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121.
Evaluating coastal scenery using fuzzy logic: Application at selected sites in Western Black Sea coastal region of Turkey 总被引:1,自引:0,他引:1
Coastal areas of the world are under treat due to the conflicting requirements of functions such as habitation and/or recreation, which affect the strategic asset of coastal scenery itself. Coastal managers, together with planners, need coastal landscape inventories, where the quality of coastal scenery is a part of the inventory. In order to provide an evidence-based approach for sound coastal management decisions,
[Ergin et al., 2004] and [Ergin et al., 2006] developed a novel technique ‘coastal scenic evaluation’ (CSE), which addresses the evaluation of coastal scenery. The CSE technique utilizes fuzzy logic to derive values obtained from a checklist of 26 physical and human parameters. The methodology enables the calculation of an evaluation index (D), which categorizes the scenic values of coastal sites into five distinct classes. Using this technique, coastal scenic evaluations were carried out at 34 selected sites on the Western Black Sea coast of Turkey. Based on the calculated D values, a five-class differentiation was obtained for the selected sites, to provide baseline information for any envisaged subsequent management plans for these areas. 相似文献
122.
Collin?BezroukEmail authorView authors OrcID profile Jeffrey?S.?Parker 《Astrophysics and Space Science》2017,362(9):176
This work studies the evolution of several Distant Retrograde Orbits (DROs) of varying size in the Earth-Moon system over durations up to tens of millennia. This analysis is relevant for missions requiring a completely hands off, long duration quarantine orbit, such as a Mars Sample Return mission or the Asteroid Redirect Mission. Four DROs are selected from four stable size regions and are propagated for up to 30,000 years with an integrator that uses extended precision arithmetic techniques and a high fidelity dynamical model. The evolution of the orbit’s size, shape, orientation, period, out-of-plane amplitude, and Jacobi constant are tracked. It has been found that small DROs, with minor axis amplitudes of approximately 45,000 km or less decay in size and period largely due to the Moon’s solid tides. Larger DROs (62,000 km and up) are more influenced by the gravity of bodies external to the Earth-Moon system, and remain bound to the Moon for significantly less time. 相似文献
123.
Impacts of mariculture practices on the temporal distribution of macrobenthos in Sandu Bay,South China 总被引:3,自引:0,他引:3
周进 《中国海洋湖沼学报》2012,30(3):388-396
Sandu Bay is located in the East China Sea and is characterized by high-density fish farming and kelp culture. Despite this, little is known about the impacts of these different mariculture practices on the local environment. We investigated the temporal variation in macrobenthos and environmental conditions at three sites in the bay (fish farming site, kelp culture site, and a control site). We collected water and sediment samples during nine cruises between May 2009 and February 2010. The density of macrobenthos peaked at the fish farming site in July (655 ind./m2) whereas density did not fluctuate as widely at the other two sites. Biomass varied significantly at both the control and kelp culture sites, but had only a single peak at the fish farming site in June (21.90 g/m2). The dominant species varied throughout the study period at the control and kelp culture sites, whereas a single terebellid species (Lysilla pacifica) dominated the macrobenthos at the fish farming site. The diversity index H’ increased at the control site beginning in February then decreased after May, whereas H’ was low at the other sites in December. The mean dissolved oxygen level was highest at the control site (6.59 mg/L) and lowest at the fish farming site (5.54 mg/L). DO levels were lowest at all sites in summer (July and August). The sediment acid volatile sulfide content was higher at the fish farming site (1.46 mg/g dry weight) than those at the kelp culture and control sites (1.22 and 0.14 mg/g, respectively). Our results suggest that mariculture practices have a clear impact on the benthic environment/ community in Sandu Bay. 相似文献
124.
Pigment characterization for the 2011 bloom in Qinhuangdao implicated "brown tide" events in China 总被引:6,自引:0,他引:6
A large-scale bloom occurred from May to June in 2011 in sea area near Qinhuangdao of the Bohai Sea, leading to huge damage of the scallop culture industry. Similar blooms have been observed in this region for three years. The causative species of the bloom, which dominated the phytoplankton community with the maximum cell density around 109 cell/L, could not be identified with morphological features due to the small cell size (~2 mm). A pigment analytical method was then adopted to analyze the pigment profile of the phytoplankton samples collected from the blooming sea area. It was found that pico-sized (<2 mm), nano-sized (2-20 mm), and bulk phytoplankton samples had similar pigment profile, representing the pigment signature of the bloom-causative species. The major pigments detected included 19-butanoyloxyfucoxanthin (But-fuco), fucoxanthin (Fuco), diadinoxanthin (Diad) and chlorophyll a (Chl a), and high content of But-fuco was the most significant characteristics of the phytoplankton samples. Based on the pigment composition and content, the bloom-causative species could be tentatively identified as pelagophyte, "type 8" group of haptophyte, or silicoflagellate. Some unique features of the bloom, such as the extremely high cell density, small-sized and But-fuco containing cells, occurring in early summer, and the feeding-cessation effects on scallops, suggest it be a "brown tide" event similar to those reported in the east coast of the United States of America. The recurrent "brown tide" events and their dramatic impacts on the shellfish mariculture industry in Qinhuangdao need close attention in the coming years. 相似文献
125.
126.
GIS-based assessment of landslide susceptibility on the base of the Weights-of-Evidence model 总被引:4,自引:2,他引:2
The major scope of the study is the assessment of landslide susceptibility of Flysch areas including the Penninic Klippen in the Vienna Forest (Lower Austria) by means of Geographical Information System (GIS)-based modelling. A statistical/probabilistic method, referred to as Weights-of-Evidence (WofE), is applied in a GIS environment in order to derive quantitative spatial information on the predisposition to landslides. While previous research in this area concentrated on local geomorphological, pedological and slope stability analyses, the present study is carried out at a regional level. The results of the modelling emphasise the relevance of clay shale zones within the Flysch formations for the occurrence of landslides. Moreover, the distribution of mass movements is closely connected to the fault system and nappe boundaries. An increased frequency of landslides is observed in the proximity to drainage lines, which can change to torrential conditions after heavy rainfall. Furthermore, landslide susceptibility is enhanced on N-W facing slopes, which are exposed to the prevailing direction of wind and rainfall. Both of the latter geofactors indirectly show the major importance of the hydrological conditions, in particular, of precipitation and surface runoff, for the occurrence of mass movements in the study area. Model performance was checked with an independent validation set of landslides, which are not used in the model. An area of 15% of the susceptibility map, classified as highly susceptible, “predicted” 40% of the landslides. 相似文献
127.
128.
Dr. T. T. Alapieti Dr. B. A. Filén Dr. J. J. Lahtinen Dr. M. M. Lavrov Dr. V. F. Smolkin Dr. S. N. Voitsekhovsky 《Mineralogy and Petrology》1990,42(1-4):1-22
Summary Early Proterozoic layered intrusions, about 2440 Ma in age, are widespread over a large area of the northeastern Fennoscandian Shield in Finland, Sweden and the Soviet Union. Only one intrusion, the Kukkola intrusion, is encountered in Sweden whereas in Finland, their number exceeds twenty. These are concentrated principally in two areas, the dicontinuous Tornio-Närdnkävaara intrusion belt which crosses northern Finland and the Koitelainen intrusion with its satellites located in central Finnish Lapland. The intrusions in the Soviet Union are concentrated in three areas: (i) on the Kola Peninsula, (ii) in the Paanajärvi area close to the Finnish border and (iii) northeast of Lake Onega.Examples of all the ore types characteristic of layered intrusions have been found in these intrusions. Chromitite layers are encountered in the Kukkola/Tornio, Kemi, Penikat, Koitelainen and Burakovsky intrusions, but only one, the Kemi chromitite, has so far been mined. The Portimo, Koillismaa, Monchegorsk and Fedorova intrusions are characterized by PGE-bearing Cu-Ni-deposits in their marginal series. Mineralized zones enriched in PGE are also encountered in the layered series. Those in the Penikat intrusion and in the Portimo intrusions are the most remarkable and the best known to date. Vanadium-bearing Fe-Ti-oxide layers are encountered in several intrusions, but only one, the Mustavaara deposit, is presently being exploited.Two types of parental magma have tentatively been proposed for these intrusions. The first type is represented by a magma which was relatively rich in magnesium and chromium and was as a whole boninitic in composition, whereas the plagioclase-rich intrusions and megacyclic units are interpreted as having crystallized from a magma which was greatly depleted in these elements, especially Cr, and had melted crustal material incorporated in it.The emplacement of the early Proterozoic layered intrusions in Fennoscandia was part of the world-wide igneous activity indicated by other layered intrusions and mafic dyke swarms of similar age in other ancient cratons, i.e. the Jimberlana intrusion in Australia, the Great Dyke in Zimbabwe, the Scouric picrite suite in Scotland, the Hearst-Matachewan dyke swarm, Copper Cliff Formation and East Bull Lake intrusion in Ontario, Canada, and the Vestfold Hills and Napier Complex dyke swarms in Antarctica. This almost contemporaneous occurrence in different parts of the world would suggest a more intimate relationship between the Fennoscandian Shield, northwest Scotland, Canadian Shield, Yilgarn Block, Zimbabwe Craton and East Antarctic Shield at the beginning of the Proterozoic than at present.
With 7 Figures 相似文献
Früh-Proterozoische geschichtete Intrusionen im nordöstlichen Teil des Fennoskandischen Schildes
Zusammenfassung Im Nordost-Teil des Fennoskandischen Schildes in Finnland, Schweden und der Sowjetunion kommen fast vierzig frühproterozoische geschichtete Intrusionen, die ungefähr 2440 Mio J. alt sind, vor. Nur eine davon, die Kukkola Intrusion, liegt in Schweden, während in Finnland mehr als zwanzig Intrusionen vorkommen. Diese sind hauptsächlich in zwei Gebieten konzentriert, nämlich in dem nicht-zusammenhängenden Tornio-Näränkävaara Gürtel, der das nördliche Finnland durchzieht, und die Koitelainen-Intrusion mit ihren Satelliten im zentralen Finnischen Lapland. Die Intrusionen in der Sowjetunion sind in drei Gebieten konzentriert: (i) auf der Kola Halbinsel (ii) im Paanajärvi Gebiet nahe der Finnischen Grenze und (iii) östlich vom Onega-See.Beispiele aller für geschichtete Intrusionen charakteristischen Erztypen kommen vor. Chromititlagen sind in den Intrusionen von Kukkola/Tornio, Kemi, Penikat, Koitelainen und Burakovsky zu finden, aber nur eine davon, der Kemi Chromitit, ist bisher in Abbau genommen worden.Die Portimo-, Koillismaa-, Monchegorsk- und Fedorova-Intrusionen werden durch PGE-führende Kupfer-Nickel-Lagerstätten in ihren randlichen Bereichen charakterisiert. Mineralisierte Zonen die an PGE angereichert sind kommen auch in den geschich teten Serien vor. Die bemerkenswertesten sind die PGE-Vererzungen der Penikat- und der Portimo-Intrusionen. Vanadium-führende Fe-Ti-Oxidlagen kommen in verschiedenen Intrusionen vor, aber nur eine davon, die Mustavaara-Lagerstätte, ist bisher abgebaut worden.Diese Intrusionen werden auf zwei verschiedene Magmentypen zurückgeführt. Ersteres ist ein Magma das relativ reich an Magnesium und Chrom war und eine boninitische Zusammensetzung hatte, während die Plagioklas-reichen Intrusionen, und die megazyklischen Einheiten auf ein Magma das an diesen Elementen (besonders Cr) verarmt war, und das Krustenmaterial aufgeschmolzen hat, zurückgehen.Die Platznahme der frühproterozoischen geschichteten Intrusionen in Fennoskandien stellt einen Teil weltweiter magmatischer Aktivität dar, die durch andere geschichtete Intrusionen und mafische Gänge von fast identischem Alter in anderen alten Kratonen repräsentiert wird. Hier ist die Jimberlana-Intrusion in Australien, der Great Dyke in Zimbabwe, die Pikrit-Suite von Scourie in Schottland, die Gänge von Hearst-Matachewan, die Copper Cliff Formation und die East Bull Lake Intrusion in Ontario, Kanada ebenso wie die Gangsysteme der Vesthold Hills und des Napier Komplexes in Antarctica zu nennen. Diese fast gleichaltrigen Vorkommen in verschiedenen Teilen der Welt weisen auf eine engere Beziehung zwischen dem Fennoskandischen Schild, Nordwest-Schottland, dem Kanadischen Schild, dem Yilgarn Block, dem Zimbabwe-Craton und dem Ostantarktischen Schild zum Beginn des Proterozoikums hin.
With 7 Figures 相似文献
129.
The ability of turbulent nuées ardentes (surges) to transport coarse pyroclasts has been questioned on the basis that settling velocities of coarse fragments in the deposits are much too high for them to have been supported by turbulence in a dilute gas suspension. A computer model is used to evaluate the settling velocity of pyroclasts in suspensions of varying concentration and temperature. Since suspension of grains in low-concentration surges occurs if the shear velocity exceeds the settling velocity, the shear velocities related to the 16th and 84th percentiles, and the mean of the grain-size distribution are compared in surge deposits of the Vulsini, with the shear velocity necessary to move the coarsest grain on the bed surface (the Shields criterion). The results show that the settling velocities do not vary significantly in gaseous suspensions having volume concentrations lower than 15%, and that an increase in concentration to 25% is not sufficient to decrease the settling velocity of the coarser fraction, if it represents flow shear velocity. It is shown that the settling velocity of the mean grain size (M
z
) best depicts the shear velocity of a dilute turbulent suspension. Applying the results to the May 1902 paroxysmal nuées ardentes of Mount Pelée shows that the estimated mean velocities are well within the observed velocities, and sufficient to support all the clasts in dilute, turbulent suspensions. 相似文献
130.
Element Mobility During Incipient Granulite Formation at Kabbaldurga, Southern India 总被引:7,自引:2,他引:7
At Kabbaldurga, infiltration of carbonic fluids along a systemof ductile shears and foliation planes has led to partial transformationof Archaean grey biotitehornblende gneiss to coarse-grainedmassive charnockite at about 2.5 b.y. ago. The dehydration ofthe gneiss assemblage was induced by a marked metasomatic changeof the reacting system from granodioritic to granitic, and obviouslytook place under conditions of an open system at 700750?C and 57 kb. Extensive replacement of plagioclase (An1630)by K-feldspar through Na, CaK exchange reactions withthe ascending carbonic fluids led to strong enrichment in K,Rb, Ba, and SiO2, and to a depletion in Ca. Progressive dissolutionof hornblende, biotite, magnetite, and the accessory mineralsapatite and zircon resulted in a marked depletion in Fe, Mg,Ti, Zn, V, P, and Zr. Most important is the recognition of REEmobility: with advancing charnockitization, the moderately fractionatedREE distribution patterns of the grey gneisses (LaN270; LaN/YbN= 520; EuN27; Eu/Eu* = 0.60.3) give way to stronglyfractionated REE patterns with a positive Eu-anomaly (LaN200;LaN/YbN = 2080; EuN22; Eu/Eu* = 0.61.8). The systematicdepletion especially in the HREE is due to the progressive dissolutionof zircon, apatite (and monazite), which strongly concentratethe REE. Stable isotope data (18O of 6.98.0 per mille for gneissesand charnockites; 13C of 8.5 and 6.5 per millefor late carbonate) indicate a magmatogenic source for the carbonicfluids. In contrast to the currently favoured derivation ofcarbonic fluids by decarbonation of the upper mantle or degassingof underplated basaltic intrusions, it is discussed here thatabundant fluid inclusions in lower crustal charnockites providedan extensive reservoir of fossil carbonic fluids.Shear deformation has tapped this reservoir and generated thechannel-ways for fluid ascent. Charnockitization of the Kabbaldurgatypethus appears to be a metasomatic process which is tectonicallycontrolled and restricted to the crustal level of the amphiboliteto granulite transition. 相似文献