Applying an Integrated System for Ground to Space Monitoring of Anthropogenic Impacts on Coastal Waters of the Black Sea

Izvestiya, Atmospheric and Oceanic Physics - The authors describe features and the operation of an integrated ground to space monitoring system for studying anthropogenic effects on coastal waters...     

Cepheid Limb Darkening Models for the VLTI

We present a new method to compute wavelength- and phase-dependent limb darkening corrections for classical Cepheids. These corrections are derived from hydrodynamic simulations and radiative transfer modeling with a full set of atomic and molecular opacities. Comparison with hydrostatic models having the same stellar parameters show a larger limb darkening for most phases in our models, and temporal variations related to the hydrodynamics of the stellar pulsation. Weassess the implications of our results with respect to the geometric Baade-Wesselink method, which uses interferometric measurements of Cepheid angular diameters to determine their distances and radii. The relevance of the hydrodynamic effects predicted by our model on the limb darkening of pulsating Cepheids is finally discussed in terms of the predicted capabilities of the VLTI. This revised version was published online in July 2006 with corrections to the Cover Date.     

Contemporary versus long‐term denudation along a passive plate margin: the role of extreme events

Short‐term (contemporary) and long‐term denudation rates were determined for the Blue Mountains Plateau in the western Sydney Basin, Australia, to explore the role of extreme events (wildfires and catastrophic floods) in landscape denudation along a passive plate margin. Contemporary denudation rates were reconstructed using 40 years of river sediment load data from the Nattai catchment in the south‐west of the basin, combined with an analysis of hillslope erosion following recent wildfires. Long‐term denudation rates (10 kyr–10 Myr) were determined from terrestrial cosmogenic nuclides, apatite fission track thermochronology and post‐basalt flow valley incision. Contemporary denudation rates average several times lower than the long‐term average (5·5 ± 4 mm kyr^?1 versus 21·5 ± 7 mm kyr^?1). Erosion of sediment following wildfires accounts for only a small proportion (5%) of the contemporary rate. Most post‐fire sediment is stored on the lower slopes and valley floor, with the amount transported to the river network dependent on rainfall–run‐off conditions within the first few years following the fire. Historical catastrophic floods account for a much larger proportion (35%) of the contemporary erosion rate, and highlight the importance of these events in reworking stored material. Evidence for palaeofloods much larger than those experienced over the past 200 years suggests even greater sediment export potential. Mass movement on hillslopes along valleys incised into softer lithology appears to be a dominant erosion process that supplies substantial volumes of material to the valley floor. It is possible that a combination of infrequent mass movement events and high fluvial discharge could account for a significant proportion of the discrepancy between the contemporary and long‐term denudation rates. Copyright © 2006 John Wiley & Sons, Ltd.     

The Volch’etundrovsky Massif of the autonomous anorthosite complex of the Main Range, the Kola Peninsula: Geological, petrogeochemical, and isotope-geochronological studies

The Volch??etundrovsky Massif occupies the middle part of the autonomous anorthosite complex of the Main Range, has a sheet morphology and marks the tectonic suture between the Kola block and the Belomorian mobile belt. The massif is characterized by homogenous structure and consists of the volumetrically dominant Main Zone including leucogabbro, leucogabbronorites, and anorthosites, and Marginal Zone made up of leuconorites and gabbronorites with subordinate plagioclasites and orthopyroxenites. Chemically, the rocks of the Volch??etundrovsky Massif are ascribed to the normal (tholeiitic and calc-alkaline) petrochemical series with typomorphic high Al₂O₃ contents (11.71?C29.32 wt %). With Al₂O₃ increase in the leuconorite-anorthosite series, the SiO₂ and TiO₂ contents show weak variations, CaO and alkalis insignificantly increase, whereas the MgO and FeO contents sharply decrease. The rocks of the Volch??etundrovsky Massif reveal significant REE fractionation and increase in total REE content in the leuconorite-anorthosite series, most approximating the Paleoproterozoic (Sumian) anorthosites of the Kola region. The anorthosites and leucogabbro are characterized by flat HREE, while the leuconorites is strongly depleted in HREE due to garnet fractionation. All rocks of the massif have significant positive Eu anomalies caused by the plagioclase accumulation. Zircons are characterized by LREE depletion and enrichment in HREE. This defines the steep positive slope of the plots complicated by the negative Eu and positive Ce (in zircons from leucogabbro) anomalies, which is typical of the REE distribution patterns in the unaltered zircons from igneous rocks. In zircons from anorthosites, the Ce anomaly is weak to absent. The trace-element distribution in the rocks of the Volch??etundrovsky Massif show positive Ba, Ta, Pb, Sr, Sc, and V anomalies, being controlled by the mineral specifics of the massif and the presence of definite accessory minerals. New U-Pb zircon data on the rocks of the Volch??etundrovsky Massif indicate that the leuconorites from the Marginal Zone were formed 2473 ± 7 Ma and 2463 ± 2.4 Ma ago, and the leucogabbro from the Main Zone, 2467 ± 8 Ma. These rocks have negative ?_Nd(T) from -1.54 up to -3.10, which indicates their derivation from enriched mantle reservoir variably contaminated by crustal material. The anorthosites of the Main Zone define an U-Pb age of 2407 ± 3 Ma and ?_Nd(T) = ?3.78, which presumably reflect the timing of hydrothermal-metasomatic alterations in the upper part of the magmatic chamber accompanied by significant crustal contamination.     

Sapphirine-Bearing Ultrahigh-Temperature Granulites of the Anabar Shield: Chemical Composition,U–Pb Zircon Ages,and <Emphasis Type="Italic">P</Emphasis>–<Emphasis Type="Italic">T</Emphasis> Conditions of Metamorphism

The results of thermobarometry yielded the P–T parameters of formation and evolution of sapphirine- bearing granulites in the Anabar shield with peak values of UHT metamorphism in the range of T = 920–1000°C at P = 9–11 kbar. Isotope–geochronological data indicate a polymetamorphic evolution of these rocks. Detrital zircon cores in the center of crystals yielded ages of 3.36, 2.75, 2.6, and 2.5 Ga. Later, superimposed metamorphic transformations of the detrital zircon formed rims dated to 2.4, 2.3, 2.2, and 1.83 Ga. A potential provenance source of the detrital zircons could be hypersthene plagiogneisses and metabasics of the Daldyn Group with a premetamorphic age no less than 3.32 Ga and products of their metamorphism of about 2.7 Ga old.     

Evolution of the Processes of Mineral Formation in Early Vendian Terrigenous Rocks of the Nepa–Botuoba Anteclise

Lithology and Mineral Resources - Main regularities in the manifestation of epigenetic processes in Lower Vendian terrigenous rocks of the Nepa–Botuoba anteclise are established. Evolution of...     

Stress and deformation of offshore piles under structural and wave loading

Various offshore structures, especially large structures such as Tension Leg Platforms (TLP), are usually supported by concrete piles as the foundation elements. The stress distribution within such a large structure is a dominant factor in the design procedure of an offshore pile. To provide a more accurate and effective design for offshore foundation systems under axial and lateral wave loads, a finite element model is employed herein to determine the stresses and displacements in a concrete pile under similar loading conditions. A parametric study is also performed to examine the effects of the stress distribution due to the changing loading conditions.     

Cadmium in Mytilus spp.: Worldwide survey and relationship between seawater and mussel content

A worldwide literature survey of data on cadmium concentration in the soft tissue of the mussel, Mytilus spp., from 591 stations is presented. These stations are from 13 regions. Geometric means for the regions vary from 0·6 to 3·3 μg g⁻¹ (dry weight) for the Barents Sea and the Northeastern Pacific coast, respectively.The averages of seven of these regions, for which reliable cadmium concentrations in seawater were available, were used to calculate a relationship between cadmium concentrations in seawater and mussel soft tissue. The relationship was highly significant: (Cd) mussel (μg g⁻¹, dry weight) = 0·074 (Cd) water (ng litre⁻¹) + 0·39 (P ≤ 0·0005).This model has been successfully applied in the context of the contamination of the Gironde estuary (France). It can also be used to define a water quality criterion for mussel maturing parks consistent with the quality criterion defined for shellfish for human consumption.     

Bacterial sulphate reduction in sediments of a european salt marsh: Acid-volatile and tin-reducible products

The products of ³⁵S-sulphate reduction by sedimentary bacteria were measured at two sites in a salt marsh on the east coast of England. Non-acid-volatile products were measured, after acid-volatile sulphide was removed, by their reduction to sulphide by digestion with tin. The proportion of the sulphate reduced to tin-reducible products varied between 25% in a salt marsh pan and 61% in creek sediment, over a 0–25 cm depth profile. There were also variations with depth at each site in the proportions of sulphate reduced to tin-reducible products. Further examination revealed differences in the proportions of sulphate which were reduced to free sulphide, acid-volatile sulphide, sulphur or pyrite at the two sites. The data suggest that previous work which did not measure non-acid-volatile products underestimated sulphate reduction rates by three-fold in the creek site, but by only one third in the pan.