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排序方式: 共有1113条查询结果,搜索用时 15 毫秒
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A polyphasic tectonic‐fluid system of a fault that involves crystalline and carbonate rocks (Hospital fault, Barcelona Plain) has been inferred from regional to thin section scale observations combined with geochemical analyses. Cathodoluminescence, microprobe analyses and stable isotopy in fracture‐related cements record the circulation of successive alternations of hydrothermal and low‐temperature meteoric fluids linked with three main regional tectonic events. The first event corresponds to the Mesozoic extension, which had two rifting stages, and it is characterized by the independent tectonic activity of two fault segments, namely southern and northern Hospital fault segments. During the Late Permian‐Middle Jurassic rifting, these segments controlled the thickness and distribution of the Triassic sediments. Also, dolomitization was produced in an early stage by Triassic seawater at shallow conditions. During increasing burial, formation of fractures and their dolomite‐related cements took place. Fault activity during the Middle Jurassic–Late Cretaceous rifting was localized in the southern segment, and it was characterized by hydrothermal brines, with temperatures over 180°C, which ascended through this fault segment precipitating quartz, chlorite, and calcite. The second event corresponds to the Paleogene compression (Chattian), which produced exhumation, folding and erosion, favouring the percolation of low‐temperature meteoric fluids which produced the calcitization of the dolostones and of the dolomite cements. The third event is linked with the Neogene extension, where three stages have been identified. During the syn‐rift stage, the southern segment of the Hospital fault grew by tip propagation. In the relay zone, hydrothermal brines with temperature around 140°C upflowed. During the late postrift, the Hospital fault acted as a unique segment and deformation occurred at shallow conditions and under a low‐temperature meteoric regime. Finally, and possibly during the Messinian compression, NW‐SE strike‐slip faults offset the Hospital fault to its current configuration. 相似文献
105.
G. Huelga‐Suarez M. Moldovan M. Suárez Fernández M. Ángel de Blas Cortina J. I. García Alonso 《Archaeometry》2014,56(4):651-664
This paper continues the characterization of the lead isotopic fingerprint of ancient copper mines in the north‐west of Spain. In this work, the lead isotopic compositions found in copper ores from the La Profunda mine are presented. Azurites and malachites sampled from this deposit were subjected to lead isotope analysis by multicollector ICP–MS. The results showed a clear radiogenic lead signature compatible with the presence of uranium‐rich minerals (such as zeunerite) in the same mining complex. Moreover, a rare copper artefact, found in the galleries of the mine during its modern exploitation, was also analysed and showed that local mineral was used for its manufacturing. 相似文献
106.
Relying on stochastic frontier analysis we propose a methodology to study the technological characteristics and cost efficiency levels related to the provision of public infrastructure for basic utilities. The methodology assumes a cost minimizing behaviour on the part of public officials when planning the construction of local infrastructure, which is represented by way of a flexible translog cost function. Introducing relevant definitions of scale economies, associated with larger numbers of inhabitants and dwellings, as well as economies of density, brought about by reductions in urban dispersion, we analytically determine the optimal population densities for which average cost is minimized. We illustrate our model with the water cycle sector, including water distribution, sewage collection and cleansing of wastewater, and considering data at the municipality level for the Spanish region of Castilla y León. The obtained results indicate potential cost savings in the form of decreasing average costs, as relevant scale and density economies are present, along with large inefficiency levels. Relevant policy guidelines favouring larger and denser urban sizes are drawn, as the observed cost excess is the result of a general suboptimal urban size in terms of population density, and the negative effects of dispersed settlement patterns. 相似文献
107.
The shift from the linear to the innovation system-based approach has resulted in the emergence of differentiated regional innovation policy. However, certain common presumptions bind these location-specific policies together. The set of information that is used to design these policies and the set of information excluded are fairly similar. The theoretical sections of this paper provide a critical review on the informational basis of regional innovation policy by contrasting the interpretations of the welfare effects of technological change in the utilitarian tradition and in Sen's capability approach. The empirical sections analyse the correspondence of the innovation capacity and welfare (well-being) situation in a Hungarian micro-regional data set. We conclude that the conventional informational basis of innovation policy is too narrow from a welfare perspective. Not only should the differences in the innovation systems, but also the peculiarities of the region's welfare situation be considered during the design of innovation policy. 相似文献
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Anthony P. Andrews Rafael Burgos Villanueva Luis Millet Cámara 《International Journal of Historical Archaeology》2006,10(2):179-205
The emergence of capitalism in the peninsula of Yucatán is generally presented as a process resulting from the capitalization
of the agricultural sector and the export of products from its sugar, cotton, and henequén plantations in the nineteenth century.
In addition to these products, the peninsula also had a dynamic coastal economy in which the harvesting of salt and the extraction
of logwood (Haematoxylum campechianum), played a major role and contributed to the flow of goods to international markets.
We present a preliminary archaeological survey and historical documentation of El Real de Salinas, a salt-producing port on
the north coast of Campeche, which was also involved in the extraction of other coastal products and closely linked to the
inland plantation system.
相似文献
Anthony P. AndrewsEmail: |
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Mariano Ramos Fabián Bognanni Matilde Lanza Verónica Helfer Patricia Salatino Claudio Quiroga Diego Aguirre David Pau 《International Journal of Historical Archaeology》2008,12(3):209-247
In the central-southeastern area of Buenos Aires Province, Argentina, lies a mountainous area of low height in Tandilia that
contains important outcrops of quartzite and granite. A large number of buildings are made of massive blocks of rock, some
of them with a surface of over 1 ha. In addition to these completely artificial constructions are other structures that are
semi-natural, having been made in places with special topographical characteristics and complemented with dry-stone walls.
Scanty written documents allow us to attribute some of the constructions to an age before the permanent settlement of the
Creole population. In the Tandilia Sierras these structures are commonly known as “corrales de indios” (Indian corrals). This
designation involves a double prejudice with regard to function and cultural affiliation. Out of a total of 22 structures,
we analyze a group of 4 that were excavated to use to review the written documents. 相似文献