互花米草对泉州湾盐沼表层沉积物输运的影响

海岸盐沼是海岸湿地系统的重要组成部分,具有很强的环境调节功能．互花米草（Spartina alterniflora）的引种对海岸盐沼的沉积动力产生很大影响．粒度分析结果表明,互花米草盐沼边缘与沉积物平均粒径为6．7φ的等值线分布一致．现场观测表明,互花米草对流速具有明显的阻滞作用,使得光滩流速明显大于互花米草内的流速;在互花米草滩内,随着离盐沼边缘距离、植被高度、植株直径的不同,涨落潮流速也表现出不同的变化趋势．粒径趋势分析结果显示,互花米草盐沼边缘的表层沉积物由光滩向盐沼内输运,潮水沟的存在对沉积物的输运格局具有显著影响．对比分析表明落潮后期的水动力条件控制着研究区内表层沉积物的净输运方向．     

论广西红粘土的胀缩性能

文章从由碳酸盐岩溶余堆积形成的红粘土引起产生的地裂、房裂等不良工程地质现象入手,以大量的实验资料为基础,指出广西红粘土的胶粒含量,可塑性指标高,具有较强的吸附能力和较强的亲水性,自由膨胀率接近或等于27%.论述了红粘土液限和塑限值在塑性图上的分布规律与一般膨胀土的分布规律相吻合,这种粘土应属于弱至中等级膨胀性粘土,并以收缩变形为其主要特征.     

The use of grain size trend analysis in macrotidal areas with breakwaters: Implications of settling velocity and spatial sampling density

In a macrotidal environment with offshore breakwaters (Elmer, West Sussex) a new approach for the identification of the sediment transport pathways with grain size trend analysis (GSTA) was undertaken using statistical parameters (mean, sorting and skewness) directly derived from settling velocities distributions. The same samples were analysed with sieving (quarter- and half-phi resolution) and GSTA was performed again in order to directly compare the resultant sediment transport directions derived with the two analytical techniques. Furthermore, both regular and irregular sampling distributions were used to recalculate GSTA. Hydrodynamic data were collected in different locations around the breakwaters and net sediment transport directions were calculated in order to assess the accuracy of the sediment transport pathway directions derived with the different analytical techniques.The accuracy of settling velocity in determining the statistical parameters of the grain size distribution is identified, especially for the fine-medium sand sediments. Settling velocities produced better results than the sieving; the quarter-phi resolution producing the poorer results in comparison with the coarser half-phi resolution. The results for the different spatial sampling strategies are found to depend upon the number of samples utilised; that shows that the accuracy of the GSTA is based upon the ability of representing, adequately, the spatial distribution of the sediment parameters.     

Sedimentary nutrient dynamics in a tropical estuarine mangrove ecosystem

Mangrove sediments play a pivotal role in the nutrient biogeochemical processes by behaving as both source and sink for nutrients and other materials. Surface and core sediments were collected from various locations of the Pichavaram mangrove (India) and analyzed for grain size distribution, nutrients and stable N isotope (δ¹⁵N) signatures in order to understand the spatial and vertical distribution of nutrients and biogeochemical processes of the C, N, P and S in this ecosystem. Sand is the dominant fraction followed by silt and clay. Spatial distribution of nutrients is controlled by the external and internal loadings, whereas vertical distribution is largely driven by the in situ microbial activities. Interior mangrove sediments contain higher concentrations of organic carbon (OC) than the estuarine sediments reflecting high rates of organic matter retention. Finer fractions of sediment hold ∼60% OC due to high surface area. At some sampling points, moderately high δ¹⁵N signatures were observed and this may be because of agricultural runoff and aquaculture effluents.     

基于成藏过程重建研究渤中凹陷西北缘陡坡带油气差异聚集机理

渤海湾盆地渤中凹陷西北缘陡坡带油气分布"西贫东富",成藏条件复杂.利用储层定量荧光技术、傅立叶红外光谱技术、原油地球化学参数、流体包裹体岩相学,结合埋藏史、热史及构造演化,从古流体和现代流体特征角度进行系统定时定量化成藏过程恢复,研究差异成藏原因.研究表明,陡坡带经历了两期油气充注过程,第一期开始于明化镇组沉积早期(距...     

Quantitative assessment of impacts of climate and economic-technical factors on grain yield in Jilin Province from 1980 to 2008

Climate change is one of the most important challenges threatening agricultural grain yield and food security. Determining the factors influencing grain yield in Jilin Province and the weights of their contribution are a very important task, because Jilin Province is an important agriculture base in China. In this study, the accumulation factor sequence evaluating data method was used to analyze the climate and economic-technical factor contribution weights to grain yield and grain yield changes in each city of Jilin Province. Climate yield was also estimated to study the climate effect on the grain yield, and it was calculated in two ways:an improved algorithm and a traditional quadratic method. The results show that the climate and economic-technical factors have different contribution weights to grain yield in different cities in Jilin Province. The contribution weight of the climate factor to grain yield was 0.212-0.349, while that the economic-technical factor was 0.651-0.788. Furthermore, the changes of the climate factor contributing to grain yield changes accounted for 0.296-0.546, and the changes of the economic-technical factor accounted for 0.454-0.704. The weights of climate and economic-technical factor contributing to grain yield are very different between the eastern and western cities in Jilin Province, but their weights contributing to the grain yield change are similar in these cities. In general, the amount of fertilizer used per hectare (FUPH) is the main factor affecting grain yields and yield changes from 1980 to 2008. It is noted that when the FUPH growth rate stabilized after 1995, the effects of the climate factor on the grain yield become more obvious than before. The improved algorithm is effective for estimating climate yield in Jilin Province, and the climate yields were mostly between-500 kg/ha and 500 kg/ha, and showed a slightly rising trend in most cities.     

Forms of phosphorus and silicon in the natural grain size surface sediments of the southern Bohai Sea

The forms of phosphorus and silicon in the natural grain sizes surface sediments of the southern Bohai Sea were studied. In sediments, the organic matter bound form of phosphorus was the main form of transferable phosphorus and ranged from 0.37μmol/g to 1.57μmol/g, accountingfor 10.7% of the total phosphorus, others were the carbonate bound form, iron-manganeso oxide bound form and ion-exchange able form; the transferable form of phosphorus accounted for 19.2% of the total phosphorus. Silicon‘ s carbonate bound form was predominant over others among its transferable forms, and content ranged from 1.55μmol/g to 8.94μmol/g, accounting for 0.05% of the total silicon; the total amount of transferable silicon forms accounted for only 0.12% of the total silicon. Therefore, 19.2% of the total phosphorus and 0.12 % of the total silicon contained in the surface sediments of the southern Bohai Sea could participate in the biogeochemical cycling.     

黄河口附近海域表层悬浮体分布及粒度特征

利用2001年7月进行的两船同步走航调查资料,结合同一时期的陆地卫星合成图像,对枯水期黄河口表层悬浮体空间分布和粒度特征进行了研究。低潮时,黄河河口表层悬浮体含量、温度、盐度在河口口门外5 km范围内变化迅速,表层悬浮体含量和温度向海方向呈指数方式迅速降低,悬浮体含量由519 mg/L下降到20~30mg/L,温度则下降4℃左右;盐度则由1升至33。表层悬浮体含量的变化与表层水体温度、盐度变化有很好的对应关系,温度、盐度变化反映了河流注入的淡水在表层与海水的混合过程。与调查时期接近的一景遥感图像(RGB321)对照,可以看出图像色调变化与测量数值的变化比较吻合。悬浮体平均粒径为6.64~5.26Φ,以粉砂为主。沿测线由河口向海方向,粒度成分和粒径的变化趋势明显,粒径逐渐变粗,黏土成分减少而砂的成分增多,这可能与絮凝作用有关。     

海南岛小海潟湖沉积环境演变研究

对小海潟湖南部和中部2个柱状沉积物XHK04-01和XHK04-04进行了粒度分析,210Pb分析,总有机碳、总氮、总硫的含量分析,并且利用C/N,C/S在沉积物中的不同研究了小海地区沉积环境的演变。结果表明,小海南部和中部地区以粉砂为主,近年来粘土含量增加,水动力条件变弱;海水对沉积环境的影响逐渐减小,沉积物上覆水体呈淡化趋势,但相对于小海南部,中部淡化程度小。小海南部沉积速率较大,达到0.623cm/a;总有机碳、总氮在20世纪60年代之前含量相对稳定,陆源有机碳占总有机碳80%左右,60年代之后含量迅速上升,特别是1973年以来,陆源有机碳只占到总有机碳45%左右,自生有机碳增加。小海中部沉积速率较小,为0.216cm/a;总有机碳、总氮在20世纪50年代以前含量相对稳定,陆源有机碳占到总有机碳70%左右,最近50a来总有机碳和总氮含量快速增加,陆源有机碳只占到总有机碳47%左右,自生有机碳增加。小海中部和南部沉积环境在20世纪50年代之前稳定,在最近50a发生了很大的变化,这与小海潟湖口门束窄、修筑防沙堤、入海河流改道等因素有关。     

泉州湾表层沉积物粒度指示的沉积动力端元解析

基于前期工作,采取粒度端元分析方法,结合沉积物粒度参数、研究区水深以及水动力等对福建省泉州湾海域采集的65个表层沉积物样品进行了沉积动力学解析判别,量化研究区表层沉积物复杂的沉积动力特征.结果表明:样品粒度数据中可以至少分离出4个不同的端元组分,其粒径范围大致分布在0.2～200、20～30、50～500、80～100...