Earth-moon relationships, edited by C. Barbieri and F. Rampazzi. Kluwer Academic Publishers, Dordrecht (Netherlands), 2001, 575 pp. Eur 229, GBP 140, US $199 (ISBN 0-7923-7089-9)     

Stuart Ross Taylor 《Geochimica et cosmochimica acta》2002,66(8):1495

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Optimized Seismic Threshold Monitoring – Part 2: Teleseismic Processing     

T. Kværna  F. Ringdal  J. Schweitzer  L. Taylor 《Pure and Applied Geophysics》2002,159(5):989-1004

v--vThis second paper (Part 2) pertaining to optimized site-specific threshold monitoring addresses the application of the method to regions covered by a teleseismic or a combined regional-teleseismic network. In the first paper (Part 1) we developed the method for the general case, and demonstrated its application to an area well-covered by a regional network (the Novaya Zemlya nuclear test site). In the present paper, we apply the method to the Indian and Pakistani nuclear test sites, and show results during the periods of nuclear testing by these two countries in May 1998. Since the coverage by regional stations in these areas is poor, an optimized approach requires the use of selected, high-quality stations at teleseismic distances.¶To optimize the threshold monitoring of these test sites, we use as calibration events either one of the nuclear explosions or a nearby earthquake. From analysis of the calibration events we derive values for array beamforming steering delays, filter bands, short-term averages (STA) lengths, phase travel times (P waves), and amplitude-magnitude relationships for each station. By applying these parameters, we obtain a monitoring capability of both test sites ranging from m_b 2.8-3.0 using teleseismic stations only. When including the nearby Nilore station to monitor the Indian tests, we show that the threshold can be reduced by about 0.4 magnitude units. In particular, we demonstrate that the Indian tests on 13 May, 1998, which were not detected by any known seismic station, must have corresponded to a magnitude (m_b) of less than 2.4.¶We also discuss the effect of a nearby aftershock sequence on the monitoring capability for the Pakistani test sites. Such an aftershock sequence occurred in fact on the day of the last Pakistani test (30 May, 1998), following a large (m_b 5.5) earthquake in Afghanistan located about 1100 km from the test site. We show that the threshold monitoring technique has sufficient resolution to suppress the signals from these interfering aftershocks without significantly affecting the true peak of the nuclear explosion on the threshold trace.  相似文献   

Beyond world cities: Central America in a global space of flows   总被引：1，自引：0，他引：1  

Ed Brown  Peter J. Taylor  & Gilda Catalano 《Area》2002,34(2):139-148

Central America is a region without a world city. Traditionally, the region's national projects have been based upon openness to the world economy: how do the region's contemporary transnational projects connect to the world economy under the new conditions of openness that is contemporary globalization? Focusing upon advanced producer services, three connections into the world city network are identified: global service firms operating directly in Central American cities, local service firms operating indirectly through extra-regional world cities and global service firms operating through Latin American regional offices. Miami is confirmed as the primary world city through which Central America connects into the world economy  相似文献   

Racialised representations in British and American advertising     

James Taylor 《Area》1997,29(2):160-171

Summary This paper discusses the relationship between advertising and 'race', using as its foundation the replication of a study conducted in the US which used content analysis to examine the representation of Black characters in television advertisements. The replication facilitates a comparison of the British and American cases, revealing significant differences in the frequency and perceived importance of such representations. It can also help draw out the specificities of the UK situation. The paper attempts to convey the complexity of the interplay between advertising and racialisation, and emphasises that while such quantitative, textual studies offer a useful basis for further research, they are limited by their failure to address the motivations of producers and how advertisements are read by different groups in different places.  相似文献   

Quantification and characterization of regional seismic signals from cast blasting in mines: a linear elastic model     

Sridhar Anandakrishnan  Steven R. Taylor  Brian W. Stump 《Geophysical Journal International》1997,131(1):45-60

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Reply to comments by R. Pucher and T. Wonik     

P.T. Taylor  D. Ravat 《Journal of Applied Geophysics》1997,36(4):217-219

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A macroscale analysis of coastal steepening around the coast of England and Wales   总被引：1，自引：0，他引：1  

J A Taylor  A P Murdock  N I Pontee 《The Geographical journal》2004,170(3):179-188

Coastal steepening potentially presents an array of management issues in the form of financial implications of sea defence degradation, increased risk posed to the hinterland as wave attenuation is reduced, 'coastal squeeze' and statutory requirements in the light of the Habitats Directive. The extent to which coastal steepening has occurred throughout England and Wales has been investigated through use of a GIS and dataset based on historical Ordnance Survey map information. Data were collected along 1084 selected profile lines, positioned so as to be geomorphologically representative of the coast. Features recorded from each map year included the positions of mean high water (MHW) and mean low water (MLW), the relative movements of which infer changing intertidal gradients. The results presented in this paper are on a subject and scale not previously published. It is revealed that 61% of the coastline studied has experienced a tendency towards steepening. Of the remainder, 33% has flattened, and 6% has experienced no rotational movement. This tendency towards steepening has been the dominant movement on each of the west, south, and east coasts.  相似文献   

Re-examination of the magnetic lineations of the Gascoyne and Cuvier Abyssal Plains, off NW Australia     

Masako S. Robb  Brian Taylor  Andrew M. Goodliffe 《Geophysical Journal International》2005,163(1):42-55

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Geology and Metal Contents of the Ruttan volcanogenic massive sulfide deposit, northern Manitoba, Canada     

C. Tucker. Barrie  Craig Taylor  Doreen E. Ames 《Mineralium Deposita》2005,39(8):795-812

The Paleoproterozoic Ruttan Cu–Zn volcanogenic massive-sulfide (VMS) deposit is a large, relatively low grade, bimodal-siliciclastic type deposit in the Rusty Lake volcanic belt of northern Manitoba. The deposit contained over 82.8 million tonnes of massive sulfide, of which 55.7 million tonnes were mined from 1973 to 2002. The deposit consists of a series of moderately to steeply dipping, south-facing lenses that extend along strike at the surface for 1.1 km and to a depth of 1.0 km. These lenses occur within a steeply dipping, bimodal volcanic, volcaniclastic and siliciclastic sequence. In the immediate mine area, transitional calc-alkalic to high-silica (tholeiitic), felsic, and intermediate volcanic/volcaniclastic rocks of the Mine Sequence are host to, and intercalated with, the massive-sulfide lenses. Transitional tholeiitic to calc-alkalic basalt and andesite are present in the footwall sequence, approximately 500 m down-section from the ore horizon. The overlying rocks are predominantly fine-grained volcaniclastics and siliciclastics, but include polyfragmental agglomerate that contains mafic bombs and scoriaceous felsic fragments. Syn-depositional felsic and mafic dikes, sills, and apophyses are ubiquitous throughout the Mine Sequence, including the ore lenses, indicating continued, near-vent magmatism, and volcanism during ore formation. Fabrics in altered hostrocks have consistent, down-plunge stretching lineations to the SSE that suggest the deposit has been elongated by a factor of ~1.2–1.5; otherwise, the deposit is remarkably undeformed. Syn- and post-depositional faults in the mine area have relatively minor displacements up to tens of meters. Proximal (within 200 m) footwall rocks exhibit moderate to strong chloritization, characterized by the upper greenschist to lower amphibolite facies assemblages that include cordierite–almandine–andalusite–sillimanite–biotite ± staurolite ± anthophyllite ± talc, and local silicification. The proximal hanging wall rocks are characterized by sericite ± gahnite alteration, which is restricted to within approximately 75 m of the uppermost lenses. Additional gangue minerals are anhydrite and carbonate minerals (siderite, dolomite, ankerite, and calcite), as well as chlorite, sericite, biotite, talc, and quartz. Carbonate (excluding siderite), potassium feldspar, silicification and epidotization are common distal alteration zones in the footwall to the Mine Sequence several kilometers to the northeast. There are three principal groups of massive sulfide lenses; the East lenses, the West lenses, and the Western Anomaly lenses to the far west. In general, Cu is relatively enriched at the stratigraphic base and in the center of the deposit, whereas Zn is enriched upsection and at the outer margins. Some of the Zn-rich ore exhibits primary mineralogical layering. Parts of the West and Western Anomaly lenses show two layers with Cu-rich bases and Zn-rich tops. The massive sulfide is typically 10–40-m thick; one area along the margin of the main lenses is over 130-m thick and may represent deposition adjacent to a syn-depositional fault. The main sulfide phases are pyrite, pyrrhotite, chalcopyrite, sphalerite, and galena, with tetrahedrite as the most abundant trace phase. Gahnite is ubiquitous in the chlorite-rich assemblages adjacent to the ore lenses. The average base, precious and trace metal contents estimated from Cu and Zn concentrates, and from millhead grades and recoveries. Metals easily transported as chloride and bisulfide complexes in hydrothermal fluids including: Pb, Ag, In, Cu, Cd, Au, and Zn are enriched by 1.5–2.5 orders of magnitude in comparison to the bulk continental crust. Other elements such as Sn, Mo, and As are at near-crustal concentrations, whereas Mn, Ga, and Co are significantly depleted in comparison to the crust. Calculated metal concentrations in the average hydrothermal fluid based on the average metal contents are comparable to, or higher than those measured at sediment covered ridge hydrothermal systems, which precipitate much of their metal budget in the subsurface. Average rare earth element contents for the sulfide are light rare earth element enriched (La_N/Yb_N=22) and range from 0.45 to 0.02x chondritic values, with a moderate negative Eu anomaly (Eu*=0.51). Metal and trace element contents in the Ruttan exhalite horizon, and in proximal (within 1–2 km) exhalites along strike from the 0.6 million tonne Dar-2 Cu–Zn deposit 12 km south of Ruttan, have positive Eu anomalies, whereas negative Eu anomalies are present at distance. The positive Eu anomalies reflect high temperature paleoseafloor hydrothermal venting and precipitation of Eu²⁺-enriched clays and possibly carbonates, and indicate proximity to base-metal deposits. Silver and lead are also enriched in the exhalites near the deposits, whereas Mn is enriched at ~1–3 km along strike, but not consistently. Editorial handling: B. Gemmel An erratum to this article is available at .  相似文献   

Chemical and textural equilibration of garnet during amphibolite facies metamorphism: The influence of coupled dissolution–reprecipitation          下载免费PDF全文

Tim J Dempster  Julie La Piazza  Andrew G Taylor  Nicolas Beaudoin  Peter Chung 《Journal of Metamorphic Geology》2017,35(9):1111-1130

Metamorphic equilibration requires chemical communication between minerals and may be inhibited through sluggish volume diffusion and or slow rates of dissolution in a fluid phase. Relatively slow diffusion and the perceived robust nature of chemical growth zoning may preclude garnet porphyroblasts from readily participating in low‐temperature amphibolite facies metamorphic reactions. Garnet is widely assumed to be a reactant in staurolite‐isograd reactions, and the evidence for this has been assessed in the Late Proterozoic Dalradian pelitic schists of the Scottish Highlands. The 3D imaging of garnet porphyroblasts in staurolite‐bearing schists reveals a good crystal shape and little evidence of marginal dissolution; however, there is also lack of evidence for the involvement of either chlorite or chloritoid in the reaction. Staurolite forms directly adjacent to the garnet, and its nucleation is strongly associated with deformation of the muscovite‐rich fabrics around the porphyroblasts. “Cloudy” fluid inclusion‐rich garnet forms in both marginal and internal parts of the garnet porphyroblast and is linked both to the production of staurolite and to the introduction of abundant quartz inclusions within the garnet. Such cloudy garnet typically has a Mg‐rich, Mn‐poor composition and is interpreted to have formed during a coupled dissolution–reprecipitation process, triggered by a local influx of fluid. All garnet in the muscovite‐bearing schists present in this area is potentially reactive, irrespective of the garnet composition, but very few of the schists contain staurolite. The staurolite‐producing reaction appears to be substantially overstepped during the relatively high‐pressure Barrovian regional metamorphism reflecting the limited permeability of the schists in peak metamorphic conditions. Fluid influx and hence reaction progress appear to be strongly controlled by subtle differences in deformation history. The remaining garnet fails to achieve chemical equilibrium during the reaction creating distinctive patchy compositional zoning. Such zoning in metamorphic garnet created during coupled dissolution–reprecipitation reactions may be difficult to recognize in higher grade pelites due to subsequent diffusive re‐equilibration. Fundamental assumptions about metamorphic processes are questioned by the lack of chemical equilibrium during this reaction and the restricted permeability of the regional metamorphic pelitic schists. In addition, the partial loss of prograde chemical and textural information from the garnet porphyroblasts cautions against their routine use as a reliable monitor of metamorphic history. However, the partial re‐equilibration of the porphyroblasts during coupled dissolution–reprecipitation opens possibilities of mapping reaction progress in garnet as a means of assessing fluid access during peak metamorphic conditions.  相似文献