CIFICEN   24414
CENTRO DE INVESTIGACIONES EN FISICA E INGENIERIA DEL CENTRO DE LA PROVINCIA DE BUENOS AIRES
Unidad Ejecutora - UE
artículos
Título:
Magnetic parameters and their palaeoclimatic implications?the sediment record of the last 15 500 cal. BP from Laguna Potrok Aike (Argentina)
Autor/es:
M.A. IRURZUN, M.J. ORGEIRA, C.S.G. GOGORZA, A.M. SINITO, R. COMPAGNUCCI AND B. ZOLITSCHKA
Revista:
GEOPHYSICAL JOURNAL INTERNATIONAL
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2014 p. 1 - 1
ISSN:
0956-540X
Resumen:
Lake sediments are excellent sources of palaeoenvironmental and palaeoclimatic infor mation because t hey provide continuous and high-resolution r ecords. South America is of par ticular interest because i t i s t he only l andmass t hat stretches southward i nto t he Pacific and Atlantic Oceans towards Antarctica. The aim of this study is to explore t he relationship of magnetic parameters with elemental and palaeobiological data of Laguna Potrok Aike to develop a model of lake-level changes and related hydrological and climatic fluctuations. M agnetic measurements were perfor med on subsamples from 15 500 cal. BP t o t he present, and associated rock magnetic parameters were calculated to infer magnetic mineralogy, concentration and g r ain size. According to the model, parameters dependent on magnetic concentration and g r ain s ize are directly related t o l ake-level changes. During dr y periods, t he remanent coercivity displays high values, whereas the propor tion of magnetite is relatively low. Low percentages of g r eigite are obser ved, indicating t hat the water of the l ake was stratified at least f our times during t he studied period, at approximately 10 300, 8900, 8500 and 8300 cal. BP. The preser vation of g r eigite by inhibiting its complete t ransfor mation i nto pyrite is associated with a r apid b urial that occurs with high sedimentation r ates. Ther mal s tratification could be caused by a s light cooling i n t he area triggered by a weakening of the Westerlies and/or low activity of the s un, sum t o t he effect of a flood of melt water i n t he Nor t h Atlantic.
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