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41.
无机地球化学参数与有效烃源岩发育环境的相关研究 总被引:7,自引:0,他引:7
探索海相有效烃源岩判识指标仍是我国油气勘探中尚待解决的重要科研任务之一。古生产力及氧化还原条件是研究全球变化和海洋环境的重要内容,也是重塑有效烃源岩发育环境的主要参数。Si、Ba是古生产力的替代指标,Cd对古营养盐的反演具良好前景。过渡金属及其相关比值是缺氧环境的有效判识指标,可用其推断有机质保存条件。δ13Ccarb正偏移指示有机质埋藏量增加,是底部水体缺氧的响应。过渡金属同位素(δ65Cu、δ66Zn、δ97Mo)受生物活动及氧化还原条件的影响发生较大分馏,示踪环境变化具灵敏、高效性。将这些无机参数对古环境的示踪意义引入油气地质研究,从环境角度分析某一套地层能否发育有效烃源岩,进而探讨高演化海相有效烃源岩的判识,就更具特殊意义。 相似文献
42.
C. Lerouge A. Kunov C. Flhoc S. Georgieva A. Hikov J.L. Lescuyer R. Petrunov N. Velinova 《Journal of Geochemical Exploration》2006,90(3):166-182
Voluminous areas of advanced argillic alteration (AAA) constitute major exploration targets for surficial Cu–Au epithermal and potentially underlying porphyry-type deposits. In Bulgaria, more than 30 alunite occurrences are recognised, few of them being associated with a mineralised system. A mineralogical study combined with a stable isotopic (O, H, S) study has been carried out on nine alunite occurrences of advanced argillic zones hosted by volcanic rocks of Late Cretaceous age in the Srednogorie belt and of Oligocene age in the Rhodopes belt. This work was realised in order to constrain the origin of alunite and to define criteria to discriminate alunite from ore deposits and alunite from large barren alteration systems.Mineralogy of the nine occurrences consists of alunite + quartz + minor alumino-phospho-sulphates, associated with more or less kaolinite, dickite, pyrophyllite, diaspore and zunyite, depending on formation temperature. Alunite generally occurs as tabular crystals but is also present as fine-crystalline pseudocubic phases at Boukovo and Sarnitsa, in Eastern Rhodopes. In the advanced argillic alterations associated with economic ore, the presence of zunyite in the deeper parts indicates acid–fluorine–sulphate hydrothermal systems, whereas it is absent in uneconomic and barren advanced argillic alteration. All occurrences are formed at temperatures between 200 and 300 °C.(H, O, S) isotopic signatures of alunite combined with mineralogical features from all the studied occurrences, whatever their type, show characteristics of magmatic-hydrothermal systems. Sulphur data indicate essentially a magmatic origin for sulphur. Oxygen and hydrogen data suggest that hydrothermal fluids result from a mixing between magmatic fluids and an external component, which is identified as seawater-derived fluids or meteoric water in the vicinity of a sea. In most of the alunite occurrences, magmatic fluids are dominant and H2S/SO4 ratios are estimated to be higher than 2. Two exceptions exist in the Rhodopes. At Boukovo and Sarnitsa, where the estimated formation temperatures of alunite are the lowest, the external fluids are dominant and H2S/SO4ratios are estimated to be lower than or close to 1.At this stage of the work, the mineralogical and isotopic criteria do not enable a clear distinction between economic and uneconomic systems. However, some features are common in the economic ore deposits: the presence of zunyite in the deeper part of the system, the relatively high temperatures suggested by the zunyite + pyrophyllite + alunite + diaspore assemblages, the (O, H, S) signature of alunite, which is characteristic of dominant magmatic–hydrothermal acid–sulphate–fluorine systems. 相似文献
43.
同位素指示的巴丹吉林沙漠南缘地下水补给来源 总被引:14,自引:0,他引:14
通过恢复巴丹吉林沙漠及其周边地区大气降水氚值,并结合区域稳定同位素组合特征,揭示了区域地下水氚年龄的多解性与地下水稳定同位素的温度效应。恢复的1963年核试验期氚高峰值达到2 100 TU,进入90年代平均为60 TU。1960年以来降水补给的地下水氚值都应大于15 TU,而1963年的高峰氚衰变至今应在200 TU左右。地下水实测氚值较低,表明由现代少量降水补给的地下水与大量的古水进行了混合。影响降水中δ18O和δ2H分布的主要影响因子是月平均空气温度,对δ18O与δ2H的影响权重分别占到59.9%和57.0%。巴丹吉林沙漠及其周边地区地下水较低的稳定同位素组成表明,其补给主要是晚更新世较冷环境下形成的,来源于东南部的雅布赖山区,部分浅层地下水接受现代降水与河流的补给。
相似文献
44.
Currently used and newly proposed calculation techniques for the heightof the stable boundary layer (SBL), including the bulk-Richardson-numbermethod, diagnostic equations for the equilibrium SBL height, and a relaxation-typeprognostic equation, are discussed from the point of view of their physical basis andrelevance to experimental data. Among diagnostic equations, the best fit to data exhibits an advanced Ekman-layer height model derived recently with due regard to the role of the free-flow stability. Its extension to non-steady regimes provides a prognostic equation recommended for use in practical applications. 相似文献
45.
以地域分异特征、主导生态功能、典型生态问题为基础依据,探讨江西省国土空间生态修复分区,为江西省编制和实施生态修复规划、实现国土空间管控提供科技支撑。在研究方法上,以“生命共同体理论”“三生协调理论”“适宜性管理”等理论为指导,基于主体功能区划和生态功能区划,综合“三生”空间实际生态问题及综合整治需求,采用多因素综合空间分析法,“自上而下”和“自下而上”相结合,实现国土空间生态修复三级分区。研究结果表明,可将江西省国土空间生态修复区域划为赣北平原湖泊生态修复区、赣中丘陵盆地生态修复区、赣西山地丘陵生态修复区、赣南山地丘陵生态修复区、赣东丘陵山地生态修复区5个大区及24个亚区和42个修复小区。通过江西省国土空间生态修复三级分区,摸清国土空间地域特征,明确生态主导功能,确定生态修复重点区域,承上启下,为实施生态修复工程和国土空间管治提供决策依据,为实现国土空间整体保护、系统修复、综合治理提供科技途径。 相似文献
46.
中国土壤动物生态地理研究进展(英文) 总被引:7,自引:0,他引:7
This review summarizes main research findings in soil fauna eco-geography in China in the past 30 years.The subject areas and main results were overviewed including biodiversity and eco-geological distribution of soil fauna communities.Studies of ecological distributions of soil fauna and dynamic ranges in space from tropical,subtropical to temperate regions,and in categories from forest,grassland,desert,wetland,farmland to urban ecosystems,the responses and indications of soil fauna to soil environments.Ef... 相似文献
47.
Structure refinement of astrophyllite 总被引:1,自引:0,他引:1
The crystal structure of astrophyllite K2Na(Fe, Mn, Mg,□)7[Ti2(Si4O12)2|O3](OH, F)4 has been refined. The dimensions of the triclinic unit cell are: a = 0.5359(2) nm,b = 1.1614(4) nm, c = 1.1861(4) nm, α= 113.16(2)°, β= 103.04(2)°,γ= 94.56(2)°,V = 0.6495(5) nm3, Z= 1, space group P1, R=0.057 for 5308 reflections |Fo|>3σ|Fo|. According to structural and compositional differences the monoclinic astrophyllite K2NaNa(Fe, Mn)4Mg2Ti2[Si4O12]2(OH)4(OH, F)2 and astrophyllite should be considered as two different mineral species. Astrophyllite, monoclinic astrophyllite, bafertisite
and lamprophyllite contain heteropolyhedral sheets which topologically are related with Si, O sheets of mica where one or
several SiO4 tetrahedra are replaced by TiO
n
polyhedra. Therefore this heterophyllotitanosilicate series represents a kind of functional substitution in inorganic crystals. 相似文献
48.
Isotopic analysis by compound specific gas chromatography–isotope ratio mass spectrometry (GC–IRMS) is used to detect and characterize petroleum pollution in surficial sediments along the St Lawrence River, near Quebec City. Unusually mature n-alkane distributions have been found in some recent intertidal sediments in the region. GC–IRMS results suggest that the n-alkanes are not derived from indigenous organic sources because they carry δ13C values between −30.0 and −27.0‰, as well as very small isotopic differences between odd and even numbered n-alkanes, which are both typically associated with petroleum products. Comparison of these sediments with bunker fuel, an oil used in the shipping industry, has shown a close isotopic correlation in some sites, which is further supported by biomarkers. Overall, the contamination has been dispersed along the river but is generally localized around the industrial region where hydrocarbon transfer from shore storage to ships takes place. This study illustrates how GC–IRMS can be used effectively in the detection and characterization of petroleum pollutants in sediments. 相似文献
49.
鄱阳湖湿地典型中生植物水分利用来源的同位素示踪 总被引:1,自引:0,他引:1
水分是维持植物生长、决定种群分布的关键因子,研究植物水分利用来源是揭示水文过程与植被演替作用机制的基础,作为中国最大的淡水湖泊系统,鄱阳湖水文情势的显著改变已直接影响到湿地生态系统的水分补给来源.本文通过测定降水、土壤水、地下水、湖水和植物茎水中δ18O、δD同位素组成,识别鄱阳湖湿地典型中生植被——茵陈蒿(Artemisia capillaris)群落的土壤水分补给来源,并应用直接对比法和IsoSource多源混合模型估算优势种茵陈蒿的主要吸水区间及水源利用比例.结果发现:(1)与降水同位素相比,湖水和湿地土壤水同位素较为富集,地下水同位素较少发生分馏;(2)湿地地下水主要受历史长期降水和湖水共同补给,土壤水在雨季4—6月和秋季9—10月主要受降水补给,夏季7—8月深层土壤水受湖水侧向入渗和地下水的共同补给,并在蒸发作用下水分向浅层土壤传输;(3)茵陈蒿主要利用0~80 cm深度的土壤水,且能够在不同土层水源间灵活转换.当土壤含水量较高时(4—5月),主要利用0~40 cm浅层土壤水,利用率约49%~68%;当浅层土壤含水量较低时(6—8月),主要利用40~80 cm深层土壤水,利用率高达74%~95%;当植物进入生长后期(9—10月),主要利用0~15 cm表层土壤水,利用率介于41%~70%.总体发现,湖水是鄱阳湖湿地中生植物群落土壤水分的重要补给来源,优势种茵陈蒿能够响应土壤含水量的变化改变吸水深度,具有较强的干旱适应能力.研究结果可为鄱阳湖湿地植被生态系统演变和科学保护提供理论参考. 相似文献
50.
J. M. Edwards 《Boundary-Layer Meteorology》2009,132(2):349-350
The structure of the radiatively dominated stable boundary layer is analysed using idealized calculations at high vertical
and spectral resolution. The temperature profile of a nocturnal radiative boundary layer, developing after the evening transition,
is found to be well described in terms of radiative cooling to the surface, although radiative exchanges within the atmosphere
become increasingly important with time. The treatment of non-black surfaces is discussed in some detail and it is shown that
the effect of reducing the surface emissivity is to decrease rather than to increase the radiative cooling rate in the surface
layer. It is also argued that an accurate assessment of the impact of non-black surfaces requires careful attention to the
spectral and directional characteristics of the surface emissivity. A polar nocturnal boundary layer, developing above snow-covered
ground, is simulated and found to reach a slowly evolving state characterized by a strong radiative divergence near the surface
that is comparable to observed values. Radiative boundary layers are characterized by large temperature gradients near the
surface.
An erratum to this article can be found at 相似文献