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Abstract: The Late Cretaceous Khabr–Marvast tectonized ophiolite is located in the middle part of the Nain–Baft ophiolite belt, at the south-western edge of the central Iranian microcontinent. Although all the volcanic rocks in the study area indicate subduction-related magmatism (e.g. high LILE (large ion lithophile elements) / HFSE (high field strenght elements) ratios and negative anomalies in Nb and Ta), geological and geochemical data clearly distinguish two distinct groups of volcanic rocks in the tectonized association: (1) group 1 is comprised of hyaloclastic breccias, basaltic pillow lavas, and andesite sheet flows. These rocks represent the Nain–Baft oceanic crust; and (2) group 2 is alkaline lavas from the top section of the ophiolite suite. These lavas show shoshonite affinity, but do not support the propensity of ophiolite. 相似文献
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ＲｕｐｔｕｒｅｐｒｏｃｅｓｏｆＮｏｖｅｍｂｅｒ６,１９８８,ＬａｎｃａｎｇＧｅｎｇｍａ,Ｙｕｎｎａｎ,Ｃｈｉｎａ,ｅａｒｔｈｑｕａｋｅｏｆＭｓ＝７．６ｕｓｉｎｇｅｍｐｉｒｉｃａｌＧｒｅｎ’ｓｆｕｎｃｔｉｏｎｄｅｃｏｎｖｏｌｕｔｉｏｎｍｅｔｈｏｄ... 相似文献
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ＡｕｎｉｆｏｒｍｃａｔａｌｏｇｏｆｅａｒｔｈｑｕａｋｅｓｆｏｒｓｅｉｓｍｉｃｈａｚａｒｄａｓｅｓｍｅｎｔｉｎＩｒａｎＮｏｏｒｂａｋｈｓｈＭｉｒｚａｅｉ１，２）ＭＥＮＧ－ＴＡＮＧＡＯ１）（高孟谭）ＹＵＮ－ＴＡＩＣＨＥＮ１）（陈运泰）ＪＩＡＮＷＡＮＧ１... 相似文献
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The movement of bedload in subcritical flow produces additional roughness as compared to flow in a rigid bed. The magnitude of this bed load roughness is proportional to the thickness of the sediment layer moving along the bed, the particle size and the sediment concentration. In a supercritical flow, however, further resistance is expected due to the momentum absorption by the high flow velocity. In this study the effect of sediment movement on the flow resistance in supercritical flow was experimentally investigated. The experiments included flows over smooth and rough beds carrying sediment of mean diameters D50=2.80, 5.42 and 7.06 mm in a rigid rectangular channel. The results show that the sediment transport may increase the friction factor by up to 90% and 60% in smooth and rough beds, respectively. Bedload extracts its momentum from the flow, which causes a reduction of near bed flow velocity and steeper velocity gradient near the bed resulting in an increase in shear velocity as well as in roughness height. The increase in friction factor is directly related to bedload concentration and particle size. 相似文献
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Seismicity in Major Seismotectonic Provinces of Iran 总被引：1，自引：0，他引：1
Mirzaei Noorbakhsh 《中国地震研究》1997,(4)
Seismicity parameters,i.e.,seismic activity rate,X,the so-called Gutenberg-Richter b value(orβ),and maximum possible magnitude,Mmax,for major seismotectonic provinces of Iran are estimated through the application of Kijko and SellevolPs uncertainty models.The uncertainty models facilitated the estimation of seismic activity parameters from incomplete and uncertain data files in the catalog of earthquakes in major seismotectonic provinces of Iran.Zagros has the highest seismic activity rate,and is characterized by the occurrence of mainly small-and mid-sized earthquakes.Kopeh Dagh has the lowest activity rate but is characterized by a greater occurrence of major earthquakes.However,the Makran and Alborz-Azarbayejan seismotectonic provinces are most likely the regions which are capable of generating great earthquakes. 相似文献
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M.S.Seif M.Askari 《中国海洋工程》2004,18(3):477-484
The paper contains the results of an experimental study on a planing catamaran. The aim of this study is resistance reduction with application of foils. Experiments are performed in different conditions and the results are compared with each other. The foils are used in different configurations and it is concluded that unsuitable design may result in larger resistance. But, it is also shown that, for a good design, the resistance may be reduced considerably. 相似文献
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1 INTRODUCTION Scouring in the bend ways leads to deep sections at the toe of the outer bank of the bend. The presenceof secondary currents and the greater depths at the outer bank cause high velocity along the outer bank.The high velocity and shear stres… 相似文献
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Mohammad Saeed SEIF Ebrahim JAHANBAKHSH Roozbeh PANAHI Mohammad Hossein KARIMI 《中国海洋工程》2009,23(3):517-528
High speed planing hulls have complex hydrodynamic behaviors. The trim angle and drafts are very sensitive to speed and location of the center of gravity. Therefore, motion simulation for such vessels needs a strong coupling between rigid body motions and hydrodynamic analysis. In addition, free surface should be predicted with good accuracy for each time step. In this paper, velocity and pressure fields are coupled by use of the fractional step method. On the basis of integration of the two-phase viscous f... 相似文献
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