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1.
Experiments were conducted in the field to determine the non-chemical loss rate of methyl iodide in seawater and to examine production rates of methyl halides. The loss rate of added C13 labelled methyl iodide, present at concentrations similar to those found in seawater, corrected for chemical loss due to reaction with Cl− varied from < 1 to 18% day− 1, with a mean value of 7%. This rate of loss is much lower than that which was proposed by Bell et al. [Bell, N., Hsu, L., Jacob, D. J., Schultz, M. G., Blake, D. R., Butler, J. H., King, D. B., Lobert, J. M., Maier-Reimer, E., 2002. Methyl iodide: Atmospheric budget and use as a tracer of marine convection in global models, Journal of Geophysical Research-Atmospheres 107(D17), 4340-4351.] to account for the large discrepancies between observed and predicted mid-latitude concentrations of CH3I based on their global photochemical source model. The suitability of several types of container for seawater incubations was studied and only quartz tubes appeared to be free of experimental artifact. Collapsible polyvinyl fluoride containers showed major production of methyl halides on irradiation with simulated sunlight. Polyethylene containers caused spurious production of methyl iodide at lower rates. 相似文献
2.
Based on the determination of composition of volcanic volatiles and petrologic estimation of the total mass of volatiles erupted,
we showed important advances in the study of the impact of Mesozoic and Cenozoic volcanic activities on paleo-environmental
changes in China. The volcanic activities include western Liaoning and Zhangjiakou Mesozoic intermediate-acidic explosive
eruptions, southern Tibet and Shanwang Cenozoic volcanism, and Mt. Changbai volcanic eruption around one thousand years ago.
The paper predominantly discusses the earth’s surface temperature changes, ozone depletion, acidic rain formation and mass
mortalities of vertebrate induced by the Mesozoic and Cenozoic volcanism in China.
__________
Translated from Bulletin of Mineralogy, Petrology and Geochemistry, 2007, 26(4): 319–322 [译自: 矿物岩石地球化学通报] 相似文献
3.
Bruce A. Callander 《GeoJournal》1997,42(1):55-63
IPCCs statement in its 1995 report (IPCC 1996) that a human influence was discernible in global climate has been widely quoted but often misunderstood. The character of the evidence underpinning this detection statement is explained so that its strengths and weaknesses can be better understood and the subtleties of its message better appreciated. To demonstrate the close linkage between the government-approved summary and the underlying chapters of the IPCC report the detailed evolution of the detection statement from first draft through to the form finally approved by the IPCC is described. 相似文献
4.
As a legacy of the centrally planned economy, the economies in transition of Central and Eastern Europe (CEE) have a unique
potential to reduce their greenhouse gas emissions through the improvement in their high energy intensities. Since much of
this `low-hanging fruit' in energy-efficiency improvements can be highly cost-effective, many developed countries facing difficulties
in meeting their greenhouse gas (GHG) emission targets domestically are eager to find such opportunities in the CEE region.
Therefore, studies analysing the potentials and costs of carbon dioxide reduction through technology improvement in the region
have come into the limelight. While there are a few excellent studies in the region aimed at analysing climate change abatement
potentials, they all embark on different assumptions, methodologies and boundary conditions. It is hence difficult, if not
impossible, to compare and analyse the results of these studies across different authors, countries or time horizons. Consequently,
the purpose of this paper is to place four leading studies on GHG mitigation through technology improvement from the CEE region
into an internationally comparable framework. Four studies were selected from three countries, Poland, Hungary and Estonia,
which are all the results of major national and international efforts to assess costs and potentials of GHG reduction. The
paper places their assumptions, methods and final results into a framework which enables policy-makers and project designers
to compare these across geographical and technological boundaries. Since other studies from around the globe have been analysed
in this framework in the literature, this paper provides a vehicle for the findings of these four studies to be compared to
others worldwide. In addition, the paper highlights a few areas where similar studies to be completed in the future in the
region may be enhanced by incorporating features used in GHG mitigation research in other parts of the world.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
6.
S. E. Beaubien G. Ciotoli S. Lombardi 《Journal of Volcanology and Geothermal Research》2003,123(1-2):63
The sudden and catastrophic, or slow and continuous, release at surface of naturally occurring toxic gases like CO2, H2S and Rn poses a serious health risk to people living in geologically active regions. In general this problem receives little attention from local governments, although public concern is raised periodically when anomalous toxic-gas concentrations suddenly kill humans or livestock. For example, elevated CO2 concentrations have been linked to the death of at least 10 people in the central Italian region of Lazio over the last 20 years, while it was the CO2 asphyxiation of 30 cows in a heavily populated area near Rome in 1999 which prompted the present soil-gas study into the distribution of the local health risk. A detailed geochemical survey was carried out in an area of about 4 km2 in the Ciampino and Marino districts, whereby a total of 274 soil-gas samples were collected and analysed for more than 10 major and trace gas species. Data were then processed using both statistical and geostatistical methods, and the resulting maps were examined in order to highlight areas of elevated risk. General trends of elevated CO2 and Rn concentrations imply the presence of preferential pathways (i.e. faults and fractures) along which deep gases are able to migrate towards the surface. The CO2 and Rn anomalous trends often correspond to and are usually elongated parallel to the Apennine mountain range, the controlling structural feature in central Italy. Because of this fundamental anisotropy in the factors controlling the soil-gas distribution, it was found that a geostatistical approach using variogram analysis allowed for a better interpretation of the data. With regard to the health risk to local inhabitants, it was found that although some high risk areas had been zoned as parkland, others had been heavily developed for residential purposes. For example, many new houses were found to have been built on ground which has soil-gas CO2 concentrations of more than 70% and radon values of more than 250 kBq m−3. It is recommended that land-use planners incorporate soil-gas and/or gas flux measurements in environmental assessments in areas of possible risk (i.e. volcanic or structurally active areas). 相似文献
7.
辽宁宽甸新生代火山岩和地幔包体He-Ar同位素组成 总被引:8,自引:1,他引:8
宽甸新生代碱性玄武岩、地幔包体及辉石巨晶的稀有气体同位素组成和流体含量分析表明,不同岩性稀有气体含量的差异反映了岩浆作用过程中轻、重稀有气体的分馏特性,较轻的稀有气体(He、Ne)比较重的稀有气体(Kr、Xe)具有更高的活动性和不相容性;该地区上地幔源区具有典型的MORB型源区特征,以辉石巨晶为代表;地幔包体的3^He/^4He值较低,可能与地幔上隆过程中富集地幔流体的交代作用或地幔塑性变形作用丢失了部分原始He有关;大陆碱性玄武岩具有与大洋玄武岩截然不同的He同位素组成,反映了大陆区地幔岩浆上升过程中受到了陆壳物质混染。地幔源区^40Ar/^36Ar值为350左右,二辉橄榄岩和碱性火山岩的^40Ar/^36Ar值比大气略高,可能有大气组分的混入。部分样品中有^21Ne、^22Ne、^129Xe、^134Xe和^136Xe相对于大气的过剩现象。 相似文献
8.
Laser microprobe for the study of noble gases and nitrogen in single grains: A case study of individual chondrules from the Dhajala meteorite 总被引:1,自引:0,他引:1
A laser microprobe capable of analysing nitrogen and noble gases in individual grains with masses less than a milligram is
described. It can be used in both continuous wave (CW) mode, useful for stepwise heating of an individual grain, as well as
in pulsed mode, useful for ablating material from a small selected area of a sample, for gas extraction. We could achieve
low blanks (in ccSTP units) for 4He(4.8 x 10{-12}),22Ne(1.0 x 10{-12}),36Ar(1.0 x10
-13),84Kr(2.9 x 10{-14}),132 Xe(2.6 x 10{-14}), and N (87 pg), using this system. Preliminary data for individual chondrules from the Dhajala meteorite show that noble
gases and nitrogen from grains as small as 170 microgram can be analysed using the present laser microprobe setup. The amount
of trapped neon in Dhajala chondrules is very small, and nitrogen in the chondrules is isotopically heavier as compared to
the bulk meteorite. 相似文献
9.
TH. Blumenstock H. Fisher A. Friedle F. Hase P. Thomas 《Journal of Atmospheric Chemistry》1997,26(3):311-321
During SESAME phase I ground-based FTIR measurements were performed atEsrange near Kiruna, Sweden, from 28 January to 26 March 1994. Zenith columnamounts of ClONO2, HCl, HF, HNO3,O3, N2O, CH4, and CFC-12 werederived from solar absorption spectra. Time series of ClONO2and HCl indicate a chlorine activation at the end of January and around 1March. On 1 March a very low amount of HCl of 2.09times; 1015molec. cm-2 was detected, probably caused by a second chlorineactivation phase starting from an already decreased amount of HCl. The ratioof column amounts of HCl to ClONO2 decreased inside the vortexfrom about 1 in January to 0.4 in late March compared to values of about 2outside the vortex. Although the Arctic stratosphere was rather warm in winter1993/94 and PSCs occurred seldom, chlorine partitioning into its reservoirspecies HCl and ClONO2 changed during that winter andClONO2 is the major chlorine reservoir at the end of thewinter as in cold winters like 1991/92 and 1994/95. 相似文献
10.
地幔流体的前缘研究 总被引:19,自引:8,他引:19
地幔流体是与地幔环境处于平衡的气体和挥发分。其主要化学组分为碳、氢、氧、氮、硫(CHONS)。它以富于地球内部原始组分为特征,但也包含部分再循环组分。地幔挥发分在弱还原条件下主要为CO2-H2O,强还原环境则以CH4-H2O-H2为主。地幔流体地球化学的重要性质为:(1)易溶于硅酸盐熔体;(2)净化作用;(3)再沉淀作用。近年来,有关地幔流体中稀有气体和挥发分的起源、分布及同位素组成等前缘领域的研究已取得重要进展。当前拟优先探索的问题包括气体裂化与金刚石成因,非生物成因地幔烃,地幔流体与成矿作用,以及地幔挥发分注入与地壳重熔等。 相似文献