共查询到19条相似文献，搜索用时 546 毫秒
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莱州湾南岸地下卤水高浓度溶解铀及其成因研究 总被引：1，自引：0，他引：1
用α能谱法对莱州湾南岸地下卤水中的铀进行分析,发现卤水中溶解铀的浓度范围为3.4～96.0μg/L,80%以上站位卤水铀浓度超过了30μg/L,高于某些铀矿区地下水中铀的浓度。从卤水的形成过程及环境、含水层沉积物的铀含量及地下卤水对沉积物的淋溶作用、地表水下渗等几个方面对高浓度铀的成因进行了分析,发现卤水形成时海水的蒸发浓缩和锰氧化物还原可能是主要成因,藻类的矿化分解使其吸附的大量铀解吸进入地下水也可能是1个重要影响因素。 相似文献
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第四纪滨海相地下卤水的研究 总被引：7，自引：1，他引：6
1 第四纪滨海相地下卤水的分布规律在我国黄、渤海沿岸低地平原区,第四纪滨海相地下卤水有着广泛的分布,卤水的储量、储层结构及水化学特征随着各海岸区岸段的不同存在着一定的差异。这与卤水赋存区所经历的第四纪古海洋环境、古气候环境、地貌及构造活动的演化历史密切相关,并受地下和地表水体混合作用的影响。在中国北方主要有两大类海岸地貌单元,滨海平原海岸和基岩港湾海岸。渤海三大海湾沿岸都属于滨海平原海岸,第四纪地下卤水呈连续的平行海岸线的带状分布,矿带宽几公里到几十公里不等。受陆向山前冲、洪积平原区的地下淡水径流及海… 相似文献
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渤海莱州湾南岸，是我国海水入侵灾害最严重的岸段。依据入侵物源可将广义海水入侵划分为两种基本类型：来源于现代海水的狭义海水入侵和物源于浅层第四纪沉积层中古海水（包括一般地下咸水及地下卤水）的地下咸水入侵。它们的成因、机理和危害差异明显；地下卤水入侵是一种特殊类型，造灾程度最高。海岸地貌和第四纪水文地质环境，是控制海水入侵类型区划的主导因素。莱州湾南岸不同岸段海岸环境差异，形成了海水入侵区、地下咸水入侵区和海、咸水混合入侵区３种类型区，可具体区划为：莱州市北部海岸海水入侵区，胶莱河－沙河河口平源海、咸水混合入侵区，昌邑北部潍河河口平原海、咸水混合入侵区，寿光北部平原地下咸水入侵区等４个区。类型区划分将有助于海水入侵灾害防治工程。 相似文献
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1 滨海地下咸水分布、类型及成因 矿化度(即总含盐量)大于1g/l(CI~-含量大于250mg/I)的地下水,称为地下咸水。由于地下咸水来源于海水,其水化学类型属CI—Na型(氯化物型),基本化学组成与海水相同。 地下咸水形成:①深层(如埋藏几米深),是由现代海水与陆源淡水混融而成。②高浓度地下卤水(埋藏几米至几十米)是由古海水 相似文献
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莱州湾南岸海水入侵类型及其分区 总被引：6，自引：0，他引：6
渤海莱州湾南岸，是我国海水入侵灾害最严重的岸段。依据入侵物源可将广义海水侵划分为两种基本类型：来源于现代海水的狭义海水入侵和物源于浅层第四沉积层中古海水的地下咸水入侵，它们的成因，机理和危害差异明显；地下卤水入侵是一种特殊类型，造灾程度最高。海岸地貌和第四纪水文地质环境，是控制海水入侵类型区划的主导因素。莱州湾南岸不同岸段海岸环境差异，形成了海水入侵区，地下咸水入侵区和海、咸水混合入侵区３种类型区 相似文献
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Detailed analysis of the morphology of Bacino Bannock, a deep-sea basin filled by a hypersaline brine, shows with unusual
detail the effect on the ocean floor topography of the deformation and dissolution of a salt body under tectonic stress. Although
salt diapirism occurs in the central part of the investigated area, the major cause of basin formation is dissolution of subsurface
evaporites which creates negative relief that exceeds by about one order of magnitude the positive relief. The true shape
of the deformed salt deposit is preserved as a result of the absence of a thick post-evaporites sedimentary cover. 相似文献
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A. Camerlenghi 《Marine Chemistry》1990,31(1-3)
A brief review of the geological knowledge on the anoxic basins of the eastern Mediterranean is presented. Anoxic basins have been discovered in two different geological settings in the eastern Mediterranean. Bannock Basin belongs to the compressional style of the Mediterranean Ridge, and Tyro and Poseidon Basins belong to the transcurrent tectonic style of the Strabo Trench. The origin of the basins is subsurface salt dissolution triggered by tectonic deformation of the sediments on the Mediterranean Ridge, and tectonic subsidence (pull-apart mechanism) in the Strabo Trench. The onset of a deep-sea brine lake is always related to the outcrop of Messinian salts on the side-walls of the basin. The rate of basin subsidence controls the evolution of the brine lakes, which can also be completely diluted by bottom water circulation. 相似文献
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夏季北冰洋无冰海域次表层暖水结构的形成机理 总被引：1，自引：0，他引：1
在夏季北冰洋的无冰海域,经常可以观测到次表层暖水现象,即在水深20～50m的范围内发生海水温度的极大值。建立了一个一维的热力学解析模式,用于研究夏季北冰洋次表层暖水的形成机制。模式的计算结果表明,太阳辐射作用是形成次表层暖水的关键因素。在北冰洋的开阔水域,大气吸收海洋热量的过程导致了海面温度下降,使温度极大值出现在次表层。海洋垂向湍流热扩散对次表层暖水温度有显著影响;当湍流热扩散较弱时,热扩散的范围较小,有利于形成次表层暖水。次表层暖水的位置随着时间的推移不断加深,温度不断增高。在北极,大气温度低于海面温度是普遍现象,次表层暖水经常发生。虽然当海面气温发生变化时,次表层海水温度结构会发生相应的变化,但次表层暖水结构形成之后,如果不受强烈天气过程的破坏,则会一直存在下去。按照本文的结论,随着北极气候变暖,海冰将进一步减少,次表层暖水现象还会明显增加,海洋对气候变化将有更加强烈的响应和反馈,对全球气候变化产生意义深远的影响。 相似文献
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西沙岛礁白云岩化特征与成因模式分析 总被引：1，自引：0，他引：1
关于碳酸盐岩的白云岩化作用至今仍是一个争论颇大的科学问题。在2012-2013年期间,中海石油（中国）有限公司湛江分公司在西沙石岛钻取了长达1 268.02 m的“西科1井”岩心,在0~1 257.52 m主要由碳酸盐岩组成的岩心中存在有7个白云岩层。本文基于西科1井岩心样品的矿物组成、常量、微量及稀土元素含量等地球化学特征分析,探讨了西沙岛礁特有的白云岩化作用过程。结果表明:西科1井7层白云岩在成因上与埋深和压实成岩作用无关,其分布与海平面下降的地质事件有良好的对应关系,白云岩层元素地球化学特征表明白云岩成岩流体为浓缩的高盐度海水。根据白云岩层的矿物学和地球化学特征,提出了礁滩潟湖环境下高盐卤水渗透回流作用的白云岩化模式:伴随海平面的升降,礁体处于淹没与暴露的交替之中,海平面下降导致了礁滩潟湖的形成,由于西沙海区蒸发量大于降水量而使澙湖中海水盐度增高,最终形成富Mg卤水;澙湖中高盐度富Mg卤水在礁体内下渗和侧向扩散,Mg逐渐替代早期CaCO3晶格中Ca而形成白云石;海平面的升降变化和礁体淹没与暴露的交替导致了钻井岩心多个白云岩层的形成。海平面升降直接控制了岛礁碳酸盐岩的发育和白云岩化作用,导致海平面升降的古气候变化在岛礁的形成发育中起到主导作用。 相似文献
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J. Acosta E. Uchupi A. Muñoz P. Herranz C. Palomo M. Ballesteros 《Marine Geophysical Researches》2003,24(1-2):41-57
Circular to elliptical mounds in the Canary Channel with reliefs of 75 to 375 m and diameters of 4 to 8 km partially surrounded by moats with reliefs of 25 to 75 m, were formed by piercement of the seafloor by Mesozoic evaporites. Several long gullies, < 1km wide, with abrupt terminations and pockmarks associated with these mounds were probably eroded by dense brine and hydrocarbon seeps. The salt brines that eroded the gullies were formed where salt diapirs intersect the seafloor, or in the subsurface by circulating ground water heated by igneous activity along the Canary Ridge. If the brines originated in the subsurface they reached the seafloor along faults. Displacement of the surficial sediments by sliding and creep is probably the result of the expulsion of hydrocarbons and/or vertical motion of the Mesozoic evaporites. Microtopographic features along or near the east flank of the Canary Ridge are the creation of uplift of the ridge, hydrothermal activity, mass wasting processes and turbidity currents. 相似文献
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The physical processes responsible for the formation in a large‐scale ice–ocean model of an offshore polynya near the Greenwich meridian in the Southern Ocean are analysed. In this area, the brine release during ice formation in autumn is sufficient to destabilise the water column and trigger convection. This incorporates relatively warm water into the surface layer which, in a first step, slows down ice formation. In a second step, it gives rise to ice melting until the total disappearance of the ice at the end of September. Two elements are crucial for the polynya opening. The first one is a strong ice‐transport divergence in fall induced by south‐easterly winds, which enhances the amount of local ice formation and thus of brine release. The second is an inflow of relatively warm water at depth originating from the Antarctic Circumpolar Current, that sustains the intense vertical heat flux in the ocean during convection. The simulated polynya occurs in a region where such features have been frequently observed. Nevertheless, the model polynya is too wide and persistent. In addition, it develops each year, contrary to observations. The use of a climatological forcing with no interannual variability is the major cause of these deficiencies, the simulated too low density in the deep Southern Ocean and the coarse resolution of the model playing also a role. A passive tracer released in the polynya area indicates that the water mass produced there contributes significantly to the renewal of deep water in the Weddell Gyre and that it is a major component of the Antarctic Bottom Water (AABW) inflow into the model Atlantic. 相似文献
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Victor Quintino Ana Maria Rodrigues Rosa Freitas Ana R 《Estuarine, Coastal and Shelf Science》2008,79(3):525-532
Most of the studies on biological and ecological effects associated with brine discharge into the marine environment are related to the operation of desalination plants, for the production of freshwater. In this study we analysed the biological effects of a brine effluent from a completely different source, produced from the lixiviation of rock salt caves, for the creation of natural gas storage caverns. Lethal and sub-lethal endpoints following exposure to the brine were studied in a range of macrofauna species characteristic of the soft and hard bottom habitats in the vicinity of the discharge area, namely the isopod Eurydice pulchra, the annelids Sabellaria alveolata and Ophelia radiata, the sea-urchin Paracentrotus lividus and the bivalve Mytilus galloprovincialis. In a first series of experiments, brine, with salinity above 300, was diluted in distilled water to a salinity value close to that of the seawater in the discharge area (salinity 36) and, surprisingly, none of the exposed species was able to survive or develop into viable larvae. A second series of experiments exposed the species to brine diluted with seawater, simulating more realistic discharge circumstances. All the tested species at all the measured endpoints (adult survival, larval abnormal development, sperm fertilization success) showed negative biological effects in brine solutes always at a lower salinity than that of a salinity control obtained with concentrated seawater. The sub-lethal experiments with larval development of P. lividus, S. alveolata and M. galloprovincialis, and the fertilization success of P. lividus gave EC50 values for the brine solute with salinity in the range of 40.9–43.5, whereas the EC50 values for the concentrated seawater were in the range of salinity 44.2–49.0. It is hypothesised that differences in the ionic composition of the brine cause the inability of the species to tolerate the exposure to brine. 相似文献
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《Deep Sea Research Part II: Topical Studies in Oceanography》2009,56(24):2460-2473
Eddies in the Gulf of Alaska are important sources of coastal water and associated nutrients, iron, and biota to the high-nutrient, low-chlorophyll central Gulf of Alaska. Three primary eddy formation regions along the eastern boundary of the gulf have been identified, (from south to north, Haida, Sitka, and Yakutat). In the spring of 2005, three eddies (one of each type) were sampled soon after their formation. The subsurface eddy core water in all three eddies was defined by high iron concentrations and low dissolved oxygen compared with surrounding basin water. The Sitka and Yakutat core waters also exhibited a subsurface temperature maximum (mesothermal water) coincident in depth with the iron maximum, suggesting that eddies may play a role in the formation of temperature inversions observed throughout the Gulf of Alaska. The data suggest different formation regions, with the Yakutat eddy forming in shallow shelf water with riverine input, while the Sitka and Haida eddies appear to form in deeper water. 相似文献