El mundo de Homero, de Pierre Vidal-Naquet, Buenos Aires, Fondo de Cultura Económica, 2001, 123 páginas

Fil: Sarachu, Pablo. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Sonia Contardi, José Martí. La lengua del destierro. Rosario, Universidad Nacional de Rosario Editora, 1995, 123 páginas

Fil: Basile, Teresa. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Franco Cardini et al. L'Europa del pellegrinaggio, Rimini: II Cerchio, 1998, 123 páginas

Fil: Disalvo, Santiago Aníbal. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Franco Cardini et al. L'Europa del pellegrinaggio, Rimini: II Cerchio, 1998, 123 páginas

Fil: Disalvo, Santiago Aníbal. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

El mundo de Homero, de Pierre Vidal-Naquet, Buenos Aires, Fondo de Cultura Económica, 2001, 123 páginas

Fil: Sarachu, Pablo. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Sonia Contardi, José Martí. La lengua del destierro. Rosario, Universidad Nacional de Rosario Editora, 1995, 123 páginas

Fil: Basile, María Teresa Gabriela. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Chemistry of altered basalts from ODP Hole 123-765D

Volcanic basement recovered at Hole 765D is characterized by nonpervasive, oxidative alteration, typical of seafloor weathering. Chilled margins and the mesostasis of the lavas are variably altered to assemblages of celadonite, Fe-oxyhydroxides, zeolites, and calcite with trace saponite. Plagioclase is partially altered to Ca-Na zeolites and/or albite. Well-developed alteration halos parallel fracture surfaces and extend several centimeters into the surrounding rock. These clay-rich halos are enriched in K2O and Fe2O3 relative to the adjacent clay-poor rock. The halos and adjacent rock are characterized by d18O values 2 per mil-3 per mil higher than those of fresh MORB. The "freshness" of the samples and the scarcity of saponite suggest that the duration of seawater circulation was short-lived. Albitization of plagioclase indicates that the volcanic rocks were altered initially at low temperatures and were subsequently reheated off-axis in a closed environment. Reheating did not result in significant modification of the bulk composition of the crust.

Petrography and geochemistry of organic matter in Triassic and Cretaceous sediments from the Wombat and Exmouth Plateau

Triassic (Carnian-Rhaetian) continental margin sediments from the Wombat Plateau off northwest Australia (Sites 759, 760, 761, and 764) contain mainly detrital organic matter of terrestrial higher plant origin. Although deposited in a nearshore deltaic environment, little liptinitic material was preserved. The dominant vitrinites and inertinites are hydrogen-lean, and the small quantities of extractable bitumen contain w-alkanes and bacterial hopanoid hydrocarbons as the most dominant single gas-chromatography-amenable compounds. Lower Cretaceous sediments on the central Exmouth Plateau (Sites 762 and 763) farther south in general have an organic matter composition similar to that in the Wombat Plateau sediments with the exception of a smaller particle size of vitrinites and inertinites, indicating more distal transport and probably deposition in deeper water. Nevertheless, organic matter preservation is slightly better than in the Triassic sediments. Long-chain fatty acids, as well as aliphatic ketones and alcohols, are common constituents in the Lower Cretaceous sediments in addition to n-alkanes and hopanoid hydrocarbons. Thin, black shale layers at the Cenomanian/Turonian boundary, although present at several sites (Sites 762 and 763 on the Exmouth Plateau, Site 765 in the Argo Abyssal Plain, and Site 766 on the continental margin of the Gascoyne Abyssal Plain), are particularly enriched in organic matter only at Site 763 (up to 26%). These organic-matter-rich layers contain mainly bituminite of probable fecal-pellet origin. Considering the high organic carbon content, the moderate hydrogen indices of 350-450 milligrams of hydrocarbon-type material per gram of Corg, the maceral composition, and the low sedimentation rates in the middle Cretaceous, we suggest that these black shales were accumulated in an area of oxygen-depleted bottom-water mass (oceanwide reduced circulation?) underlying an oxygen-rich water column (in which most of the primary biomass other than fecal pellets is destroyed) and a zone of relatively high bioproductivity. Differences in organic matter accumulation at the Cenomanian/Turonian boundary at different sites off northwest Australia are ascribed to regional variations in primary bioproductivity.