INITIAL SEDIMENTATION OF WASTE PARTICLES DISCHARGED IN COASTAL WATERS

Based on a puff model . and together with the consideration of convection , dispersion and descent of suspended waste particles in marine environment , a numerical model is presented to predict the initial sedimentation of waste particles discharged from ocean outfalls in coastal waters and to compute the stable sedimentation rate in homogeneous trde current fields with water depth constant . When the time step selected is small enough , the results from this model agree well with that from the semi-analytical solution , and have sufficient precision for evaluating the impact on the environment caused by sedimentation of waste particles discharged from ocean outfalls. A numerical example is given for predicting the sedimentation of waste particles discharged in Heishijiao , Dalian .     

The carbohydrates in relation to mineralogic and granulometric composition of surface sediments in the karst estuary (River Krka estuary,Yugoslavia)

The investigation of mineral, granulometric and chemical composition of sediments of the River Krka estuary (Yugoslavia) were performed in order to elucidate the origin of the sediments and the pattern of sedimentation. Estuarine surface sediments were found to be fine-grained with a bimodal distribution. Environmental conditions in estuarine sediments favour conservation of the organic matter (anoxic conditions). The carbohydrates in the sediments were investigated to determine whether they are of terrigenous or authigenous origin. Glucose, galactose, mannose, xylose, rhamnose, glucosamine and glucuronic acid were detected in the sediments. Their mutual relationship indicates a preferentially terrigenous source of sedimented organic material in estuarine sediments.     

Techniques to measure grain-size distributions of loamy sediments: a comparative study of ten instruments for wet analysis

Ten instruments for measuring the grain‐size distribution of loamy sediments in water were tested in a comparative study. Instruments tested were: the Malvern Mastersizer S, the Coulter LS 200, the Fritsch Analysette 22 (version C), the Horiba Partica LA‐950, the Sedigraph 5100, the Atterberg cylinder, the Coulter Multisizer 3, the CIS‐100, the EyeTech and the image analysis software Histolab. The first four instruments use laser diffraction. The Sedigraph and Atterberg cylinder are based on sedimentation. The Coulter Multisizer 3 uses impedance measurements and the last three instruments use optical techniques. Grain‐size analyses were carried out on four sediments with median grain diameters of approximately 35, 30, 12 and 9 μm, respectively, and with no particles >90 μm. The laser diffraction instruments produced the best results for the various criteria considered in this study, followed by the Coulter Multisizer 3 (electrical sensing zone technique), the sedimentation techniques and the optical methods. However, the study also showed that there is no such thing as an ‘ideal’ method because techniques may score differently according to the criterion tested. An appropriate evaluation thus requires that various criteria be considered. Issues to be taken into account are: type of sediment, quantity of sediment available, speed of measurement, complexity of the measurement protocol, processing of the data, reproducibility of the results and the specific aims of the study undertaken.     

U–Pb SHRIMP zircon geochronology and T–t–d history of the Kampa Dome, southern Tibet

Structural, petrographic and geochronologic studies of the Kampa Dome provide insights into the tectonothermal evolution of orogenic crust exposed in the North Himalayan gneiss domes of southern Tibet. U–Pb ion microprobe dating of zircons from granite gneiss exposed at the deepest levels within the dome yields concordia ²⁰⁶Pb/²³⁸U age populations of 506 ± 3 Ma and 527 ± 6 Ma, with no evidence of new zircon growth during Himalayan orogenesis. However, the granite contains penetrative deformation fabrics that are also preserved in the overlying Paleozoic strata, implying that the Kampa granite is a Cambrian pluton that was strongly deformed and metamorphosed during Himalayan orogenesis. Zircons from deformed leucogranite sills that cross-cut Paleozoic metasedimentary rocks yield concordant Cambrian ages from oscillatory zoned cores and discordant ages ranging from ca. 491–32 Ma in metamict grains. Since these leucogranites clearly post-date the metasedimentary rocks they intrude, the zircons are interpreted as xenocrysts that are probably derived from the Kampa granite. The Kampa Dome formed via a series of progressive orogenic events including regional ~ N–S contraction and related crustal thickening (D₁), predominately top-to-N ductile shearing and crustal extension (D₂), top-to-N brittle–ductile faulting and related folding on the north limb of the dome, localized top-to-S faulting on the southern limb of the dome, and crustal doming (D₃), and continued N–S contraction, E–W extension and doming (D₄). Structural and geochronologic variability amongst adjacent North Himalayan gneiss domes may reflect changes in the magnitude of crustal exhumation along the North Himalayan antiform, possibly relating to differences in the mid-crustal geometry of the exhuming fault systems.     

Anthropogenic affects on lake sedimentation process: a case study from Lake Sapanca, NW Turkey

Lake Sapanca in NW Turkey is a fault originated freshwater basin fed by seasonally variable flows of 15 streams. Considerations of lake–river interaction, supported by statistical measures of 47 bottom samples, suggest that sediment transport and deposition within the lake is controlled by two types of human constructed structures in addition to natural factors: (1) the dykes constructed in the front of streams, which feed the lake by strong flows, to prevent the filling of lakebed by coarse-grained sediments; (2) the constructed regulator on the outflowing Çarksuyu stream results in a higher sedimentation rate of clay-sized material on the NE corner of the lake, which is extraordinary in the shelf environment.     

Sedimentation settings of the Vendian Vanavara formation,the Siberian platform

A model of sedimentation settings is elaborated for siliciclastic deposits of the Vendian Vanavara Formation, the Katanga saddle, inner areas of the Siberian platform. Four lithologic complexes are distinguished in the formation. The lower complex is composed of proluvial continental deposits exemplifying a dejection cone of ephemeral streams. Its eroded surface is overlain by second complex largely represented by sandstones of coastal zone, which grade upward into siltstones and shales of deeper sedimentation settings (third complex). Sea transgression advanced in northeastern direction. The fourth complex resting with scouring on the third one was deposited in settings of a spacious shallow-water sea zone: in a tidal flat, sand shoals and islands. Sedimentological data are used to correlate more precisely the Vendian siliciclastic deposits of the Katanga saddle and northeastern Nepa-Botuoba anteclise, and to verify subdivision of the Vanavara Formation into subformations and character of its boundary with the overlying Oskoba Formation.     

Pelagic-Benthic Coupling in the Nordic Seas: The Role of Episodic Events

Abstract. The consequences of the following episodic phenomena for the pelagic-benthic coupling in the Nordic Seas are illustrated: (1) Advection of water masses between fjords and shelf environments, (2) freshwater run-off and vertical stability, (3) dynamics of the marginal ice zone in the central and northern Barents Sea and the Polar Ocean, (4) drift patterns of sinking particles along the North Norwegian coast, (5) advection of zooplankton into subarctic fjords and the southern Barents Sea, zooplankton overwintering and composition, and (6) transport of organic particulate matter from the Barents Sea shelf. It is shown that physical processes in the north-eastern North Atlantic and Polar Ocean can be strongly variable on time scales of days to decades. They have a significant influence on the dynamics of pelagic-benthic coupling. The physical oceanography influences the vertical and horizontal particle flux not only directly (mixing, advection, up- and down-welling), but also indirectly through its impact on the biota (for example radiation, wind, ice cover, freshwater run-off and overwintering, advection and retention of zooplankton). Understanding pelagic-benthic coupling at high latitudes depends even more on a best possible understanding of the physical oceanography and the time scales involved than elsewhere.     

台湾海峡纽形动物初报

首次报道台湾海峡产的纽形动物，包括沙栖原细首纽虫、浮游拟脑纽虫、椒状岩田纽虫、中华平裂纽虫和马顿氏潘丁纽虫，共５种。除椒状岩田纽虫在琉球群岛有报道外，均为东海新记录。     

Images of the seabed in the Faroe-Shetland Channel from commercial 3D seismic data

A large number of 3D deep seismic surveys in the Faroe-Shetland Channel gives continuous coverage over most of the region. These surveys were designed primarily to image depths in excess of 4 km, use low frequency sources and are recorded at low temporal sample rates. However, commercial 3D data can generate highly detailed images of the seabed due to the high spatial sample rate, typically 12.5 m. This is particularly true in waters below 200 m. Despite geophysical artefacts, the images reveal that there are a number of sedimentary processes at work adjacent to and within this channel. On the West Shetland Shelf, iceberg scouring and moraines reflect the impact of glaciation. On the West Shetland slope there is clear evidence for down-slope processes, such as debris flows, linear erosion channels, basal fans and (one case) slope failure. Along-slope processes are also active as indicated by the presence of sediment waves and contourite mounds. On the floor of the basin, polygonal cracking can be observed. The most spectacular feature appears to be the Judd Deeps, a system of cliffs approximately 200 m high and 40 km across. Traditionally, seabed investigation has been performed using high-resolution surveys. This study shows that deep exploration data can also provide useful images of the seafloor.     

Siltation Prediction for Navigation Channels and Harbour Basins on Muddy Beach

- This paper, after briefly reviewing the experimental research on sediment transport on muddy beach since the 1950s, improves and perfects the method for forecasting siltation in navigation channels and harbour basins which was first put forward in China by the authors. In consideration of silty sediment and sand, some factors in forecasting methods have been changed and modified. Consequently, the modified methods can be used either to compute siltation in navigation channels and harbour basins on muddy beach or to compute siltation and scouring in navigation channels and harbour basins on both silty beach and sandy beach. The verification of field data from eleven large, medium and small natural harbours shows a good agreement between the forecasting by the modified method and the natural conditions. Finally, the paper deals with the rational utilization of water area after the construction of the West Dyke in Lianyungang, the maintenance of water depth of the navigation channel at the entrance, siltation distribution, siltation in the navigation channel and harbour basin for ships of 100 thousand tonnnage. Results once again prove that the prospect of constructing Lianyungang Harbour into a deepwater harbour is bright.