993 resultados para 340.56
Resumo:
Quantitative records of Globorotalia puncticulata and Globorotalia inflata, the last two members of the Globorotalia (Globoconella) lineage, obtained from North Atlantic sediments collected at DSDP Site 552, ODP Site 659 and ODP Site 665, are used to examine fluctuations in the biogeographic distribution of these species in the Late Pliocene between 3 and 2 Ma. Abundance data indicate that prior to the expansion of Northern Hemisphere glaciation at about 2.5 Ma, Gr. puncticulata was an important component of the planktonic foraminiferal fauna and had a geographic distribution ranging from 2°N to at least 56°N in the North Atlantic. A previously undescribed 6 chambered variant of Gr. puncticulata is found at both Sites 659 and 665. The stratigraphic distribution of this morphotype is restricted, first occurring at 2.9 Ma and then disappearing when glacial intensity increased at 2.75 Ma (isotope stage 110). Similar declines in Gr. puncticulata abundances occurred during glacial isotope stages 102, 100, and 98 immediately prior to the extinction of Gr. puncticulata during glacial isotope stage 96. It appears that this extinction event was latitudinally diachronous within the North Atlantic, occurring earliest in the north at Site 552 (2.453 Ma), then at Site 659 (2.443 Ma) and later still in the Site 665 equatorial record (2.438 Ma). At Site 665 the first record of Gr. inflata occurs during glacial isotope stage 94 (2.416 Ma), shortly after the extinction of Gr. puncticulata. In the mid latitude North Atlantic there was a 340,000 year period following the disappearance of Gr. puncticulata when the Globoconella lineage was absent (the Gr. inflata gap). The Gr. inflata population found in the equatorial Atlantic must therefore have been introduced from the South Atlantic, probably by the South Equatorial Current. Faunal records from Sites 552 and 659 show that it was not until glacial isotope stage 78 (2.10 Ma) that Gr. inflata became widely established in the North Atlantic. Prior to this large-scale migration event, there were two limited colonisation events during glacial isotope stages 86 and 82 when Gr. inflata populations reached as far as Site 659 in the eastern North Atlantic. These incursions are believed to be reflect the entrainment of Gr. inflata within South Atlantic Central Water and the northward subsurface transport of individuals to the coastal upwelling zone off northwest Africa. It seems likely that the same mechanism was responsible for the re-establishment of the Globoconella lineage in the North Atlantic at 2.10 Ma, but in this instance additional factors, such as enhanced glacial circulation patterns and ecological changes within planktonic foraminiferal faunas, resulted in the successful expansion of Gr. inflata across the North Atlantic and the Mediterranean.
Resumo:
Mineral assemblages of DSDP Holes 436 and 438A and the upper section of Hole 439 (871.5-911.0 m sub-bottom) resemble each other and are composed of montmorillonite (probably a small portion of montmorillonite/illite mixed-layer clays), illite, chlorite, kaolinite, quartz, plagioclase, hornblende, calcite, dolomite, siderite, gypsum, pyrite, and halite. In the middle section of Hole 439 (933.5-1041.0 m), clinoptilolite is also found. In the lower section of Hole 439 (1077.5-1150.0 m), montmorillonite is not confirmed, and clinoptilolite and mixed-layer illite are found. These assemblages, which also contain detrital kaolinite, are generally found in sediments from brackish-water environments. At Site 439, more than 1000 meters of sediment might have been removed by erosion at the base.
Resumo:
C1-C5 hydrocarbons from DSDP Legs 56 and 57 sediment gas pockets were analyzed on board ship. Results suggest that the C2-C5 hydrocarbons accompanied biogenic methane and were generated at low temperatures - less than 50° C - either by microorganisms or by low-temperature chemical reactions. Neopentane, a rare constituent of petroleum, is the major C5 component (about 80%) in much of the sediment at Site 438. This compound, which appeared in smaller amounts at Sites 434, 439, 440, and 441, seems to correlate with either fractured or coarse-grained sediments. Scatter in C4 and C5 isomer ratios and generally good correlation between C3, C4 and C5 components suggest local sources for these molecules.
Resumo:
At all DSDP Leg 56 drilling sites, exotic pebbles occur commonly, throughout the cores. Chips of carbonate nodules occur only at Site 434 on the lower inner trench wall. Both exotic pebbles and carbonate nodule chips sometimes tend to be concentrated at particular levels of cores. Exotic pebbles are generally well rounded and consist of various rock types, such as dacite, andesite, basalt, tuff, gabbro, granodiorite, metaquartzite, biotite hornfels, lithic wacke, mudstone, etc., of which dacite occurs commonly at all the sites. Almost all pebbles at Site 436 and most at Sites 434 and 435 may have been rafted by ice. Some at the latter sites may have been derived by down-slope slumping. Carbonate nodules consist of microcrystalline dolomite, manganoan calcite, and siderite; CaCO3 content ranges from 22 to 65 per cent. They are also generally characterized by a high content of P2O5. The nodules are commonly rich in diatom remains, some of which indicate that the nodules are autochthonous. Some nodules contain abundant glass shards, with a modal refractive index of 1.499, almost identical to shards in the surrounding mud and ooze. These facts suggest that the carbonate nodules may have been formed diagenetically, in situ. This may throw light on problems of the formation of carbonate nodules in ancient "geosynclinal" sediments. It is also very important to point out that these carbonate nodules were formed within sediment deposited well below the CCD.
Resumo:
A presente pesquisa tem como objetivo examinar as origens da Lei n. 11.340 de 2006 (Lei Maria da Penha), e evidenciar, para tanto, os dados levantados sobre a condiçao jurídica da mulher no Brasil desde a codificaçao do primeiro Código Civil do país (Lei n. 3.071 de 1916) até a atualidade. Pretende-se, também, apresentar os instrumentos utilizados no Brasil para efetivar o diploma legal, ilustrando o quadro coevo de proteçao à mulher vítima de violência doméstica e familiar, com ênfase nas iniciativas e perspectivas de açao. O procedimento metodológico constitui-se de pesquisa bibliográfica e documental, fundada na discussao teórica do vasto acervo levantado. Tem-se por resultados, em primeiro plano, a demonstraçao de que, no Brasil, somente a partir da Constituiçao Federal de 1988 e da Lei n. 11.340 de 2006, os direitos da mulher foram, de fato, reconhecidos, restando, em igual sentido, comprovada, a influência de instrumentos internacionais de proteçao à mulher como norteadores dessa nova prática. E, sob um segundo prisma, pôde-se corroborar, face às inúmeras interpretaçoes suscitadas, a dificuldade de efetiva aplicaçao de algumas das consignaçoes previstas pela Lei Maria da Penha, contudo, comprovou-se a busca por alternativas viáveis para dotar de efetividade aludida legislaçao