<Emphasis Type="Italic">P-T</Emphasis> conditions of the Jandagh metapelitic schists,Northeastern Isfahan Province,Iran     

S. M. Tabatabaei Manesh  M. Sharifi  A. Romanko 《Petrology》2010,18(3):308-317

The metapelitic schists of Jandagh or simply Jandagh metapelites can be divided into four groups based on mineral assemblages: (1) quartz-muscovite schists, (2) quartz-muscovite-biotite schists, (3) garnet-muscovite-chlorite schists, and (4) garnet-muscovite-staurolite schists. The Jandagh garnet-muscovite-chlorite schists show the first appearance of garnets. These garnets contain 58–76% almandine, 1–18% spessartine, and 8–20% grossular. Microprobe analysing across the garnets demonstrates an increase in Mg# from core to rim. This is a feature of the prograde metamorphism of metapelites. Well-preserved garnet growth zoning is a sign that metapelites were rapidly cooled and later metamorphic phases had no effect here. The appearance of staurolite in garnet-muscovite-chlorite schists signifies a beginning of the amphibolite facies. The absence of zoning in staurolite suggests that its formation and growth during prograde metamorphism occurred at a widely spaced isograde. Thermobarometric investigations show that the Jandagh metapelites were formed within a temperature range of 400–670°C and pressures of 2.0–6.5 kbar. These results are in agreement with the mineral paragenetic evidence and show the development of greenschist and amphibolite facies in the area studied.  相似文献   

Accuracy of Normal Heights Determined Using Improved Geopotential Models     

Raděj  Karel 《Studia Geophysica et Geodaetica》1997,41(3):217-220

The accuracy of determining the Molodensky normal heights using geopotential models has been investigated. On the basis of geopotential model JGM-3/OSU91A the Molodensky normal heights can be computed with an accuracy of about ±35 cm at the GPS sites in the central part of Europe. On the basis of JGM-3/OSU91A improved the accuracy becomes higher, about ±14 cm.  相似文献   

Germination and growth of six plant species on contaminated soil with spent oil   总被引：1，自引：2，他引：1  

M. Sharifi Ph.D.  Y. Sadeghi M.Sc.  M. Akbarpour M.Sc. 《International Journal of Environmental Science and Technology》2007,4(4):463-470

Effects of contaminated soil with spent oil on germination, above ground height and biomass of six herbaceous plant species were investigated by conducting a general phytotoxicity test and growth inhibition assessment. Six local plant species were used in order to investigate plant’s ability to germinate and survive in a gradient of contaminated soil with spent oil. The species selected for this experiment include one species of Fabaceae (Medicago truncatular), four species of Gramineae (Bromous mermis, Secal seral, Triticum sativa and A gropyron deserterum) and one species of Linaceae (Linum ussitasimum). Inhibitory effect of contaminated soil on germination, height of young seedling and dry weight were measured. In this study an artificial soil with a light texture included 85% sand, 10% silt and 5% clay was used. The exposure to the contaminated soil carried out using four consecutive concentrations (25, 50, 75, 100 g/kg). Results obtained from the current investigation indicate that all species perform dose-dependent responses to the contaminated soils. Reduction in germination, above ground height and biomass for all species were significantly (P < 0.05) different when compared to their controls, however, Medicago truncatular performed the highest and Linum ussitatisimum the lowest inhibitory effect for germination, above ground height and dry weight of seedling.  相似文献   

Active mud volcanoes on- and offshore eastern Makran, Pakistan   总被引：3，自引：0，他引：3  

G. Delisle  U. von Rad  H. Andruleit  C. von Daniels  A. Tabrez  A. Inam 《International Journal of Earth Sciences》2002,91(1):93-110

To study the activity, source and driving force of the venting of fluidized mud in the coastal Makran, we carried out reconnaissance surveys of two active onshore mud volcano fields (Chandragup and Jebel-u-Ghurab) and of a newly born (March 1999) offshore mud volcano (Malan Island). All studied on- and offshore mud volcanoes line up along one southwest/northeast-trending structural lineament, the axis of the Dhak Anticline. Isotopic data point to a bacterial origin of the gas (mainly methane). Mixed benthic foraminiferal faunas and calcareous nannofloras suggest that the source level of the extruded mud is at a sub-surface depth of 2-3 km. Observed mud discharge varied between 0 and 1.4 m³ h^-1 and gas discharge rates between negligible amounts to 1 m³ s^-1. Mud temperatures in the crater lake of Chandragup I are near-ambient temperatures. They rise slightly (Б.5°C) during episodes of modest mud outflow. An area of 160,000 m³ of soft mud was vigorously extruded from the sea floor at a water depth of 10 m within days after 15 March 1999, forming Malan Island. The island was destroyed within a few months after its birth by deep-reaching wave action during the SW monsoon. This was possibly aided by local subsidence of the mud volcano structure due to the volume loss following rapid degassing and mud extrusion.  相似文献   

Intergrowth and twinning in opal-CT lepispheres     

O. W. Flörke  R. Hollmann  U. von Rad  H. Rösch 《Contributions to Mineralogy and Petrology》1976,58(3):235-242

Under conditions of unobstructed diagenetic growth, opal-CT usually forms spherical aggregates, so-called lepispheres. From a scanning electron microscope study of deep-sea porcelanites, the development of these structures is described, from isolated opal-CT platelets via complete lepispheres to large coalescent aggregates. The conspicuous symmetric ultrastructure of lepispheres—reflected by the constancy of angles between interpenetrating crystal blades—is crystallographically determined: The lepispheres consist of groups of opal-CT blades intergrown according to the (30–34) and (10–16) twinning laws of tridymite. The same rules of intergrowth can be applied to the morphology of hydrothermally synthesized opal-CT lepispheres.  相似文献   

Triassic to Cenozoic evolution of the NW Australian continental margin and the birth of the Indian Ocean (preliminary results of ODP Legs 122 and 123)     

Dr. Ulrich von Rad  Dr. Jürgen Thurow  Bilal U. Haq  Felix Gradstein  John Ludden  the ODP Leg / shipboard scientific parties 《International Journal of Earth Sciences》1989,78(3):1189-1210

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Comparison of plant species diversity with different plant communities in deciduous forests   总被引：2，自引：1，他引：1  

J. Eshaghi Rad Ph.D.  M. Manthey Ph.D.  A. Mataji Ph.D. 《International Journal of Environmental Science and Technology》2009,6(3):389-394

Species diversity is one of the most important indices used for evaluating the sustainability of forest communities. This study aims to characterize the forest communities and to identify and compare the plant species diversity in the study area. For this purpose, 152 relevés were sampled by a randomized-systematic method, using the Braun-Blanquet scale. Classification of the vegetation was conducted by the twinspan algorithm. Four communities, including Querco-Carpinetum betulii, Carpineto-Fagetum Oriental, Rusco-Fagetum Oriental and Fagetum Oriental were recognized. Species richness, Shannon, and Simpson indices were applied to quantify diversity of the different communities. Turkey test was used to investigate the differences in the species richness, diversity and evenness indices among the different communities. The results illustrate that Querco-Carpinetum betulii and Carpineto-Fagetum Oriental communities are significantly more diverse than Rusco-Fagetum Oriental and Fagetum Oriental communities. The spatial structure of the releves becomes more ‘homogenous’ and the dominance structure changes: the proportion of beech-forest species is gradually increasing. At the same time, the number of species per unit area decreases constantly, reaching eventually the value comparable to that recorded for hornbeam forest. Generally, species diversity is inversely correlated with the dominance of shade tolerant climax species.  相似文献   

Local Ionospheric Modeling Using the Localized Global Ionospheric Map and Terrestrial GPS     

Mohammad Ali Sharifi  Saeed Farzaneh 《Acta Geophysica》2016,64(1):237-252

global ionosphere maps are generated on a daily basis at CODE using data from about 200 GPS/GLONASS sites of the IGS and other institutions. The vertical total electron content is modeled in a solargeomagnetic reference frame using a spherical harmonics expansion up to degree and order 15. The spherical Slepian basis is a set of bandlimited functions which have the majority of their energy concentrated by optimization inside an arbitrarily defined region, yet remain orthogonal within the spatial region of interest. Hence, they are suitable for decomposing the spherical harmonic models into the portions that have significant strength only in the selected areas. In this study, the converted spherical harmonics to the Slepian bases were updated by the terrestrial GPS observations by use of the least-squares estimation with weighted parameters for local ionospheric modeling. Validations show that the approach adopted in this study is highly capable of yielding reliable results.  相似文献   

Die Oberflächensedimente der Straße von Otranto (Mittelmeer)     

Dr. F. Fabricius  Dr. U. von Rad  Dr. R. Hesse  Dr. W. Ott 《International Journal of Earth Sciences》1970,60(1):164-192

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Deformation analysis of the Lake Urmia causeway (LUC) embankments in northwest Iran: insights from multi-sensor interferometry synthetic aperture radar (InSAR) data and finite element modeling (FEM)     

Roghayeh Shamshiri  Mahdi Motagh  Marzieh Baes  Mohammad Ali Sharifi 《Journal of Geodesy》2014,88(12):1171-1185

This paper presents deformation analysis of Lake Urmia causeway (LUC) embankments in northwest Iran using observations from interferometry synthetic aperture radar (InSAR) and finite element model (FEM) simulation. 58 SAR images including 10 ALOS, 30 Envisat and 18 TerraSAR-X are used to assess settlement of the embankments during 2003–2013. The interferometric dataset includes 140 differential interferograms which are processed using InSAR time series technique of small baseline subset approach. The results show a clear indication of large deformation on the embankments with peak amplitude of \(>\) 50 mm/year in 2003–2010, increasing to \(>\!\!80\)  mm/year in 2012–2013 in the line of sight (LOS) direction from ground to the satellite. 2D decomposition of InSAR observations from Envisat and ALOS satellites that overlap in the years 2007–2010 shows that the rate of the vertical settlement and horizontal motion is not uniform along the embankments; Both eastern and western embankments show significant vertical motion, while horizontal motion plays a more significant role in eastern embankment than western embankment. The InSAR results are then used to simulate deformation using FEM at two cross-sections at the distance of 4 and 9 km from the most western edge of the LUC for which detailed stratigraphy data are available. Results suggest that consolidation due to dissipation of excess pore pressure in embankments can satisfactory predict settlement of the LUC embankments. Our numerical modeling indicates that nearly half of the consolidation since the construction time of the causeway 30 years ago has been done.  相似文献