Northwards and eastwards velocities extracted from a historical run (for the year 2000) of the UVic Earth System Climate Model of Weaver et al. (2001)

This study provides a theoretical assessment of the potential bias due to differential lateral transport on multi-proxy studies based on a range of marine microfossils. Microfossils preserved in marine sediments are at the centre of numerous proxies for paleoenvironmental reconstructions. The precision of proxies is based on the assumption that they accurately represent the overlying watercolumn properties and faunas. Here we assess the possibility of a syn-depositional bias in sediment assemblages caused by horizontal drift in the water column, due to differential settling velocities of sedimenting particles based on their shape, size and density, and due to differences in current velocities. Specifically we calculate the post-mortem lateral transport undergone by planktic foraminifera and a range of other biological proxy carriers (diatoms, radiolaria and fecal pellets transporting coccolithophores) in several regions with high current velocities. We find that lateral transport of different planktic foraminiferal species is minimal due to high settling velocities. No significant shape- or size-dependent sorting occurs before reaching the sediment, making planktic foraminiferal ideal proxy carriers. In contrast, diatoms, radiolaria and fecal pellets can be transported up to 500km in some areas. For example in the Agulhas current, transport can lead to differences of up to 2°C in temperature reconstructions between different proxies in response to settling velocities. Therefore, sediment samples are likely to contain different proportions of local and imported particles, decreasing the precision of proxies based on these groups and the accuracy of the temperature reconstruction.

Fossil manganese deposits buried within DSDP/ODP cores, Legs 1-126

Probable in-situ manganese deposits larger than 1 cm in diameter buried in ODP/DSDP cores were selected for study after examining previous descriptions of the manganese deposits in site reports and the ODP data base. Most of the selected samples from 11 cores occur at or just above sedimentary hiatuses or in slowly deposited sediments and are overlain by rapidly deposited sediments of biogenic, terrigenous or volcanogenic origin. The changes in sedimentation recorded in the lithostratigraphic sections around these deposits are closely related to changes in tectonic evolution, deep water circulation or biological productivity at the sites. The similarity in composition and structure of the buried deposits to those of the modern manganese nodules and crusts with no evidence of post-depositional change suggest that buried manganese deposits may be used as indicators of past sedimentary conditions during which they formed. Their major components are hydrogenetic and earlydiagenetic manganese minerals as well as detrital minerals. The characteristics of these manganese deposits suggests that similar processes of deposition have taken place since the Paleogene or older.

Patrimonio y producción en los entornos rurales de Buenos Aires. San José de Flores, 1800-1875

En el presente artículo reconstruimos a partir de la información proporcionada por testamentos e inventarios post mortem las características productivas de los establecimientos frutihortícolas y cerealeros del partido de San José de Flores. Abordamos, además, el estudio de los esquemas de inversión de los propietarios y/o arrendatarios de estas unidades esbozando su perfil socioeconómico y político, deteniéndonos especialmente en aquellos que han accedido a la propiedad legal de los terrenos.

Nuevas iluminaciones en las sombras biográficas de Alejandro Sawa - Max Estrella (1892- 1896)

Las nuevas noticias referidas a la biografía de Alejandro Sawa propor¬cionan datos de gran interés para desentrañar las andanzas de la bohemia Hispanoamérica en el París de finales del siglo XIX, a la sombra de la Casa Editorial Garnier y de las tertulias presididas por P. Verlaine, así como para descifrar las claves históricas diseminadas por Valle-Inclán en Luces de bohemia, homenaje póstumo a la memoria del introductor de las novedades literarias francesas en la cultura española de fin de siglo, Alejandro Sawa - Max Estrella.