Real-time gas monitoring at the Tekke Hamam geothermal field (Western Anatolia,Turkey): an assessment in relation to local seismicity     

Süer  Selin  Wiersberg  Thomas  Güleç  Nilgün  Erzinger  Jörg  Parlaktuna  Mahmut 《Natural Hazards》2020,104(2):1655-1678

Natural Hazards - This study presents the results of a real-time gas monitoring experiment conducted, via the use of a quadrupole mass spectrometer, in a mofette field within the Tekke Hamam...  相似文献   

Oil well produced water discharges to the North Sea. Part I: comparison of deployed mussels (Mytilus edulis), semi-permeable membrane devices, and the DREAM model predictions to estimate the dispersion of polycyclic aromatic hydrocarbons     

Durell G  Utvik TR  Johnsen S  Frost T  Neff J 《Marine environmental research》2006,62(3):194-223

The oil companies operating in the Norwegian sector of the North Sea have conducted field studies since the mid-1990s to monitor produced water discharges to the ocean. These studies have been used to refine monitoring methods, and to develop and validate a dispersion and impact assessment model. This paper summarizes monitoring data from surveys conducted in two major oil and gas production areas, and compares the results to concentrations of polycyclic aromatic hydrocarbons (PAH) in surface waters predicted by the dose-related risk and effect assessment model (DREAM). Blue mussels and semi-permeable membrane devices (SPMDs) were deployed in the Ekofisk and Tampen Regions and analyzed for more than 50 PAH. PAH concentrations in ambient seawater were estimated based on the mussels and SPMD concentrations, and compared to model predictions. Surface water total PAH concentrations ranged from 25 to 350 ng/L within 1 km of the platform discharges and reached background levels of 4-8 ng/L within 5-10 km of the discharge; a 100,000-fold dilution of the PAH in the discharge water. The PAH concentrations in surface water, predicted by three methods, compared well for the Ekofisk Region. The model predicted higher concentrations than the field-based methods for parts of the Tampen Region; particularly the most tidally influenced areas. Tidally-mediated fluctuations in PAH concentrations in surface water must be considered because they affect the estimation of PAH concentrations from mussel and SPMD residue data, and the predictions by the DREAM model. Predictions using mussels, SPMDs, and modeling support and complement each other; all are valuable tools for estimating the fate and impact of chemical contaminants in produced water that are discharged to the ocean.  相似文献   

Oil well produced water discharges to the North Sea. Part II: comparison of deployed mussels (Mytilus edulis) and the DREAM model to predict ecological risk     

Neff JM  Johnsen S  Frost TK  Utvik TI  Durell GS 《Marine environmental research》2006,62(3):224-246

Large volumes of water often are produced with oil and gas from offshore platforms. The produced water is separated from the oil and gas and either reinjected into a deep formation or discharged to the ocean. The Norwegian oil and gas industry advocates ecological risk assessment as the basis for managing produced water discharges to the North Sea. In this paper, we compare estimates of ecological risks to water-column communities based on data on hydrocarbon residues in soft tissues of blue mussels deployed for a month near offshore platforms and based on predictions of the Dose related Risk and Effect Assessment Model (DREAM). The study was performed near produced water discharges to the Tampen and Ekofisk Regions of the Norwegian Sector of the North Sea. Because polycyclic aromatic hydrocarbons (PAH) are considered the most important contributors to the ecological hazard posed by produced water discharges, comparisons made here focus on this group of compounds. The mussel approach is based on predicted environmental concentrations (PECs) of individual PAH, estimated from PAH residues in mussels following deployment for a month near several produced water discharges, and predicted no effects concentrations (PNECs) based on a K(ow) regression model. In the DREAM method, PECs for three PAH fractions are estimated in the three-dimensional area around produced water discharge with the DREAM model. PNECs for each fraction are based on the chronic toxicity of a representative PAH from each fraction divided by an assessment factor to account for uncertainty in the chronic value. The mussel method gives much lower estimates of ecological risk than the DREAM method. The differences are caused by the much lower PNECs used in DREAM than derived from the regression model, and by the lower concentrations of aqueous PAH predicted by DREAM than estimated from PAH residues in mussel tissues. However, the two methods rank stations at different distances from produced water discharges in the same order and both identify 2- and 3-ring PAHs as the main contributors to the ecological risk of produced water discharges. Neither method identifies a significant ecological risk of PAH in the upper water column of the oil fields. The DREAM model may produce an overly conservative estimate of ecological risk of produced water discharges to the North Sea.  相似文献   

Ce anomalies in Gough Island lavas — Trace element characteristics of a recycled sediment component     

Cornelia Class  Anton P. le Roex 《Earth and Planetary Science Letters》2008,265(3-4):475-486

High precision trace element data obtained by inductively coupled plasma mass spectrometry and Sr–Nd isotope analyses are presented for mafic volcanic rocks from Gough Island, South Atlantic. The new data reveal negative Ce anomalies, with Ce/Ce^? values in Gough lavas extending down to ～ 0.92. Ce is only fractionated from other rare earth elements (REE) due to formation of Ce⁴⁺ under oxidizing conditions of near-surface environments while other REE remain trivalent. Ce anomalies in convergent margin magmas have been shown to indicate a contribution of a subducted sediment component. In contrast, Ce anomalies in intra-plate basalts have been attributed to weathering processes, but can be excluded here based on element–element systematics indicating magmatic trends rather than weathering-induced element mobility. Shallow-level contamination by local marine sediments with negative Ce anomaly inherited from seawater can be excluded because Gough lavas with increasingly negative Ce anomalies do not trend towards low Ce/Pb ratios characterizing such sediments. Rather, it is argued that the negative Ce anomalies in Gough Island lavas are consistent with variable amounts of a sediment component in the mantle plume source. Mixtures between estimates of subducting sediment columns with negative Ce anomaly and mantle capable of giving rise to Gough Island magmas without Ce anomalies reproduce the Gough compositional array with the exception of highly fluid-mobile elements. The calculated trace element composition of the deeply recycled sediment in the Gough plume source is depleted in fluid-mobile elements such as Ba and Pb relative to the composition of some present-day subducting sediments. This loss is attributed to the dehydration or flushing of sediment in the subduction factory, consistent with constraints from arc magmas.  相似文献   

Water column monitoring near oil installations in the North Sea 2001-2004     

Hylland K  Tollefsen KE  Ruus A  Jonsson G  Sundt RC  Sanni S  Røe Utvik TI  Johnsen S  Nilssen I  Pinturier L  Balk L  Barsiene J  Marigòmez I  Feist SW  Børseth JF 《Marine pollution bulletin》2008,56(3):414-429

Fisheries have been vital to coastal communities around the North Sea for centuries, but this semi-enclosed sea also receives large amounts of waste. It is therefore important to monitor and control inputs of contaminants into the North Sea. Inputs of effluents from offshore oil and gas production platforms (produced water) in the Norwegian sector have been monitored through an integrated chemical and biological effects programme since 2001. The programme has used caged Atlantic cod and blue mussels. PAH tissue residues in blue mussels and PAH bile metabolites in cod have confirmed exposure to effluents, but there was variation between years. Results for a range of biological effects methods reflected exposure gradients and indicated that exposure levels were low and caused minor environmental impact at the deployment locations. There is a need to develop methods that are sufficiently sensitive to components in produced water at levels found in marine ecosystems.  相似文献   

Evidence of sea level drawdown at the end of the Messinian salinity crisis and seismic investigation of the Nahr Menashe unit in the northern Levant Basin,offshore Lebanon     

Kyrre Heldal Kartveit  Heidrun Breiset Ulsund  Stle Emil Johansen 《Basin Research》2019,31(5):827-840

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L'évolution géologique de Madagascar et la dislocation du Gondwana: une introduction     

A Piqu  |Groupe campus &#x;le rifting malgache&#x; 《Journal of African Earth Sciences》1999,28(4):919-930

Between eastern Africa and the Indian Ocean, Madagascar was a part of the Gondwana at the end of the Proterozoic. Its evolution, from the Carboniferous through to the present times, displays successive stages of the Gondwana disintegration.The original location of Madagascar, close to present Kenya, is deduced from sedimentological, structural and palæomagnetic data. During Permo-Triassic times, it was submitted to a northeast-southwest regional extension, which resulted in the opening of the Karoo Basins. During the Mid-Late Jurassic, opening of the Somalian and Mozambican Oceanic Basins was accompanied by the translation of Madagascar along a north-south trending transform fault, located along the present Davie Ridge. The Late Cretaceous was characterised in the island by an acceleration of the subsidence in the coastal basins and by an important magmatic, essentially effusive, activity. This marked the beginning of a northeast-southwest extension, opening of the Mascarene Oceanic Basin and separation of India from Madagascar. Since the Neogene up to present times, another extensional regime developed, as in eastern Africa, characterised by a roughly east-west extensional horizontal direction, which results in the opening of faulted basins and the emission of Pliocene-Quaternary alkaline magmas.  相似文献   

胶东望儿山金成矿亚带控矿条件与成矿预测     

李念凤  董建乐 《黄金地质》2000,6(1):27-31

论述望儿山金成矿亚带控矿地质条件和成矿规律 ,总结找矿标志 ,对界河、上庄、付家金矿区和河东金矿区 -50 0 m标高以上地带进行了成矿预测 ,指明了找矿方向。  相似文献   

中国金矿床成矿时代及其特征   总被引：3，自引：0，他引：3  

王科强  董建乐 《黄金地质》2000,6(1):74-78

根据 70 4个主要金矿床的成矿时代研究 ,将中国金矿床划分为古元古代、中新元古代、早古生代、晚古生代、三叠纪、侏罗 -白垩纪、新生代 7个成矿期。统计分析了各成矿期形成的金矿床数量、储量及矿床类型 ,总结了各成矿期金矿床的分布特征。  相似文献   

弹性矩型板与非线性地基共同作用的简化计算法   总被引：10，自引：1，他引：9  

倪光乐  苏克之  李成明 《岩土力学》2000,21(3):239-243

提出一种考虑地基非线性特性的地基模型,并把它应用到弹性板基础与非线性地基共同作用的分析中。计算结果表明,考虑地基非线性特性时,地基反力及弹性板基础的受力大为改善且结果更接近于实际  相似文献