共查询到20条相似文献，搜索用时 15 毫秒
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.
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
4.
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
5.
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
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.
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
8.
9.
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
10.
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
11.
Wei Yan Yanyao Zhang Yunlu Ma Mingyue He Lifei Zhang Weidong Sun Christina Yan Wang Xi Liu 《地学前缘(英文版)》2021,12(1):313-326
A series of coesite,coexisting with or without a liquid phase,was synthesized in the nominal system SiO2-H2O at800-1450℃and 5 GPa.Micro-Raman spectroscopy was used to identity the crystalline phase,electron microprobe and LA-ICP-MS were employed to quantity some major and trace elements,and unpolarized FTIR spectroscopy was applied to probe the different types of hydrogen defects,explore water-incorporation mechanisms and quantify water contents.Trace amounts of A1 and B were detected in the coesite.Combining our results with the results in the literatures,we have found no positive correlation between the Al contents and the"Al"-based hydrogen concentrations,suggesting that previously proposed hydrogen-incorporation mechanism H^++Al^3+■Si^4+does not function in coesite.In contrast,we have confirmed the positive correlation between the B contents and the B-based hydrogen concentrations.The hydrogen-incorporation mechanism H^++B3^+■Si^4+readily takes place in coesite at different P-T conditions,and significantly increases the water content at both liquid-saturated and liquid-undersaturated conditions.For the SiO2-H2O system,we have found that type-Ⅰhydrogarnet substitution plays a dictating role in incorporating water into coesite at liquid-saturated condition,type-II hydrogarnet substitution contributes significantly at nearly dry condition,and both operate at conditions in between.The water solubility of coesite,as dictated by the type-Ⅰhydrogarnet substitution,positively correlates with both P and T,cH2O=-105(30)+5.2(32)×P+0.112(26)×T,with cH2O in wt ppm,P in GPa and T in℃.Due to its low water solubility and small fraction in subducted slabs,coesite may contribute insignificantly to the vertical water transport in subduction zones.Furthermore,the water solubility of any coesite in exhuming ultra-high pressure metamorphic rocks should be virtually zero as coesite becomes metastable.With an adequately fast waterdiffusion rate,this metastable coesite should be completely dry,which may have been the key factor to the partial preservation of most natural Coe.As a byproduct,a new IR experimental protocol for accurate water determination in optically anisotropic nominally anhydrous minerals has been found.Aided with the empirical method of Paterson(1982)it employs multiple unpolarized IR spectra,collected from randomly-orientated mineral grains,to approximate both total integrated absorbance and total integrated molar absorption coefficient.Its success relies on a high-level orientation randomness in the IR analyses. 相似文献
12.
David E. Ellis 《Geochimica et cosmochimica acta》1978,42(8):1271-1281
At 750°C and 4000 bar scapolite is stable relative to plagioclase + calcite over the range of plagioclase compositions An53–An83. The assemblage plagioclase + scapolite + calcite is stable relative to plagioclase + calcite over the ranges of plagioclase composition An48-An53 and An83–An91.5. When NaCl is present in the coexisting fluid the range of scapolite compositions stable relative to plagioclase increases. High mole fractions of NaCl in the fluid stabilize scapolite relative to plagioclases from An25 to An87 in the presence of excess calcite. Determination of the ratios of the synthetic scapolites shows that the range of stable scapolite compositions is significantly larger than heretofore proposed, and that even the chloride and carbonate bearing scapolites must be considered a four component solid solution. The KD for the exchange of NaCl and CaCo3 between coexisting scapolite, fluid and carbonate is given by the equation In . This equation implies that Cl-poor natural scapolites coexisted with fluids low in NaCl, and that regional occurrences of Cl-rich scapolites are likely to represent metamorphosed evaporite sequences. 相似文献
13.
Thermal expansion has been measured by laboratory and synchrotron X-ray powder diffraction for end-member åkermanite (ak, Ca2MgSi2O7) and gehlenite (ge, Ca2Al2SiO7) in the range 20–1,500 K. In ak in the range 340–390 K, there is a negative linear thermal expansion in [001] direction. This is related to the phase transition from an incommensurate modulated structure (IC) to a normal one (N). The volumetric mean thermal expansion coefficients for ak and ge, obtained with a linear fit of the experimental data in the temperature range 298–1,400 K, are respectively 32.1×10–6 and 28.3×10–6 K–1 . The variation of the c/a ratio with temperature, due to different thermal expansion along the crystallographic axes, can be related to the different behaviour of the tetrahedral layers in the N and IC phases. Analysis of the variation of the superstructure peaks intensity across the phase transition confirms the tricritical behaviour of the IC/N transition in ak. 相似文献
14.
15.
《中国地球化学学报》2006,(Z1)
Chemical and biological reactions occurring in lake sediments (early diagenesis) can influence the vertical distribution of trace metals and compromise the use of sediment profiles as historical records of anthropogenic metal pollution. There is thus a ne… 相似文献
16.
Protein and RNA in lake sediments tend to be decomposed progressively with time and sedimentation depth. Their concentrations
tend to decrease starting from the sedimentation depth of 17 cm and that of 19 cm, respectively. However, the products of
their decomposition —amino acids and nucleotides show different rules of variation. At the depth from 27 cm to 30 cm the amino
acids are most abundant in the pore waters of lake sediments. Such variation tendency seems to be related to the extent to
which microbes utilize amino acids and nucleotides. Due to polymerization in the geological processes and the adsorption of
protein on minerals and organic polymers, below the sedimentation depth of 17 cm there is still a certain amount of protein
in the sediments. With the time passing by, protein has been well preserved in various sediment layers, indicating that its
decomposition is relatively limited. The peak values of protein content in the sediments of the two lakes are produced in
the surface layers at the depth of 10 cm, implicating that the surface sediments are favorable to the release of protein.
The contents of amino acids in the pore waters of lake sediments are closely related to the activities of microbes. Below
the depth of 27 cm, the amino acids are significantly accumulated in Lake Aha sediments, probably indicating the weakening
of microbial activities.
The research project was financially supported jointly by the Ntional Natural Science Foundation of China (No. 40173038) and
the Guizhou Provincial Foundation (No. 3090) and the Chinese Academy of Sciences Knowledge-Innovation Foundation (KZCX2-105). 相似文献
17.
Chen Fajing Wang Xinwen Zhang Guangya Cao Shoulian Luo ChuanrongDepartment of Geology Energy Resources China University of Geosciences Beijing 《中国地质大学学报(英文版)》1995,(2)
About 26 sedimentary basins bearing oil and gas are developed in China. They can be classified into two main types , extensional basins and foreland basins . The former are chiefly distributed in the eastern part and the latter in the central and northwestern parts of the country . The present paper discusses the structural characteristics of these basins , including subsidence history , thermal history and structural style and kinematics . Combined with tectonic setting analysis of geophysical data and eruptive rocks , the geodynamic setting of the basins is established , and the formation mechanism of the basins is deduced to have been related to the subduction of the Izanagi and west Pacific plates and the closing of the Tethys ocean. 相似文献
18.
Geotectonics - The article discusses the ratio of the size and spatial position of ancient and modern areas of geodynamic processes (tectonic-sedimentary systems) and the resulting geological... 相似文献
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20.
Werner Lottermoser Karl Forcher Georg Amthauer Martin Kunz Thomas Armbruster 《Physics and Chemistry of Minerals》1997,24(1):2-6
Mössbauer measurements on neptunite (KNa2Li(Fe,Mn,Mg)2Ti2Si8O24) at 400?K reveal the distribution of Fe-ions on the crystallographic sites in agreement with neutron diffraction results published elsewhere. Even the previously postulated small amount of Fe-ions on the Ti(2) site has been detected, combined with a charge transfer which is in agreement with optical absorption investigations by other authors. A qualitative site occupation model is able to explain the different features of our observations. Single crystal Mössbauer measurements with the k-vector of incident γ-rays parallel to the crystallographic b-axis (space group Cc) of neptunite at different temperatures yield the angle β between the main component of the electric field gradient (EFG), V zz and b. This angle is in close accordance with a calculated value of β for the Fe(1) position from electron density maps. The latter also reveal an absolute value of V zz which is in satisfactory agreement with V zz derived from Mössbauer spectroscopy. 相似文献