Cadomian terranes,wrench faulting and thrusting in the central Europe Variscides: geophysical and geological evidence

Sixty five per cent of the Paleozoic basement of western and central Europe is hidden by a sedimentary cover and/or sea. This work aims to remove that blanket to detect new structures which could used to build a more comprehensive model of the Variscan orogeny. It is based on the interpretation of various forms of data: (a) published gravity maps corrected for the effects of the crust-mantle boundary topography and light sedimentary basins; (b) aeromagnetic maps; (c) measurements of densities; and (d) induced and remanent magnetizations on rocks from Paleozoic outcrops of the upper Rhenish area. From the northern Bohemian Massif to the eastern Paris Basin, the Saxothuringian is characterized by a 500 km long belt of gravity highs, the most important being the Kraichgau high. Most of the corresponding heavy bodies are buried under a post-early Viséan cover. They are interpreted as relics of Late Proterozoic terranes overlain by an Early to Middle Paleozoic sequence, equivalent to the Bohemian terrane in the Bohemian Massif. The most probable continuation of these dense Bohemian terranes toward the west is the Southern Channel-Northern Brittany Cadomian terrane. The gravity lows are correlated with Variscan granites and pre- and early Variscan metagranites.Gravity and magnetic maps demonstrate large-scale displacement in Devonian-Early Carboniferous times along the parallel and equidistant, NW-SE striking, Vistula, Elbe, Bavarian, Bray and South Armorican dextral wrench faults. In the Vosges-Schwarzwald and Central Massif the faults continue with the east-west striking Lalaye-Lubine-Baden-Baden and Marche faults and with south vergent thrusts. The Bavarian faults shift the Kraichgau terrane by 150 km relative to the Bohemian terrane, whereas the offset of the Northern Brittany Cadomian relative to the Northern Vosges-Kraichgau terranes is estimated at 400 km along the Bray fault. Sinistral wrench faults are the NE-SW striking Sillon Houiller, Rheingraben, Rodl, Vitis and Diendorf faults. The southern Vosges-Schwarzwald Devonian-Dinantian basin is interpreted as a pull-apart basin at the south-easterly extremity of the Bray fault. The Bohemian and Kraichgau body form allochthonous terranes which were thrust over the Saxothuringian crust. Thrusting to the north-west was accompanied by back-thrusting and led to the formation of pop-up structures. Contemporaneous dextral and sinistral wrench faulting resulted in transpressive strain during collision. The zonal structure of the Variscides in the sense of Kossmat (1927) is relevant only to the Rhenohercynian Foreland Belt. Kossmat (1927) already spoke of a Moldanubian Region because it displays no real zonal structure. The Saxothuringian Zone was formed by terrane accretion. Their apparent zonal structure is not a pre-collisional feature, but only the result of accretion and collision.     

Die Gliederung des Rotliegenden und die Stellung seiner Vulkanite am Südwestrand des Frankenwaldes

Zusammenfassung Auswirkungen der saalischen Phase sind nun auch im Stockheimer Becken erstmals festgestellt. In der Hauptsache ist in diesem Gebiet jedoch mit orogenetischen Bewegungen im Unterrotliegenden selbst zu rechnen. — Der Vulkanismus entwickelte sich im Becken bzw. an seinen Rändern vermutlich bereits im jüngsten Oberkarbon (1. Phase, am stärksten ausgebildet) und hält dann im Unterrotliegenden an (2. Phase, evtl. noch Gehrener Stufe). Aus dem mittleren Rotliegenden sind bisher nur Porphyr-Fanglomerate angeführt worden. Allerdings muß berücksichtigt werden, daß deren Neubearbeitung noch nicht abgeschlossen ist und das Stockheimer Becken ohnehin nur einen kleinen Ausschnitt aus der Gesamtentwicklung am Südwestrand des Frankenwaldes darstellt. Mit einem Vulkanismus im mittleren Rotliegenden (3. Phase, ? Goldlauterer Stufe) ist demnach auch hier noch zu rechnen.     

Man-Made earthquakes Ein Weg zum Verständnis natürlicher seismischer Aktivität

The occurrence of earthquakes causing damage in regions, where no seismic activity had been observed previously, has confirmed the suspicion that the construction of high dams and pumped storage hydroelectric plants as well as the pressing of fluid into petroleum reservoirs and of waste water into deep boreholes will trigger the release of tectonic stresses in the earth's crust. A great number of examples indicates that a similar mechanism must be operative in all cases. Comparing the results of laboratory experiments to seismological observations, it is evident that the causes for the “loss of internal balance” must be sought in zones of low velocity and of relatively high energy absorption within the upper part of the earth's crust.     

Zur Auswertung des ebenen Dreischichtenfalles in der Reflexionsseismik durch Potenzreihenentwicklung

Zusammenfassung Ein Verfahren zur Bestimmung der im Sinne der Methode der kleinsten Quadrate bestangepassten Schichtparameter an eine gemessene Laufzeitkurve wird angegeben. Es können höchstens drei Parameter berechnet werden, die drei übrigen Parameter müssen bekannt sein. Die Brechung wird exakt berücksichtigt. Das Verfahren ist für Berechnung durch Computer geeignet. Einfache Formeln gestatten eine angenäherte Bestimmung der unbekannten Parameter.

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Summary A procedure for determining the best fitted parameters of a three layer case to a given travel time curve by the least squares method is described. At most three parameters can be calculated, the other three have to be known. Refraction is taken into account exactly. The calculations have to be made with the aid of a computer. The unknown parameters can be determined approximatively by simple formulas.

     

Electricity consumption patterns within cities: application of a data-driven settlement characterization method

ABSTRACT

Urban areas presently consume around 75% of global primary energy supply, which is expected to significantly increase in the future due to urban growth. Having sustainable, universal energy access is a pressing challenge for most parts of the globe. Understanding urban energy consumption patterns may help to address the challenges to urban sustainability and energy security. However, urban energy analyses are severely limited by the lack of urban energy data. Such datasets are virtually non-existent for the developing countries. As per current projections, most of the new urban growth is bound to occur in these data-starved regions. Hence, there is an urgent need of research methods for monitoring and quantifying urban energy utilization patterns. Here, we apply a data-driven approach to characterize urban settlements based on their formality, which is then used to assess intra-urban urban energy consumption in Johannesburg, South Africa; Sana’a, Yemen; and Ndola, Zambia. Electricity is the fastest growing energy fuel. By analyzing the relationship between the settlement types and the corresponding nighttime light emission, a proxy of electricity consumption, we assess the differential electricity consumption patterns. Our study presents a simple and scalable solution to fill the present data void to understand intra-city electricity consumption patterns.     

An experimental study of illite dissolution kinetics as a function of ph from 1.4 to 12.4 and temperature from 5 to 50°C

Dissolution rates of natural illite (Illite du Puy) were measured from Si release rates during closed system experiments at pH ranging from 1.4 to 12.4 and temperatures ranging from 5 to 50°C. Experiments performed at 4<pH<11 exhibited reactive fluid Si/Al concentration ratios that were inconsistent with stoichiometric illite dissolution likely due to secondary phase precipitation. In contrast, after an initial preferential release of aluminum relative to silicon, the reactive fluid Si/Al concentration ratio evolution was consistent with stoichiometric illite dissolution for all experiments conducted at 4>pH>11. Si release rate decreased with time during all experiments; for those experiments performed at 4>pH>11 this observation can be attributed to either 1) changing reactive surface area; 2) the effect of initial fine particle dissolution; or 3) a negative order of the illite dissolution reaction with respect to aqueous Al and/or Si. Measured dissolution rates exhibited a typical variation with pH; rates decrease with increasing pH at acid conditions, minimize at near to neutral pH and increase with increasing pH at basic conditions. An empirical expression describing rates obtained in the present study is given by

     

Do stratocumulus clouds detrain? FIRE I data revisited

Analyses of aircraft observations of the stratocumulus-topped boundary layer during the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment (FIRE I) show the frequent presence of clear, but relatively moist, air patches near the stratocumulus cloud-top interface. A conditional sampling of measurements in these clear air patches shows that their thermodynamic properties do more resemble boundary-layer air characteristics than those of free troposphere air. From an aircraft leg through cloud tops it is demonstrated that turbulent mixing across the cloud-top interface can lead to the local dissipation of the cloud top. Analogous to the terminology used for shallow cumulus parameterizations this process can be considered as detrainment, with which we mean that after a mixing event across the cloud-top boundaries, mixed unsaturated parcels become part of the clear environment of the cloud.