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1.
Slab breakoff: a model for Caledonian, Late Granite syn-collisional magmatism in the orthotectonic (metamorphic) zone of Scotland and Donegal, Ireland 总被引：12，自引：0，他引：12
None of the existing models for calc-alkaline “Late Granite” (Siluro–Devonian) genesis in the metamorphic Caledonian orogenic belt of Ireland and Scotland fully explains their spatial, age or chemical character. A consistent model must involve the closure of Iapetus Ocean, where slab breakoff is a natural consequence of attempted subduction of continental crust. Expected outcome is a long linear belt of high-K, calc-alkaline magmas, some with characteristic trace element signatures, specifically high Ba, Sr and Zr. Other features include the critical magmatic association of coeval appinite and granite, rapid uplift, erosion and the low-grade regional metamorphism in the Southern Uplands. The linear heat pulse on breakoff is spatially, intensity and time limited producing small volume melts emplaced as separated plutons, over a short time span. Magmatism in the Caledonian metamorphic belt is accurately accounted for by slab breakoff on collision of Baltica with the Scoto–Greenland margin during the Scandian orogeny, following Iapetus Ocean closure. The two chemically, isotopically and areally distinctive suites in the metamorphic belt in Scotland, viz. the Argyll and Cairngorm Suites, can be modelled by reference to the Donegal granites where sequential partial melting of new, lamprophyric underplated crust, then shallower old crust, as heat conduction moved up through the crust on slab breakoff, produced magmas characteristic of the two suites. 相似文献
2.
Norazlina Ab Halim Faradiella Mohd. Kusin Khairul Nizam Mohamed 《International Journal of Environmental Science and Technology》2018,15(4):733-742
This study was carried out to determine the concentration of heavy metals (Cd, Ni, Pb, Cr, Ni and Zn) in ordinary Portland cement (OPC) produced from the co-processing with hazardous waste in comparison with OPC produced using natural raw materials. The results showed that the concentration of heavy metals in cement produced from natural raw material was in the order of Zn > Pb > Cr > Ni > Cu > Cd. Zn and Cd were the highest and the lowest concentrations, respectively, in cements produced from the co-processing activity. The difference between heavy metals concentrations in OPC produced with and without co-processing was found to be statistically significant. The concentration of heavy metals in the cement produced is generally factory dependent. The human risk assessment associated with the heavy metals for non-carcinogenic and carcinogenic risks has been evaluated. The calculated hazard index (HI) and total lifetime cancer risks (LCR) were lower than the acceptable threshold reference values, HI < 1 and LCR < 1 × 10?4, respectively. Thus, it is anticipated that there is no potential of non-carcinogenic and carcinogenic risks for both adult and children. However, the findings indicated that there is a need for regulatory monitoring. The exposure pathway for both non-carcinogenic and carcinogenic risks are both in the order of ingestion > dermal > inhalation. 相似文献
3.
Integrated geoelectrical resistivity and hydrogeochemical methods for delineating and mapping heavy metal zone in aquifer system 总被引：1，自引：0，他引：1
Nur Islami Samsudin Hj Taib Ismail Yusoff Azman Abdul Ghani 《Environmental Earth Sciences》2018,77(10):383
A novel study on using geoelectrical resistivity, soil property, and hydrogeochemical analysis methods for delineating and mapping of heavy metal in aquifer system is presented in this paper. A total of 47 surveys of geoelectrical resistivity with Wenner configuration were conducted to determine the subsurface and the groundwater characteristics. The groundwater sample from 53 existing wells and 2 new wells has been analyzed to derive their water chemical content. The chemical analysis was done on the soil sample obtained from new two wells and from selected locations. The water and soil chemical analysis results from the new two wells were used as calibration in resistivity interpretation. The occurrence of heavy metal in aquifer system was expected to detect using the geoelectrical resistivity survey for the whole study area. The result of groundwater analysis shows that the groundwater sample contains a relatively low concentration of Fe (<?0.3 mg/L) elongating from the south up to the middle region. While in the middle and the northwestern, Fe concentration is relatively high (around 12 mg/L). Chemical analysis of soil sample shows that in the lower resistivity zone (<?18 Ωm), Al and Fe concentrations are comparatively high with an average of 68,000 and 40,000 mg/kg, respectively. Starting from the middle to the northwestern zone, the resistivity value appears to be low. It is definitely caused by higher Al and Fe concentration within the soil, and it is supported also by lower total anion content in the groundwater. While the resistivity value of more than 40 Ωm in aquifers is obtained in the zone which Fe concentration is relatively lower in the soil but not present in the groundwater. Correlation Fe concentration in the soil and Fe concentration in the groundwater sample shows the trend of positively linear; however, the Al concentration in soil has no correlation with Al content in groundwater. Finally, the probability of high heavy metal zone in the aquifer system is easily delineated by the distribution of geoelectrical resistivity presented in depth slice shapes which extend from the Boundary Range Composite Batholith in the north to the northwest. 相似文献
4.
Guanabara Bay (GB) is considered to be one of the most polluted environments of the southern Brazilian coastline. This typical estuarine system is impacted by the heavy discharge of both industrial and domestic waste from the Rio de Janeiro metropolitan area. The mollusc community structure and distribution was investigated between 2000 and 2001, using a three month sampling design of 38 stations, according to austral seasons. Species abundance was aggregated into progressively higher taxa matrices (genus, family, order) and were analysed using multivariate techniques. Mollusc distribution in GB varied significantly in space and time and was probably ruled by the organic enrichment effects of hypoxia and altered redox conditions coupled with prevailing patterns of circulation. Within the sectors of GB an increasing gradient in mollusc diversity and occurrence was observed, ranging from the azoic and impoverished stations in the inner sector to a well-structured community in terms of species composition and abundance inhabiting the outer sector. The non-metric multidimensional scaling (nMDS) and cluster analysis showed similar results when species were aggregated into genera and families, while greater difference occurred at coarser taxonomic identification (order). The literature about taxonomic sufficiency has demonstrated that faunal patterns at different taxonomic levels tend to become similar with increased pollution. In Guanabara Bay, an analysis carried out solely at family level is perfectly adequate to describe the ecophysiological stress. Further aggregation to order level changed the perceived patterns of differences. However, a different taxonomic resolution can be chosen depending on the type of ecological patterns investigated. 相似文献
5.
Najat Qader Omar Mohd Sanusi S. Ahamad Wan Muhd Aminuddin Wan Hussin Narimah Samat Siti Zubaidah Binti Ahmad 《Journal of the Indian Society of Remote Sensing》2014,42(1):165-178
The cellular automata (CA) model is an important tool in land use change studies. Swift increases in population and long-term expectations of rapid urbanization have led to extensive land use change, and normal living conditions have affected the natural resources of the land. This paper highlights and analyzes the historical urban changes in Kirkuk City, Iraq, considering repeated changes undergone by the state such change as government infrastructures, wars, and economic blockade. In this paper, an integrated model, built-in multi regression model, and multi-criteria evaluation were considered to improve the representation of CA transition rules. Environmental and socioeconomic factors were used to produce Suitable Maps (SMs). These SMs were practicalities to create factor layers and weight usage, rating method process for variance expert decision-making groups, and geographic information systems for the periods 1984, 1990, 2000, and 2010. The roots of the equation (R2) values are compared and these values are chosen to produce a good model of suitable maps. The approach used in this study provides a mechanism for monitoring suitability maps in Kirkuk. Furthermore, the model Markov CA is implemented and evaluated. The results indicate that the model, its related concepts performs sufficiency 相似文献
6.
Le Sénonien du Haut Atlas occidental, Maroc: sédimentologie, analyse séquentielle et paléogéographie
Based on new geological studies of the Senonian series in the southern part of the western High Atlas, Morocco, new insights on stratigraphy and palmogeography are presented. The palæogeography was generally shallow inner neritic with some palæorelief forming small confined basins that were affected by marine incursions under a hot and arid climate. During the Coniacien, a regression occurred caused by pre-Senonien embryonic tectonic phases. In the Campanian, an important regression, due to tectonic movement, caused the eastern sector of Erguita to emerge. During the Maastrichtian, an important Atlantic marine transgression followed pre-Maastrichtian embryonic tectonics and covered the area. 相似文献
7.
E. A. Rahim Bahaa-eldin I. Yusoff S. Abdul Rahim W. Y. Wan Zuhairi M. R. Abdul Ghani 《Environmental Earth Sciences》2011,63(5):1043-1055
This paper aims at determining of inorganic leachate contamination for a capped unsanitary landfill in the absence of hydrogeological data. The 2D geoelectrical resistivity imaging, soil physicochemical characterization, and surface water analysis were used to determine contamination load and extent of selective heavy metal contamination underneath the landfill. The positions of the contaminated subsoil and groundwater were successfully delineated in terms of low resistivity leachate plumes of <10 Ωm. Leachate migration towards the reach of Kelang River could be clearly identified from the resistivity results and elevated concentrations of Fe in the river downslope toe of the site. Concentration of Fe, Mn, Ca, Na, K, Mg, Cu, Cr, Co, Ni, Zn, and Pb was measured for the subsoil samples collected at the downslope (BKD), upslope (BKU), and the soil-waste interface (BKI), of the landfill. The concentration levels obtained for most of the analyzed heavy metals significantly exceed the normal range in typical municipal solid waste landfill sites. The measured heavy metal contamination load in the subsoil is in the following order Fe ? Mn > Zn > Pb > Cr > Cu. Taking into consideration poor physical and chemical characteristics of the local soil, these metals first seem to be attenuated naturally at near surface then remobilize unavoidably due to the soil acidic environment (pH 4.2-6.18) which in turn, may allow an easy washing of these metals in contact with the shallow groundwater table during the periodic fluctuation of the Kelang River. These heavy metals are believed to have originated from hazardous industrial waste that might have been illegally dumped at the site. 相似文献
8.
H. Md. Azamathulla Yong Chong Cuan Aminuddin Ab. Ghani Chun Kiat Chang 《Arabian Journal of Geosciences》2013,6(9):3469-3480
This study presents gene expression programming (GEP), an extension of genetic programming, as an alternative approach to modeling the suspended sediment load relationship for the three Malaysian rivers. In this study, adaptive neuro-fuzzy inference system (ANFIS), regression model, and GEP approaches were developed to predict suspended load in three Malaysian rivers: Muda River, Langat River, and Kurau River [ANFIS (R 2?=?0.93, root mean square error (RMSE)?=?3.19, and average error (AE)?=?1.12) and regression model (R 2?=?0.63, RMSE?=?13.96, and AE?=?12.69)]. Additionally, the explicit formulations of the developed GEP models are presented (R 2?=?0.88, RMSE?=?5.19, and AE?=?6.5). The performance of the GEP model was found to be acceptable compare to ANFIS and better than the conventional models. 相似文献
9.
The use of data‐driven modelling techniques to deliver improved suspended sediment rating curves has received considerable interest in recent years. Studies indicate an increased level of performance over traditional approaches when such techniques are adopted. However, closer scrutiny reveals that, unlike their traditional counterparts, data‐driven solutions commonly include lagged sediment data as model inputs, and this seriously limits their operational application. In this paper, we argue the need for a greater degree of operational reasoning underpinning data‐driven rating curve solutions and demonstrate how incorrect conclusions about the performance of a data‐driven modelling technique can be reached when the model solution is based upon operationally invalid input combinations. We exemplify the problem through the re‐analysis and augmentation of a recent and typical published study, which uses gene expression programming to model the rating curve. We compare and contrast the previously published solutions, whose inputs negate their operational application, with a range of newly developed and directly comparable traditional and data‐driven solutions, which do have operational value. Results clearly demonstrate that the performance benefits of the published gene expression programming solutions are dependent on the inclusion of operationally limiting, lagged data inputs. Indeed, when operationally inapplicable input combinations are discounted from the models and the analysis is repeated, gene expression programming fails to perform as well as many simpler, more standard multiple linear regression, piecewise linear regression and neural network counterparts. The potential for overstatement of the benefits of the data‐driven paradigm in rating curve studies is thus highlighted. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
10.
Mohamed Yacine Tebbouche Djamel Machane Souhila Chabane El-Hadi Oubaiche Aghiles Abdelghani Meziani Dalila Ait Benamar Hakim Moulouel Ghani Cheikh Lounis Rabah Bensalem Abderrahmane Bendaoud 《Arabian Journal of Geosciences》2018,11(7):154
The original version of this paper was published with incomplete affiliation. Given in this article are the complete affiliations. 相似文献