373 resultados para Ore deposits.


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The cores described in this report were taken during the CHINOOK Expedition in July to August 1956 by the Scripps Institution of Oceanography from the R/V Spencer F. Baird. A total of 20 cores and dredges were recovered and are available at Scripps for sampling and study.

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In 1905, the Percy Sladen Trust Expedition, under the supervision of Stanley Gardiner in H.M.S. 'Sealark' made an extensive cruise in the Indian Ocean. The author received 79 samples from Mr. Gardiner which were thoroughly examined.

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The cores described in this report were taken on the FANFARE Expedition in July 1959 by Scripps Institution of Oceanography from the R/V H. M. Smith and the R/V Spencer F. Baird. A total of 49 cores and dredges were recovered and are available at Scripps for sampling and study. The coring sites, all in the eastern tropical central Pacific.

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The research cruise SO79 with RV SONNE (April 18 to June 09 1992) aimed to assess the impact of a potential mining activity on the sensitive deep-sea ecosystem of the Peru Basin. Up to now only results of reconnaissance surveys of the extended manganese nodule field discovered in 1978 in the Peru Basin are available. The hydroacoustic, sedimentological, and geochemical studies on data and sample material of SO79 came to the following results: a small-scaled variation in thickness respectively type of surface sediments shown by the sediment echosounder respectively the side-scan-sonar is assumably due to variations in deposition or erosion. The composition of sediments is controlled by climatic cycles of different length which were caused by the variable influence of glaciation of the northern hemisphere. We think that during the quaternary a deep-water circulation reduced in intensity and O2-content may have produced a suboxic diagenetic environment which led to a remobilization and redeposition of Mn forming manganese nodules in the oxic surface sediments. Near the distinct redox boundary at about 10 cm depth the growth conditions for nodules are extremely favourable. Due to the great variability of sediments the impact of deep-sea mining will be highly variable and the disturbance of the seafloor will change the ecosystem considerably.

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The cores and dredges described in this report were taken during the VEMA 15 Expedition from October 1958 until July 1959 by the Lamont Geological Observatory, Columbia University from the R/V Vema. A total of 410 cores and dredges were recovered and are available at Lamont-Doherty Earth Observatory for sampling and study.

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Prof. H. H. W. Menard has brought together nearly all that was known of the Pacific geology in the early 1960s. His book contains a particular chapter on manganese nodules giving a stimulating review of the features and processes known to govern their distribution and chemical composition.

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Baltic sediments have been studied by Behrens, Munthe, Küppers, Spethmann, Apstein, Sjöstedt, Pratje and the writer. The following types of sediments have been observed: varved and non-varved late-glacial clays, gray and black, post-glacial muds, and sands. The organic content of late-glacial clays ordinarily is less than 1.3 per cent, and of post-glacial muds more than 3 per cent. Sediments containing intermediate quantities are scarce. This can be explained as a result of the changed balance between organic and inorganic sedimentation when the glacial period ended; the abundance of fresh detritus then suddenly ceased and inorganic sedimentation became very much slower than before; consequently, the relative amount of organic detritus increased. As most of the material was not subjected to biological analysis, it has not been possible to distinguish different ages among post-glacial sediments.

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The cores and dredges described at this site were taken on the RIDA cruise from 1 May until 25 May 1984 by the Muséum National d'Histoire Naturelle from the R/V Marion Dufresne. A total of 45 cores and dredges were recovered along with underwater camera runs. They are available at MNHN for sampling and study.

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Captain Wharton, the Hydrographer of the Admiralty sent to the author a series of the deposit-samples collected in the Indian and Antarctic Oceans during the expeditions in 1887 of H.M.S. Flying Fish, H.M.S. Egeria and H.M.S. Investigator. These deposits were submitted to careful microscopical examination and chemical analysis.