Lipsitz, Mario. Eros y Nacimiento fuera de la ontología griega: Emmanuel Levinas y Michel Henry, Buenos Aires, Prometeo Libros, 2004, pp. 204

Fil: Casale, Rolando Héctor. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Claude Calame. Prométhée généticien: Profits techniques et usages de métaphores. Editions Les Belles Lettres- Encre Marine, Paris, 2010, 204 pp. (Collection A présent)

Fil: Moretti, María Inés. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Thomas Van Nortwick. Somewhere I Have Never Travelled. The Hero's Journey. New York-Oxford, Oxford University Press, 1996, 204 pp.

Fil: Errecalde, Alejandro Martín. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Lipsitz, Mario. Eros y Nacimiento fuera de la ontología griega: Emmanuel Levinas y Michel Henry, Buenos Aires, Prometeo Libros, 2004, pp. 204

Fil: Casale, Rolando Héctor. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Claude Calame. Prométhée généticien: Profits techniques et usages de métaphores. Editions Les Belles Lettres- Encre Marine, Paris, 2010, 204 pp. (Collection A présent)

Fil: Moretti, María Inés. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Thomas Van Nortwick. Somewhere I Have Never Travelled. The Hero's Journey. New York-Oxford, Oxford University Press, 1996, 204 pp.

Fil: Errecalde, Alejandro Martín. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Hydrate, ice and quartz content of eight holes of Leg 204

The state of preservation of natural gas hydrate samples, recovered from 6 sites drilled during ODP Leg 204 at southern summit of Hydrate Ridge, Oregon Margin, has been investigated by X-ray diffraction (XRD) and cryo-scanning-electron-microscopy (cryo-SEM) techniques. A detailed characterization of the state of decomposition of gas hydrates is necessary since no pressurized autoclave tools were used for sampling and partial dissociation must have occurred during recovery prior to the quench and storage in liquid nitrogen. Samples from 16 distinct horizons have been investigated by synchrotron X-ray diffraction measurements at HASYLAB/ Hamburg. A full profile fitting analysis ("Rietveld method") of synchrotron XRD data provides quantitative phase determinations of the major sample constituents such as gas hydrate structure I (sI), hexagonal ice (Ih) and quartz. The ice content (Ih) in each sample is related to frozen water composed of both original existing pore water and the water from decomposed hydrates. Hydrate contents as measured by diffraction vary between 0 and 68 wt.% in the samples we measured. Samples with low hydrate content usually show micro-structural features in cryo-SEM ascribed to extensive decomposition. Comparing the appearance of hydrates at different scales, the grade of preservation seems to be primarily correlated with the contiguous volume of the original existing hydrate; the dissociation front appears to be indicated by micrometer-sized pores in a dense ice matrix.