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Gomez Samus M.L.,Laboratorio Of Entrenamiento Multidisciplinario Para La Investigacion Tecnologica Lemit | Gomez Samus M.L.,CONICET | Gomez Samus M.L.,National University of La Plata | Rico Y.,Laboratorio Of Entrenamiento Multidisciplinario Para La Investigacion Tecnologica Lemit | And 2 more authors.
Revista de la Asociacion Geologica Argentina | Year: 2016

Based on geological and paleomagnetic studies a stratigraphic ordering of Neogene-Quaternary deposits in the Sierras de Balcarce area is proposed. Two stratigraphic sections are presented in this contribution. One corresponds to a quarry situated in the southern slope of Sierra Bachicha, the other to a roadside section in the locality of Ramos Otero. In the field, several lithological units were recognized and described and a paleomagnetic sampling was performed. By the application of conventional paleomagnetic laboratory techniques, it was possible to establish magnetic polarity zonations. The magnetozone of the upper part in both sections was assigned to the Brunhes Polarity Chron (<0.781 Ma) and is basically composed composed of two lithostratigraphic units. The youngest one is an aeolian sandy loam -probably deposited during the Last Glacial Maximum- lying discordantly on top of an older unit. The latter is of fluvial origin and contains abundant CaCO3; its age would be less than 450 Ka. Below, through an unconformity, we found deposits with loessoid aspect and psefitic dispersed materials, well represented in the section of Sierra Bachicha. They are interpreted as distal colluvial deposits. Several polarity changes have been recorded in them. The youngest polarity change, at the top of the unit, would have a minimum age of Brunhes-Matuyama Boundary (0.781 Ma), and the oldest, placed at the base of the quarry, would have a minimum age of Middle Matuyama-Olduvai Boundary (1,778 Ma). Although older ages are not discarded, the studied sediments are younger than 3.2 Ma. © 2016, Asociacion Geologica Argentina. All rights reserved.


Samus M.L.G.,Laboratorio Of Entrenamiento Multidisciplinario Para La Investigacion Tecnologica Lemit | Samus M.L.G.,CONICET | Rico Y.,Laboratorio Of Entrenamiento Multidisciplinario Para La Investigacion Tecnologica Lemit | Bidegain J.C.,Laboratorio Of Entrenamiento Multidisciplinario Para La Investigacion Tecnologica Lemit
GeoResJ | Year: 2017

The South America Loess plateau covers a large part of Argentina. In this country, the Balcarce Hills represent at the moment a poorly studied area from a stratigraphic and paleoenvironmental point of view. This area is located in an intermediate place between other zones with a greater data density; for this reason, the geochronological and environmental knowledge of this area is key to a better regional understanding of Argentine loess formation mechanisms. For these purposes, Paleomagnetism, Rock Magnetism and chemical analyses were used as the main supports for this study. Two stratigraphic sections in the Balcarce area were studied. Both sections have lithostratigraphic units in common which allow to correlate them. Three lithostratigraphic and six pedogenetic cycles were recognized. The two younger lithostratigraphic units were deposited during the Brunhes Chron (< 0.781 Ma) while the oldest unit during Matuyama Polarity Chron (0.781 - 2.588 Ma). Towards the base of the oldest unit, normal polarity levels were recorded and they referred to Olduvai (1.778 - 1.945 Ma). The youngest reversal, assigned to the Brunhes-Matuyama Boundary (BMB), was found in the paleosoil of the top of oldest lithostratigraphic unit. This is very important because it allows to correlate it with other paleosols in the BMB of Argentina. With regards to magnetic signature, this is relatively homogeneous along the profiles and corresponds mainly to ferrimagnetic minerals, as titanomagnetites and probably maghemite in the paleosols. The magnetic grain size would dominantly be SD and the low coercivity fine to ultrafine particles increase in the pedogenetic horizons (A, Bw and Bt). The source rocks giving rise to the observed magnetic contribution seem to have been relatively constant in the last 1.9 Ma. In a first approach, the susceptibility values recorded in the sediments of Balcarce are higher than in areas located further north from the pampean loess plateau, but lower than those in the south. The mentioned differences would be linked to both the distance and the mineral composition of the source rocks. © 2017 Elsevier Ltd


Lavornin J.M.,National University of Central Buenos Aires | Kristensen M.J.,National University of Central Buenos Aires | Kristensen M.J.,National University of La Plata | Rosato V.G.,Comision Nacional de Investigaciones Cientificas y Tecnologicas CON ICET | Rosato V.G.,Laboratorio Of Entrenamiento Multidisciplinario Para La Investigacion Tecnologica Lemit
Revista del Museo Argentino de Ciencias Naturales, Nueva Serie | Year: 2016

This work provides a dichotomous key to recognize all the saxicolous lichen species known from "La Poligonal" Protected Landscape in Tandillia orographic System, Buenos Aires, Argentina. This key also includes notes on their distribution and chemistry characteristics. A Total of 70 species are listed, 9 of which are new records for Tandilia, while 7 are new records for the province of Buenos Aires and one is a new record for Argentina. A detailed description is given for 5 species recognized at genus level and for the new species in the area.


Martins I.,National Laboratory for Civil Engineering | Muller A.,University Weimar | Dimaio A.,Laboratorio Of Entrenamiento Multidisciplinario Para La Investigacion Tecnologica Lemit | Forth J.,University of Leeds | And 4 more authors.
RILEM State-of-the-Art Reports | Year: 2013

As an outcome of recycling the mineral part of construction and demolition waste significant quantities of the fine fraction, particle size below 4 mm in Europe, are generated. A common feature of the produced fine recycled aggregates is the high content of cement paste that could impair its quality. With the recent advances on the processing technologies improvement on the characteristics of the fine fraction of C&DW can be envisaged and new perspectives to their application arise. After a brief review of the new technologies developed for C&DW processing, of the characteristics of fine recycled aggregates and of the requirements they must fulfill, an overview of different solutions for the use of the fine fraction is provided. The use in the field of precast concrete elements, of rendering and bedding mortars or for producing cement blends constitute some of the highlighted applications. © RILEM 2013.


Bidegain J.C.,Laboratorio Of Entrenamiento Multidisciplinario Para La Investigacion Tecnologica Lemit | Jurado S.,Laboratorio Of Entrenamiento Multidisciplinario Para La Investigacion Tecnologica Lemit | Chaparro M.A.E.,CONICET | Gomez Samus M.,CONICET | And 2 more authors.
Environmental Earth Sciences | Year: 2013

Late Cenozoic sediments exposed in a quarry in the locality of Marcos Paz (Buenos Aires province) were studied by applying paleomagnetism and environmental magnetism. The whole sequence, with the exception of the recent soil, belongs to the Pleistocene and is integrated by clayey silts (sandy) and also by a layer of fine sand. Eleven different depositional/postdepositional units, numbered in descending order from unit 1 to 11, were determined. The units 1, 2 and 3 in the upper portion of the geological section should be assigned to Brunhes (<0.78 Ma). Below a depth of 6 m, the reverse polarity zone corresponds to Matuyama (>0.78 Ma). Matuyama magnetozone includes some subzones of normal polarity that should be assigned to the subchron Jaramillo (0. 99 Ma) and to the subchron Olduvai (1.9 Ma). The reverse polarity levels determined at the bottom of the profile should be assigned to the lower Matuyama (>1.9 Ma). The highest volume susceptibility values are recorded in the less pedogenized sediments (400 × 10-5), while the lowest values are always obtained in gleyed horizons (30 × 10-5). The data support the wind-vigor magnetoclimatological model, although affected by different pedogenesis degrees and weathering as demonstrated by the behavioral pattern of chemical elements. © 2012 Springer-Verlag.


Bidegain J.C.,Laboratorio Of Entrenamiento Multidisciplinario Para La Investigacion Tecnologica Lemit | Jurado S.S.,Laboratorio Of Entrenamiento Multidisciplinario Para La Investigacion Tecnologica Lemit | Gomez Samus M.L.,Laboratorio Of Entrenamiento Multidisciplinario Para La Investigacion Tecnologica Lemit
Revista de la Asociacion Geologica Argentina | Year: 2011

Late Cenozoic sediments exposed in a quarry in the locality of Marcos Paz (Buenos Aires province) are studied from a stratigraphic and paleomagnetic point of view. The whole sequence, with the exception of the recent soil, belongs to the Pleistocene and is integrated by clayey silts, partly sandy and also by a layer of fine sand. Eleven different depositional/postdepositional units, numbered from unit 1 to 11 downwards, were determined. The units 1, 2 and 3 at the upper part of the geological section should be assigned to Brunhes (< 0.78 Ma). Below a depth of 6 meters the reverse polarity zone corresponds to Matuyama (> 0.78 Ma). Matuyama Magnetozone includes some subzones of normal polarity that should be assigned to the Subchron Jaramillo (0.99 Ma) and to the Subchron Olduvai (1.9 Ma). The reverse polarity levels determined at the bottom of the profile should be assigned to the lower Matuyama (> 1.9 Ma). The highest susceptibility values are recorded in the less pedogenized sediments (400 × 10 -5) while the lowest values are always obtained in gley horizons (30 × 10 -5). The data support the wind-vigor magnetoclimatological model although damped by pedogenesis and weathering as it was established previously.

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