IIMYC   23581
INSTITUTO DE INVESTIGACIONES MARINAS Y COSTERAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
MINERALOGICAL AND MICROPALEONTOLOGICAL COMPOSITION IN MARSH SEDIMENTS IN THE RIO DE LA PLATA
Autor/es:
MARK SCHUERCH; MARGARITA OSTERIETH; MICAELA PAOLICCHI; LYDIA CALVO MARCILESE; SILVINA CARRETERO; MARÍA FERNANDA ALVAREZ; JUAN PABLO PÉREZ PANERA
Lugar:
Tucumán
Reunión:
Congreso; XX Congreso Geológico Argentino; 2017
Resumen:
This study characterizes thesediments from marshes on the shores of the Río de la Plata estuary, from amineralogical and micropaleontological standpoint. Samples were taken in fourlocations, cores were cut in slices, and material was separated and treatedaccording to the techniques required to make the measurements. At amineralogical level, abundant quartz, potassium feldspar and plagioclaseminerals were identified, with lower content of mafics and accessories. Clayswere present (illite, kaolinite, smectites, chlorites, interstratifiedillite/smectite). Calcareous foraminifera and nannofossils were identified, butgenerally in low abundance and number of species. The described amorphoussilica biomineralizations include the predominant presence of silicophytoliths,along with variable amounts of Chrysophyceae cysts, sponge spicules and brokenand intact diatoms. With regard to the minerals, the conclusion drawn is thatthe Uruguayan river banks seem to receive different sediment than theArgentinian coastal sector, the differences being an absence of mafic minerals,as well as the sole presence of kaolinite and illite as part of the claymineral group. Based on the micropaleontological analysis, it is possible toinfer that the environment inhabited by the foraminifera and nannofossils wasmarginal-marine, restricted and subjected to environmental stresses. Amorphoussilica biomineralizations show there is a high degree of similarity betweenspecimens from the Salado River and Punta Rasa, as well as between those fromIsla Martín García and Santa Lucía. Keywords:mineral determination, foraminifera, silicophytoliths, coastal environments