Characterization of organic matter in surface sediments of the Mackenzie River Basin, Canada     

Jesse Carrie  Hamed Sanei  Fariborz Goodarzi  Gary Stern  Feiyue Wang   《International Journal of Coal Geology》2009,77(3-4):416-423

The particulate organic matter in < 63 µm surface sediments from the Mackenzie River and its main tributaries was studied using Rock-Eval pyrolysis and organic petrology. The organic matter in the sediments is dominated by refractory residual organic carbon (RC) of mainly terrigenous nature, as indicated by abundant inertinite, vitrinite, and type III kerogen. Sediments from the tributaries contained significantly more algal-derived organic matter than from the main channel of the river, highlighting the importance of low-energy system dynamics in the tributaries, which allows modest algal production, more accumulation, and better preservation of autochthonous organic matter. This is particularly true for tributaries fed by lacustrine systems, which showed the highest S1 and S2 fractions, and consequently higher total particulate organic carbon (POC) in the basin. Organic petrology of the sediment samples confirms abundant liptinitic materials (i.e., fat-rich structured algae, spores and pollen, cuticles, and resins). Forest fire and coal deposits are also confirmed to contribute to the basin. Assuming that suspended and fine surfacial sediments have a similar OC composition, the Mackenzie River is estimated to deliver a total POC flux of 1.1 Mt C/yr to its delta, of which 85% is residual carbon with liptinitic OC (S1 + S2) and S3 accounting for another 9% and 6%, respectively.  相似文献   

Analysis of large thermal maturity datasets: Examples from the Canadian Arctic Islands     

Keith Dewing  Hamed Sanei 《International Journal of Coal Geology》2009,77(3-4):436-448

This paper describes an approach for verifying thermal maturity data in a large historical dataset from the Canadian Arctic Islands. A compilation of more than 6000 maturity measurements (vitrinite reflectance and Rock-Eval Tmax) collected over the span of three decades involved a rigorous assessment of data quality. Some common anomalies in interpreting thermal maturity dataset include: (i) elevated thermal maturity due to Cretaceous igneous intrusion in the region, (ii) reworking of refractory material from older rocks into younger strata during the Triassic period, (iii) suppression of vitrinite reflectance and Tmax in hydrogen-rich samples, (iv) low maturity values due to cross-contamination by the younger sediments during drilling process (caving), and (v) offset maturity values obtained from different maturity measurements. The study discusses various independent checks to verify the obtained maturity parameters. The comparison between thermal maturity data with the sonic velocity of shale resulted in a satisfactory correlation. While such a correlation may vary in different sedimentary basins, it produces a useful independent assessment of thermal maturity. The results indicate that increased heat flow during the Jurassic–Early Cretaceous rifting of the Canada Basin may have caused the elevated maturity beyond the expected burial level as suggested by the discrepancy between thermal maturity and sonic velocity data. Given the fact that vitrinite reflectance records only the maximum temperature to which the enclosing rocks were exposed, deviation of the collected reflectance values from the current depth of burial serves as an indicator for the amount of geological uplift.  相似文献   

Assesing the effect of an olive mill wastewater evaporation pond in Sousse, Tunisia     

Rakia S’habou  Moncef Zairi  Amjed Kallel  Abdelwaheb Aydi  Hamed Ben Dhia 《Environmental Geology》2009,58(3):679-686

Olive oil is a typical and valuable agro-industrial product in Mediterranean countries. In Tunisia, olive mill wastewaters (OMW) reach an amount of about 1,000,000 t year⁻¹ and constitute a serious organic pollution risk because of the high chemical oxygen demand values and the presence of phytotoxic and antibacterial polyphenols. OMW have been generally stored in pond sites to be eliminated by natural evaporation or valorised by spreading on cultivated soils or by composting. Many researches on the interactions of OMW with soils at laboratory scale (columns) have been reported, but less attention have been paid to the effect of OMW on soils at field scale. The aim of this work is to investigate an area used for >15 years as an uncontrolled OMW pond site. The transformations of soil properties and groundwater occurring during OMW storage were characterised by the pH, phenolic contents, electrical conductivity (EC), moisture content and organic contents. The soil samples were taken from two borings and compared to those of a control one located near the pond site. Groundwater samples were taken on the accessible and nearest water wells to the evaporation ponds. The permeable silty and sandy layers in the site support the infiltration of OMW near the evaporation ponds. This infiltration has reached a depth of 6 m at a distance of almost 50 m laterally. The results show that the OMW infiltration in the subsoil has affected the pH, EC, organic content, phenolic compounds and the moisture.  相似文献   

Accumulation of trace elements on the surface soil around the Trail smelter, British Columbia, Canada   总被引：1，自引：0，他引：1  

F. Goodarzi  H. Sanei  R. Garrett  W. Duncan 《Environmental Geology》2002,43(1-2):29-38

  相似文献   

Mercury in Western Canadian subbituminous coal—a weighted average study to evaluate potential mercury reduction by selective mining     

F. Goodarzi  N. N. Goodarzi 《International Journal of Coal Geology》2004,58(4):251-259

Western Canadian subbituminous coal is mined using strip-mining methods. The coal is used to feed coal-fired power plants for electricity generation. Parameters that influence the mercury content of these coals include the occurrence and frequency of partings in the seam, weathering, and epigenetic mineralization. Most partings have higher mercury content than the coal layers in the same seam, with the single bentonite bed having the highest Hg content. However, some high ash components, such as sandy siltstone, do not follow this trend. The incorporation of the high mercury partings into the as-mined coal may increase the Hg content in the feed coal. Epigenetic mineralization may also increase the mercury content of coal, depending on the nature of the mineralization.Calculation of the weighted mean of mercury content for various combination of lithological components of a seam illustrates how these components influence the total mercury content of the seam. This approach also suggests how selective mining might be used to reduce mercury in “as-mined” coal.Results of weighted average calculations of mercury indicate that the thin lithological units with moderate mercury may not necessarily influence that overall weighted average of Hg for a seam. However, there can be exception, such as presence of thin (3.5 cm) bentonite parting with high mercury in a 94.5 cm seam that increased the mercury content of seam by 83.4%.  相似文献   

Principales caractéristiques des réservoirs du Sud-Ouest tunisien     

Moncef Chalbaoui  Hamed Ben Dhia 《Comptes Rendus Geoscience》2004,336(13):1191-1198

A study of the form and characteristics of the reservoirs and aquifers of southwestern Tunisia has been carried out from 62 petroleum explorations and hydrogeologic wells and structural maps. The evolution of basins can be deduced from the tectonic history. The Jurassic reservoirs are represented by the Upper Nara carbonates. The petrophysical characteristics and the fracturation affecting the Nara carbonates reveal the existence of very good reservoirs. Several reservoirs have also been identified in the Lower Cretaceous. These reservoirs are made of sandy levels, interbedded with shale, carbonates and dolomites. In addition, petroleum and hydrogeologic studies have revealed that potential aquifers may occur in two provinces (near the Chott Basin and east–west faults). Most of the geological formations in the South West of Tunisia are composed of sand, sandstone and limestone, with the existence of real aquifers. To cite this article: M. Chalbaoui, H. Ben Dhia, C. R. Geoscience 336 (2004).  相似文献   

Chalcophile elements in western Canadian coals     

F. Goodarzi  D.J. Swaine 《International Journal of Coal Geology》1993,24(1-4)

Concentrations of chalcophile elements (As, Co, Cu, Hg, Mo, Ni, Pb, Sb and Zn) in western Canadian coals were determined using INAA and AAS. The concentrations of these elements in western Canadian coals are within the range for most world coals. However, there are some high values for coals from outcrops and from areas which are not currently being mined.Arsenic content in the majority of western Canadian coals, particularly those currently being mined, is low (0.2–3 ppm). However, there are coals with high arsenic content; for example, lignites from Hat Creek A zone contain between 4.0 and 14.0 ppm As. In some samples from Comox and Suquash, the As concentration is as high as 240 ppm and 1400 ppm, respectively. The enrichment of As in high arsenic coals is related to the geology and nature of country rocks associated with the coal seams. The concentration of other elements for most western Canadian coals, particularly those being mined, are within the range for most world coals. In these coals, the concentration ranges (in ppm) of chalcophile elements are 0.3-3.6 for Sb, 0.8-4.6 for Co, 7–35 for Cu, <0.1 for Hg, 2–6 for Mo, 4–94 for Ni, 6–22 for Pb, 2–7 for Se and 7–110 for Zn.  相似文献   

Petrology, rank and evidence for petroleum generation, Upper Triassic to Middle Jurassic coals, Central Alborz Region, Northern Iran     

L.D. Stasiuk  F. Goodarzi  H. Bagheri-Sadeghi 《International Journal of Coal Geology》2006,67(4):249-258

Upper Triassic to Middle Jurassic coals from the Alborz region of northern Iran were analyzed by reflected light-fluorescence microscopy and Rock Eval 6® pyrolysis to evaluate their regional rank variation, degree of hydrothermal alteration, and petroleum generative potential. The coal ranks in the region range from a low of 0.69%Ro_R in the Glanddeh-Rud area to a high of 1.02%Ro_R in the Gajereh area. T_max (°C) values (Rock Eval 6 pyrolysis) also increase progressively with increasing vitrinite %Ro values, however T_max is suppressed lower than would be expected for each rank ranging from 428 °C for the Glandeeh coal to 438 °C for the Gajereh coal. T_max suppression may be caused by maceral composition and soluble organics within the coal. Moderately high hydrogen indices, persistent and oily exudations from the coals during UV exposure, and traces of hydrocarbon fluid inclusions suggest that liquid petroleum was likely generated within some of the coals.  相似文献   

Évaluation de la qualité de l'eau par application de la méthode géoélectrique : exemple de la plaine d'El Mida–Gabes nord (Sud tunisien)     

Abdelkader Mhamdi  Mouez Gouasmia  Mohamed Gasmi  Salem Bouri  Hamed Ben Dhia 《Comptes Rendus Geoscience》2006,338(16):1228-1239

The Mida plain, which is part of the North Gabès region (southern Tunisia), is characterized by the deep sandy units of the ‘Continental intercalaire’ (CI) or the limestone of the Lower Senonian. A geophysical survey, by electrical sounding (ES), was undertaken in the studied region to better characterize the deep geological structure of this plain and therefore its aquifer resources potential. The analysis of the results shows that the prospected zone is characterized by the succession of several levels with contrasted resistivities, which are often affected by faults. Among these observed geoelectrical levels, the highly conductor one could host a saline aquifer. Another geoelectrical level corresponding to the resistant bedrock detected at Oudhref horst can contain better-quality water than that of the aquifer detected in the El Mida Graben. In this work, we tried to explain the origin of the salinity of this aquifer. Thus, we hypothesise about a contamination from Jebel Zemlet El Beida through a border fault and another one from the Sebkhet El Hamma. To cite this article: A. Mhamdi et al., C. R. Geoscience 338 (2006).  相似文献   

Groundwater salinization of the Sfax superficial aquifer,Tunisia   总被引：5，自引：0，他引：5  

Rouaida Trabelsi  Moncef Zairi  Hamed Ben Dhia 《Hydrogeology Journal》2007,15(7):1341-1355

Groundwater salinization has become a crucial environmental problem worldwide and is considered the most widespread form of groundwater contamination. The origin of salinity in the coastal aquifer of the Sfax Basin, Tunisia was investigated by means of chemical analyses of groundwater samples from 65 wells. The groundwater samples present a clear gradation from calcium sulphate salinization to that of sodium chloride. The saturation indices for calcite and gypsum, and binary diagrams of different ions, together with multivariate analysis, indicate the existence of various salinization processes such as: dissolution of gypsum and calcite dispersed through the reservoir rock; ion exchange; intensive agricultural practices that produce effluents that infiltrate to the saturated zone; and sea-water intrusion, enhanced by excessive withdrawal of groundwater.  相似文献