99 research outputs found
New expert- based coastal classification: a GIS tool to compare and analyze coastal regions
A coastline is the area where interaction of the sea and land processes occurs. Coastal areas are very high- dynamic regions, continuously affected and permanently formed by littoral geomorphologic processes (Bird 2008). The configuration of a coast is associated with variou s factors, such as the geological setting, s ub strate -lithology, ecosystem characteristics, regional climate, wave and tidal regimes, human development and near shore infrastructure.
To conduct a coastal classification in broad se n se i s a fairly com plex task, depending on the objective of the work. Many di.fferent concepts h ave been applied to coasts in attempts to characterize dominant features in terms of physical or biological propertie s, modes of evolution, geographic occurrence, among others (Finkl 2004). Also, the need for a better coastal management dueto the wodd-wide human pressures on the coastal zone and the resulting vulnerability when erosion processes and human activity come into conflict, motivated the development of coastal classification criteria that fit di.fferent purposes (Finkl 2004, I h1 et al 2006, Appelq ui st 2013, Appelq uist y B alstr0m 2014 ). Sorne of the ear lier classification approaches were broad in scope but lacked important details while other specialized systems were topicallytoo focused.
As a result of more com prehensive studies of coasts and the increasing availability of digital information, such as Geographic Information System (GIS) frameworks, integrated and systematics approaches to coastal cla ssifi cation are now the preferred options (Finkl 2004 y Scheffers et al 2012). Present-day managem e nt demands require problem solutions, which ovedook and integrate the marine, littoral and terrestrial sphere of the coastal zone
Ichnology of the marine Puente de Pascua Formation, Late Pleistocene, Buenos Aires, Argentina
Ichnological assemblages from the Late Pleistocene of Buenos Aires, Argentina, have been largelyneglected in paleontological literature. Here we describe, interpret, and discuss the ichnologicalassemblages of the Late Pleistocene Puente de Pascua Formation at its type locality(35o55 ́37 ́ ́S?57o43 ́7,6 ́ ́W). Based on sedimentology and trace fossils, four units wererecognized. The lowermost unit A comprises sandy clay with lenticular stratification withPaleophycus isp. (Hall, 1847) (produced by marine polychaetes) and Ophiomorpha isp. (Lundgren,1891) and Thalassinoides isp. (Ehrenberg, 1944) (ascribed to mud-shrimps). Unit B is composedof light brown fine friable sand extensively bioturbated by Tagelus plebeius (Lightfoot, 1786)preserved in life position, apparently contemporaneous with Psilonichnus isp. (Fürsich, 1981)(associated with crabs). Unit C, composed of friable fine sand, does not contain any burrow, butabundant chaotically arranged mollusks. The uppermost Unit D is composed of friable silt andcontains crotovines produced typically by the rodent Ctenomys (Blainville, 1826), represented by a6 cm-diameter branchy gallery and an isolated infilled burrow possibly created, based on itsdiameter, by Lagostomus (Brookes, 1828). Based on the ecology of the producers, thisichnoassemblage succession reflects the paleoenvironmental evolution of the Buenos Airescoastal plain during the Late Pleistocene regressive hemicycle (from the base to the top) fromsubtidal (Unit A) and intertidal settings (Unit B), to typical upper shoreface facies. The presence oftrace fossils assigned to continental vertebrate taxa in Unit D reflects the pedogenetic processeswhich altered the carbonatic deposits of the Pascua Formation after the rapid sea-level fall.Fil: Laprida, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Gingras, M. Earth Science and Atmospheric Sciences.Edmonton; CanadáFil: Pereyra, Cristian Ramon. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Fucks, Enrique Eduardo. Universidad Nacional de La Plata; ArgentinaReunión de Comunicaciones de la Asociación Paleontológica ArgentinaLa PlataArgentinaAsociación Paleontológica Argentin
Aspectos estratigráficos y geomorfológicos del sector oriental patagónico bonaerense
The southern Buenos Aires province, between the Colorado and Negro rivers, is characterized by a wide variety of geomorphologic environments mostly linked to fluvial and littoral dynamics. The coastal region includes deposits realted to both, progradation processes of the Colorado River delta, and Quaternary eustatic variation. At the final stretch of the Colorado River delta there are deposits of the Holocene-Pleistocene marine ingression, alternating with fluvial deposits, suggesting deltaic progradation over older intertidal or supratidal deposits. Farther south, the San Blas region has been repeatedly occupied by Quaternary marine transgressions, being those deposits of the MIS 1 and 5e, best represented in the landscape as littoral ridges, beach strand plains and tidal plains at maximum heights of 6 and 10 m respectively. Other older transgressive episodes have been observed, and tentatively assigned to the MIS 7 and ≥9, represented by thin deposits, often forming hillocks, sometimes elongate, along a plain slightly sloping to the sea. In turn, the last of these transgressions could be subdivided, on the basis of altimetric differences and cementation degree, into two independent units.La región comprendida entre los ríos Colorado y Negro del sur de la Provincia de Buenos Aires, Argentina, está caracterizada por una amplia variedad de ambientes geomorfológicos vinculados mayormente a la dinámica fluvial y litoral. La región costera comprende depósitos relacionados con los procesos de progradación deltaica del río Colorado y aquellos generados por las variaciones eustáticas del nivel de mar en el Cuaternario. En el sector terminal del delta del río Colorado se observan depósitos de la ingresión marina holocena y pleistocena alternando con depósitos fluviales, indicando progradación deltaica sobre los depósitos intermareales o supramareales más antiguos. Hacia el sur, la región de San Blas ha sido ocupada reiteradamente por las transgresiones marinas cuaternarias, correspondiendo las de mejor representación a los MIS 1 y 5e, representados en el paisaje por cordones litorales, planicies con crestas de playa y llanuras de mareas, y a cotas máximas de 6 y 10 metros respectivamente. Otros episodios transgresivos más antiguos han sido observados, asignados tentativamente a los MIS 7 y ≥9, representados por depósitos de escaso espesor, en muchas oportunidades conformando lomadas las que pueden presentar morfologías alargadas, dispuestas a lo largo de unas planicies de suaves pendientes hacia el mar. La última de estas transgresiones, podría en base a las diferencias altimétricas y grado de cementación, subdividirse a su vez en dos unidades independientes
Geomorphologic Map of Northeastern Sector of San Jorge Gulf (Chubut, Argentina)
This paper presents a 1:100,000 scale geomorphologic map of the Northeastern sector of San Jorge Gulf
(Chubut Province) in Patagonia, Argentina, covering more than 1,000 km2. Derived from remote sensing
data and validated by three field surveys, it has been compiled in order to understand the past and recent evolution of the area with particular reference to sea-level oscillation studies, for which this map is the
basic tool. The very low human impact and rates of dynamic landscape change allow the preservation
of extensive palaeo deposits and landforms, including those indicative of sea-level variations. The relative
change of sea level dominates landscape evolution, allowing the formation of widespread marine
and lagoon deposits often interfingering with fluvial deposits and reworked by aeolian process in the framework of consequent beach progradation
Características hidroquímicas en la vertiente oriental de la Sierra de Famatina, provincia de La Rioja, Argentina
La red hídrica que drena la ladera oriental de la sierra de Famatina, ubicada en el centro-norte de la provincia de La Rioja, está constituida principalmente por los ríos Amarillo, del Oro y Miranda. En este trabajo, se destacan las características químicas de las aguas superficiales y subterráneas que integran la cuenca del río del Oro, con el objetivo de dilucidar la relación existente entre sus características hidroquímicas y los ambientes geomorfológicos a los que se asocian las aguas. En base a la bibliografía e imágenes del área, se delimitó esta cuenca de drenaje y se establecieron sus principales características. Asimismo, se incluyen los resultados obtenidos de los muestreos realizados en Septiembre del 2016, que, asociados a estudios previos, permiten incrementar el conocimiento del recurso hídrico dentro de esta zona.The water network that drains the eastern slope of the Famatina mountain range, located in the north-central part of La Rioja province, is mainly constituted by Amarillo, del Oro and Miranda rivers. In this work, we pretend to highlight the chemical characteristics of the surface water and groundwater that integrate the basin of del Oro river, in order to elucidate the relationship between their hydrochemical characteristics and the geomorphological environments to which waters are associated. Based on the bibliography and images of the area, this drainage basin was delimited and its main characteristics were established. Also included are the results obtained from the sampling carried out in September 2016, which, associated with previous studies, allow to increase the knowledge of the water resource within this zone.Trabajo publicado en Filippini, María Flavia (comp.). Congreso Internacional Aguas, Ambiente y Energía de la Asociación de Universidades Grupo Montevideo: Resúmenes de trabajos. Mendoza: Universidad Nacional de Cuyo, 2017.Facultad de Ciencias Naturales y Muse
Características hidroquímicas en la vertiente oriental de la Sierra de Famatina, provincia de La Rioja, Argentina
La red hídrica que drena la ladera oriental de la sierra de Famatina, ubicada en el centro-norte de la provincia de La Rioja, está constituida principalmente por los ríos Amarillo, del Oro y Miranda. En este trabajo, se destacan las características químicas de las aguas superficiales y subterráneas que integran la cuenca del río del Oro, con el objetivo de dilucidar la relación existente entre sus características hidroquímicas y los ambientes geomorfológicos a los que se asocian las aguas. En base a la bibliografía e imágenes del área, se delimitó esta cuenca de drenaje y se establecieron sus principales características. Asimismo, se incluyen los resultados obtenidos de los muestreos realizados en Septiembre del 2016, que, asociados a estudios previos, permiten incrementar el conocimiento del recurso hídrico dentro de esta zona.The water network that drains the eastern slope of the Famatina mountain range, located in the north-central part of La Rioja province, is mainly constituted by Amarillo, del Oro and Miranda rivers. In this work, we pretend to highlight the chemical characteristics of the surface water and groundwater that integrate the basin of del Oro river, in order to elucidate the relationship between their hydrochemical characteristics and the geomorphological environments to which waters are associated. Based on the bibliography and images of the area, this drainage basin was delimited and its main characteristics were established. Also included are the results obtained from the sampling carried out in September 2016, which, associated with previous studies, allow to increase the knowledge of the water resource within this zone.Trabajo publicado en Filippini, María Flavia (comp.). Congreso Internacional Aguas, Ambiente y Energía de la Asociación de Universidades Grupo Montevideo: Resúmenes de trabajos. Mendoza: Universidad Nacional de Cuyo, 2017.Facultad de Ciencias Naturales y Muse
Características hidroquímicas en la vertiente oriental de la Sierra de Famatina, provincia de La Rioja, Argentina
La red hídrica que drena la ladera oriental de la sierra de Famatina, ubicada en el centro-norte de la provincia de La Rioja, está constituida principalmente por los ríos Amarillo, del Oro y Miranda. En este trabajo, se destacan las características químicas de las aguas superficiales y subterráneas que integran la cuenca del río del Oro, con el objetivo de dilucidar la relación existente entre sus características hidroquímicas y los ambientes geomorfológicos a los que se asocian las aguas. En base a la bibliografía e imágenes del área, se delimitó esta cuenca de drenaje y se establecieron sus principales características. Asimismo, se incluyen los resultados obtenidos de los muestreos realizados en Septiembre del 2016, que, asociados a estudios previos, permiten incrementar el conocimiento del recurso hídrico dentro de esta zona.The water network that drains the eastern slope of the Famatina mountain range, located in the north-central part of La Rioja province, is mainly constituted by Amarillo, del Oro and Miranda rivers. In this work, we pretend to highlight the chemical characteristics of the surface water and groundwater that integrate the basin of del Oro river, in order to elucidate the relationship between their hydrochemical characteristics and the geomorphological environments to which waters are associated. Based on the bibliography and images of the area, this drainage basin was delimited and its main characteristics were established. Also included are the results obtained from the sampling carried out in September 2016, which, associated with previous studies, allow to increase the knowledge of the water resource within this zone.Trabajo publicado en Filippini, María Flavia (comp.). Congreso Internacional Aguas, Ambiente y Energía de la Asociación de Universidades Grupo Montevideo: Resúmenes de trabajos. Mendoza: Universidad Nacional de Cuyo, 2017.Facultad de Ciencias Naturales y Muse
Effective DBHF Method for Asymmetric Nuclear Matter and Finite Nuclei
A new decomposition of the Dirac structure of nucleon self-energies in the
Dirac Brueckner-Hartree-Fock (DBHF) approach is adopted to investigate the
equation of state for asymmetric nuclear matter. The effective coupling
constants of , , and mesons with a density
dependence in the relativistic mean field approach are deduced by reproducing
the nucleon self-energy resulting from the DBHF at each density for symmetric
and asymmetric nuclear matter. With these couplings the properties of finite
nuclei are investigated. The agreement of charge radii and binding energies of
finite nuclei with the experimental data are improved simultaneously in
comparison with the projection method. It seems that the properties of finite
nuclei are sensitive to the scheme used for the DBHF self-energy extraction. We
may conclude that the properties of the asymmetric nuclear matter and finite
nuclei could be well described by the new decomposition approach of the G
matrix.Comment: 16 pages, 5 figure
Strong enhancement of extremely energetic proton production in central heavy ion collisions at intermediate energy
The energetic proton emission has been investigated as a function of the
reaction centrality for the system 58Ni + 58Ni at 30A MeV. Extremely energetic
protons (EpNN > 130 MeV) were measured and their multiplicity is found to
increase almost quadratically with the number of participant nucleons thus
indicating the onset of a mechanism beyond one and two-body dynamics.Comment: 5 pages, 2 figures, submitted to Physical Review Letter
New record of Hippidion (Mammalia Perissodactyla) from the late Pleistocene of Buenos Aires province, Argentina
En este estudio se describen dos nuevos cráneos referidos a Hippidion principale (Lund) y varios elementos del esqueleto apendicular referidos a H. devillei procedentes de dos localidades clásicas de la provincia de Buenos Aires, las márgenes de los ríos Salado y Quequén Grande. Para la identificación taxonómica de los restos apendiculares, se realizó un análisis multivariante en el que se incluyeron los metacarpianos y falanges descritos y los registrados en varias localidades de Argentina y Brasil. Para la determinación de los cráneos se realizó un estudio comparativo con otros cráneos de diversas localidades. Estos hallazgos incrementan el registro de Hippidion en América del Sur y aportan nuevas evidencias sobre la cronología de sus especies en Argentina. Se realizó una datación por AMS para el ejemplar de Río Salado (MHM-P54) que ha suministrado una edad 14C 14120 ± 50 BP. En general, los sedimentos portadores en ambas localidades son referibles a la Edad Lujanense, Biozona de Equus (Amerhippus) neogeus.This study describes two new skulls referred to Hippidion(Lund) and various elements of the appendicular skeleton referred to H. devillei from two classic localities from Buenos Aires province: the Salado and Quequén Grande Rivers. For taxonomic identification of the appendicular remains was performed a multivariate analysis that included the metacarpals and phalanges described and several remains recorded in various locations in Argentina and Brazil. For the determination of the skulls was made a comparative study with other skulls from different localities. These data increasing the record of Hippidion in South America and provide new evidence about the chronological distribution of two species of Hippidion. One radiometric data was obtained by the method of AMS dating to the skull from Salado River (MHM-P54) about a 14C age 14120 ± 50 BP. In general, bearing sediments at both localities are referable to the Lujanian Age and the Biozone of Equus (Amerhippus) neogeus.Facultad de Ciencias Naturales y MuseoFacultad de Ciencias Agrarias y Forestale
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