Response of alluvial systems to Late Pleistocene climate changes recorded by environmental magnetism in the Añavieja Basin (Iberian Range, NE Spain)
Oliva Urcia, B. (Instituto Pirenaico de Ecología)
Muñoz, Arsenio (Universidad de Zaragoza. Departamento de Ciencias de la Tierra)
Larrasoaña, J. C. (Instituto Geológico y Minero de España)
Luzón Aguado, Mª Aránzazu (Universidad de Zaragoza. Departamento de Ciencias de la Tierra)
Pérez García, Antonio (Universidad de Zaragoza. Departamento de Ciencias de la Tierra)
González Rodríguez, Ángel (Universidad de Zaragoza. Departamento de Ciencias de la Tierra)
Jiang, Z. (Chinese Academy of Sciences. Institute of Geology and Geophysics)
Liu, Q. (Chinese Academy of Sciences. Institute of Geology and Geophysics)
Román Berdiel, María Teresa (Universidad de Zaragoza. Departamento de Ciencias de la Tierra)

Data:	2016
Resum:	Environmental magnetic proxies were analyzed in a relatively monotonous, ~25. 3m thick alluvial sedimentary sequence drilled in the Añavieja Basin (NE Spain). Results from the core AÑ2 suggest that the concentrationdependent magnetic parameters mainly reflect variations in the content of detrital magnetite, sourced in the catchment rocks and soils of the basin, via changes in the dynamics of alluvial fans due to temperature changes in the northern hemisphere during the Late Pleistocene. The correspondence between the magnetic proxies and the temperature variations in the North Atlantic region (NGRIP curve) indicates that higher (lower) concentrations and finer (coarser) magnetite grains coincide with warm (cold) periods. We propose that during cold periods, a sparser vegetation cover favored the incoming of higher energy runoff bearing coarser sediments to the basin that are relatively impoverished in magnetite. In contrast, during warm periods, the wider distribution of the vegetation cover associated with the lower runoff energy lead to finer, magnetite-richer sediment input to the basin. Maghemite, presumably of pedogenic origin, appears to be present also in the studied alluvial sediments. Further studies are necessary to unravel its palaeoclimatic significance.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Magnetite ; Environmental magnetism ; Añavieja basin ; Alluvial sequence ; Vegetation cover ; Temperature ; Ngrip curve
Publicat a:	Geologica acta, Vol. 14 Núm. 2 (June 2016) , p. 139-154 (Articles) , ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/310442
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/GeologicaActa2016.14.2.4
DOI: 10.1344/GeologicaActa2016.14.2.4

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