Nouvelles données structurales et datations 40K–40Ar sur les roches métamorphiques de la région de Neyriz (zone de Sanandaj–Sirjan,Iran méridional). Leur intérêt dans le cadre du domaine néo-téthysien du Moyen-Orient     

Reza Sheikholeslami  Hervé Bellon  Hachem Emami  Mossaı̈eb Sabzehei  Alain Piqué 《Comptes Rendus Geoscience》2003,335(13):981-991

The metamorphic rocks of the Neyriz area (Sanandaj–Sirjan zone) represent a Palaeozoic sequence, the upper part of which being palaeontologically dated from the Carboniferous and the Permian. Field structural analysis of the whole sequence, detailed in laboratory by microstructural one and ⁴⁰K–⁴⁰Ar dating carried on separated minerals, lead to establish that the whole sequence, from gneisses to Permian rocks, has suffered a unique synmetamorphic deformation, of variable intensity, marked by a foliation. Isotopic ages measured on extracted amphiboles and micas, clustered in four groups between 300 and 60 Ma, show the successive stages of their slow exhumation, which ended by the end of the Cretaceous. To cite this article: R. Sheikholeslami et al., C. R. Geoscience 335 (2003).  相似文献   

Application of Geographic Information Systems to Analyses and Modeling of Hydrocarbons Anomaly in Yakla,North Tarim Basin,Xinjiang,China     

Mohammad Reza Hosseinnejad 《中国地质大学学报(英文版)》1998,9(2):2

ＩＮＴＲＯＤＵＣＴＩＯＮＡｈｙｄｒｏｃａｒｂｏｎａｎｏｍａｌｙｉｓｇｅｎｅｒａｌｙｄｅｆｉｎｅｄａｓｔｈｅｃｈａｎｇｅｉｎｖａｌｕｅｏｆｏｎｅｏｒｍｏｒｅｈｙｄｒｏｃａｒｂｏｎｓｉｎｔｈｅｆｉｅｌｄｃｏｍｐａｒｅｄｔｏｂａｃｋｇｒｏｕｎｄｌｅｖｅｌｏ...  相似文献   

Petrology of Igneous Rocks in Northern Golpayegan, Iran     

Mohammad Ebrahimi 《中国地质大学学报(英文版)》1998,9(1):2

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｓｔｕｄｉｅｄａｒｅａｉｓｌｏｃａｔｅｄｉｎｔｈｅｎｏｒｔｈｏｆＧｏｌｐａｙｅｇａｎ,Ｉｒａｎ,ｂｏｕｎｄｅｄｂｙｌａｔｉｔｕｄｅｓ３３．３１°Ｎａｎｄ３３．３７°Ｎａｎｄｌｏｎｇｉ－ｔｕｄｅｓ５０．１１°Ｅａｎｄ５０．...  相似文献   

Precision rectification of high resolution satellite imagery without ephemeris data     

Saeid Sadeghian  Mohammad Javad Valadan Zoej  Mahmoud Reza Delavar  Ahmad Abootalebi 《International Journal of Applied Earth Observation and Geoinformation》2001,3(4):366

The huge capability of high resolution satellite imageries (HRSI), that includes spatial, spectral, temporal and radiometric resolutions as well as stereoscopic vision introduces them as a powerful new source for the Photogrammetry, Remote Sensing and GIS communities. High resolution data increases the need for higher accuracy of data modeling. The satellite orbit, position, attitude angles and interior orientation parameters have to be adjusted in the geometrical model to achieve optimal accuracy with the use of a minimum number of Ground Control Points (GCPs). But most high resolution satellite vendors do not intend to publish their sensor models and ephemeris data. There is consequently a need for a range of alternative, practical approaches for extracting accurate 2D and 3D terrain information from HRSI. The flexibility and good accuracy of the alternative models demonstrated with KFA-1000 and the well-known SPOT level 1A images. A block of eight KFA-1000 space photos in two strips with 60% longitudinal overlap and 15% lateral sidelap and SPOT image with rational function, DLT, 2D projective, polynomials, affine, conformal, multiquadric and finite element methods were used in the test. The test areas cover parts of South and West of Iran. Considering the quality of GCPs, the best result was found with the DLT method with a RMSE of 8.44 m for the KFA-1000 space photos.  相似文献   

The subsistence crisis and migration in the Sahelian Zone of the Sudan —     

Dr.  Assoc. Prof. Abdel Hamid M. A. Bakhit 《GeoJournal》1991,25(1):39-45

Burush is a small village in the N Sahelian Zone of the Sudan, whose population are basically sedentary agriculturists. The recurring drought conditions of the last two decades have significantly influenced the local resource base, so that the subsistence of the majority of the households was highly challenged. Nevertheless, the people are still surviving and resisting. The explanation of this resistence can be sought in the endogenous coping mechanisms adopted by the people. One of these mechanisms is migration, especially the seasonal labour migration of the heads and grown-up members of households, which used, even in good years, to be highly integrated in the strategies of survival of the majority of households. However under the recurring crop failures and the growing competition in the seasonal labour opportunities, this seasonal migration is changing gradually into stays of longer duration in the traditional destinations of seasonal labour. On the other hand, the male members of households are actively involved in migration of long duration, especially into the urban centres. Yet, the constributions of these migrant members to the subsistence of their households are limited, because of the rising costs of living in uurban centres as compared with the incomes. The rehabilitation of Burush lies obviously in the development of long-term strategies which aim at strengthening the endogenous resilience mechanisms.  相似文献   

Hydraulic parameters of a multilayered aquifer system in Kuwait City     

Shabbir A. S. Sayed  Hamid S. Saeedy  Ferenc Sz  kely 《Journal of Hydrology》1992,130(1-4):49-70

The Kuwait Group consists mainly of clastic sediments overlying unconformably the Dammam Formation of Tertiary age. The Kuwait Group is generally divided into three main hydrostratigraphic units: the upper and lower aquifers separated by an aquitard. The upper aquifer is further divided into the water table aquifer, an aquitard and a semiconfined aquifer. This semiconfined unit was pumped and the drawdowns were observed in piezometers screened in various subunits of the Kuwait Group. Some pumping tests of short duration were carried out in the top water table aquifer as well. These tests showed that the subunits of the Kuwait Group are hydraulically interconnected to a varying degree.

The pumping test data were analysed using conventional analytical solutions. The semiconfined pumping test was also simulated by a quasi-three-dimensional model using a leaky multiaquifer modelling technique. The initial hydraulic parameters were improved manually in the model till best fit drawdowns were obtained.

The final parameters obtained by simulation of the pumping tests were used in designing a pilot drainage system for the control of a rising groundwater table in parts of Kuwait City.  相似文献   

Elasto‐plastic analytical model for the design of grouted bolts in a Hoek–Brown medium     

Reza. R. Osgoui  Pierpaolo Oreste 《国际地质力学数值与分析法杂志》2010,34(16):1651-1686

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Environmental characterization of a karst polje: an example from Izeh polje,southwest Iran     

Hamid Reza Nassery  Farshad Alijani  Leila Mirzaei 《Environmental Earth Sciences》2009,59(1):99-108

Groundwater contamination is a well-known phenomenon, which occurs on local and regional scales in Izeh polje. The aims of this paper are investigation of the impact of human activities on the polje ecosystem, determination of the vulnerability of ground water, and to solve environmental problems. Nitrate contamination of groundwater in the Izeh polje was predicted using a solute transport model. The nitrate concentration in groundwater in most parts of Izeh polje is greater than maximum concentration permissible for drinking water, i.e., 45 mg/l. The main source of nitrate in the eastern underground areas of Izeh city is the domestic sewage. Bacterial pollution of shallow ground water in Izeh polje is severe and widespread. About 45% of ground water samples in May and September 2001 have positive MPN coliforms. Infiltration of polluted surface waters and decrease of water table depth, have lead to bacterial pollution of 80% of ground water samples in January 2002. The northeast, south and southwest areas of Izeh polje have higher pollution potential rather than its middle parts. The aquifer vulnerability indices in the middle, eastern, and northern parts of the polje are moderately lower as a result of decreased sediment size of the aquifer. The pollution in the polje depends on the amount and presence of pollutants. If they do exist, the possibility of pollution is considerable due to the coarseness of materials and shallow depth of groundwater table.  相似文献   

胡杨和灰杨的叶绿素荧光参数及茎水势对塔克拉玛干沙漠腹地生境的响应     

韩炜  海米提·依米提  李利  李生宇  郑婷婷 《中国沙漠》2011,31(6):1472-1478

通过测定胡杨（Populus euphratica）、灰杨（Populus pruinosa）叶绿素荧光参数和茎水势,研究了二者成龄叶片样本的电子传递和光能的吸收、分配和耗散对塔克拉玛干沙漠腹地生境的适应特征。结果表明,无论清晨弱光下还是正午强光下,胡杨茎水势均比灰杨低,胡杨具有更强的吸水能力;在光合有效辐射不十分高的晴天内,胡杨的光系统Ⅱ的电子传递速率ETR对时间的积分面积大于灰杨,表明胡杨的日能量积累量大于灰杨;胡杨的非光化学淬灭系数NPQ呈单峰状,灰杨呈双峰态,正午的光合有效辐射对灰杨造成了一定程度的光抑制;午后14时（光合有效辐射最大,PAR=1216 μmo·m-2·s-1）,胡杨Y(NO)∶Y(NPQ)∶Y(Ⅱ)=18%∶50%∶32%,主动耗散能量的比例占到50%,表现了极强的抗性,而灰杨3者比例为Y(NO)∶Y(NPQ)∶Y(Ⅱ)=16%∶19%∶65%,通过提高主动散热（NPQ机制）比例,胡杨较灰杨具有更强的强光适应能力。胡杨与灰杨皆可通过提高激发能热耗散比例适应较高光合有效辐射,但胡杨较灰杨具有更强的调节能力和抗性。  相似文献   

Evaluation of total load sediment transport formulas using ANN   总被引：2，自引：0，他引：2  

Chih Ted YANG  Reza MARSOOLI  Mohammad Taghi AALAMI 《国际泥沙研究》2009,24(3):274-286

The calculated results from various sediment transport formulas often differ from each other and from measured data. Some parameters in the sediment transport formulas are more effective than others to estimate total sediment load. In this study, an Artificial Neural Network （ANN） model is trained using four dominant parameters of sediment transport formulas. ANN models are able to reveal hidden laws of natural phenomena such as sediment transport process. The results of ANN and some total bed material load sediment transport formulas have been compared to indicate the importance of variables which can be used in developing sediment transport formulas. To train ANN, average flow velocity, water surface slopes, average flow depth, and median particle diameter are used as dominant parameters to estimate total bed material load. Two hundreds and fifty samples are used to train the ANN model. Twenty-four sets of field data not used in the training nor calibration of ANN are used to compare or verify the accuracy of ANN and some well-known total bed material load formulas. The test results show that the ANN model developed in this study using minimum number of dominant factors is a reliable and uncomplicated method to predict total sediment transport rate or total bed material load transport rate. Results show that the accuracy of formulas in descending order are those by Yang （1973）, Laursen （1958）, Engelund and Hansen （1972）, Ackers and White （1973）, and Toffaleti （1969）. These results are similar to those made by ASCE （1982） based on laboratory and field data not used in this paper. Study results also show that the formulas based on physical laws of sediment transport, like those formulas that were developed based on power concept, are more accurate than other formulas for estimating total bed material sediment load in rivers.  相似文献