The Variscan tectonic inheritance of the Upper Rhine Graben: evidence of reactivations in the Lias,Late Eocene–Oligocene up to the recent     

J.-B. Edel  K. Schulmann  Y. Rotstein 《International Journal of Earth Sciences》2007,96(2):305-325

Processing of gravity and magnetic maps shows that the basement of the Upper Rhine Graben area is characterized by a series of NE–SW trending discontinuities and elongated structures, identified in outcrops in the Vosges, Black Forest, and the Odenwald Mountains. They form a 40 km wide, N30–40° striking, sinistral wrench-zone that, in the Visean, shifted the Variscan and pre-Variscan structures by at least 43 km to the NE. Wrenching was associated with emplacement of several generations of plutonic bodies emplaced in the time range 340–325 Ma. The sub-vertical, NE–SW trending discontinuities in the basement acted as zones of weakness, susceptible to reactivation by subsequent tectonism. The first reactivation, marked by mineralizations and palaeomagnetic overprinting along NE–SW faults of the Vosges Mountains, results from the Liassic NW–SE extension contemporaneous with the break-up of Pangea. The major reactivation occurred during the Late Eocene N–S compression and the Early-Middle Oligocene E–W extension. The NE–SW striking basement discontinuities were successively reactivated as sinistral strike-slip faults, and as oblique normal faults. Elongated depocenters appear to form in association with reactivated Variscan wrench faults. Some of the recent earthquakes are located on NE–SW striking Variscan fault zones, and show sinistral strike-slip focal mechanisms with the same direction, suggesting also present reactivation.  相似文献   

Behaviour of H₂O₂, NH₃, and black carbon in mixed-phase clouds during CIME     

Paolo Laj  Andrea I. Flossmann  Wolfram Wobrock  Sandro Fuzzi  Giordano Orsi  Loretta Ricci  Stephan Mertes  Alfons Schwarzenbck  Jost Heintzenberg  Harry Ten Brink 《Atmospheric Research》2001,58(4):256

We investigated the partitioning of trace substances during the phase transition from supercooled to mixed-phase cloud induced by artificial seeding. Simultaneous determination of the concentrations of H₂O₂, NH₃ and black carbon (BC) in both condensed and interstitial phases with high time resolution showed that the three species undergo different behaviour in the presence of a mixture of ice crystals and supercooled droplets. Both H₂O₂ and NH₃ are efficiently scavenged by growing ice crystals, whereas BC stayed predominantly in the interstitial phase. In addition, the scavenging of H₂O₂ is driven by co-condensation with water vapour onto ice crystals while NH₃ uptake into the ice phase is more efficient than co-condensation alone. The high solubility of NH₄⁺ in the ice could explain this result. Finally, it appears that the H₂O₂–SO₂ reaction is very slow in the ice phase with respect to the liquid phase. Our results are directly applicable for clouds undergoing limited riming.  相似文献   

利用非金属矿制备白炭黑现状及发展前景   总被引：8，自引：0，他引：8  

周光  王廷吉 《华东地质学院学报》2001,24(4):298-302

简术了白炭黑的用途和制备方法，综述了利用非金属矿制备白炭黑的方法和技术现状，对充分利用非金属矿制备白炭黑提供思路并展望其发展前景。  相似文献   

中国西北地区1993年5月5日黑风暴的机理探讨   总被引：16，自引：0，他引：16       下载免费PDF全文

刘景涛  郑明倩 《应用气象学报》1996,7(3):371-376

该文用天气学、诊断分析方法对1993年5月5日我国西部地区黑风暴天气过程的发生发展及形成机理进行研究。结果表明，这次黑风暴是由强寒潮爆发，在特定季节（春季）和裸露、疏松的下垫面（沙漠、戈壁）条件下形成的中尺度现象。在对流层中低层垂直方向上存在很强的风切变，利于湍流发展；非地转强迫作用对次级环流贡献大于地转强迫作用；黑风暴前后显著的辐射加热不均匀分布所形成的热力正反馈作用，造成近地层局地锋生，并使热力正环流大大加强。  相似文献   

“93.5”黑风暴发展结构和不同模式分辨率的数值试验   总被引：25，自引：0，他引：25       下载免费PDF全文

程麟生  马艳 《应用气象学报》1996,7(4):385-395

1993年5月4～6日在我国西北部地区发生了一次“黑风暴”。用改进的MM1和高分辨PBL参数化及40 km细网格控制试验能基本上模拟出“93.5”黑风暴的结构和演变。模拟结果表明，黑风暴发展时段，在PBL内与一个中尺度气旋性强涡旋相伴，在对流层内与一个垂直涡柱相伴。这个伸展至对流层顶的涡柱下（上）半部是与低（高）空强烈辐合（辐散）入（外）流相伴的气旋（反气旋）性涡柱。该黑风暴结构不同于一般锋面结构，其主要判别是:界面坡度陡，θe水平梯度大，斜压性强，PBL内暖心明显。该暖心结构与下垫面剧烈热力强迫有关。不  相似文献   

Elucidation of the Alum Shale kerogen structure using a multi-disciplinary approach     

Sunil Bharati  Richard L. Patience  Steve R. Larter  Guy Standen  Iain J. F. Poplett 《Organic Geochemistry》1995,23(11-12)

The significance and validity of integrating data obtained from a variety of analytical techniques to understand, elucidate and model kerogen's complex chemical structure is reported here using degradative (open and closed system pyrolysis, chemical oxidation), non-degradative (¹³C CP/MAS NMR) and optical (incident white light and blue light) methods. Seven Cambrian Alum Shale samples, ranging in maturity from immature to post-mature with respect to petroleum generation, were studied and were chosen for their simple geological history, uniform organic matter type and high organic carbon content. The Alum Shale kerogens, which primarily consist of algal organic matter, liberate low molecular weight gaseous and aromatic compounds on pyrolysis and give mostly branched dicarboxylic acids on chemical oxidation. ¹³C NMR spectroscopy shows that the Alum Shale kerogens are anomalously rich in oxygen-bearing functional groups (such as C = O, ArCO, CHO, CH_xO), most of which apparently remain intact within the kerogen macro-molecule (KMM) through the diagenetic and catagenetic stages. Fragments released by different degradative techniques are quantified and the aromaticity (f_a), O/C and relative proportions of various carbon types estimated by ¹³C NMR. A synthesis of these data has allowed us to better understand the chemistry of the Alum Shale kerogen.  相似文献   

Authigenic sericite record of a fossil geothermal system: the Offenburg trough,central Black Forest,Germany     

Olaf?Brockamp  Norbert?Clauer  Michael?ZutherEmail author 《International Journal of Earth Sciences》2003,92(6):843-851

A fossil geothermal area is hosted by the Carboniferous, Permian and Bunter sandstones of the Offenburg intramontane trough in the central Black Forest. The hydrothermal alteration is identified on the basis of newly formed sericites, which appear as pseudomorphs after feldspar and filling of pore spaces. According to K–Ar dating of sericite, serititization occurred about 145 Ma ago (Jurassic). On the basis of ¹⁸O analyses of sericite, sericite composition and vitrinite reflectance, the hydrothermal fluids had temperatures of 150–210 °C. Because their electrolyte content was low, these fluids are assumed to have derived from meteoric water. A second pulse of electrolyte-rich hydrothermal fluids resulted in quartz overgrowths. Fluid mobilization seems to be linked to the disintegration of Pangaea and to reactivated fault systems extending from the crystalline basement into the intramontane sediments.  相似文献   

不同矿化度下泥质对岩石电性影响的逾渗网络研究   总被引：4，自引：1，他引：4       下载免费PDF全文

王克文  孙建孟  耿生臣  吴金龙 《地球物理学报》2006,49(6):1867-1872

为了进一步认识泥质对岩石宏观电性的影响规律，本文利用非规整三维逾渗网络模型，通过数值模拟研究了不同矿化度下泥质对岩石电性影响的规律. 模拟结果表明：在中低矿化度下，泥质对岩石导电整体上呈现减阻作用，随着泥质含量的增加，电阻率降低的速度减慢；中等矿化度下泥质的减阻效果明显弱于低矿化度下的减阻效果；在高矿化度下泥质对岩石导电整体上呈现增阻作用. 在高矿化度、高含水饱和度下泥质对岩石电性的影响较小. 泥质起减阻、增阻作用的具体矿化度范围取决于储层的孔隙度、连通性以及地层温度等特性.  相似文献   

Line emission from accretion discs around black holes: the analytic approach     

Andrej ?ade?  Claudio Fanton  Massimo Calvani 《New Astronomy》1998,3(8):528-654

The broad X-ray iron line observed in many active galactic nuclei spectra is thought to originate from the accretion disc surrounding the putative supermassive black hole. We show here how to perform the analytical integration of the geodesic equations that describe the photon trajectories in the general case of a rotating black hole (Kerr metric), in order to write a fast and efficient numerical code for modelling emission line profiles from accretion discs.  相似文献   

南海区4种鲷鱼精子的适盐性比较     

江世贵  李加儿  区又君  郑运通 《广东海洋大学学报》1998,(4)

研究了盐度对黄鳍鲷SparuslatusHouttuyn、平鲷Rhabdosargussarba（Forskal）、黑鲷Sparusmacrocephalus（Basilewsky）和真鲷Pagrsomusmajor（TemmincketSchlegel）4种鲷鱼精子活力的影响。对南海区4种鲷鱼精子的适盐性及其活力进行了比较,黄鳍鲷、平鲷、黑鲷和真鲷精子激活所需的最低盐度分别为8、10、＞8、＞10;激活的最适盐度则分别为21、22、25、25,与之相应的精子活动（涡动）时间分别为14．7、17．7、17．2、18．0min;在高盐条件（盐度40左右）下,黄鳍鲷精子的适应性最强,精子活力最好,其次是黑鲷、真鲷的精子,平鲷精子对高盐条件的适应性最差。  相似文献