INVESTIGADORES
FERNANDEZ HONAINE mariana
congresos y reuniones científicas
Título:
Environmental role of biomineralizations and biogeochemistry of iron.
Autor/es:
OSTERRIETH, MARGARITA; BORRELLI, NATALIA; ALVAREZ, M FERNANDA; FERNÁNDEZ HONAINE, MARIANA
Reunión:
Simposio; 20th International Symposium on environmental biogeochemistry; 2011
Resumen:
The biomineralizations present in every level of the biosphere, are the result of the metabolic
^jnctíon of the biota. The goal of this paper is the mineral-chemical characterization of the
Diomineraizations of iron, calcium and amorphous silica, in pedosedimentary sequences, located at
the Buenos Aires province (36° 00´ to 39° 05´ S; 60 °10´ to 5 7 0 0 0 ^ ) . Sampling was carried out in
pedosedimentary sequences from different geomorphological settíngs, that include: eolian dunes,
estuarine, paleoestuarine, salt marsh, and fluvio-eolian plain. Sampled sections were representative
profiles,disturbed and undisturbed samples (micromorphology blocks) were studied by means of
routine procedures. The presence of silica biomineralizations (silicophytoliths) revealed six
pedological cycles in the, in the complex geomorphological units of the continental and coastal áreas,
with some episodes of rapid burial, from the Plio-Pleistocene to current times. Biomineralizations of
¡ron we found in the form of framboidal and polyframboidal pyrite, greigite, mackinawite and iron
oxyhydroxides associated with gypsum, barite, calcite and halite, which permit us to define the
redoxymorphic conditions in paleoestuary pedosedimantary sequences. The biofilms are recurrent,
which is a product of the intense microbiological and multifunctional activity. The biominerlaizations
of calcium we found in the bioclastic and calcretized levéis, associated with the processes of
dissolution and reprecipitation of calcium carbonates and oxalates via biogenic action. The
relationship between different types of biomineralizations, and the evolution and degradation of soils
¡n the different environments of the southeast pampean plain of the Buenos Aires province, show the
qualitative characteristics and intensity of the pedogenesis, as well as paleoenvironmental
characteristics.The contribution of these elements in the matrix conformation of soils, paleosoils and
sediments in these environments is related to climatic changes and sea level oscillations during the
Late Quaternar. In continental áreas the amorphous silica-enriched matrices of the soil, contribute to
mcreased resistance to erosión caused by the extensive and intensive agricultural activities