945 resultados para stone fragmentation
Resumo:
A high-resolution record of foraminiferal fragmentation (a dissolution indicator) for the last 250 k.y. (isotopic Stages 1 to 7) is identified in the upper 61.9 m of Ocean Drilling Program (ODP) Hole 828A, west Vanuatu. This record is comparable in detail to the atmospheric CO2 record and the d18O stack. Phase shifts between preservation spikes and maximum ice volumes (d18O of Globigerinoides sacculifer) are analogous to those on Ontong Java Plateau. Mass spectrometer (AMS14C) dating of a sample taken at the base of dissolution cycle B1 and the position of the last glacial maximum indicates a lag in time of ~8 k.y. in the Vanuatu region for the last glacial termination. When dissolution spikes are compared with minimum ice volumes there is no phase shift for the last two glacial terminations. The difference between Vanuatu and Ontong Java Plateau may be explained by local CO2 sinks and the interplay between intermediate and deep water masses. Terrigenous input increasingly affected sediment of Hole 828A on the North d'Entrecasteaux Ridge (NDR) as it approached Espiritu Santo Island. Mud and silt suspended in mid-water flows become important after 125 ka, while turbidites bypass the New Hebrides Trench only towards the last glacial maximum (LGM). Terrigenous supply seems to affect the lysocline profile that changed from an "open ocean" to a "near continent" type, thus favoring dissolution. Fragmentation of planktonic foraminifers is a more sensitive indicator of lysocline variations than is foraminiferal susceptibility to dissolution, the foraminiferal dissolution index, the abundance of benthic foraminifers, or CaCO3 content. A modern foraminiferal lysocline for the neighboring area (between 10°S and 30°S, and 160°E and 180°E) is found at 3.1 km below sea level, compared to west Vanuatu where it is shallower. The past lysocline level was deeper than 3086 m during intervals of dissolution minima, and ranged from ~2550 to 3000 m during intervals of dissolution maxima. The high sedimentation rates (in the order of 10 to 50 cm/k.y.) found in Hole 828A offer a great potential for future high-resolution studies either in this hole or other western localities along the NDR. Areas of high sedimentation near continental regions have been discarded for paleoceanographic and/or paleoclimatic studies. Nonetheless, conditions analogous to those found in Hole 828A are expected to occur in many trench areas around the world where mid-water flows have preserved as yet undiscovered fine high-resolution sedimentary records.
Resumo:
En Harry Potter and the Philosopher's Stone, texto inaugural del ciclo novelístico de J. K. Rowling, aparecen diversos elementos y situaciones que inscriben el relato dentro del género bildungsroman (o novela de formación) y que a su vez son constitutivos del monomito estudiado por Joseph Campbell. Dentro de ese marco, el presente trabajo analizará la función que desempeña la palabra en el desarrollo del protagonista de la novela. Se sostendrá que la adquisición y el dominio pleno de una palabra permiten construir la subjetividad del personaje, quien valiéndose de esta herramienta se volverá capaz de disipar sus inquietudes frente a lo desconocido y al peso de la voz popular. El estudio se centrará en el nombre del antagonista, Lord Voldemort, su influencia en la saga y en cuán importante es que Harry sea capaz de nombrarlo por ese apelativo. Para este abordaje se utilizarán algunos conceptos de diversas disciplinas que nos permitirán advertir la injerencia de la palabra en la novela seminal de esta serie literaria y en el tránsito del personaje por la compleja senda del héroe
Resumo:
En Harry Potter and the Philosopher's Stone, texto inaugural del ciclo novelístico de J. K. Rowling, aparecen diversos elementos y situaciones que inscriben el relato dentro del género bildungsroman (o novela de formación) y que a su vez son constitutivos del monomito estudiado por Joseph Campbell. Dentro de ese marco, el presente trabajo analizará la función que desempeña la palabra en el desarrollo del protagonista de la novela. Se sostendrá que la adquisición y el dominio pleno de una palabra permiten construir la subjetividad del personaje, quien valiéndose de esta herramienta se volverá capaz de disipar sus inquietudes frente a lo desconocido y al peso de la voz popular. El estudio se centrará en el nombre del antagonista, Lord Voldemort, su influencia en la saga y en cuán importante es que Harry sea capaz de nombrarlo por ese apelativo. Para este abordaje se utilizarán algunos conceptos de diversas disciplinas que nos permitirán advertir la injerencia de la palabra en la novela seminal de esta serie literaria y en el tránsito del personaje por la compleja senda del héroe
Resumo:
Early diagenetic ultrastructural alterations of benthic foraminifers of the genera Elphidium and Ophthalmina from the shallow water sediments of the Kiel Bight were investigated by scanning electron microscopy. Pure solution patterns were deduced from supplementary experiments.//Several carbonate destroying processes can be specified by ultrastructural patterns of the shell surfaces. Based on these patterns three zones are established, each showing different mechanisms of shell fragmentation: 1) zone of abrasion, 2) zone of disintegration, 3) zone of corrosion. This zonation depends on the water depth and is caused primarily by water agitation and by under saturation of the bottom water with respect to carbonate.