Neoproterozoic Volhynia-Brest magmatic province in the western East European craton: Within-plate magmatism in an ancient suture zone     

A. A. Nosova  O. F. Kuz’menkova  N. V. Veretennikov  L. G. Petrova  L. K. Levsky 《Petrology》2008,16(2):105-135

The reasons for the isotopic and geochemical heterogeneity of magmatism of the Neoproterozoic large Volhynia-Brest igneous province (VBP) are considered. The province was formed at 550 Ma in response to the break up of the Rodinia supercontinent and extends along the western margin of the East European craton, being discordant to the Paleoproterozoic mobile zone that separates Sarmatia and Fennoscandia and the Mesoproterozoic Volhynia-Orsha aulacogen. The basalts of VBP show prominent spatiotemporal geochemical zoning. Based on petrographic, mineralogical, geochemical, and isotopic data, the following types of basalts can be distinguished: olivine-normative subalkaline basalts consisting of low-Ti (sLT, < 1.10–2.0 wt % TiO₂; ε_Nd(550) from ?6.6 to ?2.7) and medium-Ti (sMT, 2.0–3.0 wt % TiO₂, occasionally up to 3.6 wt % TiO₂; ε_Nd(550) from ?3.55 to + 0.6) varieties; normal quartz-normative basalts (tholeiites) including low-Ti (tLT, < 1.75–2.0 wt % TiO₂) and medium-to-high-Ti (tHT1, 2.0–3.6 wt % TiO₂, ε_Nd(550) from ?1.3 to + 1.0) varieties. The hypabyssal bodies are made up of subalkaline low-Ti olivine dolerites (LT, 1.2–1.5 wt % TiO₂; ε_Nd(550) = ?5.8) and subalkaline high-Ti olivine gabbrodolerites (HT2, 3.0–4.5 wt % TiO₂; ε_Nd(550) = ?2.5). Felsic rocks of VBP are classed as volcanic rocks of normal (andesidacites, dacites, and rhyodacites) and subalkaline (trachyrhyodacites) series with TiO₂ 0.72–0.77 wt% and ε_Nd(550) of ?12. The central part of VBP is underlain by a Paleoproterozoic domain formed by continent-arc accretion and contains widespread sills of HT2 dolerites and lavas of LT basalts; the northern part of the province is underlain by the juvenile Paleoproterozoic crust dominated by MT and HT1 basalts. MT and LT basalts underwent significant AFC-style upper crustal contamination. During their long residence in the upper crustal magmatic chambers, the basaltic melts fractionated and caused notable heating of the wall rocks and, correspondingly, nonmodal melting of the upper crustal protolith containing high-Rb phase (biotite), thus producing the most felsic rocks of the province. The basalts of VBP were derived from geochemically different sources: probably, the lithosphere and a deep-seated plume (PREMA type). The HT2 dolerites were generated mainly from a lithospheric source: by 3–4% melting of the geochemically enriched garnet lherzolite mantle. LT dolerites were obtained by partial melting of the modally metasomatized mantle containing volatile-bearing phases. The concepts of VBP formation were summarized in the model of three-stage plume-lithosphere interaction.  相似文献   

An operational multiscale system for hazards prediction, mapping, and response     

David P. Bacon  Nash’at N. Ahmad  Thomas J. Dunn  Michael C. Monteith  Ananthakrishna Sarma 《Natural Hazards》2008,44(3):317-327

By definition, a crisis is a situation that requires assistance to be managed. Hence, response to a crisis involves the merging of local and non-local emergency response personnel. In this situation, it is critical that each participant: (1) know the roles and responsibilities of each of the other participants; (2) know the capabilities of each of the participants; and (3) have a common basis for action. For many types of natural disasters, this entails having a common operational picture of the unfolding events, including detailed information on the weather, both current and forecasted, that may impact on either the emergency itself or on response activities. The Consequences Assessment Tool Set (CATS) is a comprehensive package of hazard prediction models and casualty and damage assessment tools that provides a linkage between a modeled or observed effect and the attendant consequences for populations, infrastructure, and resources, and, hence, provides the common operational picture for emergency response. The Operational Multiscale Environment model with Grid Adaptivity (OMEGA) is an atmospheric simulation system that links the latest methods in computational fluid dynamics and high-resolution gridding technologies with numerical weather prediction to provide specific weather analysis and forecast capability that can be merged into the geographic information system framework of CATS. This paper documents the problem of emergency response as an end-to-end system and presents the integrated CATS–OMEGA system as a prototype of such a system that has been used successfully in a number of different situations.  相似文献   

Urban consolidation and house prices: a case study of Melbourne 1990–2004     

Sun Sheng Han  Kevin O’Connor 《GeoJournal》2008,73(4):285-295

This paper explores the links between a strategic policy, urban consolidation, and house prices by examining the changes in the mix of housing and in house price for the period 1991–2004. We contend that urban consolidation could be seen as a source of additional supply, (which might be expected to be felt in lower prices and so contribute to a local policy objective) but also as a stimulus to demand (by developers who could bid up the price of lots where it was understood more housing could be built). Analyses were carried out at the metropolitan and sub-regional scales using correlation tests. The research finds very weak statistical connections, and concludes that this policy has not been associated with price changes.  相似文献   

Spatial variability in the primary productivity in the East China Sea and its adjacent waters   总被引：7，自引：0，他引：7  

T. Hama  K. H. Shin  N. Handa 《Journal of Oceanography》1997,53(1):41-51

Primary productivity in the East China Sea and its adjacent area was measured by the¹³C tracer method during winter, summer and fall in 1993 and 1994. The depth-integrated primary productivity in the Kuroshio Current ranged from 220 to 350 mgC m⁻²d⁻¹, and showed little seasonal variability. High primary productivity (above 570 mgC m⁻²d⁻¹) was measured at the center of the continental shelf throughout the observation period. The productivity at the station nearest to the Changjiang estuary exhibited a distinctive seasonal change from 68 to 1,500 mgC m⁻²d⁻¹. Depth-integrated primary productivity was 2.7 times higher in the shelf area than the rates at the Kuroshio Current. High chlorophyll-a specific productivity (mgC mgChl.-a⁻²d⁻¹) throughout the euphotic zone was mainly found in the shelf area rather than off-shelf area, probably due to higher nutrient availability and higher activity of phytoplankton at the subsurface layer in the shelf area.  相似文献   

Photochemical models of the atmosphere and their application in ozonosphere and climate studies: A review     

I. L. Karol’  A. A. Kiselev 《Izvestiya Atmospheric and Oceanic Physics》2006,42(1):1-31

This review is devoted to problems in the photochemical modeling of atmospheric processes. The physicochemical and mathematical foundations underlying the construction of photochemical models are described, a classification of the atmospheric reactions is presented, and the features of photochemical modeling are considered under various irradiance conditions for various atmospheric layers and geographical regions. Atmospheric processes that are important to photochemical models are discussed. Applications involving photochemical models are outlined. Some results are presented to illustrate the capabilities of photochemical models. Special attention is given to relatively recent directions in photochemical modeling, such as data assimilation and inverse problems. The review can be used by experts in areas related to atmospheric chemistry as a basic source of knowledge on the subject and for the development of photochemical modules for atmospheric models.  相似文献   

Depth distribution of radiolarians from the Chukchi and Beaufort Seas, western Arctic     

Takuya Itaki  Masashi Ito  Hisashi Narita  Naokazu Ahagon  Hideo Sakai 《Deep Sea Research Part I: Oceanographic Research Papers》2003,50(12):1507

The depth distributions of the radiolarian fauna in the Chukchi and Beaufort Seas, marginal seas of the western Arctic Ocean, were examined quantitatively in depth-stratified plankton tows from 4 or 5 intervals above 500 m and in surface sediments from various depths between 163 and 2907 m. The radiolarian assemblage from the water column in September 2000 was dominated by Amphimelissa setosa and followed by the Actinomma boreale/leptoderma group, Pseudodictyophimus gracilipes and Spongotrochus glacialis. These species are related to the Arctic Surface Water shallower than 150 m. This assemblage is similar to that in the Greenland Sea relating to the ice edge, but did not contain typical Pacific radiolarians in spite of the flow of water of Pacific origin in this region. The living depth of Ceratocyrtis historicosa was restricted to the relatively warm water between 300 and 500 m corresponding to the upper Arctic Intermediate Water (AIW) originating from the Atlantic Ocean. Radiolarian assemblages in the surface sediments are similar to those in the plankton tows, except for common Cycladophora davisiana in sediment samples below 500 m. C. davisiana is probably a deep-water species adapted to the lower AIW or the Canadian Basin Deep Water ventilated from the shelves.  相似文献   

Relationship between the depth of visibility of Secchi disk and biooptical characteristics of the Black-Sea waters     

V. I. Man’kovsky 《Physical Oceanography》2001,11(5):491-494

We present the parameters of empirical relationships between the depth of visibility of Secchi disk and optical and biological characteristics of the Black-Sea surface waters. Translated by Peter V. Malyshev and Dmitry V. Malyshev  相似文献   

Geological structure of the Curonian Spit (of the Baltic Sea) and its evolution history (revised)     

E. N. Badyukova  L. A. Zhindarev  S. A. Luk’yanova  G. D. Solov’eva 《Oceanology》2007,47(4):554-563

The origin and evolution history of the Curonian Spit in the Baltic Sea are discussed based on geological and geomorphologic data. Evidence of the correlation between the spit formation stages and the Holocene sea level oscillations is presented. The ledges of moraine basement and marine accumulative features formed a single barrier. Its subsequent transformation occurred under the influence of the wave-related lithodynamic and eolian processes.  相似文献   

Estimating the underwater light field from remote sensing of ocean color     

Cheng-Chien Liu  Richard L. Miller  Kendall L. Carder  Zhongping Lee  Eurico J. D’Sa  James E. Ivey 《Journal of Oceanography》2006,62(3):235-248

We present a new approach that incorporates two models to estimate the underwater light field from remote sensing of ocean color. The first employs a series of analytical, semi-analytical, and empirical algorithms to retrieve the spectrum of inherent optical properties (IOPs), including the absorption and the backscatter coefficients, from the spectrum of remote sensing reflectance. The second model computes the profile of photosynthetically available radiation E _0,PAR (z) for a vertically homogeneous water column using the information of the retrieved IOPs and the ambient optical environment. This computation is based on an improved look-up table technology that possesses high accuracy, comparable with the full solution of the radiative transfer equation, and meets the computational requirement of remote sensing application. This new approach was validated by in situ measurements and an extensive model-to-model comparison with a wide range of IOPs. We successfully mapped the compensation depth by applying this new approach to process the SeaWiFS imagery. This research suggests that E _0,PAR (z) can be obtained routinely from ocean-color data and may have significant implications for the estimation of global heat and carbon budget.  相似文献   

Diagnosis of the interaction of tropical cyclones     

M. I. Yaroshevich  L. Kh. Ingel’ 《Izvestiya Atmospheric and Oceanic Physics》2006,42(6):704-708

At present the mutual influence of tropical cyclones (TCs) has been investigated to a much lesser extent than the cyclones themselves. Most frequently, such investigations are restricted to the study of the influence of the interaction of two TCs on their motion. However, actually, the mutual influence of TCs is much more diverse. For example, each cyclone alters the state of the medium (in particular, decreases the heat store of the upper ocean layer), i.e., affects the subsequent cyclones. Under conditions of a limited energy resource of the medium, cyclones, existing simultaneously, “compete,” to a degree, with each other. These and other similar circumstances have made it practical to consider tropical cyclones and the environment as interdependent elements of a complex open system. This study considers two versions of nonlinear models describing the interaction of TCs with the upper ocean layer and with one another similarly to a number of well-known and verified models of synergetics (interaction of populations, dynamics of optical quantum generators). It is shown that the models reproduce some very important qualitative features of the evolution of TC intensity.  相似文献