Reactions between olivine and CO2-rich seawater at 300 °C: Implications for H2 generation and CO2 sequestration on the early Earth     

《地学前缘(英文版)》2017,8(2):387-396

To understand the influence of fluid CO₂ on ultramafic rock-hosted seafloor hydrothermal systems on the early Earth, we monitored the reaction between San Carlos olivine and a CO₂-rich NaCl fluid at 300 °C and 500 bars. During the experiments, the total carbonic acid concentration (ΣCO₂) in the fluid decreased from approximately 65 to 9 mmol/kg. Carbonate minerals, magnesite, and subordinate amount of dolomite were formed via the water-rock interaction. The H₂ concentration in the fluid reached approximately 39 mmol/kg within 2736 h, which is relatively lower than the concentration generated by the reaction between olivine and a CO₂-free NaCl solution at the same temperature. As seen in previous hydrothermal experiments using komatiite, ferrous iron incorporation into Mg-bearing carbonate minerals likely limited iron oxidation in the fluids and the resulting H₂ generation during the olivine alteration. Considering carbonate mineralogy over the temperature range of natural hydrothermal fields, H₂ generation is likely suppressed at temperatures below approximately 300 °C due to the formation of the Mg-bearing carbonates. Nevertheless, H₂ concentration in fluid at 300 °C could be still high due to the temperature dependency of magnetite stability in ultramafic systems. Moreover, the Mg-bearing carbonates may play a key role in the ocean-atmosphere system on the early Earth. Recent studies suggest that the subduction of carbonated ultramafic rocks may transport surface CO₂ species into the deep mantle. This process may have reduced the huge initial amount of CO₂ on the surface of the early Earth. Our approximate calculations demonstrate that the subduction of the Mg-bearing carbonates formed in komatiite likely played a crucial role as one of the CO₂ carriers from the surface to the deep mantle, even in hot subduction zones.  相似文献   

煤中微量元素赋存状态的逐提试验研究   总被引：12，自引：0，他引：12  

王运泉  任德贻 《中国煤田地质》1997,9(3):23-25

首次通过逐级化学提取试验对高级煤中10余个微量元素的赋存状态（水溶态及可交换态，碳酸盐铁锰氧化物结合态，有机质结合态，进入晶格或呈单矿物态）进行研究，结果表明：绝大多数元素具有一种以上的赋存状态；不同沉积环境条件下，元素的赋存态可以发生改变；元素的赋存状态不同，其入侵环境及对环境的危害程度不同。  相似文献   

震电效应原理和初步实验结果   总被引：10，自引：6，他引：10       下载免费PDF全文

石昆法 《地球物理学报》2001,44(5):720-728

从电化学理论、薄膜效应以及浓差极化，解释了震电效应的基本原理.通过室内沙槽和岩芯标本实验，发现了震电信号，且在砂土上的震电信号比粘土上的大；含石油岩芯标本上的震电效应信号比含水岩芯标本上的强.通过室外实验，也已经测量到可信的震电效应信号，从而为石油测井继续研究提供了实验数据.  相似文献   

陆面过程野外观测试验的进展   总被引：5，自引：0，他引：5  

胡隐樵 《地球科学进展》1992,7(3):37-42

Progresses in field observational experiments, which are three large international programs at present，about land一surface process are introduced comprehensively in the paper. Major results obtamed by the HAPEX and the FIFE and some preliminary results by the HEIFE are reviewed. Some problems, which should further be solved，in the field observational experiments are pointed out.
  相似文献   

冬季花卉无土育苗栽培生产技术试验   总被引：1，自引：0，他引：1  

许彦平  姚晓红  秘晓东  李建国 《干旱气象》2003,21(1):28-30,43

通过有采暖设施日光温室相同基质不同育苗设施花卉扦插育苗和相同育苗设施有机生态基质与营养土基质花卉扦插育苗试验，得出双膜弓棚大畦营养纸钵育苗设施不仅有显著的增热保温效果，而且较小的昼夜温差相对延续并减少了弓棚内插德根部基质的热量流失，为植物根系生长提供了有效的热量条件。采用冬暖日光温室内套双膜弓棚大畦营养纸钵花卉育苗，使供试花卉扦插至成苗移栽或上盆期缩短45—46d，≥10℃积温减少700—770℃日，扦插成活串提高了6个百分点。  相似文献   

强夯法处理软弱粉土地基试验研究   总被引：3，自引：2，他引：3  

张忠苗  杨什生  辛公锋  叶兴永 《工程地质学报》2003,11(2):148-154

介绍了钱塘江南岸软弱粉土地基试验区通过降水强夯与填石强夯的试验效果, 并对不同夯击能夯击前后粉土地基的物理力学性质、变形特性、抗液化性能等静力动力特性进行了对比研究。  相似文献   

Thermodynamic structure of the marine atmosphere over the region 80–87°E along 13°N during August (phase II) BOBMEX-99     

Savita B. Morwal  P. Seetaramayya 《Journal of Earth System Science》2003,112(2):295-312

Thermodynamic structure of the marine atmosphere in the region between 80 and 87‡E along 13‡N over the Bay of Bengal was studied using 13 high resolution radiosonde profiles from surface-400 hPa collected onboard ORV Sagar Kanya during the period 27th–30th August, during BOBMEX-99. Saturation point concept, mixing line analysis and conserved variable diagrams have been used to identify boundary layer characteristics such as air mass movement and stability of the atmosphere. The results showed relatively dry air near the ocean surface between 1000 and 950 hPa. This feature is confirmed by the conserved teta_v structure in this layer. Further, teta_v seldom showed any inversions in this region. The teta_e and teta_es profiles showed persistent low cloud layers between 900 and 700 hPa. The conserved variable diagrams (teta_e-q) showed the existence of double mixing line structures approximately at 950 and 700 hPa levels.  相似文献   

孕震类型与应变成核的实验研究   总被引：3，自引：1，他引：3  

杨润海  许昭永  王彬  赵晋明 《地震研究》2003,26(4):332-337

根据岩石强度的差异，组合成不同类型的试样，采用不同的加力方式，模拟不同的地震孕震类型，用多功能高频地震勘探仪和光线示波器对比记录各测点的应变变化。实验结果发现，在岩石主破裂前，不同类型试样各点应变都出现趋势性变化；除软包体型试样外，各点应变除趋势性变化外，都出现应变突变。据此提出应变成核概念。  相似文献   

Satellite gradiometry using a satellite pair   总被引：1，自引：1，他引：1  

W. Keller  M.A. Sharifi 《Journal of Geodesy》2005,78(9):544-557

The GRACE mission has substantiated the low–low satellite-to-satellite tracking (LL-SST) concept. The LL-SST configuration can be combined with the previously realized high–low SST concept in the CHAMP mission to provide a much higher accuracy. The line of sight (LOS) acceleration difference between the GRACE satellite pair, the simplest form of the combined observable, is mostly used for mapping the global gravity field of the Earth in terms of spherical harmonic coefficients. As an alternative observable, a linear combination of the gravitational gradient tensor components is proposed. Being a one-point function and having a direct relation with the field geometry (curvature of the field at the point) are two noteworthy achievements of the alternative formulation. In addition, using an observation quantity that is related to the second-instead of the first-order derivatives of the gravitational potential amplifies the high-frequency part of the signal. Since the transition from the first- to the second-order derivatives includes the application of a finite-differences scheme, the high-frequency part of the noise is also amplified. Nevertheless, due to the different spectral behaviour of signal and noise, in the end the second-order approach leads to improved gravitational field resolution. Mathematical formulae for the gradiometry approach, for both linear and higher-degree approximations, are derived. The proposed approach is implemented for recovery of the global gravitational field and the results are compared with those of LOS acceleration differences. Moreover, LOS acceleration difference residuals are calculated, which are at the level of a few tenths of mGal. Error analysis shows that the residuals of the estimated degree variances are less than 10^–3. Furthermore, the gravity anomaly residuals are less than 2 mGal for most points on the Earth.  相似文献   

Experimental Research on Microscopic Indicators of Temperature's Returning-to-Zero in Deformation of Calcite and Discussions of Correlation Problem     

Yao Daquan 《中国地震研究》2005,19(1):35-42

1 RESEARCHINTOTHEACTIVITYTIMEOFFAULTSINBEDROCKAREASDatemeasurementoffaultactivityisessentialforrecognizingtheactivitybehaviorofafault,inversingseismologicalandgeologicaleventsandprobingintoearthquakerhythms .Itismoredifficulttodeterminetheactivitytimeoffa…  相似文献