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51.
Cyril Aubert Elodie Brisset Morteza Djamali Arash Sharifi Philippe Ponel Belinda Gambin Tayebeh Akbari Azirani Frédéric Guibal Hamid Lahijani Abdolmajid Naderi Beni Jacques-Louis de Beaulieu Ali Pourmand Valérie Andrieu-Ponel Alain Thiéry Emmanuel Gandouin 《Journal of Paleolimnology》2017,58(2):151-167
We reconstructed the paleohydrologic and climatic history of the Lake Neor region, NW Iran, from the end of the late glacial to the middle Holocene (15,500–7500 cal yr BP). Subfossil chironomid and pollen assemblages in a sediment core from a peatland located south of Lake Neor enabled identification of four main hydrologic phases. The period 15,500–12,700 cal yr BP was characterized by a relatively dry climate with an open landscape, suggested by the abundance of Irano-Turanian steppe plants (e.g. Amaranthaceae, Artemisia and Cousinia). Dominance of several shallow-water and semi-terrestrial chironomid taxa (e.g. Pseudosmittia, Smittia/Parasmittia and Paraphaenocladius/Parametriocnemus) during this period is indicative of lower water tables in the wetland. Between 12,700 and 11,300 cal yr BP, chironomid taxa indicate higher wetland water tables, as suggested by the presence of Zavrelia, Chironomus anthracinus/plumosus-type and Micropsectra, which are inhabitants of open-water, lacustrine areas. The open-steppe vegetation remained dominant in the watershed during this time. Increasing wetland moisture could be explained by: (1) cool summers that reduced the evaporation rate; and/or (2) a decrease in duration of the summer dry season. The period 11,300–8700 cal yr BP was characterized by lower wetland moisture, contemporaneous with a delay in the expansion of deciduous forest, suggesting persistent dry climate conditions throughout the beginning of the Holocene, which may have been related to the intensified seasonality of precipitation. Around 8700 cal yr BP, higher wetland water levels, inferred from chironomids, occurred simultaneously with the onset of regional deciduous forest expansion, probably caused by a shortening of the summer dry period. We concluded that chironomids are appropriate paleoecological proxies to investigate global and local hydrologic variability in the Middle East. 相似文献
52.
53.
Abbas?GhaderiEmail author Morteza?Taherpour Khalil Abad Ali?Reza?Ashouri Dieter?Korn 《Arabian Journal of Geosciences》2016,9(17):699
Micropaleontological investigations on Permian successions in the NW of Iran based on algae led to the determination of taxa belonging to some families such as Ungdarellaceae (Ungdarella uralica), Gymnocodiaceae (Gymnocodium bellerophontis and Permocalculus sp.), Dasycladales (Mizzia cf. M. yabei), and some microproblematics (Vermiporella nipponica and Pseudovermiporella sodalica). These investigations are mainly focused on the Khachik Formation at the Ali Bashi Mountains. According to the algal community, a lagoon environment is offered for the studied successions. 相似文献
54.
Water leakage paths in the Doosti Dam,Turkmenistan and Iran 总被引:2,自引:2,他引:0
The Doosti Dam, with a reservoir capacity of 1,250 million cubic meters, was constructed on the Harirood River at the border
of Turkmenistan and Iran. The reservoir is in direct contact with permeable formations on the right abutment of the dam including
the Neyzar Sandstone, the Kalat Limestone and the Pesteleigh alternative layers of marlstone and sandstone. After the reservoir
impoundment, several new springs and seepages emerged from these formations and the alluvium. The amount of leakage increased
with the rise in reservoir water level. Fifteen kilograms of sodium fluorescein were injected into a 113-m deep borehole intersecting
three permeable sandstone layers of the Pesteleigh formation. Dye was detected downstream of the grout curtain in boreholes
and springs that were in direct contact with parts of the Pesteleigh formation having the same sandstone layers as the injection
borehole. The dye velocity was in the range of diffuse flow, confirming the good performance of the grout curtain in the Pesteleigh
formation. No dye was detected in the other formations because the injection borehole was not in direct contact with these
formations. The hydraulic relation of the other formations with the reservoir was determined by considering direct contact
of the formations with the reservoir, emergence of new springs and seepages after reservoir impoundment, correlation of time
variations of the springs discharge and the borehole’s water level with the reservoir water level, and in some cases the hydrochemistry
of the water. The results show that the Kalat and Neyzar formations are hydraulically connected to the reservoir, but the
small amounts of leakage from these formations at a hydraulic gradient of 24% indicates good performance of the built grout
curtain. The total reservoir leakage at maximum reservoir water level was 100 l/s which is insignificant compared with the
15 m3/s average annual release of the reservoir. 相似文献
55.
Iman Tahmasbian Azadeh Nasrazadani Hojat Shoja Ali Akbar Safari Sinegani 《Environmental Earth Sciences》2014,71(4):1551-1560
The excessive input of trace elements into urban soil has become one of the most important concerns in industrial and crowded cities all over the world. The contamination of urban soils can affect the health of people living in urban areas, and the surrounding ecosystems. Current study was conducted to assess the effects of human activities as well as different land-use on accumulation of trace elements in urban topsoil and also identify the potential risks to human health in Isfahan (Iran). A total of 95 topsoil samples were taken from different localities of Isfahan City and analyzed for Zn, Pb, Cu and Cr using the atomic absorption spectrophotometric method. Pollution index (PI) was calculated for each trace element to identify the rate of trace element accumulation with respect to the background values. Land-use map and geochemical maps were also created for evaluating of spatial distribution of pollution index and trace elements’ concentration in the studied area. Overlapping the concentrations’ map and land-use map revealed that the highest values of pollution index and trace elements’ concentration were located in central part of the city and highways with a great vehicle traffic load and also in the vicinity of industrial factories that increased potential health hazards to the local community. On the other hand, lowest values of trace elements were located in green-lands with strict vehicle traffic laws. These results indicated that different land-use and human activities have affected quality of urban topsoil of Isfahan resulting in great apprehensions regarding public health in crowded parts of the city. 相似文献
56.
AbstractThe Shahr-e-Babak region located in the Kerman metallogenic belt is one of the high potential segments of Urumieh–Dokhtar magmatic arc for porphyry copper and epithermal gold mineralization in the south of Iran. This high potential zone encompasses several porphyry copper deposits under exploitation, development and exploration stages. The aim of this study is to evaluate Landsat-8 data and comparison with the Advanced Spaceborne Thermal Emission and Reflection Radiometer data-sets for mapping hydrothermal alteration zones related to Cenozoic magmatic intrusions in Shahr-e-Babak region. Previous studies have proven the robust application of ASTER in lithological mapping and mineral exploration; nonetheless, the Landsat-8 data have high capability to map and detect hydrothermal alteration zones associated with porphyry copper and epithermal gold mineralization. In this investigation, several band combinations and multiplications, developed selective principal component analysis and image transformations were developed for discriminating hydrothermal alteration zones associated with porphyry copper mineralization using Landsat-8 data. 相似文献
57.
M. Nozibul Haque Shamsuddin Shahid Mumnunul Keramat Morteza Mohsenipour 《Water Resources》2016,43(2):283-291
Geographical Information System (GIS) has been used in this paper to delineate groundwater resources potential in the western part of greater Kushtia district of Bangladesh, where urgent attention for augmentation of irrigation water supply is required. Thematic maps of transmissivity, hydraulic conductivity, specific yield, net recharge, aquifer thickness, surface water bodies, aquifer resistivity, overburden aquitard thickness and its resistivity have been prepared and assigned weight according to their relative importance using Analytical Hierarchical Process for the preparation of groundwater potential model. Since the values within each thematic map vary significantly, they are classified into various ranges or types and assigned ratings. Finally, the thematic maps are integrated using GIS to prepare the groundwater potential map for the study area in terms of Ground Water Potential Index (GWPI). The evolved map indicates that 22.51% of the study area have GWPI more than 0.70 and therefore, have excellent prospective for exploitation. About 69.12% of the area with GWPI ranging from 0.50 to 0.70 is also quite promising for groundwater abstraction, while the rest 8.37% area having GWPI below 0.50 indicates moderate potential. The obtained map of groundwater potential is found in good agreement with the yields of available pumping test data. 相似文献
58.
Deriving preference order of post-mining land-uses through MLSA framework: application of an outranking technique 总被引:1,自引:0,他引:1
Hossein Soltanmohammadi Morteza Osanloo Abbas Aghajani Bazzazi 《Environmental Geology》2009,58(4):877-888
This study intends to take advantage of a previously developed framework for mined land suitability analysis (MLSA) consisted
of economical, social, technical and mine site factors to achieve a partial and also a complete pre-order of feasible post-mining
land-uses. Analysis by an outranking multi-attribute decision-making (MADM) technique, called PROMETHEE (preference ranking
organization method for enrichment evaluation), was taken into consideration because of its clear advantages on the field
of MLSA as compared with MADM ranking techniques. Application of the proposed approach on a mined land can be completed through
some successive steps. First, performance of the MLSA attributes is scored locally by each individual decision maker (DM).
Then the assigned performance scores are normalized and the deviation amplitudes of non-dominated alternatives are calculated.
Weights of the attributes are calculated by another MADM technique namely, analytical hierarchy process (AHP) in a separate
procedure. Using the Gaussian preference function beside the weights, the preference indexes of the land-use alternatives
are obtained. Calculation of the outgoing and entering flows of the alternatives and one by one comparison of these values
will lead to partial pre-order of them and calculation of the net flows, will lead to a ranked preference for each land-use.
At the final step, utilizing the PROMETHEE group decision support system which incorporates judgments of all the DMs, a consensual
ranking can be derived. In this paper, preference order of post-mining land-uses for a hypothetical mined land has been derived
according to judgments of one DM to reveal applicability of the proposed approach. 相似文献
59.
Masoumeh Molaei Seyed Hamid Vaziri Morteza Taherpour-Khalil-Abad Jafar Taheri 《Arabian Journal of Geosciences》2017,10(14):317
Neotrocholina Reichel, 1956 is one of the most important benthic foraminifera in Early Cretaceous. Some of the species of this genus are indexes in biostratigraphy especially for this interval (e.g., Neotrocholina friburgensis: Late Barremian–Early Aptian; Neotrocholina aptiensis: Early Aptian). In order to conduct accurate paleontological investigations, sampling from the carbonate units of the Tirgan Formation in Kopet Dagh sedimentary basin is done. According to the occurrence level in the studied stratigraphic sections as well as biometric interpretations, two species of this genus (N. friburgensis and Neotrocholina valdensis) are pointed out. 相似文献
60.
1 INTRODUCTION Estuaries and coastal zones have been used as means of navigation, disposal of waste material, fishing and many commercial and economic activities over the centuries. One of the most important phenomena in these regions is the suspended sediment transport, which may cause erosion and deposition, and hence changes in the estuarys morphology. In turn, such changes may lead to problems relating to navigation and estuarine management. When the bed boundary of an estuary change… 相似文献