Pyrogenic organic matter from palaeo-fires during the Holocene: A case study in a sequence of buried soils at the Central Ebro Basin (NE Spain).

Autor: Armas-Herrera CM; Departamento de Ciencias Agrarias y del Medio Natural, Escuela Politécnica Superior de Huesca, Universidad de Zaragoza, Carretera de Cuarte s/n, 22071 Huesca, Spain. Electronic address: cmarmas@unizar.es., Pérez-Lambán F; Departamento de Ciencias de la Antigüedad, Universidad de Zaragoza, Zaragoza, 50009, Spain., Badía-Villas D; Departamento de Ciencias Agrarias y del Medio Natural, Escuela Politécnica Superior de Huesca, Universidad de Zaragoza, Carretera de Cuarte s/n, 22071 Huesca, Spain; Instituto de Investigación en Ciencias Ambientales de Aragón (IUCA), Universidad de Zaragoza, Spain., Peña-Monné JL; Instituto de Investigación en Ciencias Ambientales de Aragón (IUCA), Universidad de Zaragoza, Spain; Departamento de Geografía y Ordenación del Territorio, Universidad de Zaragoza, Zaragoza, 50009, Spain., González-Pérez JA; Grupo de Materia Orgánica en Suelos y Sedimentos (MOSS), Instituto de Recursos Naturales y Agrobiología (IRNAS-CSIC), Avda. Reina Mercedes, 10, 41012 Sevilla, Spain., Picazo Millán JV; Departamento de Ciencias de la Antigüedad, Universidad de Zaragoza, Zaragoza, 50009, Spain; Instituto de Investigación en Ciencias Ambientales de Aragón (IUCA), Universidad de Zaragoza, Spain., Jiménez-Morillo NT; Departamento de Fitotecnia, Escola de Ciências e Tecnologia, ICAAM, Universidade de Évora, Núcleo da Mitra, Ap. 94, 7006-554 Évora, Portugal., Sampietro-Vattuone MM; CONICET and Laboratorio de Geoarqueología, Universidad Nacional de Tucumán, San Miguel de Tucumán 4000, Argentina., Gracia MA; Departamento de Ciencias de la Antigüedad, Universidad de Zaragoza, Zaragoza, 50009, Spain; Instituto de Investigación en Ciencias Ambientales de Aragón (IUCA), Universidad de Zaragoza, Spain.
Jazyk: angličtina
Zdroj: Journal of environmental management [J Environ Manage] 2019 Jul 01; Vol. 241, pp. 558-566. Date of Electronic Publication: 2018 Oct 11.
DOI: 10.1016/j.jenvman.2018.09.104
Abstrakt: We studied the fire record and its environmental consequences during the Holocene in the Central Ebro Basin. This region is very sensitive to environmental changes due to its semiarid conditions, lithological features and a continuous human presence during the past 6000 years. The study area is a 6 m buried sequence of polycyclic soils developed approximately 9500 years ago that is exceptionally well preserved and encompasses four sedimentary units. The content and size distribution of macroscopic charcoal fragments were determined throughout the soil sequence and the analysis of the composition of charcoal, litter and sediments via analytical pyrolysis (Py-GC/MS). The high amount of charcoal fragments recovered in most horizons highlights the fire frequencies since the beginning of the Neolithic, most of which were probably of anthropogenic origin. In some soil horizons where charcoal was not found, we detected a distribution pattern of lipid compounds that could be related to biomass burning. On the other hand, the low number of pyrolysates in the charcoal could be attributed to high-intensity fires. No clear pattern was found in the composition of pyrolysates related to the age of sediments or vegetation type. The most ancient soil (Unit 1) was the richest in charcoal content and contains a higher proportion of larger fragments (>4 mm), which is consistent with the burning of a relatively dense vegetation cover. This buried soil has been preserved in situ, probably due to the accumulation of sedimentary materials because of a high-intensity fire. In addition, the pyrogenic C in this soil has some plant markers that could indicate a low degree of transformation. In Units 2-4, both the amount of charcoals and the proportions of macrofragments >4 mm are lower than those in Unit 1, which coincides with a more open forest and the presence of shrubs and herbs. The preservation of this site is key to continuing with studies that contribute to a better assessment of the consequences of future disturbances, such as landscape transformation and climate change.
(Copyright © 2018 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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