POSITION OF ARSENIC MINERALS IN THE METALLOGENIC SERIES.

The fact that there is certain definite order in the distribution of metallic ores around a central magma has now been generally recognized by economic geologists and its effects on the geographic distribution as well as     

Active wrench faults of Iran,Afghanistan and Pakistan

The fault pattern of Iran, Afghanistan, and Pakistan has been mapped from air-photo-mosaics. The Herat, Chaman, Shahrud, Doruneh, and Zagros are the five major active faults and are wrench in character. With the exception of the Chaman fault, which lies to the east, the faults or their extensions spiral out from a centre in the Dasht Lut Depression of eastern Iran, the dextral faults spiralling out clockwise and the sinistral faults anticlockwise. The spiral fault pattern is consistent with that expected from a central force, and from the relation between the sense of horizontal displacement and the direction of outspiralling it is inferred that the crustal blocks west of the Chaman fault are moving in towards the Lut Centre. Similar spiral fault patterns can be recognized at many places in the world, and their centres are probably critical for explaining present day tectonics.-- , , , . — , , , — . , , , .

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Zusammenfassung Auf einer beigegebenen Karte wird der Verlauf von aktiven und von vermutlichen Hauptverwerfungen in Afghanistan, Pakistan und im Iran gezeigt, wie er anhand von Luftbild-Mosaikkarten und Luftaufnahmen bestimmt wurde. Die fünf wichtigsten aktiven Dislokationen sind die Herat-, Chaman-, Sharud-, Doruneh- und die Zagros-Verwerfung.Die deutlich sichtbare Herat-Verwerfung erstreckt sich in ENE-Richtung über 800 km durch den Nordteil Afghanistans zur chinesischen Grenze. Ihre Verschiebung erfolgte rechtsläufig, so daß die nördliche Scholle relativ zur südlichen nach E versetzt wurde.Die etwa 700 km lange nach SSW weisende Chaman-Verwerfung zieht sich in zwei schwach gegensinnig geschwungenen Bögen von der Herat-Verwerfung wenig N Kabul die afghanisch-pakistanische Grenze entlang, um in zahlreiche Zweigverwerfungen aufzuspalten, die in Westpakistan nach W umbiegen. Die Verschiebung erfolgte linksläufig und ist gut sichtbar.Die Sharud-Verwerfung im Iran erstreckt sich nach ENE durch die Achse des Elburs-Gebirges und biegt dann nach SE parallel zur russischen Grenze ab. Die Verwerfung ändert häufig ihre Richtung und ist nur schwer zu verfolgen. Sie hat eine sichere Länge von 800 km und ist linksläufig.Die gut sichtbare Doruneh-Verwerfung verläuft in Kurven 250 km südlich der Sharud-Verwerfung derselben parallel. Nach E spaltet sie sich auf, nach W vereinigt sie sich vermutlich mit der Sharud-Verwerfung. Sie ist 600 km lang und linksläufig.Die Zagros-Verwerfung tritt auf Luftaufnahmen am wenigsten hervor, auf geologischen Karten ist sie jedoch eine Hauptverwerfung. Sie erstreckt sich vom Schnittpunkt der drei Grenzen des Iran, Irak und der Türkei 950 km nach SE bis fast zur pakistanischen Grenze, wo sie wahrscheinlich anfangs nach NW, später nach N umbiegt. Die Verwerfung ist wahrscheinlich rechtsläufig.Die fünf Hauptverwerfungen, zusammen mit vier kleineren Verwerfungen, deren horizontaler Verschiebungssinn bekannt ist, bilden ein relativ einfaches Strukturmuster.Mit Ausnahme der Chaman-Verwerfung, die im E liegt, verlaufen die Verwerfungen oder ihre Ausläufer ausgehend von einem in der Dasht Lut-Senke gelegenen Zentrum in Gestalt einzelner Spiralen sternförmig nach allen Seiten; die in ihrem Verschiebungssinn rechtsläufigen im Uhrzeigersinn gebogen, die linksläufigen in Gegenrichtung gekrümmt. Die übrigen geologischen und morphologischen Hauptlinien zeigen ebenfalls eine derartige Anordnung mit demselbenZentrum. Das damit gegebene Strukturmuster läßt die Einwirkung einer zentralen Kraft vermuten. Aus dem Zusammenhang zwischen horizontalem Verschiebungssinn und der Richtung der einzelnen Spiralen ist zu schließen, daß sich die westlich der Chaman-Verwerfung liegenden Krustenblöcke in Richtung auf das Lut-Zentrum bewegten.Derartige Verwerfungssysteme sternförmig-spiraler Anordnung scheinen kritische Punkte im heutigen tektonischen Bild der Erde zu sein, wobei das Westende der Poebene und die Banda-See zwei der auffallendsten Zentren sind. Ebenso verlaufen die pazifischen Inselbögen in Spiralen, die sich gleichfalls in solchen Zentren treffen könnten.

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Résumé Une carte des failles actives de la Perse, de l'Afghanistan, et de la Pakistan a été dressée d'après des photos-aériennes et des photos-mosaïques. Les ruptures des filets et des rivières montrent que le rejet net est presque horizontal. Cinq failles sont dextrales, et quatre sont sinistrales. Des lignes qui montrent la direction de la maximum contraction horizontale, déterminée par les failles, encerclent la Dasht Lut dépression dans la Perse orientale.

     

OBSERVATIONS ON THE HINTEREIS AND VERNAGTFERNER

Abstract

Adequate water resources management at the basin level needs quality downscaling of climate change scenarios for application to impact assessment and adaptation work. This study evaluates the ability of a regional climate model (RegCM3) to simulate the present-day climate and regional water balance over the Niger River Basin (NRB). RegCM3 gives a good simulation of the NRB hydroclimatic features. The mean bias error for monthly temperature is 1.5°C, 0.3 mm d^-1 for rainfall, and 0.4 mm d^-1 for runoff. Moderate to high correlations (0.66–0.95) were found between the modelled and the observed variables. RegCM3-based water cycling indices were not statistically different from the observation. Seasonal moistening efficiency (m) ranges between 19% and 37%; 66% of the available atmospheric moisture over NRB precipitates between June and September, of which 21% originates from local evaporation. The result suggests that the moisture sink period is July to October with very high precipitation efficiency over the basin. The model reproduces the hydroclimatology of the NRB and hence is a suitable tool for further studies relating to the assessment of climate change impacts on river basin water systems.

Editor Z. W. Kundzewicz; Associate editor D. Hughes     

The response of ionospheric convection in the polar cap to substorm activity

We report multi-instrument observations during an isolated substorm on 17 October 1989. The EISCAT radar operated in the SP-UK-POLI mode measuring ionospheric convection at latitudes 71°-78°. SAMNET and the EISCAT Magnetometer Cross provide information on the timing of substorm expansion phase onset and subsequent intensifications, as well as the location of the field aligned and ionospheric currents associated with the substorm current wedge. IMP-8 magnetic field data are also included. Evidence of a substorm growth phase is provided by the equatorward motion of a flow reversal boundary across the EISCAT radar field of view at 2130 MLT, following a southward turning of the interplanetary magnetic field (IMF). We infer that the polar cap expanded as a result of the addition of open magnetic flux to the tail lobes during this interval. The flow reversal boundary, which is a lower limit to the polar cap boundary, reached an invariant latitude equatorward of 71° by the time of the expansion phase onset. A westward electrojet, centred at 65.4°, occurred at the onset of the expansion phase. This electrojet subsequently moved poleward to a maximum of 68.1° at 2000 UT and also widened. During the expansion phase, there is evidence of bursts of plasma flow which are spatially localised at longitudes within the substorm current wedge and which occurred well poleward of the westward electrojet. We conclude that the substorm onset region in the ionosphere, defined by the westward electrojet, mapped to a part of the tail radially earthward of the boundary between open and closed magnetic flux, the “distant” neutral line. Thus the substorm was not initiated at the distant neutral line, although there is evidence that it remained active during the expansion phase. It is not obvious whether the electrojet mapped to a near-Earth neutral line, but at its most poleward, the expanded electrojet does not reach the estimated latitude of the polar cap boundary.     

Buchbesprechungen

Ohne Zusammenfassung     

Dynamic racking tests of curtain wall glass elements with in-plane and out-of-plane motions

This project was conducted to investigate the breakage and fallout behaviour of various types of architectural glass elements in a dry-glazed curtain wall system under in-plane and out-of-plane dynamic motions. The project was a follow-up to an earlier project that focused exclusively on in-plane dynamic racking performance of curtain wall glass elements. The recent data indicated that adding out-of-plane motions caused significantly higher amounts of glass breakage and subsequent glass fallout in most glass types that were found during the in-plane tests to be prone to glass fallout. Specifically, 1/4 in (6 mm) annealed monolithic glass, 1/4 in annealed monolithic glass with a 0·004 in (0·10 mm) PET film (not anchored to the mullions), and 7/16 in (11 mm) fully tempered laminated glass exhibited comparable or higher fallout rates than the already substantial fallout rates that were observed during the in-plane only racking tests. Unanchored window film was found to be ineffective in resisting post-breakage glass fallout under dynamic racking motions. In contrast, 1/4 in (6 mm) annealed laminated glass and 7/16 in (11 mm) heat-strengthened laminated glass exhibited no glass fallout during the out-of-plane tests, just as they exhibited no fallout during the in-plane tests. Out-of-plane test results also showed that 3/8 in (10 mm) heat-strengthened monolithic glass exhibited no fallout, while 3/8 in annealed monolithic glass exhibited very negligible glass fallout. The addition of torsional motions was not found to induce glass fallout in those glass types that resisted glass fallout in previous tests performed without torsional motions.     

Performance of Foundations in Sabkha Soil: Numerical Investigation

Sabkha or salt flat soil is one of the most unpredictable and potentially dangerous soils in the Middle East. This soil covers a large and strategically important area of the Arabian Gulf coast, as it contains the world biggest oil reserve and a number of petrochemical plants are either have been built or are scheduled to be built in this area. The performance of shallow and deep foundations in the Eastern Province of Saudi Arabia’s sabkha soil is investigated numerically using the finite element method. The parameters used to simulate this soil in the numerical models were based on a large number of laboratory tests to determine the shear strength and stiffness parameters of the sabkha soil. In addition, the characteristics of the interface between the foundation and soil used in the numerical model were established from shear box tests that were conducted to evaluate the concrete-sabkha soil interface properties. The developed numerical model was calibrated/verified using the results of full-scale pile load testing program from an ongoing project to further enhance the accuracy of the results. A parametric study was then conducted using the verified model to establish the performance characteristics of foundations constructed in sabkha soil and provide guidelines for their design.     

Estimation of monotonic behavior of reinforced concrete columns considering shear‐flexure‐axial load interaction

Reinforced concrete columns with insufficient transverse reinforcement and non‐seismic reinforcement details are vulnerable to brittle shear failure and to loss of axial load carrying capacity in the event of a strong earthquake. In this paper, a procedure is presented after examining the application of two macro models for displacement‐based analysis of reinforced concrete columns subjected to lateral loads. In the proposed model, lateral load‐deformation response of the column is simulated by estimating flexural and shear deformation components separately while considering their interaction and then combining these together according to a set of rules depending upon column's yield, flexural and shear strengths. In addition, lateral deformation caused by reinforcement slip in beam–column joint regions and buckling of compression bars are taken into account and considered in the analysis. Implementation of the proposed procedure produces satisfactory lateral load–displacement relationships, which are comparable with experimental data. Copyright © 2012 John Wiley & Sons, Ltd.