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91.
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The concentrations of lipids were determined in atmospheric particle, gas and rain samples collected from the tropical North Pacific to assess lipid sources, transport mechanisms and fluxes to the ocean surface. Four lipid compound classes (aliphatic hydrocarbons, fatty alcohols, fatty acid esters, and salts) all unequivocally show a terrestrial vascular plant source. These aerosol lipids originate from wind erosion of Asian and American soils and direct emission from vegetation. The major fluxes result from rain rather than dry deposition. These fluxes are large enough to have a major potential impact on the inventory of terrestrially derived lipid material found in deep-sea sediments. This has been showm for n-alkanes, fatty alcohols, fatty acids, total lipids and for organic carbon. By comparing atmospheric and sediment trap fluxes with sediment accumulation rates, it is suggested that some biogenic terrestrial material is more protected from degradation than marine-derived material. 相似文献
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Effects of calculation procedure and sampling site on trap method estimates of sediment resuspension in a shallow lake 总被引:1,自引:0,他引:1
Resuspension estimates given by two different trap methods in a shallow lake were compared. The sensitivity of the methods to errors in estimates of gross sedimentation and organic fraction of trapped material was explored. The methods were label method, in which resuspension is estimated by determining the organic fraction of surface sediment, suspended seston and trapped material, and SPIM/SPM method, where the relationship between settling particulate inorganic matter (SPIM) and total settling particulate matter (SPM) is used. During the whole 111 day study period, according to the label method, at a sheltered station 1949 g m−2 dry weight of sediment was resuspended, whereas SPIM/SPM gave an estimate of 1815 g m−2. The difference in the estimates was probably due to mineralization loss of organic material in the traps during the two week exposure periods. Sensitivity analysis showed that of the two methods, the label method was more sensitive to variations in the organic content of trapped material. At a wind-exposed station, the total amounts of resuspended matter given by the label method and by the SPIM/SPM method were 4966 g m−2 and 4971 g m−2, respectively. Due to wind effects, escape of trapped material took place, which caused underestimation of gross sedimentation and compensated the effects of mineralization loss to diminish the difference between the methods. Of the two methods, the SPIM/SPM method seems thus more suitable for lakes, where bacterial activity is high. If cyanobacterial blooms take place, the label method is probably more reliable, providing that the exposure time of sediment traps is kept adequately short. 相似文献
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在对3套烃源岩的质量和成熟度描述基础上,通过对原油物理性质、族组成和生物标志化合物参数的研究,在达尔其油田内划分出成熟度有明显差异的低熟油和成熟油。油源对比结果认为它们分别由都红木组一段低熟烃源岩和阿尔善组二段成熟烃源岩所生。推测成熟度参数介于低熟和成熟之间的原油为混源油。通过原油混合试验和油砂连续抽提试验证实了混源油的推测。通过油藏剖面中不同性质油层的分布特征研究,结合断层发育史与油气运移关系分析认为不同油源原油的混合是控制该油田石油富集度较高的关键因素。此外,还分析了控制混源的断层组合特征。 相似文献
97.
贵州天柱磨山─油麻坳金矿化带地球化学特征及成矿作用 总被引:9,自引:0,他引:9
贵州天柱磨山油麻坳金矿化带地球化学特征及成矿作用*张杰余大龙李明琴张先煜杨勇俊(贵州工业大学资源工程系,贵阳550003)关键词金矿化带金矿地球化学金矿成矿作用黔东天柱本文主要研究了黔东天柱磨山—油麻坳金矿化带内主要类型岩石矿石的地质-地球化学特征,... 相似文献
98.
秦岭地区砂金分布特征与成矿机理 总被引:1,自引:0,他引:1
秦岭地区砂金矿床大部分分布在嘉陵江、汉水及其它们的支流流域。总结了砂金矿床分布特征,并将3种类型进行了对比。系统地对矿源、搬运、储存和富集的成矿模式、成因机理进行了研究。地貌与产构造运动在成矿中占有重要地位。 相似文献
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100.
三江源地区水资源的涵养和保护 总被引:1,自引:0,他引:1
分析了三江源区水资源现状,论述了建立水资源三级保护区的意义、作用和划分方案,实施林草植被的保护和恢复的水文生态效益及健全水资源补偿机制的必要性。 相似文献