杨金沟白钨矿床地质特征及找矿前景分析

杨金沟白钨矿床是目前我国东北地区发现最大的钨矿资源地,其资源量已超过大型规模.文章通过大量野外地质调查和室内观察,总结了杨金沟白钨矿床基本地质特征,并对主要控矿因素及矿床成因类型进行了深入研究;另外,在该矿床现有勘查成果基础上,结合矿体空间产出特征和断裂构造等主要控矿因素,剖析了该矿床钨矿化富集规律,进一步明确了杨金沟地区白钨矿床的找矿远景和方向.     

Tidal time-scale variation in nutrient flux across the sediment–water interface of an estuarine tidal flat

We determined the range of the tidal variations in nutrient flux across the sediment–water interface and elucidated mechanisms of the flux variation in two estuarine intertidal flats (one sand, one mud) in northeastern Japan. Nutrient flux was measured using in situ light and dark chambers, which were incubated for 2 h, 2–6 times per day. Results showed that nutrient concentration in overlying water varied by tide and was also affected by sewage-treated water inflow. The nutrient fluxes responded quickly to the tidal variation in overlying water chemistry and the range of the variation in flux was as large as the seasonal-scale variation reported in previous studies. In the sand flat, salinity increase likely enhanced benthos respiration and led to increases in both O₂ consumption and PO₄³⁻ regeneration under low illumination, while benthic microalgae were likely to actively generate O₂, uptake PO₄³⁻ and suppress PO₄³⁻ release under high illumination (>900 μmol photons m⁻² s⁻¹). Also in the mud flat, PO₄³⁻ flux was related with O₂ flux, although the range of temporal variation in PO₄³⁻ flux was small. In both the flats, NH₄⁺ flux was always governed by NH₄⁺ concentration in the overlying water; either an increase in NH₄⁺ uptake or a decrease in NH₄⁺ release was observed as the NH₄⁺ concentration rose due to inflow of river water or input of sewage-treated water. Although NO₃⁻ tended to be released in both tidal flats when low NO₃⁻ concentration seawater dominated, their relationship was likely to be weakened under conditions of low oxygen consumption and suppressed denitrification. It is likely that tidal variation in nutrient flux is governed more by the nutrient concentration than other factors, such as benthic biological processes, particularly in the case where nutrient concentration in the overlying water is relatively high and with wide amplitude.     

水温、盐度和饵料密度对橄榄蚶滤水率的影响

用实验生态学的方法研究了不同水温(15、20、25、30℃)、盐度(16、21、26、31、36)和饵料密度(0.5×104、1.5×104、2.5×104、3.5×104、5×104个/m L)对橄榄蚶(Estellarca olivacea)滤水率的影响。实验结果表明,以金藻作为饵料,水温、盐度、饵料密度对橄榄蚶的滤水率有显著影响(P0.05)。水温15~30℃、盐度16~36、饵料密度为0.5~5×104个/m L时,橄榄蚶的滤水率都呈峰值变化。水温25℃、盐度26、饵料密度3.5×104个/m L时,其滤水率分别达到最大值。在所研究的范围内,水温、盐度、饵料密度与滤水率之间分别满足函数关系:FRT=–0.3396T2+1.8937T+0.2728(R2=0.9857,P0.05);FRS=–0.3424S2+1.9626S+0.7112(R2=0.9683,P0.05);FRC=1.7395 C 0.4607,(R2=0.9062,P0.05)。     

Delineating suspended sediment concentration patterns in surface waters of the Changjiang Estuary by remote sensing analysis

Three Landsat TM imageries (taken on 18 May 1987, 4 August 1998 and 28 July 2007) were used as the data source to identify the spatial and temporal variations of the suspended sediment concentration (SSC) in surface waters of the Changjiang Estuary. Atmospheric correction was carried out to determine the water-leaving reflectance using the FLAASH module. A regression equation between surveyed SSC and suspended sediment index was chosen to retrieve the SSC from the Landsat TM images. In addition, tidal harmonic analysis was performed to calculate tidal conditions corresponding to the acquisition time of satellite images. The results show that the SSC spatial patterns are similar to the in situ observation results, which show the highest SSC in the region of turbidity maximum zone in the Changjiang Estuary. For the period of 1987 to 2007, the SSC pattern is controlled mainly by tidal dynamic conditions and wind speeds, rather than sediment discharges from the river.     

胶州湾海域潮流动力特征及其与含沙量的关系

根据2009年胶州湾海域的悬沙、流速、流向的实测资料,应用短期资料的潮流准调和分析方法,对连续海流资料进行了分析,并结合悬沙资料,对含沙量与潮流之间动力关系进行了探讨。研究结果表明:该海域潮流属于正规半日潮流性质,半日分潮流的东分量大于北分量,潮流以带有旋转性质的往复流为主,涨潮流流向偏西,落潮流流向偏东。胶州湾内含沙量分布特征与海底沉积物粒径特征基本一致。含沙量在涨落潮的交替和流速的更迭作用下出现明显的周期性变化,含沙量的峰值基本与海域半日潮流特点相对应,几乎每1个流速峰值对应1个含沙量的峰值,含沙量的峰值一般出现在流速峰值之后。胶州湾口处流速和单宽输沙量都为最大,涨潮单宽输沙量大于落潮单宽输沙量,输沙方向为偏西向。     

氮浓度对盐生杜氏藻和纤细角毛藻叶绿素荧光特性及生长的影响

在温度为(23±1)℃,盐度为31,光照强度为5000lx的条件下,用含有不同氮浓度(0μmol/L,55μmol/L,440μmol/L,880μmol/L,1760μmol/L,7040μmol/L)的培养基对中国海洋大学微藻种质库保存的盐生杜氏藻(Dunaliella salina)和纤细角毛藻(Chaetoceros gracilis)进行培养,研究两种微藻在一次性培养过程中,不同氮浓度对其PSⅡ最大光能转化效率(Fv/Fm)、叶绿素含量以及细胞密度的影响。单因子方差分析结果表明,氮浓度对两种微藻的光合作用及生长均有显著影响(P<0.05)。两种微藻的Fv/Fm比值、叶绿素含量以及细胞密度均随着起始氮浓度的增加而增加,在1760μM时达到最大值,其后随着起始氮浓度的增加,上述指标反而下降。多重比较结果表明,盐藻和纤细角毛藻进行光合作用和生长的最适氮浓度都为1760μmol/L。。     

水污染的导电性和激电性与污染浓度变化关系的几个实验结果

为了解用电阻率法、电磁法和激发极化法监测地下水污染的可能性,给出了在水样和含水砂样中,加入了不同浓度的无机污染物和有机污染物时,样品电阻率、极化率、半衰时和偏离度等导电性和激电性参数与浓度变化关系的几个实验观测结果．水样中的观测结果表明,除个别有机污染样品的电阻率随浓度增加有所增大外,其余所有无机污染和有机污染样品的电阻率均随浓度的增加而减小．含水砂样中的观测结果表明,不同污染成分样品的电阻率和极化率,均随孔隙液浓度的增加而减小,但对反应样品激电时间特性的参数而言,则有半衰时随浓度增加而减小,偏离度随浓度增加而增大的规律．同时指出,用电阻率法、电磁法和激发激化法监测地下水污染是十分困难的．     

Atmospheric concentrations and deposition of heavy metals over the North Sea: A literature review

A literature review of the atmospheric concentration rates and dry and wet deposition fluxes of particulate Cd, Cr, Cu, Pb and Zn to the North Sea and adjacent areas is given. The results of direct measurements of dry and wet deposition fluxes are compared to indirect estimates and to modelling values. This work points out the large uncertainties in results of different studies on atmospheric input of trace elements into the North Sea. The current knowledge about the dependence of the deposition velocity upon the particle size and about the processes controlling wet deposition fluxes, and the quality and completeness of the emission data are still inadequate for describing the environmental cycle and impact of heavy metals in the North Sea.     

稳态风沙流中沙粒体积浓度的模型分析

本文建立了一个简单有效的稳态风沙流中沙粒体积浓度的数学模型,包括3个部分:稳态风沙流的风速廓线描述、跃移沙粒轨迹的计算、床面沙粒起跳速度分布的描述。利用已知实验的风速廓线作为气流速度场输入参数,跃移沙粒轨迹的计算主要考虑重力和拖曳力,基于体积观点的床面起跳沙粒的水平速度和垂直速度概率密度分布函数分别采用正态分布和指数分布函数来描述。根据稳态风沙流中运动沙粒的动态平衡特征可推导计算沙粒体积浓度。计算的沙粒体积浓度与风洞实验结果基本一致,说明本模型有较好的预测能力。     

蒙古国北部Gun Nuur湖表层沉积物花粉分布特征

 蒙古国北部Gun Nuur湖20个表层沉积物孢粉组合与数量分析研究揭示,孢粉组合及浓度分布存在显著空间差异。结果表明：双束松型花粉百分含量由湖泊东南向西北降低,桦属、蒿属、藜科以及禾本科百分含量增加,湖泊东南侧赤松林是造成孢粉组合空间分异的主要原因。孢粉浓度分布与湖泊水深具有良好的对应关系,体现了湖水流对孢粉的二次搬运和富集作用。现代森林草原地带Gun Nuur湖表层孢粉组合中松属含量较高,具超代表性;受松属影响蒿属和藜科花粉含量较低,代表性较低。