979 resultados para As interstitial couples


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Chemical analyzes show that interstitial waters from ore-bearing bottom sediments of the Atlantis II and Discovery Deeps are enriched in Fe, Mn, Cu, Ni, Co, Zn, Pb, and Cd compared to sea water. Enrichment factors of these trace elements in the interstitial waters of the Atlantis II Deep relative to the sea water vary within the following ranges: for Fe from 100 to 7000, for Mn from 19047 to 32738, for Zn from 500 to 1600, for Pb from 78333 to 190000, for Cu from 107 to 654. Comparison of average weighted concentrations of Fe, Mn, Zn, Pb, Cu, Ni in the bottom sediments and the interstitial waters of the Atlantis II Deep indicates common regularities and good relationship in distribution of these elements along sediment cores. Differences in concentrations and distribution of the studied trace elements in the interstitial waters of the Atlantis II and Discovery Deeps result from different chemical compositions of hydrothermal fluids entering these deeps.

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We determined oxygen isotopic compositions of interstitial water (IW) recovered during Ocean Drilling Program Leg 207. Five sites were cored (3200- to 1900-m water depth) on Demerara Rise off Suriname, South America, recovering a Cenomanian-Paleogene sedimentary sequence consisting of black shales and chalks. A total of 115 IW oxygen isotopic analyses are presented.

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The landward part of the 7 km wide sabkha at Umm Said, SE Qatar, is filled with a stagnant brine virtually saturated with halite. Recent dolomite occurs in the sabkha sediments, the quantity being fully accounted for by the amount of Mg++ ions lost from the interstitial brine. The existence of a reflux system in the seaward parts of the sabkha was established. It was not, however, possible to gi ve any unequivocal demonstration of the effect of this potential system for dolomitization . Although both a reflux mechanism and Recent dolomite formation occur in this tidal flat, the first process has apparently not influenced the second sufficiently to permit the demonstration of reflux dolomitization.