most widespread) DBPs. However new more restrictive legal regulations relating to the use of bromine compounds have been put in place prohibiting the use of certain bromine-based substances or restricting their amount in finished products. In the light of current legislation, the monitoring of water contamination with potentially toxic, mutagenic and endocrine-disrupting organobromine compounds is still unsatisfactory because newly discovered compounds are not included and certain factors governing the exposure to those substances are still left out.The effects of bromine (bromide and organobromine compounds) on water quality have been investigated by researchers from several fields of expertise. The water management authorities ought to make use of the available research data and identify the problems which need to be addressed directly and those which may emerge in the future. 相似文献
10.
11.
湖泊沉积物中蛋白质和氨基酸的动态变化 总被引：5，自引：0，他引：5
测定了阿哈湖和百花湖沉积物孔隙水中蛋白质和氨基酸的含量。蛋白质含量分别在0．32－1．71mg/ml和0．22－1．38mg/ml之间，氨基酸含量分别在1．15－5．01μg/ml（以含N量计）和1．41－4．16μg/ml之间。两湖沉积物氨基酸含量逐渐增高，表明扩散作用的存在。随着时间的推移，蛋白质在沉积物各层中得到了很好的保存，说明它的分解比较有限。沉积物孔隙水中氨基酸含量和微生物活动有关，氨基酸在27cm以后的阿哈湖沉积物中明显积累，可能指示微生物活动的减弱。 相似文献
12.
Precipitation of dolomite using sulphate-reducing bacteria from the Coorong Region, South Australia: significance and implications 总被引：9，自引：0，他引：9
Dolomite was successfully precipitated in culture experiments that simulated microbiogeochemical conditions prevailing during late stages of evaporation in ephemeral, hypersaline dolomitic lakes of the Coorong region, South Australia. Analyses of lake- and pore-water samples document rapid geochemical changes with time and depth in both dolomitic and non-dolomitic lakes. Extremely high sulphate and magnesium ion concentrations in lake waters decline rapidly with depth in pore waters throughout the sulphate-reduction zone, whereas carbonate concentrations in pore waters reach levels up to 100 times those of normal sea water. Ultimately, sulphate is totally consumed and no solid sulphate is recorded in the dolomitic lake sediments. ‘Most probable number’ calculations of lake sediment samples record the presence of large populations of sulphate-reducing bacteria, whereas sulphur-isotope analyses of lake-water samples indicate microbial fractionation in all the lakes studied. Viable populations of microbes from the lake sediments were cultured in anoxic conditions in the laboratory. Samples were then injected into vials containing sterilized clastic or carbonate grains, or glass beads, immersed in a solution that simulated the lake water. Falls in the levels of sulphate and rising pH in positive vials were interpreted as indicating active bacterial sulphate reduction accompanied by increased concentrations of carbonate. Within 2 months, sub-spherical, sub-micron-size crystals of dolomite identical to those of lake sediments were precipitated. It is concluded that bacterial sulphate reduction overcomes kinetic constraints on dolomite formation by removing sulphate and releasing magnesium and calcium ions from neutral ion pairs, and by generating elevated carbonate concentrations, in a hypersaline, strongly electrolytic solution. The results demonstrate that bacterial sulphate reduction controls dolomite precipitation in both the laboratory experiments and lake sediments. It is proposed that dolomite formation, through bacterial sulphate reduction, provides a process analogue applicable to thick platformal dolostones of the past, where benthic microbial communities were the sole or dominant colonizers of shallow marine environments. 相似文献
13.
The patterns of concentration of dissolved free amino acids (DFAA) are different and more variable in pore water of soils from a Georgia salt marsh than in most surface waters. Elevated concentrations of DFAA (up to 8850 nmoles liter?1) and high relative levels of alanine and glutamic acid suggest that bacteria may produce these amino acids. In addition to the common protein amino acids, an unidentified compound was present and was the dominant free amino acid in some sections. This compound appeared to be specific to pore waters as it was not observed in surface waters or in hydrolysates of sediments, bacteria or plants from the marsk. 相似文献
14.
Michael J. Barcelona 《Geochimica et cosmochimica acta》1980,44(12):1977-1984
The results of a study of the contribution of microbial metabolic products to total dissolved organic carbon (DOC) levels in coastal sediments are presented. The data indicate that acidic volatile compounds make up a substantial fraction of pore water DOC's in both oxic and anoxic pore waters of coastal marine sediments. Formic, acetic and butyric acids are the principal volatile species identified at levels exceeding 10 μM. Acid concentrations are up to five times higher in anoxic pore waters than in oxic waters. Volatile organic acids show promise as indicators of diagenetic processes in marine sediments and of the ecological succession of microorganisms, in particular. 相似文献
15.
The sediments of the Port Camargue marina (South of France) are highly polluted by Cu and As (Briant et al., 2013). The dynamics of these pollutants in pore waters was investigated using redox tracers (sulfides, Fe, Mn, U, Mo) to better constrain the redox conditions.In summer, pore water profiles showed a steep redox gradient in the top 24 cm with the reduction of Fe and Mn oxy-hydroxides at the sediment water interface (SWI) and of sulfate immediately below. Below a depth of 24 cm, the Fe, Mn, Mo and U profiles in pore waters reflected Fe and Mn reducing conditions and, unlike in the overlying levels, sulfidic conditions were not observed. This unusual redox zonation was attributed to the occurrence of two distinct sediment layers: an upper layer comprising muddy organic-rich sediments underlain by a layer of relatively sandy and organic-poor sediments. The sandy sediments were in place before the building of the marina, whereas the muddy layer was deposited later. In the muddy layer, large quantities of Fe and Mo were removed in summer linked to the formation of insoluble sulfide phases. Mn, which can adsorb on Fe-sulfides or precipitate with carbonates, was also removed from pore waters. Uranium was removed probably through reduction and adsorption onto particles. In winter, in the absence of detectable pore water sulfides, removal of Mo was moderate compared to summer.Cu was released into solution at the sediment water interface but was efficiently trapped by the muddy layer, probably by precipitation with sulfides. Due to efficient trapping, today the Cu sediment profile reflects the increase in its use as a biocide in antifouling paints over the last 40 years.In the sandy layer, Fe, Mn, Mo and As were released into solution and diffused toward the top of the profile. They precipitated at the boundary between the muddy and sandy layers. This precipitation accounts for the high (75 μg g−1) As concentrations measured in the sediments at a depth of 24 cm. 相似文献
16.
《Russian Geology and Geophysics》2015,56(10):1437-1450
We studied recent sedimentation in small saline and brackish lakes located in the Ol’khon region (western Baikal area) with arid and semiarid climate. The lakes belong to the Tazheran system; it is a series of compactly located closed shallow lakes, with a limited catchment area and different mineralization, under the same landscape, climatic, geologic, and geochemical conditions. Two complementary approaches are applied in the research: (1) a detailed study of individual lake and (2) a comparison of the entire series of lakes, which can be considered a natural model for studying the relationship between endogenic mineral formation and the geochemistry of lake waters. The lake waters and bottom sediments were studied by a set of modern methods of geochemistry, mineralogy, and crystal chemistry. The mineral component of the bottom sediments was analyzed by powder X-ray diffraction (XRD), IR spectroscopy, and electron microscopy. The lakes are characterized by predominant carbonate sedimentation; authigenic pyrite, smectite, chlorite, and illite are detected in assemblage with carbonate minerals in the bottom sediments. Carbonate phases have been identified, and their proportions have been determined in the samples by decomposition of the complex XRD profiles of carbonate minerals into peaks using the Pearson VII function. Mathematical modeling of the XRD profiles of carbonates has revealed that predominantly Mg-calcites with variable Mg content and excess-Ca dolomite accumulate in lake bottom sediments influenced by biogenic processes. Aragonite, monohydrocalcite, and rhodochrosite form in some lakes along with carbonates of the calcite-dolomite series. We show a dependence of the composition of the assemblages of the newly formed endogenic carbonate minerals and their crystallochemical characteristics on the chemical composition of lake waters. 相似文献
17.
《Russian Geology and Geophysics》2007,48(11):886-900
Results of study of pore waters of bottom sediments from different Baikal basins are presented. The most typical ion distribution patterns reflecting the Baikal sediment diagenesis are given. We have established that in areas with regular sedimentation, in the absence of faults and inflows, the sediment pore waters of three lake basins inherit the chemical composition of the Baikal water, which is stable in time and space. Changes in pore water composition mark general natural anomalies, such as the presence of active faults, tectonic movements, and inflows along permeable zones. In areas with the subsurface occurrence of gas hydrates, thorough long-term research has revealed an anomalous composition of pore waters. It has been established that the anomalies are caused by a discharge of deep-level mud-volcanic fluids. The ejected mud-volcanic waters differ from each other in mineralization, ion composition, and sources, which determines the difference in hydrate formation and the composition of gas hydrates. 相似文献
18.
纹层计年与137Cs、210Pb法对比研究东北二龙湾玛珥湖现代沉积速率 总被引：1，自引：0，他引：1
通过对东北二龙湾玛珥湖顶部无扰动岩心显微研究,证明此岩心发育有良好的年纹层。据精确统计,0~5.5 cm间为36个年纹层,纹层计年的误差为4％~7％,年纹层厚度为1.1~2 mm不等,平均沉积速率为1.53 mm/a,5.5 cm处对应于1965年。而二龙湾沉积物（从6.5 cm到5.5 cm)岩心的137Cs比活度值急剧增加,从（4.67±0.29） dpm/g增加到（12.06±0.47） dpm/g,在5.5 cm处有一个较为明显的蓄积峰值,这一峰值被确认对应为1963年全球137Cs散落的高峰期。另外据210Pbex比活度CIC模式,5.5 cm处约为1962年,这和137Cs比活度曲线的1963年时标相一致。印证了纹层计年的精确性,完全可以建立高分辨率时间序列。 相似文献
19.
内蒙古乌梁素海~(210)Pb和~(137)Cs测年与现代沉积速率 总被引：6，自引：2，他引：4
对乌梁素海沉积物柱心样品进行210Pb、137Cs测年分析表明,柱心剖面上有明显的1963年蓄积峰,这个蓄积峰对乌梁素海的现代沉积有明显的时标意义。根据210Pb的CRS模式,可以计算出每个样品深度所对应的年代,在该沉积柱心中与137Cs时标吻合较好。乌梁素海的沉积速率并不稳定,变化比较大,表明乌梁素海近113 a来沉积环境不稳定。210Pb、137Cs两种计年方法的结合有助于认识沉积速率变化较大的沼泽的沉积状况,也有助于对核素计年方法的理解。 相似文献
20.
Five surface sediment samples (0–3 cm), two suspended sediment samples and a zooplankton sample from Lake Ontario were analysed for nitrogen-containing compounds. Amino acids, amino sugars, ethanolamine and urea were separated and characterized by ion-exchange chromatography. Free amino acids and soluble combined amino acids and amino sugars accounted for less than 0–25 per cent of the total nitrogen in the sediments. Insoluble combined amino acids and amino sugars were the most abundant nitrogen fraction in the sediments, making up from 49 to 55 per cent of the total nitrogen. Evidence is presented that asparagine, glutamine and citrulline are present in the interstitial waters and may make up part of the sediment organic nitrogen that was not characterized.The free amino acids released by the proteolytic enzyme, pronase, from the interstitial waters and sediment humic and fulvic acid extracts were determined. Pronase released 65 per cent of the soluble combined amino acids and 34 per cent of the fulvic acid amino acids as free amino acids. Enzyme activity was inhibited in the presence of the humic acid extract. The results indicate that the combined amino acids in the interstitial waters and fulvic acid extracts are intermediates between the primary aquatic detritus and the sediment humic acids. The enzyme experiments and infra-red data indicate that part of the sediment amino acids are combined through peptide linkages. 相似文献