Evidence for sinistral strike-slip deformation in The Solomon Island arc

During the SOPACMAPS 2 crusie carried out by IFREMER (Institut Français de Recherche pour l'Exploitation de la Mer) and ORSTOM (Institut Français de Recherche Scientifique pour le dévelopement en Coopération) on theR/V L'Atalante, in the Central Solomon Arc area, multibeam bathymetric and imagery data and single-channel seismic reflection profiles were collected from an area of about 3500 km², to evaluate regional tectonics. Structural data geophysical profiles interpretation provide evidence for left-lateral transtensional tectonics on the southern edge of the Central Solomon Trough. This transtensional deformation is represented by faulting, block tilting, and rhombohedral deformation. The regional geology and the analysis of the sedimentary cover allow us to demonstrate that this tectonic occurred in two different phases during Oligocene to Miocene and Pliocene to Pleistocene times.     

Formation and distribution of manganese nodule deposit in the northwestern margin of Clarion-Clipperton fracture zones,northeast equatorial Pacific

In the northwestern margin of the Clarion and Clipperton fracture zones, manganese nodules are latitudinally variable in character, resulting from the progressive (re)generation of nodules since the Oligocene as the Pacific Plate migrates northwestward beneath the equatorial production zone. Complemented by the surface water productivity, bottom current activities have concentrated nodules in the Oligocene to Miocene siliceous clay. Resedimentation processes on nodules form three types of nodules with concentric structures and 10 Å-manganaterich bottoms, by periodically causing the diagenetic growth of nodules within the topmost sediment layer.     

Numerical modelling of tsunami propagation in the open Black Sea

This paper focuses on the numerical modelling of tsunami propagation in the open Black Sea. Two types of numerical models are discussed: a model for the radial propagation of long waves and an evolutionary finite-difference prognostic model. Experimentally derived numerical data on the model source of tsunamis are reported. Translated by Vladimir A. Puchkin.     

Depth and Seasonal Distribution of Some Groups of the Vagile Fauna of the Posidonia oceanica Leaf Stratum: Structural and Trophic Analyses

Abstract. The taxonomical and trophic structures of the vagile fauna communities of the leaf stratum in a Posidonia oceanica meadow at Ischia (Gulf of Naples, Italy) were investigated at five stations along a depth gradient (1 to 25 m). Sampling was performed in July, November, February, and May. The analyzed groups - polychaetes, molluscs, tanaids, isopods, amphipods, and decapods - exhibited similar distributional trends in all seasons, with coenotic discontinuities occurring at well-defined depths. The same zonation pattern was produced by feeding-guild analysis. Eleven trophic groups were identified. The most abundant groups were: Herbivores, which were found mainly at the shallow stations; Herbivores-deposit feeders, which were widely distributed along the transect; Deposit feeders-carnivores, found mainly at the deep stations.
This study suggests that in the Posidonia leaf stratum, herbivores and herbivores-deposit feeders, as consumers of epiphytic micro- and macroflora and deposited particulate organic matter, play an important role in the energy transfer from producers to higher trophic levels of the system.     

The role of organic coatings in the enrichment of marine particles with selenium. The fixation of selenite on an adsorbed amino acid

The enrichment of marine particles with selenium cannot be explained as that with metals present in cationic form by complexation with anionic functional groups of adsorbed organic matter. Physicochemical data obtained using a model system are reported. The surface of the particles is modelized by a mercury electrode whose surface charge density can be easily changed, covered by a layer of adsorbed polymers. Studies with different kinds of macromolecules and salts show a specific interaction between adsorbed polyalanine and selenite. The results can be explained by the concordance of the distances between two oxygen atoms in this oxyanion and between two amine groups of the adsorbed polypeptide. A similar mechanism could occur in marine aggregates whatever their nature, as long as they contain amine groups at their surface which result in this concordance. Some prospects derived from the results are discussed.     

塞曼石墨炉原子吸收法直接测定海水中的铬

海水基体对Cr有增感作用。本文研究了抗坏血酸、柠檬酸三铵、酒石酸、乙酸铵等有机基体改进剂对消除基体干扰效果。前二者均有效地消除基体干扰,但1％抗坏血酸 1％柠檬酸三铵混合试剂的效果更好,它不仅可以消除基体干扰,还可降低背景及噪声,Cr的吸收峰也较平滑。本法准确,相对偏差在0.7—4.4％范围内。回收率在92—109％范围内。若海水Cr含量低于定量下限时,可采用多次进样法。     

A study on sample pretreatment of analysis of Cd, Pb and Zn in seawater by IDMS

Isotope dilution mass spectrometry (IDMS) and ultra-clean room approach are successfully used in the determination of Cd, Pb and Zn in seawater and the sample pretreatment of analysis. The precision in the determination of Cd, Pb and Zn in seawater is better than±3% and the limits of detection are 6×10-12, 6×10-11 and 2.4×10-10 respectively. The effects of sample pretreatment such as filtration and acidification on the results of determination of Cd- Pb and Zn in seawater are disscussed.     

Mediterranean outflow through the Strait of Gibraltar since 18,000 Years B.P.: Mineralogical and geochemical arguments

Data obtained from mineralogical and geochemical analyses of piston and gravity cores, recovered from an area off Lisbon (Portugal) to the Alboran Sea (Mediterranean), serve as a basis for better understanding the past 18,000 years of hydrological exchanges at Gibraltar. Tracers used in this study are smectite, kaolinite, Ta, Th, La. One of the primary sources of particles both into and out of the Mediterranean is the Guadalquivir River. These particles are transported back into the Atlantic in the Mediterranean outflow water, and deposited along the Iberian slope. No evidence for reversal of this outflow current was found in those cores, since 18,000 years B.P.     

长期非平稳荷载调谐质量减振阻尼器优化设计

研究外荷载为长期非平稳随机过程。考虑长期荷载的特性 ,采用 1个概率谱密度函数来反映长期非平稳随机荷载及其特征 ;概率谱密度函数是基于大量的一般谱密度函数的统计特性获得。以延长结构的抗疲劳使用寿命为目标函数 ,提出了调谐质量减振阻尼器的优化设计方法 ,这在实际工程中有着极为广阔的应用前景。本文旨在从理论上发展长期非平稳随机荷载作用下调谐质量减振阻尼器的优化设计方法 ;文中采用长期波浪实测数据 ,给出了 1个数值算例说明整个设计过程。