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Magnetismo y cambios ambientales en registros terrestres: El lago de Marboré, Parque Nacional de Ordesa y Monte Perdido (Huesca)

2013; University of La Rioja; Volume: 39; Issue: 1 Linguagem: Inglês

10.18172/cig.2002

1697-9540

Belén Oliva-Urcía, Ana Moreno, Blas L. Valero‐Garcés, M. Pilar Mata, Grupo Horda,

Archaeological and Geological Studies

The study of the magnetic properties and their variations with time in lacustrine sediment cores allow deducing paleoenvironmental changes in the last millennia. This study presents a multiproxy approach that integrates geochemical, sedimentological and magnetic properties records from a long core (~6 m) of the Marboré Lake at 2500 m. a.s.l. in the West-central Pyrenees. The core spans over the last 12.7 ky cal BP. Facies, geochemical composition and magnetic properties clearly identify sedimentological environments with a great glaciar influence from 12.7-11.7 ky cal BP, including the Youger Dryas. These colder periods (YD) are characterized by a lower content in ferromagnetic minerals s.l. The beginning of the Holocene is marked by a slightly increase in the lake bioproductivity. During 9.2- 4.1 ky cal BP the increase in bioproductivity, higher content of detrital carbonates and a general decrease in the concentration and variety of the ferromagnetic s.l. minerals are coherent with a more humid period. The transition ca. 5-4.5 ky cal BP is the most significant change during the whole Holocene and it is characterized by an increase in the ferromagnetic minerals s.l., a decrease in TOC and detrital carbonates, which are interpreted as a response to an increase of aridity