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Geochemical Fingerprint and Iron Ore Potential of the Siliceous Itabirite from Palaeoproterozoic Nyong Series,Zambi Area,Southwestern Cameroon
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Sylvestre Ganno Cyriel Moudioh Adjija Nzina Nchare Gus Djibril Kouankap Nono Jean Paul Nzenti 《Resource Geology》2016,66(1):71-80
The study area forms part of an emerging iron ore province of southern Cameroon. Geochemistry analyses reveal that the siliceous itabirite has a very simple chemical composition, with Fe2O3 and SiO2 representing more than 96 wt.% of the average composition; suggesting chemical precipitates of silica and iron. Low Al2O3 and TiO2 concentrations and a weak positive correlation between them point to a minor detrital component in the precipitated marine sediments. The Si/Al ratio (average 52.7) indicates the hydrothermal origin of the studied itabirite. The Al–Si discrimination diagram supports this interpretation through the plot of all data in the hydrothermal field. The studied samples have low iron content (about 39.32% Fe), high gangue content (40.97% SiO2 and 1.3 % Al2O3) and low concentration of the deleterious elements (0.16 % P and < 0.01% S). The main gangue mineral is silica which can be efficiently removed from iron ores during preparation of raw materials for the blast furnace process. According to commercial standards for crude iron ores, it may be concluded that the Zambi iron ores are a low‐grade magnetic ore that can be profitably exploited for the production of iron for steel production. 相似文献
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Tell Jemmeh (Tell Re'im) is in the climatically sensitive transitional zone between the southern Coastal Plain of Israel and the northwestern Negev. It is a major site that was inhabited from about 3500 to 200 B.C. with an occupation gap between ca. 3100 and 1800 B.C., possibly a result of a particularly dry period. Quaternary loess derived by winter dust storms from the Sinai and Sahara and reworked loess blanket the region. Imposed on these are well-developed Holocene and Quaternary pedocal profiles that have been identified in the field and substantiated in the lab by variations in bulk chemical composition, petrography, and mineralogy by X-ray diffraction. Pluvial events are evidenced by dark-colored A-horizons high in clay minerals, Al2O3, and Fe2O3 and by periods of loess accumulation. Interpluvials and the Holocene commonly involved wind ablation and water erosion, and led to shallow depths with very high-calcite B-horizons. Some of the loessial soil horizons were found to be suitable ceramic clays, and their composition and petrography provide a basis for distinctions between locally made and imported ceramics, as well as to identifying modifications of local clay resources by potters. 相似文献
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E. G. Gus’kova O. M. Raspopov V. A. Dergachev A. G. Iosifidi G. V. Sinitsyna 《Izvestiya Atmospheric and Oceanic Physics》2012,48(8):823-831
Palaeomagnetic investigations of deposits at the Baranova Gora archaeological site located near Volgo Lake (56.9°N, 33.2°E) in the Central Russian Upland have been carried out. The palaeomagnetic studies have revealed the development of the Gothenburg geomagnetic excursion dated at 13000–12350 BP. Revealing the Gothenburg excursion allowed us to use the findings of the palaeomagnetic investigations as a chronological benchmark, in addition to the results of palynological and archaeological (comparative analysis of archaeological artifacts) methods of dating the cultural layers of this archaeological monument, as well as to refine the time frame of the climatic Allerød interstadial in the Central Russian Upland. The data obtained in our study indicate that the Allerød interstadial in the Central Russian Upland began several hundred years before 12000 BP, the date commonly believed to be the beginning of the Allerød interstadial. 相似文献
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Distribution,abundance and growth of New Zealand sea lion Phocarctos hookeri pups on Campbell Island
Simon Childerhouse Nadine Gibbs Gus McAlister Shaun McConkey Helen McConnell Nathan McNally 《新西兰海洋与淡水研究杂志》2013,47(4):889-898
Nine weeks field work was completed during two trips in January/February and March/ April 2003 to investigate the distribution and abundance of New Zealand sea lion Phocarctos hookeri pups at Campbell Island. A total of 161 pups were tagged and a further 138 dead pups were found. A closed mark‐recapture model was used to estimate the total number of live pups (e.g., tagged plus untagged pups) at Campbell Island in April as 247 (SE = 28, 95% CI 198–308). Pup production at Campbell Island is estimated at 385, which comprises 13% of the total pup production for the species in the 2003 season. This is the first robust estimate of pup production for New Zealand sea lions at Campbell Island. The figure of 385 pups is considerably higher than any of the previous estimates reported from Campbell Island. The high level of pup mortality (36%) at Campbell Island for approximately the first 2 months after birth is higher than the 17% reported for the Auckland Islands for approximately the same period in 2003, but is similar to unusually high levels of mortality (20–30%) reported at the Auckland Islands in recent years. It was not possible to determine the cause of death of the 138 dead pups owing to scavenging and decomposition. Pups were found over the whole Island, with the exception of its northern end. Male pups were significantly heavier and faster growing than female pups over the same period. 相似文献