679 resultados para MMS


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This paper discusses the occurrence of manganese-rich concretions in the lakes of Northern Savolax in Eastern Finland. The samples were collected in the summer of 1905 and left to dry for 2 months at room temperature. The quantity of H2O mentionned in the analysis was obtained by dessication at 155°C. The amount of Mn is calulated as MnO2 although other valences might be present in the samples. The contents in CO2 and organic substances was not determined. J. Aschan determined that as a general rule, in Finland the manganese rich lake deposits are rather associated with soft bottom sediments while the iron rich deposits are more assocaited with hard or sandy bottoms.

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The cores described are taken during the R/V Caryn Cruise 25 in August-September 1951 by the Woods Hole Oceanographic Institution. A total of 11 cores were recovered and are available at Woods Hole Oceanographic Institution for sampling and study.

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The cores described are taken during the USS San Pablo Cruises 10 and 11 in 1952 by the Scripps Institute of Oceanography. A total of 21 cores were recovered and are available at Scripps Institute of Oceanography for sampling and study.

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Deep-sea sediment cores from Scripps Institution of Oceanography's ANTIPODE Expedition were described to identify visually distinct units based on color, texture, or other feature, sedimentary structures, lithology and abundance of component grains, and paleontology. Sixty-eight cores were examined, of which 34 are large diameter piston cores. Photographs and graphic lithology legs are included as PLATES 1-48. ANTIPODE Expedition recovered cores from: the Monterey-Ascension Fan, the Northeast Pacific, the Aleutians, the Northwest Pacific, the Philippine Sea, Indonesia, the Tonga Ridge, the Seychelles, Chagos Archipelago, the Mid-Indian Ridge, the Bay of Bengal, near Sumatra, and near the Cocos Island in the Indian Ocean. The purpose of this report is to present sufficient basic data on ANTIPODE cores for invesiigators to choose samples for their own research.

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A near-bottom geological and geophysical survey was conducted at the western intersection of the Siqueiros Transform Fault and the East Pacific Rise. Transform-fault shear appears to distort the east flank of the rise crest in an area north of the fracture zone. In ward-facing scarps trend 335° and do not parallel the regional axis of spreading. Small-scale scarps reveal a hummocky bathymetry. The center of spreading is not a central peak but rather a 20-40 m deep, 1 km wide valley superimposed upon an 8 km wide ridge-crest horst. Small-scale topography indicates widespread volcanic flows within the valley. Two 0.75 km wide blocks flank the central valley. Fault scarps are more dominant on the western flank. Their alignment shifts from directions intermediate to parallel to the regional axis of spreading (355°). A median ridge within the fracture zone has a fault-block topography similar to that of the East Pacific Rise to the north. Dominant eastward-facing scarps trending 335° are on the west flank. A central depression, 1 km wide and 30 m deep, separates the dominantly fault-block regime of the west from the smoother topography of the east flank. This ridge originated by uplift due to faulting as well as by volcanism. Detailed mapping was concentrated in a perched basin (Dante's Hole) at the intersection of the rise crest and the fracture zone. Structural features suggest that Dante's Hole is an area subject to extreme shear and tensional drag resulting from transition between non-rigid and rigid crustal behavior. Normal E-W crustal spreading is probably taking place well within the northern confines of the basin. Possible residual spreading of this isolated rise crest coupled with shear drag within the transform fault could explain the structural isolation of Dante's Hole from the remainder of the Siqueiros Transform Fault.

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The cores and dredges described in this report were taken on the Southern Borderland (SOB) Expedition in February-March 1960 by the Scripps Institution of Oceanography from the R/V Spencer F. Baird. A total of 34 cores and dredges were recovered and are available at Scripps for sampling and study.

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The cores described in this report were taken on the CLIMAX I Expedition in September 1968 by the Scripps Institution of Oceanography from the R/V Horizon. A total of 3 cores were recovered and are available at Scripps for sampling and study.

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The cores and dredges described in this report were taken on the PROA Expedition in April 1962 until August 1962 by the Scripps Institution of Oceanography from the R/V Spencer F. Baird. A total of 180 cores and dredges were recovered and are available at Scripps for sampling and study.

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A 0.25 m US Naval Electronics Lab box corer was used to take replicate samples from an oligotrophic bottom under the North Pacific Central Water Mass (approx. 28 degrees N, 155 degrees W). The bottom is a red clay with manganese nodules at a depth of 5500-5800 m. Macrofaunal density ranges from 84 to 160 individuals per m super(2) and is therefore much the same as in Northwest Atlantic Gyre waters. Of the macrofaunal taxa, polychaetes dominate (55 per cent), followed by tanaids (18 per cent), bivalves (7 per cent), and isopods (6 per cent). Meiofaunal taxa were only partially retained by the 297 micrometer screen used in washing. Even then, they are 1.5-3.9 times as abundant as the microfaunal taxa, with nematodes being numerically dominant by far. Foraminifera seem to comprise an important portion of the community, but could not be assessed accurately because of the inability to discriminate living and dead tests. Remains of what are probably xenophyophoridans are also very important, but offer the same problem. Faunal diversity is extremely high, with deposit feeders comprising the overwhelming majority. Most spp are rare, being encountered only once. The distributions of only 3 spp show any significant deviation from randomness. The polychaete fauna from box cores collected from 90 m to the north was not significantly different from that of the principal study locality. Concordance appeared at several taxonomic levels, from spp through microfaunal/ meiofaunal relationships. As a result, the variation in total animal abundance shows aggregation among cores. The authors discuss Sokolova's concept of a deep-sea oligotrophic zone dominated by suspension feeders, and reconcile it with our present findings. The high diversity of the fauna combined with the low food level contradict theories that relate diversity directly with productivity.

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The cores described in this report were taken on JAPANYON Expedition in June-September 1961 by Scripps Institution of Oceanography from, the R/V Spencer F. Baird. A total of 85 cores and dredges were recovered and are available at Scripps for sampling and study. The coring sites are all in the eastern tropical central Pacific.

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The data given in this and previous communications is insufficient to assess the quantitative role of these supplementary sources in the Indian Ocean, but they do not rule out their local significance. Elucidation of this problem requires further data on the characteristics of the composition and structure of nodules in various different metallogenic regions of the ocean floor. A study of the distribution of ore elements in nodules both depthwise and over the area of the floor together with compilation of the first schematic maps based on the results of analyses of samples from 54 stations) enables us to give a more precise empirical relation between the Mn, Fe, Ni, Cu, and Co contents in Indian Ocean nodules, the manganese ratio and the values of the oxidation potential, which vary regularly with depth. This in turn also enables us to confirm that formation of nodules completes the prolonged process of deposition of ore components from ocean waters, and the complex physico-chemical transformations of sediments in the bottom layer. Microprobe investigation of ore rinds revealed the nonuniform distribution of a num¬ber of elements within them, owing to the capacity of particles of hydrated oxides of manganese and iron to adsorb various elements. High concentration of individual elements is correlated with local sectors of the ore rinds, in which the presence of todorokite, in particular, has been noted. The appearance of this mineral apparently requires elevated Ca, Mg, Na, and K concentrations, because the stable crystalline phase of this specific mineral form of the psilomelane group may be formed when these cations are incorporated into a lattice of the delta-MnO2 type.

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The cores and dredges described in this report were taken on the HILO Expedition in March-April 1962 by Scripps Institution of Oceanography from, the R/V Stranger. A total of 21 cores and dredges were recovered and are available at Scripps for sampling and study.

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The ability of the hydrated oxides of manganese and iron to adsorb ions from solution (scavenging) is considered in relation to some problems in marine geology, chemistry, and biology. In the ferruginous sediments of the Pacific Ocean, iron oxides are accompanied by titanium, cobalt, and zirconium in amounts proportional to the iron content. Similarly, copper and nickel are linearly related to the manganese content. These observations are explained on the basis of scavenging. An electrochemical theory for the formation of manganese nodules is presented. Marine sediments are classified on the basis of the geosphere in which the solid phases originate. The distribution of certain ionic species in sea water between the solid and aqueous phases is considered on the basis of scavenging and co-ordination compound theory. The concentration of minor elements by members of the marine biosphere is explained either by the direct uptake of the element or by the uptake of iron or manganese oxides with the accompanying scavenged element.

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The cores and dredges described in this report were taken during the Swedish Deep Sea Expedition from July 1947 until October 1948 aboard the S/S Albatross (Boström). A total of 370 cores and trawls during this World circumnavigation.

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The cores and dredges described are taken during the MUKLUK expedition of the R/V Spencer Baird in July-August 1957 by the Scripps Institute of Oceanography. A total of 31 cores and dredges were recovered and are available at Scripps Institute of Oceanography for sampling and study.