789 resultados para North-Eastern Atlantic


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According to Solitander C. P., the extraction of lake ore from Eastern Finland lakes considerably rose in the 1870 - 1880 period in relation with the increasing demand from the ironworks being operated in the region. In St. Petersburg, Nicholas Putiloff, a business tycoon and State Minister owned the Haapakosken, Huutokosken and Oravin ironworks which were using 99% of lake ore for their supply. During this period the biggest production came from lake Sysmäjärvi in the Joroinen county with 3676 tonnes at an average concentration of 35.94% Fe, 4.55% Mn, 0.26% P and 0.04% S. The Värtsilä ironworks used the lake ore coming from 49 lakes, the biggest production coming from lake Loitimojärvi with 14535 tonnes of ore with a medium at concentration of 30.8% Fe. Möhkö ironworks took advantage of the 59 lakes, the largest of which was from lake Koitere with 4301 tonnes at 41.3% Fe. The Karttula ironworks were also significant in the consumption of ferromanganese lake ore.

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Aim: Concepts about patterns and rates of post-glacial tree population migration are changing as a result of the increasing amount of palaeobotanical information being provided by macroscopic plant remains. Here we combine macrofossil, pollen and stomata records from five sites in north-eastern European Russia and summarize the results for the late-glacial-early Holocene transition. The late-glacial-early Holocene transition encompasses the first indications of trees (tree-type Betula, Picea abies, Abies sibirica and Larix sibirica) and subsequent forest development. Considerable time-lags between the first macrobotanical and/or stomata finds of spruce (Picea abies) and the establishment of a closed forest are reconsidered. Location: Pechora basin, north-eastern European Russia. Methods: We used plant macrofossil, stomata, pollen and radiocarbon analyses to reconstruct late-glacial and early Holocene tree establishment and forest development. The data were derived from lake sediment and peat archives. Results: Palaeobotanical data reveal an early Holocene presence (11,500-10,000 cal. yr bp) of arboreal taxa at all five sites. One site presently located in the northernmost taiga zone, shows the presence of spruce and reproducing tree birch during the late-glacial. Given the current view of post-glacial population dynamics and migration rates, it seems likely that the source area of these early tree populations in north-eastern European Russia was not located in southern Europe but that these populations had local origins. Results thus support the emerging view that the first post-glacial population expansions in non-glaciated regions at high latitudes do not reflect migration from the south but were a result of an increase in the size and density of small persisting outlying tree populations. Main conclusions: Results suggest that the area east of the margin of the Scandinavian ice sheet to the Ural Mountains had isolated patches of trees during the late-glacial and early Holocene and that these small populations acted as initial nuclei for population expansion and forest development in the early Holocene.