ON THE TERRESTRIAL ORIGIN OF THE TEPEXITL CRATER,MEXICO     

Lucrecia Maupom  Romn Alvarez  Susan W. Kieffer  Robert S. Dietz 《Meteoritics & planetary science》1975,10(3):209-214

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A geophysical study of the Rhinegraben — II. Gravity anomalies and geothermal implications     

Hans-Gert Kahle  Dietrich Werner 《Geophysical Journal International》1980,62(3):631-647

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Satellite lines in the solar X-ray spectrum     

Werner M. Neupert 《Solar physics》1971,18(3):474-488

Observations of solar X-ray line emission using crystal spectrometers during a large chromospheric flare have provided a list of wavelengths with a precision of 0.003 Å in first order of diffraction and correspondingly better in higher orders. In addition to the resonance, intersystem (1 ¹ S ₀-2 ³ P ₁) and forbidden (1 ¹ S ₀-2 ³ S ₁) transitions of ions of the Hei isoelectronic sequence, we have recorded satellite lines arising from ions in the Lii, Bei and Bi isoelectronic sequences. These satellite features are most prominent in the iron spectrum. Apparent decreases in the ratio of forbidden and intersystem line intensities of Mgxi and Sixiii during the flare are used to derive electron densities possibly as high as 1 × 10¹³ cm^–3 in the Mgxi emitting region and 1 × 10¹⁴ cm^–3 in the Sixiii region during the event. A search for satellite lines on the long-wavelength side of the Lyman-alpha line of Hi-like ions has yielded no positive identifications.  相似文献   

Estimating Deep Seafloor Interface and Volume Roughness Parameters Using the Multibeam-Hydrosweep System     

Bishwajit Chakraborty  Hans Werner Schenke  Vijay Kodagali  Rick Hagen 《Marine Geodesy》2013,36(1-2):19-26

Utilizing a hull-mounted, multinarrow beam echosounder onboard RV Polarstern, we measured variation of acoustic backscatter with incidence angles at two different sites in the Southern Oceans (Agulhas Plateau and the Riiser Larsen Sea). We modeled the data, using a composite roughness model, including water-sediment interface roughness and sediment volume roughness parameters. The model effectively uses the near normal incidence angle backscatter to determine the seafloor interface roughness parameters employing Helmholtz-Kirchhoff theory. Beyond 20° incidence angles, an application of Rayleigh-Rice theory is made by using a necessary splicing technique (combining both of the theories at 20° incidence angle). The estimated interface and volume roughness parameters are found to be in accordance with the known area geology.  相似文献   

Dynamics of initial ecosystem development at the artificial catchment Chicken Creek, Lusatia, Germany   总被引：1，自引：1，他引：0  

Michael Elmer  Werner Gerwin  Wolfgang Schaaf  Markus K. Zaplata  Karin Hohberg  Rossen Nenov  Oliver Bens  Reinhard F. Hüttl 《Environmental Earth Sciences》2013,69(2):491-505

In autumn 2005, the artificial catchment Chicken Creek was completed in an open-cast lignite mine in Lusatia, Germany. The 6 ha area has been constructed as a two-layer system consisting of a clay aquiclude and a sandy aquifer at the top. After construction, the site was left to an unrestricted and unmanaged succession. A comprehensive environmental monitoring program started immediately after the site was completed. Time series of essential environmental parameters were recorded with high temporal and spatial resolution. This paper presents selected time series of the past 6-year ecosystem development. Important changes registered in this period allow for the definition of distinctive phases of the still ongoing initial ecosystem evolution. A primary, short, but pronounced geo-phase—characterized by surface runoff, excessive erosion and sedimentation as well as very rapid immigration of biota—was followed by a hydrological dominated phase with processes, such as groundwater recharge. At the end of the study period, biotic processes became more evident. It can be concluded that the artificial catchment offers unique opportunities for interdisciplinary research on the establishment of an ecological system with rapidly growing complexity. The highly dynamic development of the Chicken Creek catchment provides the possibility to observe manifold changes within short time and to detect feedbacks and their modifications between different ecosystem compartments.  相似文献   

Chinese Scientists Have Obtained Great Achievements in Comprehensive Research on the Qinghai-Tibet Plateau     

HAO Ziguo  FEI Hongcai  LIU Lian  and Susan TURNER 《《地质学报》英文版》2013,87(2):629-630

The China Geological Survey carried out 1:250000 regional geological surveys of the Qinghai-Tibet Plateau from 1999 to 2005.With a total investment of 300 million yuan,more than 1000 geologists were involved annually to conduct mapping at a grid of one line to every four km along the Kunlun Mts-Altyn Shan-Tanggula Shan,Kokoxili-Qiangtang,Gangdese,Yalun Zangbu River,and finally to the Himalayan ranges.The extensive mapping culminated in a total of 112maps covering an area of 152 square kilometers.Based on this success,the China Geological Survey launched another program,the "Integration and Comprehensive Study of Basic Geological Survey Result(s) in the Qinghai-Tibet Plateau".The program lasted from 2006 to 2010 and has yielded copious research results,making big strides in upgrading our understanding of the Qinghai-Tibet Plateau.The achievements are manifold.  相似文献   

2013 Production of China’s Shale Gas Reaches 200 Million Cubic Meters and the First Transportation Pipeline Constructed     

HAO Ziguo  FEI Hongcai  LIU Lian  Susan TURNER 《《地质学报》英文版》2013,87(5):1472-1472

Results of the global shale gas resources show that minable resources of global shale gas are 187 trillion cubic meters(tcm),of which China accounts for 36 tcm(about 20%of the total amount),which is mainly distributed in the Sichuan Basin,Yangtze Terrace,and Ordos Basin.From 2009 to 2012,China completed an accumulative number of 129 drilling wells related to shale gas,including 46 investigated vertical wells,55 exploration wells and  相似文献   

Breakthrough in the China’s Separation Technology for Extraction of Rare Earth Elements     

HAO Ziguo  FEI Hongcai  LIU Lian  and Susan TURNER 《《地质学报》英文版》2013,87(6):1743-1744

Separation technology of rare earth elements （REEs）, as the critical step in the separation process, had long been fraught with technical difficulty. A research project conducted by Baotou Shibo Rare Earth Extraction ＆ Equipment Co. Ltd., Baotou REE Research Institute, and Baotou Steel ＆ REE Group Hi-Tech Co. Ltd （Inner Mongolia）, has successfully solved the problem using a centrifugal extractor and advanced techniques to achieve a key breakthrough.  相似文献   

Neotectonic state of stress in the Jura Mountains     

Dietrich Werner 《Geodinamica Acta》2013,26(2):99-111

Abstract

For the determination of the tectonic stress field in the region of the Jura Mountains, three different relief techniques have been used in 18 test sites. In six test sites measurements have been carried out in horizontal boreholes using the doorstopper method. In the remaining test sites measurements were made in vertical boreholes by the doorstopper method (8), triaxial strain cell method (3) and borehole slotter (1). Additionally, analyses of borehole breakouts from six deep wells are presented.

Orientation of maximum horizontal stress clearly deviates from the uniform NW-SE orientated central and western European stress field. Local stress sources, which are probably related to active decollement tectonics in the Jura Mountains, may explain the deviation in stress orientations in comparison to the foreland. Normal stress magnitudes perpendicular to the trend of compressional structures in the Folded Jura are largest in the southeastern Upper Rhine Graben and its southwards prolongation into the Jura Mountains. Low stress magnitudes are characteristic for the eastern termination, intermediate ones for the southern foreland of the Jura Mountains.  相似文献   

Permeability of Wellbore-Cement Fractures Following Degradation by Carbonated Brine   总被引：1，自引：0，他引：1  

Stuart D. C. Walsh  Wyatt L. Du Frane  Harris E. Mason  Susan A. Carroll 《Rock Mechanics and Rock Engineering》2013,46(3):455-464

Fractures in wellbore cement and along wellbore-cement/host-rock interfaces have been identified as potential leakage pathways from long-term carbon sequestration sites. When exposed to carbon-dioxide-rich brines, the alkaline cement undergoes a series of reactions that form distinctive fronts adjacent to the cement surface. However, quantifying the effect of these reactions on fracture permeability is not solely a question of geochemistry, as the reaction zones also change the cement’s mechanical properties, modifying the fracture geometry as a result.This paper describes how these geochemical and geomechanical processes affect fracture permeability in wellbore cement. These competing influences are discussed in light of data from a core-flood experiment conducted under carbon sequestration conditions: reaction chemistry, fracture permeability evolution over time, and comparative analysis of X-ray tomography of unreacted and reacted cement samples. These results are also compared to predictions by a complementary numerical study that couples geochemical, geomechanical and hydrodynamic simulations to model the formation of reaction fronts within the cement and their effect on fracture permeability.  相似文献