Spatial and temporal variability of hard-bottom macrofauna in a disturbed coastal lagoon (Sacca di Goro, Po River Delta, Northwestern Adriatic Sea)

The sessile and mobile macrobenthos on artificial hard bottoms was studied in 12 stations of the Sacca di Goro lagoon, a brackish, highly stressed water basin in the delta of the river Po, open to the Northwestern Adriatic Sea. Three sampling surveys were carried out in June and September 2000 and June 2001 in order to make three types of temporal comparisons: (i) on a seasonal scale, before and after a summer dystrophic event; (ii) on an annual basis, before and after the works of excavation of a canal through the outer sand bank; (iii) on a multiannual scale, comparing the data with those of a survey carried out in 1988. The biocoenoses did not show large fluctuations after a moderately severe summer dystrophic crisis, while the digging of the canal caused clear changes in the macrobenthos community structure after one year. The long-term comparison showed a shift in the community patterns after a decade.     

加拿大铁建造中的金含量及地球化学

引言大约在一个世纪以前人们就在世界范围内发现了金矿床和铁建造具有共同伴生组合关系。金矿床中金的来源有同生的,也有后生的。在加拿大除了由砂矿床转变而来的金矿外,大多数金矿产在岩脉、剪切带和破碎带里。可见在金矿的沉淀过程中构造因素是十分重要的。铁建造是原来的化学沉积物,它一方面作为同生金的来源,另一方面,这些硬而脆的燧石质岩石又为矿脉的形成提供了一个有利的环境。岩石的构造控制了金的     

Sources of salinity in ground water from Jericho area, Jordan Valley

One of the major problems in the lower Jordan Valley is the increasing salinization (i.e., chloride content) of local ground water. The high levels of salinity limit the utilization of ground water for both domestic and agriculture applications. This joint collaborative study evaluates the sources and mechanisms for salinization in the Jericho area. We employ diagnostic geochemical fingerprinting methods to trace the potential sources of the salinity in (1) the deep confined subaquifer system (K2) of Lower Cenomanian age; (2) the upper subaquifer system (K1) of Upper Cenomanian and Turonian ages; and (3) the shallow aquifer system (Q) of Plio-Pleistocene ages. The chemical composition of the saline ground water from the two Cenomanian subaquifers (K1 and K2) point to a single saline source with Na/Cl approximately 0.5 and Br/Cl approximately 7 x 10(-3). This composition is similar to that of thermal hypersaline spring that are found along the western shore of the Dead Sea (e.g., En Gedi thermal spring). We suggest that the increasing salinity in both K1 and K2 subaquifers is derived from mixing with deep-seated brines that flow through the Rift fault system. The salinization rate depends on the discharge volume of the fresh meteoric water in the Cenomanian Aquifer. In contrast, the chemical composition of ground water from the Plio-Pleistocene Aquifer shows a wide range of Cl- (100-2000 mg/L), Na/Cl (0.4-1.0), Br/Cl (2-6 x 10(-3)), and SO4/Cl (0.01-0.4) ratios. These variations, together with the high SO4(2-), K+, and NO3- concentrations, suggest that the salinity in the shallow aquifer is derived from the combination of (1) upconing of deep brines as reflected by low Na/Cl and high Br/Cl ratios; (2) leaching of salts from the Lisan Formation within the Plio-Pleistocene Aquifer, as suggested by the high SO4(2-) concentrations; and (3) anthropogenic contamination of agriculture return flow and sewage effluents with distinctive high K+ (80 mg/L) and NO3- (80 mg/l) contents and low Br/Cl ratios (2 x 10(-3)). Our data demonstrates that the chemical composition of salinized ground water can be used to delineate the sources of salinity and hence to establish the conceptual model for explaining salinization processes.     

新疆垦区碱化土和苏打化土的改良

据不完全统计,垦区碱化土和苏打化土共有三千余万亩。碱化土集中分布在准噶尔盆地南部的古老冲积平原上,以下野地和莫索湾垦区南部面积最大,奇台、五家渠垦区和南疆的焉耆盆地、塔里木河和阿克苏河灌区,中昆仑山北麓平原,也有小面积的分布。苏打化土集中分布在阿勒泰、哈密、焉耆和库尔勒垦区,以及昆仑山北麓的平原地区。     

A procedure for identifying significant environmental aspects in sea ports

A new methodology has been designed to identify and rank the significant environmental aspects in sea ports. The main objective of the Strategic Overview of Significant Environmental Aspects (SOSEA) is to help port managers to identify significant environmental aspects and to reinforce the awareness about them in order to prioritise work in environmental management. Developed in close collaboration with port environmental managers and tested in a set of ports, it is a user-friendly tool that can be applied in approximately half a working day. It is based on ISO 14001 vocabulary and requirements and it can be considered as the base for the implementation of any Environmental Management System for port communities.     

熊耳群的金矿控矿构造及其大地构造背景

熊耳群目前已成为一重要的含金地层，金矿床类型多样，包括构造蚀变岩型、煤破角砾岩型、石英脉型和铅－金矿型，各种类型金矿床均与构造有密切关系。     

Petrogenesis and geotectonic setting of the PanAfrican basement rocks in Bamenda Massif, Obudu Plateau, southeastern Nigeria： Evidence from trace element geochemistry

1 IntroductionThe study area is part of the Obudu Plateau,which forms part of the Precambrian Pan-African tec-tonothermal belt, lying between the West African Cra-ton and the Gabon-Congo Craton ( Fig. 1). It isbounded by the Benue Trough, in the NE-SW axi…