Petrology and geochemistry of the Izu-Bonin Forearc tephras

Numerous marine tephra layers cored at Sites 792 and 793 in the Izu-Bonin forearc region offer additional information about the timing and spatial characteristics of arc volcanism and the evolution of island arcs. Explosive volcanism along the Izu-Bonin Arc, with maxima just before rifting of the arc at ~40 and 5-0 Ma, produced black and white tephras of variable grain sizes and chemical compositions. Most of the tephras belong chemically to low-K and low-alkali tholeiitic rock series with a few tephra of the high-K and alkalic rock series. Most of the tephras (low-K series) were derived from the Izu-Bonin Arc, although a few were produced far to the west of the Izu-Bonin Arc (e.g., from the Ryukyu Arc). Black tephras may have come from nearby sources, such as Aogashima, Sumisu, and Torishima islands. The high-K series of tephras, within the sediments younger than 3 Ma, may reflect thickening of the island-arc crust.

David García Pérez y Carolina Olivares Chávez (Eds). La persistencia de los clásicos. Supplementum IV, Noua Tellus, Anuario del Centro de Estudios Clásicos. Universidad Nacional Autónoma de México, Instituto de Investigaciones Filológicas, México, 2012, 126 pp.

Fil: Zamperetti Martín, Deidamia Sofía. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Age determination, planktic foraminifera and stable istopes of sediment core MSM05/5_712-2

A sediment core from the West Spitsbergen continental margin was studied to reconstruct climate and paleoceanographic variability during the last ~9 ka in the eastern Fram Strait. Our multiproxy evidence suggests that the establishment of the modern oceanographic configuration in the eastern Fram Strait occurred stepwise, in response to the postglacial sea-level rise and the related onset of modern sea-ice production on the shallow Siberian shelves. The late Early and Mid Holocene interval (9 to 5 ka) was generally characterized by relatively unstable conditions. High abundance of the subpolar planktic foraminifer species Turborotalita quinqueloba implies strong intensity of Atlantic Water (AW) inflow with high productivity and/or high AW temperatures, resulting in a strong heat flux to the Arctic. A series of short-lived cooling events (8.2, 6.9. and 6.1 ka) occurred superimposed on the warm late Early and Mid Holocene conditions. Our proxy data imply that simultaneous to the complete postglacial flooding of Arctic shallow shelves and the initiation of modern sea-ice production, strong advance of polar waters initiated modern oceanographic conditions in the eastern Fram Strait at ~5.2 ka. The Late Holocene was marked by the dominance of the polar planktic foraminifer species Neogloboquadrina pachyderma, a significant expansion of sea ice/icebergs, and strong stratification of the water column. Although planktic foraminiferal assemblages as well as sea surface and subsurface temperatures suggest a return of slightly strengthened advection of subsurface Atlantic Water after 3 ka, a relatively stable cold-water layer prevailed at the sea surface and the study site was probably located within the seasonally fluctuating marginal ice zone during the Neoglacial period.

Susana Zanetti y otros, Las cenizas de la huella. Linajes y figuras de artista en torno al modernismo. Rosario, Beatriz Viterbo Editora, 1997, 126 págs.

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

Susana Zanetti y otros, Las cenizas de la huella. Linajes y figuras de artista en torno al modernismo. Rosario, Beatriz Viterbo Editora, 1997, 126 págs.

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

David García Pérez y Carolina Olivares Chávez (Eds). La persistencia de los clásicos. Supplementum IV, Noua Tellus, Anuario del Centro de Estudios Clásicos. Universidad Nacional Autónoma de México, Instituto de Investigaciones Filológicas, México, 2012, 126 pp.

Fil: Zamperetti Martín, Deidamia Sofía. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.