869 resultados para Cave mining
Resumo:
We present a new mid-latitude speleothem record of millennial-scale climatic variability during OIS3 from the Villars Cave that, combined with former published contemporaneous samples from the same cave, gives a coherent image of the climate variability in SW-France between ~55 ka and ~30 ka. The 0.82 m long stalagmite Vil-stm27 was dated with 26 TIMS U-Th analyses and its growth curve displays variations that are linked with the stable isotopes, both controlled by the climatic conditions. It consists in a higher resolved replicate of the previously published Vil-stm9 and Vil-stm14 stalagmites where Dansgaard-Oeschger (DO) events have been observed. The good consistency between these three stalagmites and the comparison with other palaoeclimatic reconstructions, especially high resolution pollen records (ODP 976 from the Alboran Sea, Monticchio Lake record from southern Italy) and the nearby MD04-2845 Atlantic Ocean record, permits to draw a specific climatic pattern in SW-France during the OIS3 and to see regional differences between these sites. Main features of this period are: 1) warm events corresponding to Greenland Interstadials (GIS) that are characterized by low speleothem d13C, high temperate pollen percentages, warm temperatures and high humidity; among these events, GIS#12 is the most pronounced one at Villars characterized by an abrupt onset at ~46.6 ka and a duration of about 2.5 ka. The other well individualized warm event coincides with GIS#8 which is however much less pronounced and occurred during a cooler period as shown by a lower growth rate and a higher d13C; 2) cold events corresponding to Greenland Stadials (GS) that are clearly characterized by high speleothem d13C, low temperate pollen abundance, low temperature and enhanced dryness, particularly well expressed during GS coinciding with Heinrich events H5 and H4. The main feature of the Villars record is a general cooling trend between the DO#12 event ~45.5 ka and the synchronous stop of the three stalagmites at ~30 ka ±1, with a first well marked climatic threshold at ~41 ka after which the growth rate and the diameter of all stalagmites slows down significantly. This climatic evolution differs from that shown at southern Mediterranean sites where this trend is not observed. The ~30 ka age marks the second climatic threshold after which low temperatures and low rainfalls prevent speleothem growth in the Villars area until the Lateglacial warming that occurred at ~16.5 ± 0.5 ka. This 15 ka long hiatus, as the older Villars growth hiatus that occurred between 67.4 and 61 ka, are linked to low sea levels, reduced ocean circulation and a southward shift of the Polar Front that likely provoked local permafrost formation. These cold periods coincide with both low summer 65°N insolation, low atmospheric CO2 concentration and large ice sheets development (especially the Fennoscandian).
Resumo:
At the end of the communist era, which was characterised as a closed social experiment, Romania found itself in the middle of a globalization process. Its industrial capacities have been considerably reduced through a poor and spendthrift management. There was a mass exodus of the labour force abroad and the educational background for the remaining part was no longer in agreement with the labour market. On these grounds, the vectors of globalization, in the form of foreign investments, entered Romania effortlessly. There even were local communities where the arrival of foreign investors was expected like a second coming of Christ. This is the context in which a Canadian company set forth the mining project Rosia Montana Gold Corporation. The implementation of the project should have started in 2005. Nevertheless, the project has not been effectively launched yet. This situation is based on what we call Romanian glocalization, namely a specific confrontation between global and local on Romanian land
Resumo:
At the end of the communist era, which was characterised as a closed social experiment, Romania found itself in the middle of a globalization process. Its industrial capacities have been considerably reduced through a poor and spendthrift management. There was a mass exodus of the labour force abroad and the educational background for the remaining part was no longer in agreement with the labour market. On these grounds, the vectors of globalization, in the form of foreign investments, entered Romania effortlessly. There even were local communities where the arrival of foreign investors was expected like a second coming of Christ. This is the context in which a Canadian company set forth the mining project Rosia Montana Gold Corporation. The implementation of the project should have started in 2005. Nevertheless, the project has not been effectively launched yet. This situation is based on what we call Romanian glocalization, namely a specific confrontation between global and local on Romanian land
