Women’s use of public space and sense of place in the Raval (Barcelona)     

Anna Ortiz  Maria Dolors Garcia-Ramon  Maria Prats 《GeoJournal》2004,61(3):219-227

This article deals with women's use of public space and sense of place in El Raval, a neighbourhood located in the historical center of Barcelona. Attention will be paid to discover to what degree the existence of a quality public space fosters the creation of socially meaningful places, thus contributing to the construction of womens sense of place and urban identities. A qualitative approach, based on direct observation and in-depth interviews with women living in the neighbourhood, has allowed us to capture the main aspects of the building of a sense of place and belonging, that is the use of public space and facilities, the attitude towards living in the neighbourhood, etc. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

A brief comparison of lava flows from the Deccan Volcanic Province and the Columbia-Oregon Plateau Flood Basalts: Implications for models of flood basalt emplacement   总被引：1，自引：0，他引：1  

Ninad R. Bondre  Raymond A. Duraiswami  Gauri Dole 《Journal of Earth System Science》2004,113(4):809-817

The nature and style of emplacement of Continental Flood Basalt (CFB) lava flows has been a matter of great interest as well as considerable controversy in the recent past. However, even a cursory review of published literature reveals that the Columbia River Basalt Group (CRBG) and Hawaiian volcanoes provide most of the data relevant to this topic. It is interesting to note, however, that the CRBG lava flows and their palaeotopographic control is atypical of other CFB provinces in the world. In this paper, we first present a short overview of important studies pertaining to the emplacement of flood basalt flows. We then briefly review the morphology of lava flows from the Deccan Volcanic Province (DVP) and the Columbia-Oregon Plateau flood basalts. The review underscores the existence of significant variations in lava flow morphology between different provinces, and even within the same province. It is quite likely that there were more than one way of emplacing the voluminous and extensive CFB lava flows. We argue that the establishment of general models of emplacement must be based on a comprehensive documentation of lava flow morphology from all CFB provinces.  相似文献   

Minority women’s microenterprises in rural areas of the United States of America: African American,Hispanic American and Native American case studies     

Helen Ruth Aspaas 《GeoJournal》2004,61(3):281-289

Women in many rural areas of the US often engage in small-scale businesses as one of several avenues for contributing to household incomes. In those geographical areas that contain a significant minority population, many of the women's businesses display the cultural diversity of the regions in which they live. Likewise, women's roles as economic providers as well as wives and mothers are reflected in the manner in which they operate their businesses. Candida Brush suggests that women's strategies for operating their businesses are highly integrative because women's business decisions are intertwined with familial responsibilities, household economic demands and desires to contribute to their communities. Hispanic and Native American women in the Four Corners region of southwestern US and African American women in central Virginia participated in interviews in which they responded to numerous short answer and open-ended questions about their businesses and decision-making strategies. From these interviews an image emerges of rural minority business women who are operating their businesses at the nexus of family obligations, economic necessities, cultural ties and with a commitment for serving their communities. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

‘Gendered spaces’ in urban and rural contexts: An introduction     

Joos Droogleever Fortuijn  Andre Horn  Wim Ostendorf 《GeoJournal》2004,61(3):215-217

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Accurate U-Pb Age and Trace Element Determinations of Zircon by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry   总被引：190，自引：0，他引：190  

Honglin Yuan  Shan Gao  Xiaoming Liu  Huiming Li  Detlef Günther  Fuyuan Wu 《Geostandards and Geoanalytical Research》2004,28(3):353-370

Various zircons of Proterozoic to Oligocene ages (1060-31 Ma) were analysed by laser ablation-inductively coupled plasma-mass spectrometry. Calibration was performed using Harvard reference zircon 91500 or Australian National University reference zircon TEMORA 1 as external calibrant. The results agree with those obtained by SIMS within 2s error. Twenty-four trace and rare earth elements (P, Ti, Cr, Y, Nb, fourteen REE, Hf, Ta, Pb, Th and U) were analysed on four fragments of zircon 91500. NIST SRM 610 was used as the reference material and ²⁹Si was used as internal calibrant. Based on determinations of four fragments, this zircon shows significant intra-and inter-fragment variations in the range from 10% to 85% on a scale of 120 μm, with the variation of REE concentrations up to 38.7%, although the chondrite-normalised REE distributions are very similar. In contrast, the determined age values for zircon 91500 agree with TIMS data and are homogeneous within 8.7 Ma (2 s ). A two-stage ablation strategy was developed for optimising U-Pb age determinations with satisfactory trace element and REE results. The first cycle of ablation was used to collect data for age determination only, which was followed by continuous ablation on the same spot to determine REE and trace element concentrations. Based on this procedure, it was possible to measure zircon ages as low as 30.37 0.39 Ma (MSWD = 1.4; 2 s ). Other examples for older zircons are also given.  相似文献   

Geochronology and petrogenesis of the post-orogenic Cu–Ni sulfide-bearing mafic–ultramafic complexes in Jilin Province, NE China     

Fu-yuan Wu  Simon A. Wilde  Guang-liang Zhang  De-you Sun 《Journal of Asian Earth Sciences》2004,23(5):781

Northeastern (NE) China is a well-documented example of a collisional zone characterized by widespread post-orogenic granites and mafic–ultramafic complexes. Based on a study of the Hongqiling and Piaohechuan Cu–Ni sulfide-bearing mafic–ultramafic complexes in central Jilin province, we present geological, petrological, geochemical and geochronological data which indicates their post-orogenic origin.The Hongqiling complex comprises pyroxenite, olivine websterite, lherzolite, gabbro and leucogabbro. Zircon U–Pb SHRIMP analyses on a leucogabbro of the Hongqiling complex yield a weighted mean ²⁰⁶Pb–²³⁸U age of 216±5 Ma. The Piaohechuan complex is composed of gabbro, pyroxenite and dolerite, exposed as dikes. A plagioclase-bearing pyroxenite has a U–Pb zircon weighted mean ²⁰⁶Pb–²³⁸U age of 217±3 Ma, identical to that of the Hongqiling complex. These ages are coeval with the emplacement of A-type granites in the area, but slightly younger than the regional metamorphism (240 Ma) and syn-orogenic granitic magmatism (246±4 Ma). This suggests that these mafic–ultramafic complexes are post-orogenic in origin. The age data also indicated a short period of lithospheric stabilization of about 30 Ma after cessation of orogenic activity.Geochemical investigation indicates that the primary mafic magma was a lithospheric mantle-derived basalt resulting from the upwelling of asthenosphere due to lithospheric delamination during post-orogenic processes. The magmatic source was contaminated by a small amount of crustal material, and subsequent crystal fractionation resulted in the Cu–Ni mineralization.The widespread occurrence of mafic–ultramafic complexes in the Xing'an–Mongolian Orogenic Belt of NE China and in the Altay–Tianshan–Junggar Orogenic Belt of Northern Xinjiang indicates that mafic intrusions are an important magmatic suite that evolved during post-orogenic processes. Portions of this mafic magma could have underplated the lower crust, and served as the heat source for associated late-stage granitic magmas.  相似文献   

Focal mechanism dependence of static stress triggering of earthquakes   总被引：6，自引：0，他引：6  

Y.G. Wan  Z.L. Wu  G.W. Zhou 《Tectonophysics》2004,390(1-4):235-243

We perform a global statistical investigation into the problem of Coulomb stress triggering of earthquakes by using the Harvard CMT catalogue of shallow earthquakes from 1976 to 2001. We consider ‘earthquake pairs’, i.e., pairs of successive earthquakes occurring near each other with similar focal mechanisms, and address the problem of whether or not the change of the Coulomb failure stress (CFS) produced by the first earthquake of the pair ‘encourages’ the occurrence of the second one. An interesting feature is that such a Coulomb stress-triggering phenomenon has an apparent focal mechanism dependence: for thrust earthquakes, a more evident triggering effect can be observed.  相似文献   

Empirical garnet-muscovite-plagioclase-quartz geobarometry in medium- to high-grade metapelites   总被引：2，自引：0，他引：2  

Chun-Ming Wu  Jian Zhang 《Lithos》2004,78(4):319-332

Based on the net transfer reactions among garnet, muscovite, plagioclase, and quartz (for both Mg and Fe end-member models), the garnet-muscovite-plagioclase-quartz (GMPQ) geobarometry was empirically calibrated under the physical conditions of P=1.0-11.4 kbar and T=505-745 °C for 128 natural metapelitic rock samples collected from the literature. The input temperatures and pressures were simultaneously determined by the garnet-biotite thermometer and the garnet-aluminosilicate-plagioclase-quartz (GASP) barometer. The GMPQ calibrations adopted the same asymmetric quaternary solid solution model of garnet and the same Al-avoidance asymmetric ternary model of plagioclase as the calibrations of the garnet-biotite geothermometer and the GASP geobarometer. A symmetric Fe-Mg-Al^VI ternary solid solution model of muscovite was adopted, and the Margules parameters of muscovite were obtained through regression. The Mg and Fe model reactions, along with the assumption of whether the ferric iron content in muscovite is 0% or 50%, resulted in four GMPQ barometry formulae. The GMPQ barometry formulae reproduce the input GASP pressures well within ±1.0 kbar (mostly within ±0.5 kbar). For both aluminosilicate-bearing and aluminosilicate-absent samples, the GMPQ barometry formulae yield identical pressures for every sample, whether the sample was included or not in calibrating the barometers. For each of the Mg or Fe model reaction, the formulae gave identical pressures within ±40 bars. The random error of the GMPQ barometry may be expected as ±1.4 kbar. The dP/dT slopes of these GMPQ formulae are close to that of the GASP barometer in the P-T space. Applications of the GMPQ barometry to aluminosilicate-absent metapelites within a limited geographic area without postmetamorphic structural discontinuity generally show no pressure difference. It may be concluded that the GMPQ barometry formulae derived in this work may be used as practical tools for metamorphic pelites under the conditions of 505-745 °C and 1-11.4 kbar, in the composition range of X_gros>3% in garnet and X_An>17% in plagioclase.  相似文献   

Acidification and Trace Metals of Lakes in Taiwan     

Chen-Tung Arthur Chen  Jiunn-Tzong Wu  Bing-Jye Wang  Kuo-Ming Huang 《Aquatic Geochemistry》2004,10(1-2):33-57

One hundred and eighty lakes, ponds and reservoirs in Taiwan, and the offshore islands have been investigated since 1985. Effects such as warming/cooling, mixing, photosynthesis and respiration on pH have been identified. These effects were found to be less profound than those resulting from the geology. Since there is little rain or lake water pH data available prior to 1970, it was necessary to use proxy data in order to ascertain the history of lake acidification. In this study, we present data based on diatoms in a sediment core collected from a lake in the remote subalpine region of southern Taiwan. The acidity of this lake water was found to have increased since 1900. We measured the concentrations of 55 chemical species in lake water samples. In addition, concentrations of 26 chemical species were obtained from sediments. Conductivity, alkalinity (HCO₃ ^?), most other major and minor chemical species, as well as the non sea-salt SO₄/Na ratio in lake water clearly decrease with elevation. Distribution of pH is similar, although the trend is less clear. Distribution of trace metals, however, shows a different trend as anthropogenic pollution, diagenetic reduction and lake acidification are at play.  相似文献   

呼和浩特市城市边缘区景观格局动态变化研究   总被引：2，自引：0，他引：2  

郝润梅  杨劼 《地域研究与开发》2004,23(5):43-46

利用GIS技术对1987，2000年两期航空遥感影像进行空间叠加对比分析，从斑块及景观2个尺度对呼和浩特市城市边缘区景观格局变化进行了研究。结果表明：在斑块尺度上，边缘区两期景观结构均以农田景观为基质，研究期内，农田景观、草地景观等缓慢减少，建筑景观明显增多；在景观尺度上，边缘区景观多样性指数趋于增大，优势度指数趋于降低．景观组分趋于复杂化、破碎化和多元化。分析其影响因素可知：经济发展和城市化的加快、政策导向是变化的根本原因，人口的增加、土地利用方式的改变是变化的直接原因。  相似文献