Effects of Energetic Solar Emissions on the Earth–Ionosphere Cavity of Schumann Resonances     

Gabriella Sátori  Earle Williams  Colin Price  Robert Boldi  Alexander Koloskov  Yuri Yampolski  Anirban Guha  Veronika Barta 《Surveys in Geophysics》2016,37(4):757-789

Schumann resonances (SR) are the electromagnetic oscillations of the spherical cavity bounded by the electrically conductive Earth and the conductive but dissipative lower ionosphere (Schumann in Z Naturforsch A 7:6627–6628, 1952). Energetic emissions from the Sun can exert a varied influence on the various parameters of the Earth’s SR: modal frequencies, amplitudes and dissipation parameters. The SR response at multiple receiving stations is considered for two extraordinary solar events from Solar Cycle 23: the Bastille Day event (July 14, 2000) and the Halloween event (October/November 2003). Distinct differences are noted in the ionospheric depths of penetration for X-radiation and solar protons with correspondingly distinct signs of the frequency response. The preferential impact of the protons in the magnetically unshielded polar regions leads to a marked anisotropic frequency response in the two magnetic field components. The general immunity of SR amplitudes to these extreme external perturbations serves to remind us that the amplitude parameter is largely controlled by lightning activity within the Earth–ionosphere cavity.  相似文献   

Kinetics of the reactions of soot surface-bound polycyclic aromatic hydrocarbons with NO<Subscript>2</Subscript>   总被引：1，自引：0，他引：1  

Mai Lan Nguyen  Yuri Bedjanian  Angélique Guilloteau 《Journal of Atmospheric Chemistry》2009,62(2):139-150

The kinetics of heterogeneous reactions of NO₂ with 17 polycyclic aromatic hydrocarbons (PAHs) adsorbed on laboratory generated kerosene soot surface was studied over the temperature range (255–330) K in a low pressure flow reactor combined with an electron-impact mass spectrometer. The kinetics of soot-bound PAH consumption due to their desorption and reaction with NO₂ were monitored using off-line HPLC measurements of their concentrations in soot samples as a function of reaction time, NO₂ concentrations in the gas phase being analyzed by mass spectrometer. No measurable decay of PAHs due to the reaction with NO₂ was observed under experimental conditions of the study (maximum NO₂ concentration of 5.5 × 10¹⁴ molecule cm⁻³ and reaction time of 45 min), which allowed to determine the upper limits of the first-order rate constants for the heterogeneous reactions of 17 soot-bound PAHs with NO₂: k < 5.0 × 10⁻⁵ s⁻¹ (for most PAHs studied). Comparison of these results to previous studies carried on different carbonaceous substrates, showed that heterogeneous reactivity of PAHs towards NO₂ is, probably, dependent on the substrate nature even for resembling, although different carbonaceous materials. Results show that particulate PAHs degradation by NO₂ alone is of minor importance in the atmosphere  相似文献   

Nonlocal bacterial electron transfer to hematite surfaces     

Kevin M Rosso  John M Zachara  Yuri A Gorby 《Geochimica et cosmochimica acta》2003,67(5):1081-1087

Mechanisms by which dissimilatory iron-reducing bacteria utilize iron and manganese oxide minerals as terminal electron acceptors for respiration are poorly understood. In the absence of exogenous electron shuttle compounds, extracellular electron transfer is generally thought to occur through the interfacial contact area between mineral surfaces and attached cells. Possible alternative reduction pathways have been proposed based on the discovery of a link between an excreted quinone and dissimilatory reduction. In this study, we utilize a novel experimental approach to demonstrate that Shewanella putrefaciens reduces the surface of crystalline iron oxides at spatial locations that are distinct from points of attachment.  相似文献   

Jovian sodium cloud geometry     

Alexander I. Ershkovich  Yuri B. Mekler 《Astrophysics and Space Science》1975,38(1):L1-L2

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U–Pb Geochronology of VMS mineralization in the Iberian Pyrite Belt     

Tucker C. Barrie  Yuri Amelin  Emilio Pascual 《Mineralium Deposita》2002,37(8):684-703

A geochronology study using U-Pb isotope dilution TIMS analyses of zircon has been conducted to determine the ages of volcanic-associated massive sulfide (VMS) deposits in the Iberian Pyrite Belt (IPB), the world's most prolific VMS province. Ages have been determined for host rocks to four VMS systems that span the IPB: the giant Rio Tinto and Aljustrel districts in the central region, Lagoa Salgada to the west, and Las Cruces to the east. A sample of chloritized quartz porphyritic dacite/rhyolite in the footwall of the San Dionisio massive sulfide deposit of the Rio Tinto district is 349.76ǂ.90 Ma. This is taken as the best age estimate of the mineralization in the Rio Tinto district, probably the world's largest volcanogenic massive sulfide system. Two xenocrystic zircons from the same sample yielded ²⁰⁷Pb/²⁰⁶Pb ages of 414 and 416 Ma, which provide a minimum estimate for the age of the inherited component. A biotite tonalite from the Campofrio area, 3.5 km north of the center of the Rio Tinto district, is chemically similar to the felsic host rock protolith at Rio Tinto. The Campofrio sample has an age of 346.26ǂ.81 Ma, slightly younger and outside of the 2C error for the Rio Tinto age; therefore, this phase of this intrusion was not a heat source for the hydrothermal system that formed the deposits of the Rio Tinto district. The Campofrio sample also has three zircon analyses with ²⁰⁷Pb/²⁰⁶Pb minimum ages of 534, 536, and 985 Ma, indicating inheritance from Ordovician and Neoproterozoic sources. In the Aljustrel VMS district, a U-Pb zircon age of 352.9ǃ.9 Ma characterizes the altered Green Tuff host rock of the Algares deposit, which is slightly older than the Rio Tinto age. Two zircons with ²⁰⁷Pb/²⁰⁶Pb ages of 531 and 571 Ma from this sample indicate inheritance from a Cambrian or older source. The age of mineralization at Lagoa Salgada is given by essentially identical ages of 356.21ǂ.73 and 356.4ǂ.8 Ma, for footwall and hanging wall samples, respectively. The hanging wall sample has two zircon analyses with ²⁰⁷Pb/²⁰⁶Pb ages of 464 and 466 Ma, indicating inheritance from an Ordovician or older source. The age for an altered dacite tuff sample from the hanging wall of the Las Cruces deposit is 353.97ǂ.69 Ma. One zircon analysis from the Las Cruces sample has a ²⁰⁷Pb/²⁰⁶Pb age of 1048 Ma, indicating inheritance from a Neoproterozoic source. These U-Pb ages refine the IPB geochronology provided by previous studies, and they suggest that either volcanism progressed toward the center of the IPB, or that volcanism was broadly static and the strata were progressively rifted to the margins during transtensional basin formation. The zircon inheritance provides direct evidence for Proterozoic to Ordovician sources, reflecting either basement rocks beneath the Phyllite-Quartzite Group during VMS formation in late Tournaisian times, or a Proterozoic to Ordovician detrital component in Phyllite-Quartzite Group source rocks. The presence of an older crustal component is consistent with VMS formation during rift development at a continental margin.  相似文献   

勘探异常压力天然气藏的新思路--探明非常规天然气资源的关键要素   总被引：4，自引：0，他引：4  

Ronald C.Surdam  焦尊生  Yuri Ganshin 《高校地质学报》2003,9(3):307-338

异常压力天然气藏(Anomalously Pressured Gas,APG)主要指“盆地中心”天然气系统(BCGS)中，天然气含量丰富，但开发程度相对较低的天然气资源。例如，美国怀俄明州Wind River盆地的面积约为8500mi^2，其USGS异常压力天然气资源量估计是900Tcf，但目前产气量累积不足1Tcf。丰富的天然气资源与开发程度的不平衡在所有“盆地中心”异常压力天然气藏中是很典型的。因此，对于蕴藏在BCGS中极其丰富的天然气资源，尚待更为有效的开发。过去，开发APG资源困难且昂贵，但最近怀俄明州Greater Green River和Wind River盆地的开发成功，以及早些时候阿尔伯达、Denver—Julesburg和San Juan盆地的成功开发均表明，更为有效的开发是做得到的。最重要的是，当异常压力天然气藏的开发取得成功的时候，财政上的回报是显著的。为了更充分地开发盆地中心APG资源，大幅度提高天然气资源转换为能源储量的比率和数量，则需要新的和更富有创新性的开发策略、技术和判断方法。经过多年的努力，天然气新技术开发公司(IDT)的研究团队已经研发出一系列高效勘探和开发异常压力天然气藏的新的有效方法。应用IDT技术可以在钻井之前为开发者提供下列必要的信息：(1)天然气饱和的岩石／流体系统的空间分布，包括压力封存箱边界；(2)区域压力界面或正常和异常压力(或超压，或欠压)的流体之间界线的位置和性质；(3)流体中天然气和水含量的确定；(4)微裂缝群的识别和空间分布；(5)断层的方位和时序；(6)储层属性特征。借助由IDT技术所提供的油气系统的信息，可以使开发者设计并应用最优化钻井方案，从而避免当前与含气异常压力地层开发有关的许多灾难性的陷阱。  相似文献   

Comment on: “Origin, timing, and temperature of secondary calcite-silica mineral formation at Yucca Mountain, Nevada” by N. S. F. Wilson, J. S. Cline, and Y. V. Amelin     

Yuri V. Dublyansky  Sergey Z. Smirnov 《Geochimica et cosmochimica acta》2005,69(17):4387-4390

Yucca Mountain in southern Nevada is being evaluated as a potential site for the geological disposal of high-level nuclear waste. A reliable assessment of the future performance of the repository will require detailed paleohydrogeological information. Hydrogenic secondary minerals from the vadose zone of Yucca Mountain are being studied as paleohydrogeological indicators. A phenomenological model envisaging the deposition of secondary minerals by meteoric fluids infiltrating downward though the vadose zone was proposed in the reviewed paper. Our evaluation reveals that the model is not supported by empiric evidence reported in the paper.  相似文献   

Modelling of viscoelastic plume–lithosphere interaction using the adaptive multilevel wavelet collocation method     

Oleg V. Vasilyev  Yuri Yu. Podladchikov  David A. Yuen 《Geophysical Journal International》2001,147(3):579-589

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Teresa Pi  Jesús Solé  Yuri Taran 《Mineralium Deposita》2006,41(3):300

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Stable and unstable damage evolution in rocks with implications to fracturing of granite   总被引：1，自引：0，他引：1  

Yariv Hamiel  Oded Katz  Vladimir Lyakhovsky  Ze'ev Reches  Yuri Fialko 《Geophysical Journal International》2006,167(2):1005-1016

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