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991.
Partitioning of Nb and Ta between rutile and felsic melt and the fractionation of Nb/Ta during partial melting of hydrous metabasalt 总被引:5,自引:0,他引:5
In order to fully assess the role of rutile in fractionation of Nb/Ta during partial melting of hydrous metabasalt, we have measured rutile - felsic melt partition coefficients (D values) for Nb and Ta with tonalitic to trondhjemitic compositions at 1.5-3.5 GPa, 900-1350 °C and ∼5.0-20 wt% H2O. DNb, DTa and DNb/DTa range from 17 ± 1 to 246 ± 13, 34 ± 2 to 232 ± 25 and 0.51 ± 0.04 to 1.06 ± 0.13, respectively. For the compositions investigated, melt composition appears to have no observable effect on the partitioning; the effect of pressure is also slight; whereas temperature and H2O have marked effects. DNb, DTa and DNb/DTa increase with decreasing temperature and H2O content, showing a reversal of DNb/DTa from <1.0 to >1.0. Using the data that approached equilibrium and obeyed Henry’s law, expressions describing the dependences of DNb, DTa and DNb/DTa on temperature, pressure and melt H2O content were obtained:
(1) 相似文献
992.
Yun LiYongqiang Xiong Chenchen FangQianyong Liang Jingru ZhangPing’an Peng 《Organic Geochemistry》2011,42(5):559-565
In this study, headspace single-drop microextraction (HS-SDME) coupled with gas chromatography-isotope ratio mass spectrometry (GC-IRMS), was employed to determine compound specific carbon isotopic values (δ13C) of gasoline range hydrocarbons. The reproducibility of the method was found to be satisfactory. By comparison with the δ13C values of the twelve target compounds determined using direct injection of their n-C16 solution, no obvious isotopic fractionation was observed during the HS-SDME procedures. Some parameters that could affect the carbon isotopic fractionation, such as ionic strength of working solutions and inlet split ratio, were examined. The results also suggest that these factors had no significant effect on the carbon isotopic determination of gasoline range hydrocarbons. The application of HS-SDME to a crude oil sample proved that this method could be a promising tool for the determination of carbon isotopic values of gasoline range hydrocarbons in oils or aqueous samples. 相似文献
993.
����������̨����б���ŵĿ��ܻ��� 总被引:4,自引:2,他引:4
???????????????????????????б????????????????????????????б????????????????????????????????????????????????б?????????????????????????????????????????????????????????б????????????????????????????????????????棬?????????????????????е????塱???? 相似文献
994.
靖州盆地是位于雪峰构造带南段的一个NE向晚三叠世-中侏罗世小型陆相盆地。作者对盆地周缘上古生界及盆地侏罗系中不同产状与运动性质的小型断裂和节理进行了大量观察研究,据此识别出近SN向挤压、NNE向挤压、NEE向挤压、近EW向挤压、NW向挤压、NW向伸展等应力事件。根据断裂构造赋存层位和部分断裂显示的次序,结合靖州盆地构造特征及区域构造演化背景,初步厘定了研究区中生代以来构造体制演化过程:中三叠世晚期印支运动中区域NW向挤压;晚三叠世-早侏罗世区域近SN向挤压;中侏罗世早、中期区域NW向挤压;中侏罗世晚期因区域NE-NNE向溆浦-靖州断裂左行走滑而具SN向挤压;白垩纪因区域NE向挤压而形成NW向伸展;晚白垩世晚期-古新世溆浦-靖州断裂右行走滑派生NEE向挤压;始新世-渐新世区域近EW向挤压;新近纪区域NNE向挤压。 相似文献
995.
黔北务正道地区铝土矿稀土元素地球化学特征 总被引:3,自引:0,他引:3
选取新模向斜的一个钻孔剖面,对铝土矿的矿物组成及稀土元素地球化学特征进行了研究。铝土矿矿石矿物以一水硬铝石为主,另有少量一水软铝石。其次为高岭石、绿泥石等黏土矿物,以及少量重矿物。此外,在含矿岩系近底部还发现有富集Ce元素的矿物氟菱钙铈矿[Ce2Ca(CO3)3F2]。从剖面顶部至底部,铝土矿中稀土元素含量呈逐渐增加的趋势,且稀土元素参数LaN/YbN、LaN/SmN和GdN/YbN的数值均随深度逐渐增大。说明从剖面顶部至底部,稀土元素的淋滤迁出逐渐减弱,且稀土元素间存在一定的分异。稀土元素间的分异可能由不同的含稀土元素矿物抗风化淋滤差异所致。铝土矿稀土元素配分模式表现为LREE明显富集、MREE中等-弱富集、HREE相对平坦的特征,且具有明显的正Ce异常。δCe异常值随深度增加逐渐减小,接近含矿岩系底部,δCe异常值再次增大。含矿岩系上部的Ce异常是由氧化条件下Ce3+向Ce4+转变并形成方铈矿(CeO2)所致。随着深度的增加,含矿岩系的氧化性逐渐减弱,从而δCe异常值逐渐减小。接近含矿岩系底部,由于氟菱钙铈矿[Ce2Ca(CO3)3F2]的形成,导致δCe异常值再次增大。氟菱钙铈矿的沉淀可通过氟化物络合物(CeF2+或CeCO3F0)与Ca2+和HCO3-发生反应来完成。 相似文献
996.
洪水地区位于沁水盆地东缘中部,15号煤层是该区主要的可采煤层之一,根据区内煤层气参数井测试数据、试井资料及煤炭地质勘查资料,对15号煤层储层特征进行了研究。结果显示:研究区15号煤层为高变质程度的贫煤,煤储层渗透率在0.047~0.1lmD,属低渗透率煤层,储层压力梯度为0.402~0.965MPa/lOOm,平均为0.672MPa/100m,属于欠压地层,煤层含气量为9.02—20.67m3/t,平均16.18m。/t,含气量较高。整体来看,研究区属于低渗透、低储层压力梯度和临储比,高含气量的煤层气富集区。 相似文献
997.
石楼北区块位于鄂尔多斯盆地东缘。该区域表土层松散易坍塌,在以往的钻探施工中,地层中不同程度的存在涌水或者漏失情况。太原组第三层灰岩可钻性较差,取心作业中频繁发生钻头被堵死的情况。为了解决以上问题,缩短施工工期,对钻具组合和钻井参数进行了调整,采用四翼PDC钻头、直螺杆的钻具结构;取心作业主要采用绳索取心,采用①215.9mm的取心钻头代替该区以往的016.9mm钻头,利用Φ127mm钻杆作为绳索取心工具的运行通道,并采用自行研制的内外管总成和内管取心工具.保证了取心效果;将钻头水眼更改为12mm×2+14mm+16ram的组合方式,有效保持了钻孔内的清洁,避免岩屑重复破碎,进一步提高钻进效率。同时介绍了钻探施工程中设备的配套、钻井液的配制、钻井技术参数的选择等。结果表明:该井取心岩心总收获率为92.15%,其中8#煤心质量总采取率为93.50%;井斜3°10′,全井水平位移44.17m,最大全角变化率耋1.1。/30m。对该区煤层气井钻探施工有很好的借鉴作用。 相似文献
998.
Jian Peng Yue Qing Xu Ren Zhang Kang Ning Xiong An Jun Lan 《Environmental Earth Sciences》2013,69(3):831-841
Over the past decades, the vast limestone mountain areas in southwestern China have suffered greatly from karst rocky desertification (KRD), which is a unique type of desertification caused by irrational land-use practices and has drawn increasing attention of international academic community. Characterizing soil erosion in this region is the key to understanding the escalating KRD problem and finding solution to it. The authors applied leveling method to study soil erosion process in the Huajiang Karst Canyon area between 1999 and 2003, and tried to relate it to KRD expansion. The monitoring data indicate that soil in the study area was losing at an alarming rate, which is much higher than soil formation rate and has already resulted in severe KRD problem. Soil loss under different land-use conditions varied greatly during the monitoring period. The highest soil erosion rate occurred in bare and newly abandoned cropland, followed by sparse grass land, forest land, and dense grass land. In addition, soil erosion could be significantly different under different micro-topographic conditions. Because soil erosion rate in the studied karst mountain areas is surprisingly high, it is urgent to take quick actions to fight against the ongoing KRD problems in Southwest China before an irreversible situation occurs. However, the traditional way to combat KRD by abandoning current cropland needs to be carefully reconsidered, since a bare newly abandoned cropland may suffer more from rapid soil loss than before. 相似文献
999.
Dingrong Xiong Haojing Zhang Xiong Zhang Yonggang Zheng Wenguang Liu Lisheng Mao Bangrong Huang Ting Kang Yongjuan Cha Fei Guo 《Astrophysics and Space Science》2013,343(1):345-360
Using γ-ray data detected by Fermi Large Area Telescope (LAT) and multi-wave band data for 40 TeV active galactic nuclei (AGNs), we have studied the correlations between flux densities (F R, F IR, F O, F X and F γ ) in the radio, infrared, optical, X-ray and γ-ray wave bands. Our results are the following: (1) For TeV HSP BL Lacertae objects (THBLs), there are strong correlations between F γ and F R and between F γ and F IR in all states (average/high/low); (2) The TeV radio galaxies (TRGs) deviate from the area occupied by THBLs; (3) The TeV flat-spectrum radio quasars (TFSRQs) have much stronger γ-ray emission than THBLs; (4) For THBLs, there are weak correlations between F γ and F X in all states as well as between F γ and F O in both average and high states, and a strong correlation between F γ and F O in the low state; (5) For THBLs, there are strong correlations between F O and F R in both low and average states as well as between F O and F IR in all states and between F IR and F R in all states, but no strong correlations among other bands are found. From these results, we suggest that for THBLs, the synchrotron self-Compton radiation (SSC) is the main mechanism of high energy γ-ray emission and the inverse Compton scattering of circum-nuclear dust is likely to be a important complementary mechanism. Compared with THBLs, TRGs and TFSRQs may have a different origin of high energy γ-ray. 相似文献
1000.
Xiong Ding-rong Zhang XiongZheng Yong-gang Huang Bang-rongMao Li-sheng Liu Wen-guang 《Chinese Astronomy and Astrophysics》2013
In this paper, we collect the redshift, bolometric luminosity, the full- width at half maximum of the Hβ emission line, the monochromatic luminosity at 5100 Å and the radio loudness for the sample of 117 quasars, including 20 radio-quiet quasars (RQQs) and 97 radio-loud quasars (RLQs). With the reverberation mapping method we calculate the black hole mass and Eddington ratio for this sample, as well as the radio luminosity from the total 5 GHz ?ux density. By analyzing the correlations among them, we obtain the following conclusions: (1) The black hole mass has weak correlations with the bolometric luminosity, radio loudness and radio luminosity for the RQQs, and has strong correlations with the bolometric luminosity, radio loudness and radio luminosity for the RLQs; (2) For the RQQs, the bolometric luminosity has weak correlations with the radio luminosity and 5 100 Å monochromatic luminosity, and for the RLQs, the bolometric luminosity has strong correlations with the radio luminosity and 5 100 Å monochromatic luminosity; (3) The RQQs and RLQs differ in the distributions of the black hole mass, emission line width and Eddington ratio. Based on these results, we suggest: the difference of emission line width between RQQs and RLQs is probably caused by the difference of black hole mass; the fundamental difference between RQQs and RLQs is caused by the difference of their intrinsic physical nature; the black hole mass, black hole spin, Eddington ratio, and host galaxy morphology are the important parameters to explain the origin of radio loudness and the double-peaked distribution; and the radio jet is closely related with the accretion rate of disk. 相似文献