995 resultados para 651.3741092


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Fil: Ercoli, César Adrián. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

During ODP Leg 107, two holes were drilled in the basement of Vavilov Basin, a central oceanic area of the Tyrrhenian sea. Hole 655B is located near the Gortani ridge in off-axis position at the western rim of the basin; Hole 651A is located on a basement swell at the axis of the basin. This paper deals with mineral chemistry, major and trace element geochemistry, and petrogenesis of the basalts recovered in the two holes. The mineralogy of the basalts is broadly homogeneous, but all of them have suffered important seawater alteration. Their major-element compositions are similar to both normal-mid-ocean-ridge-basalts (N-MORB) and back-arc-basalts (BAB) except for Na2O contents (BAB-like), and K2O which is somewhat enriched in upper unit of Hole 651 A. Their affinity with N-MORB and BAB is confirmed by using immobile trace elements such as Zr, Y, and Nb. However, basalts from the two sites present contrasting geochemical characteristics on spidergrams using incompatible elements. Hole 655B basalts are homogeneous enriched tholeiites, similar to those from DSDP Hole 373 (located on the opposite side of the basin near the eastern rim), and show affinities with enriched MORB (E-MORB). At Hole 651 A, the two basalt units are chemically distinct. One sample recovered in lower unit is rather similar to those from Hole 655B, but basalts from upper unit display calc-alkaline characteristic evidenced by the increase of light-ion-lithophile-element (LILE)/high-field-strength-element (HFSE) ratio, and appearance of a negative Nb-anomaly, making them comparable with orogenic lavas from the adjacent Eolian arc. The observed chemical compositions of the basalts are consistent with a derivation of the magmas from a N-MORB type source progressively contaminated by LILE-enriched fluids released from dehydration of the bordering subducted plate. Implications for evolution of the Tyrrhenian basin are tentatively proposed taking into consideration geochemical and chronological relationships between basalts from Leg 107 Holes 655B and 651 A, together with data from Leg 42 Site 373 and Vavilov Seamount. These data illustrate back-arc spreading in ensialic basin closely associated with the maturation of the adjacent subduction, followed by the growth of late off-axis central volcano, whereas the active subduction retreats southeastward.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

En este trabajo se llevará adelante una consideración sobre el concepto de biopolítica como una herramienta de análisis al momento de considerar la aparente paradoja que representa, por un lado, la intervención pedagógica de la Educación Física en la institución escolar bonaerense y, por el otro, la presencia del deporte escolar en los Torneos Juveniles Bonaerenses. Se pretende mostrar aquí como la paradoja entre pedagogía y deporte competitivo, mediatizada por una intencionalidad universalista de política social, se disuelve en este concepto acuñado por Foucault a finales de los años '70. Este concepto como categoría de análisis presentaría así un fuerte potencial explicativo que bien podría posibilitar el desarrollo de nuevos enfoques al momento de historizar las prácticas de la disciplina.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Fil: López, Silvina Lucrecia. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

En este trabajo se llevará adelante una consideración sobre el concepto de biopolítica como una herramienta de análisis al momento de considerar la aparente paradoja que representa, por un lado, la intervención pedagógica de la Educación Física en la institución escolar bonaerense y, por el otro, la presencia del deporte escolar en los Torneos Juveniles Bonaerenses. Se pretende mostrar aquí como la paradoja entre pedagogía y deporte competitivo, mediatizada por una intencionalidad universalista de política social, se disuelve en este concepto acuñado por Foucault a finales de los años '70. Este concepto como categoría de análisis presentaría así un fuerte potencial explicativo que bien podría posibilitar el desarrollo de nuevos enfoques al momento de historizar las prácticas de la disciplina.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Using methods of analysis from organic geochemistry and organic petrography, we investigated six Pliocene to Maestrichtian samples from DSDP Site 612 and five Pliocene to Eocene samples from DSDP Site 613 for the quantity, type, and thermal maturity of organic matter. At both sites, organic carbon content is low in the Eocene samples (0.10 to 0.20%) and relatively high in the Pliocene/Miocene samples (0.87 to 1.15%). The Maestrichtian samples from Site 612 contain about 0.6% organic carbon. The organic matter is predominantly terrigenous, as indicated by low hydrogen index values from Rock-Eval pyrolysis and the dominance of long-chain wax alkanes in the extractable hydrocarbons. The organic matter is at a low level of thermal maturity; measured vitrinite reflectance values were between 0.27 and 0.44%.