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Monthly prevalence of canine rabies in Argentina (1971-1993), Bolivia (1987-1993) and Paraguay (1976-1993) were analyzed to identify seasonal cycles of the disease. Moreover, data to forecast the evolution of rabies were studied.The time series analysis was employed. This included the Fourier Harmonie Analysis and Box-Jenkins ARIMA-SARIMA multiplicative models.Cycles were detected in Argentina and Paraguay. The seasonal cycles occurred at the end of winter and spring. Seasonal cycles were about every four years, and the next peak was estimated for 1997., Se estudió el número de casos mensuales de rabia canina en Argentina (1971-1993), Bolivia (1987-1993) y Paraguay (1976-1993), a fin de identificar fluctuaciones regulares y predecir el comportamiento futuro de la rabia en dichos países. Los métodos empleados consistieron en análisis de series de tiempo, incluyendo el análisis armónico de Fourier y los modelos multiplicativos ARIMA-SARIMA de Box-Jenkins.Se evidenciaron ciclos en Argentina y Paraguay. La estacionalidad ocurrió a fines de invierno y primavera. Las recurrencias mostraron un período de aproximadamente cuatro años, pronosticándose la próxima alza para 1997. &nbsp

The textural analysis of two gravity cores reveals that the sediments in the Central and Eastern Bransfield subbasins are mainly clayey silts with some coarser levels of sandy silts. While a turbidity origin can be attributed to the coarser levels, other processes should control the deposition of the fine fractions, e.g. settling of suspended particles, ice-rafting and ash airfall Chlorite, smectite and illite are the dominant clay minerals. While a detritic origin can be attributed to chlorite and illite the diagenetic alteration of volcanic glass origin is the most likely origin for smectite even though a minor detritic contribution cannot be completely enied Higher sand and smectite contents, and more abundant ash laminated facies suggest that the volcanic influence is higher in the Eastern Bransfield core than in the Central Bransfield core Se describen las características físicas, granulométricas y mineralógicas de los sedimentos de dos testigos de gravedad procedentes de las subcuencas Oriental y Central de Bransfield. Los sedimentos están compuestos mayoritariamente por limos arcillosos laminados con algunos niveles de limos arenosos. A los niveles más groseros se les atribuye tentativamente un origen turbidítico. No obstante, la decantación pelágica, el transporte por icebergs, y las lluvias de cenizas han podido jugar un papel significativo en la acumulación de los sedimentos más finos. Los minerales mayoritarios en la fracción arcilla son la clorita, la esmectita y la ¡Hita. A la clorita y a la ¡Ilita se les atribuye un origen detrítico, mientras que la alteración diagenética del vidrio volcánico es la fuente más probable para la esmectita. Los mayores contenidos de arena, cenizas, facies laminadas y esmectita en el testigo de la subcuenca Oriental de Bransfield indicarían una mayor influencia volcánica en este que en el testigo de la subcuenca Central

Swath bathymetry and geophysical data of the island of Hierro show that the western flank of the island is affected, at least, by two major catastrophic slope failures. One of the two, called the El Golfo debris avalanche, led to the deposition of a sedimentary body of about 150 km3 of volcanic rock debris on the upper rise. The second major instability event, named the Canary debris flow, originated at the base-of-slope of the island of Hierro, and involved a larger amount of remobilized material. New evidences suggest that the Canary debris flow is the oldest in age. As a consequence of the Canary slide event, oversteeping and undermining of the lower island flanks occurred and subsequently triggered the El Golfo debris avalanche, whose deposits covered and obliterated the source area of the Canary debris flow. The triggering of El Colfo debris avalanche seems to be related also to the rift zones in the island of Hierro. From the establishment of the complex relationships between both slides, the El Golfo debris avalanche has been dated between 12.000 and 6.000 yBP Nuevos datos de batimetría y geofísica marinas de la isla de Hierro demuestran que el flanco occidental de la isla está afectado por un deslizamiento que depositó 150 km3 de derrubios volcánicos en el glacis c o n tin e n ta l superior, la avalancha de El Colfo. Un segundo evento, llam ado "debris f lo w " de Canarias, se originó en la base del talud de la isla del Hierro y movilizó unos 400 km3 de material. Nuevas evidencias sugieren que el "debris f l o w " de Canarias precedió a la avalancha de El C olfo. La avalancha de El Colfo pudo haberse originado a consecuencia de la socavación y sobreinclinación del talud asociadas a la cicatriz del «debris flow» de Canarias. Las zonas de rift en la isla del Hierro parecen haber tenido también un papel significativo en el desencadenamiento de la avalancha de El Colfo. El resultado fue el enmascaramiento del área fue nte del "debris f l o w " de Canarias p o r los depósitos de la avalancha. De la determinación de las complejas relaciones entre ambos flujos, se desprende que la avalancha de El Golfo ocurrió entre 12.000 y 6.000 años BP

The glacial periods are recorded in the sedimentary cover of the Antarctic margins as progading units and erosive surfaces. The comparison of three margins of the Western Antarctica allows valuation of the regional significance of the ice cap growth. The results suggest that interaction between clima and lithospheric movements are the responsible of the number of sedimentary units and (he growing style. It has been recognised an extensive erosive surface in the three margins studied, dated aproximately at 6 Ma, overlied by a big progradational sedimentary unit. Above of it the agradational component becomes more important. This change in the growing style seems to be releated with the increase of the frequency of sea level rise and fall from the Upper Pliocene

A comprehensive data set of the seafloor relief and superficial sedimentary cover on the Ebro progradational continental slope, NW Mediterranean Sea, reveals that its Late Quaternary building results from complex interrelationships between processes ranging from channel abandonment to incision of inner minor courses, from retrogressive erosion and channel capture to levee cutting and new channel opening, from channel wall sliding to shelf-edge and channel spillover. These processes succeed ones to the others both in time and space conforming a canibalistic frame where the balance between destructive and constructive processes is finally favourable to the last. They result in the formation of the channel-levee complexes characteristic of the Ebro continental slope and base-of-slope

The spatial distribution at sufface (-5m) and bottom (2-5m a.s.f.) /levels of the concentration and elemental composition of the suspended particulate matter show that the main trends result from the interaction between oceanographical phenomena and the morpholsedimentary characteristics of each continental margin segment The flow of the Northern current, which parallels the continental Slope, together with the topographic effects due to the bottom reliefs control the transfer of the fluvial inputs to the open-basin. The geostrphic fronts govern the main inputs of autocthonous suspended particulate matter

The Agadir turbidite system is located on the Morocco continental margin and the Agadir Basin (South Atlantic), and extends from 200 m to 4300 m water depth. Its establishement seems to have occured during the Oligocene, when the Agadir Canyon was formed. This canyon represents the main valley that feeds the turbidite system. The sediments transported through the Agadir Canyon deposited on the Agadir Basin, developing canyon, channel, overbank and depositional lobe deposits. From the Oligocene to present, this turbidite system has migrated laterally being controlled by the (paleo)topography and the local tectonics. Its vertical sedimentary succession is clearly retrogradational. This retrogration is interpreted as the result of the interplay between tectonics and climate

Sea Surface Temperalures (SST) and salinity anomalies (AS) of the Western Alboran Sea have been evaluated since the Last Glacial maximum (18 ky Bp) using the Uk37 index. This molecular index is based on the determination of two thermic biomarkers which are fossilized in deep marine sediments. The results obtained indicate a warming of about 12°C and higher salinities (AS=2,5%) than present during the last déglaciation (15-9 ky Bp). SST and AS records evolution were not unidirectional along the last déglaciation (15-9 ky Bp); both records indicate a stepwise evolution in which the Younger Dryas and the last Heinrich event can be recognized. Early Holocene (9-5 ky Bp) is characterized by a drop in salinity and high temperatures, conditions which are synchronous with the deposition of the last sapropel (St) in the Eastern Mediterranean.

A peripheral depression with a sediment drift on its N flank develop N and E of Minorca Island. Both are interpreted to result from the activity of bottom currents circulating parallel to the base of the island slope since the Pliocene. Evidences of the contouriric activity are: the presence of a depression with an erosive character, a sedimentary ridge with the typical characteristics of contourite drifts, and large sediment waves. The depression has a maximum width of 5 km, and a depth of 150-200 m, whereas the contourite drift reaches up to 150 km in length, is 25 km wide, and 100 m high. The sediment waves developed on the inner flank of the contourite drift reach up to 5 km in length and 40 m in height. The genesis of all these structures is related to the circulation of the Mediterranean Deep Water ( MDW) in the area. The steep island slope, devoided of sediment and deeply gullied, is considered as the potential source area for the sediments reworked by the currents. Further seaward, the contourite deposits are in lateral continuity with the deposits of the North-Balearic Basin and the Valencia Fan

A comprehensive data set of the seafloor relief and superficial sedimentary cover on the Ebro progradational continental slope, NW Mediterranean Sea, reveals that its Late Quaternary building results from complex interrelationships between processes ranging from channel abandonment to incision of inner minor courses, from retrogressive erosion and channel capture to levee cutting and new channel opening, from channel wall sliding to shelf-edge and channel spillover. These processes succeed ones to the others both in time and space conforming a canibalistic frame where the balance between destructive and constructive processes is finally favourable to the last. They result in the formation of the channel-levee complexes characteristic of the Ebro continental slope and base-of-slope

This study tries to establish the chronostratigraphy of the Late Quaternary high-resolution seismic units off the present Rhône Delta. Previous works have associated the deposition of these seismic units with 5th order glacio-eustatic cycles. We have compared (7) the thickness of ¿he studied series with a multichannel seismic profile, tied with o¡¡-exploration wells drilled near the study area and (2), the stacking pattern of the Rhône shelf seismic units with other Plio-Quaternary deltaic margins in the Mediterranean. Available 14C dates concerning the youngest seismic units have been also used and plotted on the Late Quaternary high-resolution eustatic curve. Each seismic unit (B-F) has been associated with a 4th order instead 5th order glacio-eustatic cycle. This hypothesis is used to built up the absolute chronostratigraphy of the series, using the SPECMAP record

The spatial distribution at sufface (-5m) and bottom (2-5m a.s.f.) /levels of the concentration and elemental composition of the suspended particulate matter show that the main trends result from the interaction between oceanographical phenomena and the morpholsedimentary characteristics of each continental margin segment The flow of the Northern current, which parallels the continental Slope, together with the topographic effects due to the bottom reliefs control the transfer of the fluvial inputs to the open-basin. The geostrphic fronts govern the main inputs of autocthonous suspended particulate matter

Five areas, the Eastern and Central Bransfield Basins off the Antarctic Peninsula, and the Tripartite, Central Spreading and South Pandora Ridges of the North Fiji Basin, have been studied using swath-bathymetry and geophysical data. The sites can be classified in terms of backarc basin evolution , from less evolved stages dominated by rifting and incipient spreading (Bransfield Basin), to the maturest stages characterized by organized backarc seafloor spreading, like the North Fiji Basin ridges, Las Cuencas Central y Oriental de Bransfield (NO Peninsula Antartica) y las Dorsales Tripartita, Central y Sur-Pandora de la Cuenca Nor-Fidjiana (Pacifico SO) han sido estudiadas a partir de datos de batimetría de multihaz y métodos geofísicos. Dichas áreas pueden clasificarse en estadios evolutivos de tras-arco, desde estadios incipientes y de pre-expansión como la Cuenca de Bransfield, hasta los estadios maduros de expansión oceánica organizada, como las dorsales de la Cuenca Nor-Fidjiana

This paper is focused on the seismic stratigraphy of the Culf of Lions continental shelf and slope, off the present Rhone Delta. A low resolution multichannel seismic profile allows to divide the Plio-Quaternary section in 10 seismic units (S9-Sf0) bounded by unconformities. The Plio-Quaternary boundary has been tentatively correlated on this profile from oil-exploration wells drilled near the study area. High-resolution seismic profiles allows a more detailed analysis of the uppermost part of the sedimentary section. The continental shelf section is divided into 6 major units (A-F) bounded by unconformities. ■ These units are Quaternary in age and correlate with units 5? and S,0 on multichannel seismic records. Units B-F shows a wedge shaped geometry and reach a maximum thickness at the shelf edge. These wedge-shaped seismic units are traced onto the slope in an intercanyon area. Detailed analysis of the seismic facies on the slope shows that the sedimentary series defines cycles. Each basic cycle is composed of a couplet of two different sub-units: a lower mostly transparent sub-unit which correlates with a wedge shaped seismic unit on the shelf, and an upper mosdy layered seismic unit on the slope which correlates with an erosiona/ unconformity on the shelf. These sedimentary cycles are supposed to be related with sea-level fluctuations

A peripheral depression with a sediment drift on its N flank develop N and E of Minorca Island. Both are interpreted to result from the activity of bottom currents circulating parallel to the base of the island slope since the Pliocene. Evidences of the contouriric activity are: the presence of a depression with an erosive character, a sedimentary ridge with the typical characteristics of contourite drifts, and large sediment waves. The depression has a maximum width of 5 km, and a depth of 150-200 m, whereas the contourite drift reaches up to 150 km in length, is 25 km wide, and 100 m high. The sediment waves developed on the inner flank of the contourite drift reach up to 5 km in length and 40 m in height. The genesis of all these structures is related to the circulation of the Mediterranean Deep Water ( MDW) in the area. The steep island slope, devoided of sediment and deeply gullied, is considered as the potential source area for the sediments reworked by the currents. Further seaward, the contourite deposits are in lateral continuity with the deposits of the North-Balearic Basin and the Valencia Fan

The Agadir turbidite system is located on the Morocco continental margin and the Agadir Basin (South Atlantic), and extends from 200 m to 4300 m water depth. Its establishement seems to have occured during the Oligocene, when the Agadir Canyon was formed. This canyon represents the main valley that feeds the turbidite system. The sediments transported through the Agadir Canyon deposited on the Agadir Basin, developing canyon, channel, overbank and depositional lobe deposits. From the Oligocene to present, this turbidite system has migrated laterally being controlled by the (paleo)topography and the local tectonics. Its vertical sedimentary succession is clearly retrogradational. This retrogration is interpreted as the result of the interplay between tectonics and climate

This paper is focused on the seismic stratigraphy of the Culf of Lions continental shelf and slope, off the present Rhone Delta. A low resolution multichannel seismic profile allows to divide the Plio-Quaternary section in 10 seismic units (S9-Sf0) bounded by unconformities. The Plio-Quaternary boundary has been tentatively correlated on this profile from oil-exploration wells drilled near the study area. High-resolution seismic profiles allows a more detailed analysis of the uppermost part of the sedimentary section. The continental shelf section is divided into 6 major units (A-F) bounded by unconformities. ■ These units are Quaternary in age and correlate with units 5? and S,0 on multichannel seismic records. Units B-F shows a wedge shaped geometry and reach a maximum thickness at the shelf edge. These wedge-shaped seismic units are traced onto the slope in an intercanyon area. Detailed analysis of the seismic facies on the slope shows that the sedimentary series defines cycles. Each basic cycle is composed of a couplet of two different sub-units: a lower mostly transparent sub-unit which correlates with a wedge shaped seismic unit on the shelf, and an upper mosdy layered seismic unit on the slope which correlates with an erosiona/ unconformity on the shelf. These sedimentary cycles are supposed to be related with sea-level fluctuations

The textural analysis of two gravity cores reveals that the sediments in the Central and Eastern Bransfield subbasins are mainly clayey silts with some coarser levels of sandy silts. While a turbidity origin can be attributed to the coarser levels, other processes should control the deposition of the fine fractions, e.g. settling of suspended particles, ice-rafting and ash airfall Chlorite, smectite and illite are the dominant clay minerals. While a detritic origin can be attributed to chlorite and illite the diagenetic alteration of volcanic glass origin is the most likely origin for smectite even though a minor detritic contribution cannot be completely enied Higher sand and smectite contents, and more abundant ash laminated facies suggest that the volcanic influence is higher in the Eastern Bransfield core than in the Central Bransfield core, Se describen las características físicas, granulométricas y mineralógicas de los sedimentos de dos testigos de gravedad procedentes de las subcuencas Oriental y Central de Bransfield. Los sedimentos están compuestos mayoritariamente por limos arcillosos laminados con algunos niveles de limos arenosos. A los niveles más groseros se les atribuye tentativamente un origen turbidítico. No obstante, la decantación pelágica, el transporte por icebergs, y las lluvias de cenizas han podido jugar un papel significativo en la acumulación de los sedimentos más finos. Los minerales mayoritarios en la fracción arcilla son la clorita, la esmectita y la ¡Hita. A la clorita y a la ¡Ilita se les atribuye un origen detrítico, mientras que la alteración diagenética del vidrio volcánico es la fuente más probable para la esmectita. Los mayores contenidos de arena, cenizas, facies laminadas y esmectita en el testigo de la subcuenca Oriental de Bransfield indicarían una mayor influencia volcánica en este que en el testigo de la subcuenca Central

The dinoflagellate cyst assemblages in a core from the Western Alboran Sea, in the upwelling domain off Malaga, show a record of marine environmental change for the Late Glacial and Holocene periods. The dinocysts are good indicators for changes in sea surface productivity. Productivity changes, in the Western Alboran Sea, relate to upwelling intensity. The environmental change based on this record allowed to link and time the responses of the oceanic circulation to climate. Results indicate that upwelling was present over the last 20 ky. It was weakened during brief periods suggesting a weaker thermohaline circulation and a lowered E-P budget. Enhanced upwelling occurred between 14.5-12.6 ky BP, suggesting an intensification of the thermohaline circulation and pointing to the conclusion that on a long term, the main forcing of the Mediterranean circulation was thermohaline, not relative sea-level changes, Las asociaciones de cistes de algas dinoflageladas, presentes en un testigo obtenido en el afloramiento de la cuenca occidental del mar de Alborán, registran los cambios climáticos y ambientales que tuvieron lugar en el Mediterráneo durante la última deglaciación. Este registro, permite relacionar la respuesta de la circulación termohalina, a través del Estrecho de Gibraltar, con los cambios climáticos. Los resultados obtenidos indican que, el afloramiento de Alborán , ha sido activo durante los últimos 20 mil años; con breves periodos de menor intensidad y un periodo más intenso. Los primeros, sugieren una circulación termohalina más débil y valores más bajos del balance hídrico (E-P) de la cuenca mediterránea. El segundo, permite concluir que el control más importante de la circulación Mediterránea durante los últimos 20 ka fue el balance hídrico de la cuenca, y no, los cambios relativos del nivel del mar

Cruises Tydeman 80, Tyro 82 and ODP Leg 157 provided 7000 km of single-channel seismic profiles and three d rillin g sites w ith a to ta l o f 11 58 m o f core in the Madeira Abyssal Plain. Merging o f the lithological records and conventional logs into the seismic units and subunits defined, allowed their 3D mapping and calculation of both the sediment volume and approximate accumulation rates in the Great Meteor East area (central subbasin of the Madeira Abyssal Plain) since the Middle Miocene. The total volum e is arou nd 1 9 3 2 7 km3and the accum ulation rates are 2 2 .6 6 m /m y r fo r the U p p er-M id d le Miocene, 68.78 m/myr for the Lower Pliocene, 49.23 m/myr for the Upper Pliocene and 54.93 m/myr for the Quaternary Durante las campañas Tydeman 80, Tyro 82 y el "leg" 157 del Ocean Drilling Program (ODP), se obtuvieron 7000 km de sísmica de monocanal y tres sondeos de unos 350 m cada uno en la zona central de la Llanura Abisal de Madeira. A partir de los perfiles sísmicos se han diferenciado dos grandes unidades sísmicas y cuatro subunidades. La cartografía 3D de las mismas, junto con el estudio de las columnas litoestratigráficas y las diagrafías de los sondeos, ha permitido calcular el volumen de sedimento depositado en la cuenca desde el Mioceno medio hasta la actualidad. La correlación de las unidades sísmicas con la litoestratigrafía de los sondeos ha posibilitado el cálculo de las tasas de acumulación aproximadas para dicha cuenca. El volumen total depositado desde el Mioceno medio hasta la actualidad es de 19327 km3 y las tasas de acumulación son de 22.66 m/Ma para el Mioceno superior y medio, 68.78 m/Ma para el Plioceno inferior, 49.23 m/Ma para el Plioceno superior y 54.93 m/Ma para el Pleistoceno

This study tries to establish the chronostratigraphy of the Late Quaternary high-resolution seismic units off the present Rhône Delta. Previous works have associated the deposition of these seismic units with 5th order glacio-eustatic cycles. We have compared (7) the thickness of ¿he studied series with a multichannel seismic profile, tied with o¡¡-exploration wells drilled near the study area and (2), the stacking pattern of the Rhône shelf seismic units with other Plio-Quaternary deltaic margins in the Mediterranean. Available 14C dates concerning the youngest seismic units have been also used and plotted on the Late Quaternary high-resolution eustatic curve. Each seismic unit (B-F) has been associated with a 4th order instead 5th order glacio-eustatic cycle. This hypothesis is used to built up the absolute chronostratigraphy of the series, using the SPECMAP record