Vigo y la Expo Internacional Novísima Poesía/69 (CAV-ITDT, 1969) como materialización del intercambio. Posibilidades del concretismo

El epígrafe de Romero Brest (1969) expresa la incertidumbre respecto de la Expo Internacional Novísima Poesía/69 (1969, CAV-ITDT). ¿Por qué este desconcierto ante el contenido de la exposición? ¿Qué circunstancias en esos años hacen viable la experimentación, incluyendo poesía concreta? ¿Cómo ingresa ésta en el circuito institucional? ¿Qué formas de positividad (Foucault, 1990) adquieren los términos experimentación, concretismo, vanguardia? Las conexiones de la Expo con el concretismo se producen a partir del sistema de intercambios que genera Vigo con artistas de otros países; dejan entrever las fricciones con el modo de entender la vanguardia y las inscripciones de sentido del internacionalismo

Sulfide petrology of basalts at DSDP Holes 69-504B and 69-505B

Primary sulfide mineralization in basalts of the Costa Rica Rift occurs mainly in chrome-spinel-bearing olivine tholeiites. Primary sulfides form both globules, consisting of quenched single-phase solid solutions, and irregular polymineralic segregations of pyrrhotite, chalcopyrite, cubanite, and pentlandite. Two types of sulfide solid solutions - iron-nickel (Mss) and iron-copper (Iss) - were found among sulfide globules. These types appear to have formed because of sulfide-sulfide liquid immiscibility in the host magmas; as proved by the presence of globules with a distinct phase boundary between Mss and Iss. Such two-phase globules are associated with large olivine phenocrysts. Inhomogeneties among the globule composition likewise are caused by sulfide-sulfide immiscibility. Secondary sulfides form irregular segregations and veins consisting of pyrite, marcasite, and chalcopyrite.

Mechanical properties and comparisons of dynamic and static Young's moduli at DSDP Holes 69-504B, 70-504B and 83-504B

From laboratory tests under simulated downhole conditions we tentatively conclude that the higher the triaxial-compressive strength, the lower the drilling rate of basalts from DSDP Hole 504B. Because strength is roughly proportional to Young's modulus of elasticity, which is related in turn to seismic-wave velocities, one may be able to estimate drilling rates from routine shipboard measurements. However, further research is needed to verify that P-wave velocity is a generally useful predictor of relative drilling rate.