INVESTIGADORES
BERNASCONI emiliana
artículos
Título:
Late Quaternary environmental changes in southernmost South America reflected in marine calcareous macro-and-microfossils Quaternary International
Autor/es:
GORDILLO SANDRA; BERNASCONI EMILIANA; CUSMINSKY GABRIELA; CORONATO ANDREA; RABASSA JORGE
Revista:
QUATERNARY INTERNATIONAL
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2013 vol. 305 p. 149 - 162
ISSN:
1040-6182
Resumen:
Late Quaternary environmental changes, especially advances and retreat of glaciers, and sea-level fluctuations, surely affected the distribution of the benthic marine fauna which inhabited the Beagle Channel, southernmost South America. In this regard calcareous macro-and-microfossils obtained from Holocene marine sediments along a sector on the western side of the Beagle Channel have been used as multi-proxy approach to evaluate these changes. In total, 119 species were recovered: 65 mollusks (24 bivalves, 35 gastropods and 6 chitons), 33 foraminifers and 21 ostracods. Other preserve calcareous groups, which appeared in minor proportion, were brachiopods and cirripeds.The calcareous assemblages from the early Holocene represent an ecosystem transition which started with vacant niches first occupied by opportunistic species, and/or eurytopic taxa, and subsequent replacement by more diverse faunistic assemblages, associated to the proliferation of habitats occurred under truly marine conditions during the middle Holocene. Holocene calcareous fauna is compared with their Pleistocene counterparts from the same region some differences in the proportion of the taxonomic groups and taxa composition are noticed. They partly obey to the heterogeneity of habitats in the Beagle Channel, but they are also interpreted in association to water masses of different origin with greater or less influence throughout the Late Quaternary. In conclusion, our data provide insights into both spatial and temporal changes showing evidence of a gradual transformation from a brackish to a marine environment due to the occurrence of the Holocene sea transgression, but also document Late Quaternary faunistic changes associated to topographic and oceanographic local conditions in this microbasin.