格尔木河水质现状及生态风险评估

为了解经济迅速发展背景下格尔木河流域水体中痕量元素分布、水环境质量现状和生态风险,对格尔木河9个采样点水样21种痕量元素的分布及相关性进行了分析,以Cu、Zn、Hg、Cd、Cr和Pb为目标重金属,评估了格尔木河水质现状及生态风险。结果表明:重金属Pb浓度在所有水样中均低于检出限,其它痕量元素浓度在0.001(Cd)～6297.013(Sr)μg·L~(-1)范围变化。根据相关性分析,推测格尔木河水体中Li、Sc、Ti、V、Cu、Ge、Rb、Sr、Mo、Cd来源可能相同。采样点水样6种重金属浓度均达到地表水环境质量I类的标准。采用5种方法评价了格尔木河水质现状,研究区水质处于无污染的理想状态。格尔木河重金属引发的潜在生态风险处于低风险水平(生态风险指数变化范围为0.35～0.68)。     

Genesis of lithium pegmatites from the leinster granite margin,southeast ireland: Geochemical constraints

Extensive and economically-important lithium pegmatites have been described from the eastern flank of the large S-type peraluminous Leinster Granite batholith in southeast Ireland. This flank area is also the locus of a major dip-slip ductile shear zone which was active during emplacement of the Tullow Lowlands pluton of the batholith. All the known bedrock occurrences of lithium pegmatite are contained within this marginal deformation zone. Most previous studies have suggested derivation of the lithium pegmatites by fractionation from the Leinster Granite itself, though none are conclusive. More recently, an anatectic model has been proposed whereby the pegmatites were derived by melting of Li-rich sediments adjacent to the batholithic contact. Our investigation has been concerned with a detailed study of the Rb-Sr isotope systematics and trace element geochemistry of the pegmatites and their host granitoids in an attempt to resolve the problem of pegmatite genesis. The results suggest a strong geochemical and temporal coherence between the Leinster Granite and the lithium pegmatites. A model is proposed in which Li enrichment in residual magmas may be linked to the development of muscovite instead of biotite in the Leinster Granite itself. The Li excluded from entry to biotite then accumulates in highly mobile, low-viscosity pegmatitic fluids which migrate into the marginal shear zone of the Tullow Lowlands pluton where they crystallize at considerably lower temperatures.     

柴达木盆地第三系咸水湖相生油岩古沉积环境地球化学特征

在系统分析柴达木盆地西部第三系咸水湖相生油岩样品的微量元素、有机物、粘土矿物组成的基础上,揭示了研究区生油岩的无机元素和有机质组成特征;并结合沉积环境的无机与有机地球化学指标,重建了生油岩沉积时的古沉积环境。生油岩的B、Cl-及伽玛蜡烷含量表明,沉积时的水介质条件是半咸水—咸水环境,并伴随湖盆沉积中心北迁过程各层位地层的盐度发生规律性时空]化;生油岩的Fe2 /Fe3 、S2-、Pr/Ph比值、藿烷碳数分布模式及黄铁矿含量反映其沉积时的沉积环境为强还原性;粘土矿物组合特征及含量揭示这些生油岩的沉积相带介于中心咸湖相和边缘咸湖相之间。     

Improved understanding of petroleum migration history in the Hongche fault zone,northwestern Junggar Basin (northwest China): Constrained by vein-calcite fluid inclusions and trace elements

Calcite veins and cements occur widely in Carboniferous and Permian reservoirs of the Hongche fault zone, northwestern Junggar Basin in northwest China. The calcites were investigated by fluid inclusion and trace-element analyses, providing an improved understanding of the petroleum migration history. It is indicated that the Hongche fault behaved as a migration pathway before the Early Cretaceous, allowing two oil charges to migrate into the hanging-wall, fault-core and footwall reservoirs across the fault. Since the Late Cretaceous, the Hongche fault has been sealed. As a consequence, meteoric water flowed down only into the hanging-wall and fault-core reservoirs. The meteoric-water incursion is likely an important cause for degradation of reservoir oils. In contrast, the footwall reservoirs received gas charge (the third hydrocarbon event) following the Late Cretaceous. This helps explain the distribution of petroleum across the fault. This study provides an example of how a fault may evolve as pathway and seal over time, and how reservoir diagenetic minerals can provide clues to complex petroleum migration histories.     

Dissolved aluminium and the silicon cycle in the Arctic Ocean

Concentrations of dissolved (0.2 µm filtered) aluminium (Al) have been determined for the first time in the Eurasian part of the Arctic Ocean over the entire water column during expedition ARK XXII/2 aboard R.V. Polarstern (2007). An unprecedented number of 666 samples was analysed for 44 stations along 5 ocean transects. Dissolved Al in surface layer water (SLW) was very low, close to 1 nM, with lowest SLW concentrations towards the Canadian part of the Arctic Ocean and higher values adjacent to and in the shelf seas. The low SLW concentrations indicate no or little influence from aeolian dust input. Dissolved Al showed a nutrient-type increase with depth up to 28 nM, but large differences existed between the different deep Arctic basins. The differences in concentrations of Al between water masses and basins could largely be related to the different origins of the water masses. In the SLW and intermediate water layers, Atlantic and Pacific inflows were of importance. Deep shelf convection appeared to influence the Al distribution in the deep Eurasian Basin. The Al distribution of the deep Makarov Basin provides evidence for Eurasian Basin water inflow into the deep Makarov Basin. A strong correlation between Al and Silicon (Si) was observed in all basins. This correlation and the nutrient-like profile indicate a strong biological influence on the cycling and distribution of Al. The biological influence can be direct by the incorporation of Al in biogenic silica, indirect by preferential scavenging of Al onto biogenic siliceous particles, or by a combination of both processes. From the slope of the overall Al–Si relationship in the intermediate water layer (AIDW; ~ 200–2000 m depth), an Al/Si ratio of 2.2 atoms Al per 1000 atoms Si was derived. This ratio is consistent with the range of previously reported Al/Si uptake ratio in biogenic opal frustules of diatoms. In the deepest waters (>2000 m depth) a steeper slope of the Al–Si relationship of 7.4 to 13 atoms Al per 1000 atoms Si likely results from entrainment of cold shelf water into the deep basins, carrying the signal of dissolution of terrigenous particles with a much higher Al:Si ratio of crustal abundance. Only a small enrichment with such crustal Al and Si component may readily account for the higher Al:Si slope in the deepest waters.     

粤北新洲逆冲推覆断裂系统中断层岩的地球化学特征

粤北新洲逆冲推覆断裂系统由Ⅰ，Ⅱ，Ⅲ－Ⅳ级推覆断层带组成，断层带中形成一套复杂的断层岩系，断层岩中Ａｕ，Ｐｂ，Ｗ，Ｓｂ，Ｂｉ，Ｈｇ，普遍富集，由此引起不同程度的金矿化，分别形成石英碳酸盐糜棱岩型金矿，碎裂钠长石岩型金矿和石英脉型金矿，成矿时期为印支晚期到燕山期，通过系统的微量元素，同位素和流体包裹体研究表明，１级推覆断层带断层岩中的成矿物质主要来自下地壳或上地幔，ＩＩ级推覆断层带断层岩中的成矿物质     

Laboratory simulation of natural leaching processes of eastern USA oil shale

Raw and retorted spent oil shales from Kentucky, as well as soil and overburden materials, were subjected to laboratory and field leaching tests. Standard batch leaching tests grossly undervalue the amount of dissolved ions as measured in the field, being too brief to enable slow reactions of the mineral matrix, such as hydrolysis and oxidation of sulfides or reactions of acidic leachates with soluble components of the clays. Laboratory column tests, devised to closely simulate natural leaching processes, achieved concentration levels and elemental release patterns similar to those found in field tests. The column tests provide a reliable means to assess the leachability of metals in these materials.     

六合—仪征第三纪大陆碱性玄武岩微量元素地球化学

本文报道了六合-仪征第三纪大陆碱性玄武岩十八个样品的REE、Rb、Ba、Sr、Nb、Zr、Ni、Cr、V、Sc、Y、Ga、Zn、Cu等痕量元素含量,讨论了该岩套的成因及其地幔源区的特征。石榴石橄榄岩型地幔源区经较小程度部分熔融形成了基性原始岩浆;其后经过橄榄石和单斜辉石为主的结晶分异作用,演化后的岩浆喷出地表形成玄武岩套。本区碱性玄武岩的地幔源区曾受近期富集作用影响,具有富集LREE等不相容元素的特征。     

Trace elements in alluvia of the upper Vistula as indicators of palaeohydrology

In the Vistula valley near Góra, at the northern foreland of the Carpathians Mountains, there are young alluvia deposited in the historical period. These alluvia are difficult to date precisely because of the lack of organic interbedded material. In the Vistula drainage basin upstream of Góra since the second half of 18th century small centres of metal, textile, motor, and petrochemical industries have been developed. Concentrations of trace elements such as: Cr, Mn, Co, Ni, Cu, Zn, Cd, Pb, and of some macroelements were used as indicators of the age of different alluvial fills. The main part of the Vistula valley floor was built up by sediment accumulation before the development of industry but after the medieval phase of rural colonization of the Carpathians. Deposits filling the abandoned channels dissecting the valley floor have an increased content of some trace elements and deposits date from the second half of the 18th century, when the first foundries and blacksmith's shops were developed. A drastic increase of concentration of the most abundant trace elements in the youngest alluvial fill indicates that the fill dates from the last decade of rapid industrial development.     

Trace gas measurements during aircraft flights in the tropopause region over Europe and North Africa

During aircraft flights in May 1981 from Munich (40°N) to north of the Spitsbergen Islands (82°N) and to Monrovia, Liberia (6°N), air samples were obtained in the altitude range of 8 to 11 km and during the ascents and descents near the airports. These samples have been analyzed for the trace gas mixing ratios of CH₄, CO and N₂O. The results of these analyses are presented and discussed.The results provide new evidence of tropospheric-stratospheric exchange events in the vicinity of the subpolar and subtropical tropopause foldings and possibly show a case of transport of CO-enriched air in the upper troposphere above the North Atlantic Ocean.