Response of alluvial systems to Late Pleistocene climate changes recorded by environmental magnetism in the Añavieja Basin (Iberian Range, NE Spain)

• Main Authors: Oliva-Urcia, Belén, Muñoz Jiménez, Arsenio, Larrasoaña Gorosquieta, Juan Cruz, Luzón Aguado, María Aránzazu, Pérez García, Antonio, González Rodríguez, Ángel, Jiang, Z., Qingsong, Liu, Román Berdiel, Teresa
• Format: Other/Unknown Material
• Language: English
• Published: Universidad de Barcelona 2020
• Subjects: Añavieja Basin; aluvial sequence; magnetite; environmental magnetism; vegetation cover; temperature; NGRIP curve; Jaume; NGRIP; North Atlantic
• Online Access: https://hdl.handle.net/20.500.12468/377; https://doi.org/10.1344/GeologicaActa2016.14.2.4

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. Instituto Pirenaíco de Ecología, España Departamento de Geología y Geoquímica, Universidad Autónoma de Madrid, España Departamento de Ciencias de la Tierra, Universidad de Zaragoza, España Instituto Geológico y Minero de España, España Institut de Ciéncies de la Terra Jaume Almera, España Paleomagnetism and Geochronology Laboratory, Institute of Geology and Geophysics, Chinesse Academy of Sciences, China Function Laboratory for Marine Geology, National Oceanography Laboratory, China Programa Junta para la Ampliación de Estudios, Consejo Superior de Investigaciones Científicas, España Ministerio de Ciencia e Innovación, España Gobierno de Aragón, España Fondo Social Europeo, Unión Europea