华南中生代与同熔型花岗岩有关的铜铅锌多金属矿床时空分布及其岩浆源区特征

花岗岩及其成矿作用一直是地质学家关注的重要科学问题。本文在回顾花岗岩分类及其成矿专属性研究的基础上,以华南同熔型花岗岩为例,探讨了华南地区与同熔型花岗岩有关的铜铅锌矿床的特点、时空格架及其分布规律,研究了与成矿有关的同熔型花岗岩的特点、源区属性及其与华南古老地壳的关系。本文认为华南地区与同熔型花岗岩有关的铜铅锌成矿作用是壳幔相互作用的结果,且这些同熔型花岗岩具有过渡类型的特征。岩浆源区属性与成矿类型、成矿规模的关系存在着某种制约联系,该类矿床的形成是不同时期华南地区古老地壳改造的结果。     

4种微量金属元素对绿色巴夫藻生长、叶绿素a及大小的影响

把 4种微量金属离子以不同的浓度添加到绿色巴夫藻的培养液中 ,结果表明 :Hg2 +和Pb2 +浓度分别在 5μg/L和 2 0 0 μg/L时 ,对绿色巴夫藻的生长有较好的促进作用 ,同时也使叶绿素a的含量提高 ;Hg2 +≥ 2 0 μg/L时 ,绿色巴夫藻的生长受到抑制 ,叶绿素a的含量降低。Pb2 +所有的试验浓度都使绿色巴夫藻生长加快 ,叶绿素a的含量提高 ;Co2 +在 1μg/L时对绿色巴夫藻的生长有最好的促进效果 ,但当Co2 +≥ 5μg/L时 ,开始对生长出现抑制作用 ,而Co2 +所有的试验浓度都使叶绿素a的含量降低 ;Mn2 +浓度在 10 0 μg/L时 ,对促进绿色巴夫藻生长的效果最佳 ,4 0 0 μg/L的浓度开始对生长出现抑制作用 ,但所有Mn2 +的试验浓度对叶绿素a含量的变化影响不显著。 4种微量金属元素都使绿色巴夫藻略微变小。     

Do manganese nodules grow or dissolve after burial? Results from the Central Indian Ocean Basin

Fifty buried manganese nodules at different depth intervals were recovered in 12 sediment cores from the Central Indian Ocean Basin (CIOB). A maximum of 15 buried nodules were encountered in one sediment core (AAS-22/GC-07) and the deepest nodule was recovered at 5.50 m below seafloor in core AAS-04/GC-5A. Approximately 80% of the buried nodules are small in size (2 cm diameter) in contrast to the Atlantic Ocean and Peru Basin (Pacific Ocean) where the majority of the buried nodules are large, 8 cm and >6 cm, respectively. Buried nodule size decreases with core depth and this distribution appears to be similar to the phenomenon of “Brazil Nut Effect”. Buried nodules exhibit both smooth and rough surface textures and are ellipsoidal, elongated, rounded, sub rounded, irregular and polynucleated. Buried nodules from siliceous ooze are enriched in Mn, Cu, Ni, Zn, Mo, Ga, V and Rb whereas those from red clay are enriched in Fe, Co, Ti, U, Th, Y, Cr, Nb and Rare Earth Elements (REE). Buried nodules from siliceous ooze suggest their formation under hydrogenetic, early digenetic and diagenetic processes whereas those from red clay are of hydrogenetic origin.REE are enriched more than 1.5 times in buried nodules from red clay compared to siliceous ooze. However, the mode of incorporation of REE into buried nodules from both sedimentary environments is by a single authigenic phase consisting of Fe–Ti–P. Shale-normalized REE patterns and Ce anomalies suggest that nodules from siliceous ooze formed under more oxidizing conditions than those from red clay. Nodules buried at depths between 1.5 and 2.5 m are diagenetic (Mn/Fe ratio 10–15), formed in highly oxic environments (large positive Ce anomalies) and record aeolian dust (high Eu anomalies). Chemical composition, surface texture and morphology of buried nodules are similar to those of surface nodules from the same basin. Furthermore, buried nodule compositions do not exhibit any distinct patterns within the core depth, suggesting that buried nodules neither grow nor dissolve after their burial in the sediment column.     

Annual and spatial variation in the abundance length and condition of juvenile turbot (Psetta maxima L.) on nursery grounds on the west coast of Ireland: 2000–2007

Turbot (Psetta maxima Linnaeus) is a high value commercially exploited marine flatfish which occurs in European waters, from the Northeast Atlantic to the Arctic Circle, the Baltic and Mediterranean Sea. In Ireland, turbot are the most valuable commercial non-quota species. Very little is known about their population dynamics in the wild, in particular during the sandy beach nursery phase of the life history. In 2000, a survey was established to assess flatfish species on nursery grounds on the west coast of Ireland. Eleven sandy beaches were assessed for 0+ turbot by beach seining, over an eight year period (2000–2007) during the months of August and September. The objective of the study was to estimate juvenile turbot abundance and size structure to determine if any spatial and annual trends existed. Large scale variability in the recruitment of fish to nursery grounds may be indicative of fluctuations in the adult stock. Turbot were found to recruit to five beaches consistently over the eight year period. Temporal and spatial variability in the relative abundance and length of turbot was discerned, with no apparent overall trend. However, certain nursery grounds were shown in most of the years examined to support higher abundances of turbot in comparison to other areas over the eight year period. Turbot abundances on nursery grounds were significantly correlated with mean spring sea temperatures during the pelagic stage. The condition of turbot did not significantly differ on an annual or spatial scale. Mean densities of 0+ turbot along the Irish coast were found to be similar and at times higher than other areas in Europe, ranging from 0.1 (± 0.3) individuals 1000 m^− 2 to 18.5 (± 6.9) individuals 1000 m^− 2. Mean turbot total length on beaches ranged from 3.8 cm (± 0.6) to 6.6 cm (± 4.3). The observed spatial and temporal variability in abundance and length highlights the need for long-term studies when assessing juvenile flatfish populations. Results from the present study have provided much needed baseline data on wild juvenile turbot populations which is severely lacking for this species both on an Irish and on a European scale.     

Mussel fishery affects diet and reduces body condition of Eiders Somateria mollissima in the Wadden Sea

Although the Danish Wadden Sea is of international importance for several bird species, large-scale blue mussel Mytilus edulis fishing took place from 1984–1987, ceasing thereafter due to low mussel stocks. Mussel fishing removes much of the blue mussel biomass, especially larger individuals. Hence we predict that intensive mussel fishing will affect their predators, such as the Eider Somateria mollissima, which is predominantly a blue mussel feeder by, 1) reducing the amount of blue mussels in their diet relative to alternative prey items, 2) exploitation of smaller blue mussel shell classes, 3) loss of body condition, 4) changing feeding distribution to aggregate to the remaining mussel stocks, and 5) decreasing numbers. Before winter 1986/87 blue mussel biomass was estimated at 40,600 tons, decreasing to 15,400 tons in 1987/88 due to mussel fishery. We collected Eiders in both periods to monitor their diet and body mass and used aerial surveys to determine changes in numbers and distribution. Between the two periods, blue mussels declined in the Eiders diet, numbers of Eiders with empty stomachs increased and the mean length of blue mussel taken by Eiders decreased. Eider body condition declined from 1986/87 to 1987/88, mostly the result of the reduction in numbers of individuals with blue mussel remains in their gizzards and in better body condition compared to those taking alternative food items or having empty gizzards. Eiders shifted their distribution from the southern part of the Danish Wadden Sea to the northern part, where the remaining blue mussel stocks were situated. Eider numbers were lowest in 1987/88, the year of lowest blue mussel stocks. We conclude that intensive mussel fishery affected the Eider's diet, reduced their body condition and affected distribution and abundance. The results also showed that availability of blue mussels may have a key role in building up and maintaining body condition in Eiders during winter.     

Characterization of AOX by Fractionation Analysis and Size‐exclusion Chromatography

A characterization method for AOX in surface water samples was developed and tested. The method involves fractionation using a hydrophobic C18 resin and a weak anionic exchange resin and allows the fractionation of the AOX pool of surface water samples into four fractions: (1) hydrophilic acidic, (2) hydrophilic non‐acidic, (3) hydrophobic acidic, and (4) hydrophobic non‐acidic. The adsorption analysis was verified with AOX‐relevant model compounds and was applied to characterize the AOX pool of a stream sample from the Moskva river (Russia). In addition to the fractionation analysis, size‐exclusion chromatography was used to characterize the AOX pool of the sample studied. Hydrophilic acids made up the major fraction of the AOX pool (55 %). Among this fraction chlorinated high‐molecular acids (humic substances) made up the main fraction (35 %).     

多金属结核粒径分形特征初步研究

通过对东太平洋中国开辟区东、西两区的多金属结核进行粒径分析,发现其粒径分布有分形特征。无缆取样结核粒径分形有着上、下限,虽然在小粒径上没有分形关系,但却存在着另一种确定的线性关系。说明东、西区结核在粒径、重量等分布上有着客观的一致性。通过分形分析得到了结核空间分布、粒径和重量分布的线性方程,对多金属结核矿藏储量和集矿机设计具有一定的意义。     

Distribution of Grain Size and Clay Minerals in Sediments from the INDEX Area, Central Indian Basin

The granulometry of 21 box core sediments from five selected sites in the Central Indian Basin (CIB) have been studied to understand the sediment size characteristics in the Pioneer area before the benthic disturbance experiment. The sediments are predominantly clayey silt. Statistical parameters were determined to understand the control and variations in the grain size. The mean grain size (M z φ) ranged from 7.0 to 8.6 for the surface and from 6.6 to 8.6 for the subsurface sediments, indicating deposition of very fine fractions during the Neogene period. The sediments were poorly sorted as revealed from the higher σI values (2.7 to 2.9). Higher and negative values of skewness (SK I ) indicated a winnowing action of prevailing currents in the area. Average kurtosis (K G ) values for the surface (0.4 to 0.8) and subsurface (0.5 to 1.2) showed that sediments were very platykurtic and leptokurtic. Clay mineralogical studies showed that smectite had a wider range (from 6% to 55%) and decreased southward because of its terrigenous origin. The terrigenous influence of the sediments could be documented as far as 12°S. Smectite and kaolinite increased eastward and chlorite decreased southward. This observation positively correlated with the mean current direction in the area. However, the influence of Antarctic Bottom Water (AABW) in the area could be predicted from the southward increase in chlorite content.     

论岩体表征单元体积REV岩体力学参数取值的一个基本问题

本文论述了岩体力学性质的尺寸效应,提出了与岩体弹性参数相应的表征单元体REV的力学描述,根据中心极限定理推导了估算裂隙岩体REV 的数学表达式。研究表明,岩体表征单元体的大小是岩体力学性质尺寸效应的客观反映。本研究成果为合理选取岩体力学参数提供了一条新途径。