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Kaal J.,Institute Estudios Gallegos Padre Sarmiento | Kaal J.,University of Santiago de Compostela | Lopez-Saez J.A.,Institute Historia | Lopez-Merino L.,Institute Historia | Cortizas A.,University of Santiago de Compostela
Holocene | Year: 2010

Macroscopic charcoal, pollen and non-pollen palynomorphs were isolated from a colluvial soil located on a small hill in Campo Lameiro (NW Spain) in order to elucidate the vegetation history of the area and its relation to fire and human activities. The presence of macroscopic charcoal throughout the 2.10 m thick soil (42 samples) is evidence of frequent fires during the last c. 6300 years. The charcoal record was dominated by Quercus (probably Q. robur), Ericaceae (probably Arbutus unedo and Erica arborea) and Fabaceae (mainly Genista type). Abrupt changes in the charcoal assemblage are less explicit in the pollen sequence, probably as a result of pollen inflow from the downhill surroundings of the study site. Combined results indicated that the original oak woodland was gradually replaced by pyrophytic shrubs (Ericaceae and Fabaceae) as a result of fire recurrence. Non-pollen palynomorphs strongly suggested that vegetation was deliberately ignited by past human societies to facilitate grazing. No evidence of local agricultural practices was found. Episodes of accelerated shrubland expansion occurred c. 6000-5500 cal. BP, c. 4000-3500 cal. BP and c. 1700 cal. BP, the latter of which caused the definitive settlement of shrublands dominated by Ericaceae and Fabaceae which are nowadays widespread in NW Iberia. © The Author(s), 2009.


Serrano O.,CSIC - Center for Advanced Studies of Blanes | Mateo M.A.,CSIC - Center for Advanced Studies of Blanes | Duenas-Bohorquez A.,University Utrecht | Renom P.,CSIC - Center for Advanced Studies of Blanes | Lopez-Saez J.A.,Institute Historia
Science of the Total Environment | Year: 2011

The study of a Posidonia oceanica mat (a peat-like marine sediment) core has provided a record of changes in heavy metal abundances (Fe, Mn, Ni, Cr, Cu, Pb, Cd, Zn, As and Al) since the Mid-Holocene (last 4470yr) in Portlligat Bay (NW Mediterranean). Metal contents were determined in P. oceanica. Both, the concentration records and the results of principal components analysis showed that metal pollution in the studied bay started ca. 2800yrBP and steadily increased until present. The increase in Fe, Cu, Pb, Cd, Zn and As concentrations since ca. 2800yrBP and in particular during Greek (ca. 2680-2465calBP) and Roman (ca. 2150-1740calBP) times shows an early anthropogenic pollution rise in the bay, which might be associated with large- and short-scale cultural and technological development. In the last ca. 1000yr the concentrations of heavy metals, mainly derived from anthropogenic activities, have significantly increased (e.g. from ~15 to 47μgg -1 for Pb, ~23 to 95μgg -1 for Zn and ~8 to 228μgg -1 for As). Our study demonstrates for the first time the uniqueness of P. oceanica meadows as long-term archives of abundances, patterns, and trends of heavy metals during the Late Holocene in Mediterranean coastal ecosystems. © 2011 Elsevier B.V.


Blanco-Gonzalez A.,Durham University | Lopez-Saez J.A.,Institute Historia
Environmental Archaeology | Year: 2013

This study addresses the earliest strategies of permanent occupation in the mountainous regions bordering Northern Meseta in inland Iberia. This piece of work gathers together and discusses archaeological information about settlement in the Late Bronze Age and Early Iron Age and previously published high-resolution palynological cores from three study areas. Its major goal is to assess both archaeological and pollen records in order to gain a better understanding of the dynamics of occupation and transformation of these upland settings. Until cal 700 BC there are no clear signs of permanence in the highlands surrounding the Duero basin, but from that point onwards various initiatives of small-scale spontaneous colonisation have been identified. Colonisation in the Iron Age involved pastoralism, cereal agriculture and a significant use of forestry resources, causing a major anthropogenic impact with irreversible consequences. The outlined account constitutes the first synthetic overview at a macro-regional scale on the beginnings of the integrated and diversified strategies implemented in these upland regions. © Association for Environmental Archaeology 2013.


Alba-Sanchez F.,University of Granada | Lopez-Saez J.A.,Institute Historia | Benito de Pando B.,University of Granada | Linares J.C.,Pablo De Olavide University | And 2 more authors.
Diversity and Distributions | Year: 2010

Aim: Quaternary palaeopalynological records collected throughout the Iberian Peninsula and species distribution models (SDMs) were integrated to gain a better understanding of the historical biogeography of the Iberian Abies species (i.e. Abies pinsapo and Abies alba). We hypothesize that SDMs and Abies palaeorecords are closely correlated, assuming a certain stasis in climatic and topographic ecological niche dimensions. In addition, the modelling results were used to assign the fossil records to A. alba or A. pinsapo, to identify environmental variables affecting their distribution, and to evaluate the ecological segregation between the two taxa. Location: The Iberian Peninsula. Methods: For the estimation of past Abies distributions, a hindcasting process was used. Abies pinsapo and A. alba were modelled individually, first calibrating the model for their current distributions in relation to the present climate, and then projecting it into the past-the last glacial maximum (LGM) and the Middle Holocene periods-in relation to palaeoclimate simulations. The resulting models were compared with Iberian-wide fossil pollen records to detect areas of overlap. Results: The overlap observed between past Abies refugia-inferred from fossil pollen records-and the SDMs helped to construct the Quaternary distribution of the Iberian Abies species. SDMs yielded two well-differentiated potential distributions: A. pinsapo throughout the Baetic mountain Range and A. alba along the Pyrenees and Cantabrian Range. These results propose that the two taxa remained isolated throughout the Quaternary, indicating a significant geographical and ecological segregation. In addition, no significant differences were detected comparing the three projections (present-day, Mid-Holocene and LGM), suggesting a relative climate stasis in the refuge areas during the Quaternary. Main conclusions: Our results confirm that SDM projections can provide a useful complement to palaeoecological studies, offering a less subjective and spatially explicit hypothesis concerning past geographic patterns of Iberian Abies species. The integration of ecological-niche characteristics from known occurrences of Abies species in conjunction with palaeoecological studies could constitute a suitable tool to define appropriate areas in which to focus proactive conservation strategies. © 2010 Blackwell Publishing Ltd.


Palomar T.,Institute Historia | Oujja M.,CSIC - Institute of Physical Chemistry "Rocasolano" | Garcia-Heras M.,Institute Historia | Villegas M.A.,Institute Historia | Castillejo M.,CSIC - Institute of Physical Chemistry "Rocasolano"
Spectrochimica Acta - Part B Atomic Spectroscopy | Year: 2013

The feasibility and possibilities of laser induced breakdown spectroscopy (LIBS) in the full study of non-destructible historic glasses have been explored in the present work. Thirteen Roman glass samples, including seven entire glass beads, from the ancient town of Augusta Emerita (SW Spain) were characterized by LIBS in combination with other conventional techniques, such as scanning electron microscopy/energy dispersive X-ray spectrometry, X-ray fluorescence and ultraviolet-visible spectrophotometry. LIBS stratigraphic analysis, carried out by the application of successive laser pulses on the same spot, has been mainly targeted at characterizing particular features of non-destructible historic glasses, such as bulk chemical composition, surface degradation pathologies (dealkalinization layers and deposits), chromophores, and opacifying elements. The obtained data demonstrate that LIBS can be a useful and alternative technique for spectroscopic studies of historical glasses, especially for those conserved under burial conditions and when it deals with studying non-destructible samples. © 2013 Elsevier B.V. All rights reserved.


Barranco V.,CSIC - National Center for Metallurgical Research | Carmona N.,CSIC - National Center for Metallurgical Research | Galvan J.C.,CSIC - National Center for Metallurgical Research | Grobelny M.,Institute of Precision Mechanics | And 2 more authors.
Progress in Organic Coatings | Year: 2010

The behaviour/resistance of four optimised sol-gel coating systems (inorganic, hybrid organic-inorganic, containing zirconium ions and containing cerium ions) against corrosion of AZ91 magnesium alloy were studied. The coatings obtained by the sol-gel process were evaluated as autonomous protective coatings as well as a pre-treatment prior to acrylic top coat. The coating obtained from tetramethoxysilane (TMOS) and diethoxydimethylsilane (DEDMS) as precursors and doped with Ce3+ was especially effective as pre-treatment for a final acrylic coating. For non-defected coating the impedance modulus has not changed during the time of immersion (7 days) in 0.5 M Na2SO4. An inhibition of coating delamination at the defect of the acrylic coating was recorded by means of LEIS. © 2010 Elsevier B.V. All rights reserved.


Aguilera M.,University of Barcelona | Ferrio J.P.,University of Lleida | Perez G.,Institute Historia | Araus J.L.,University of Barcelona | Voltas J.,University of Lleida
Journal of Quaternary Science | Year: 2012

Precipitation has been of utmost importance in shaping the evolution of landscapes and human settlements in the Mediterranean. However, information on seasonal precipitation patterns through the Holocene is scarce. This study attempts to quantify the evolution of seasonal precipitation in the East Iberian Peninsula (5000 BC to AD 600) based on the carbon isotope composition (δ 13C) of archaeobotanical remains. Data on Holm oak, Aleppo pine and small-grain cereals were combined, and precipitation was inferred from models relating present-day records to the δ 13C of modern samples. Subsequently, charred grains were used as a proxy for ancient moisture during April-May, whereas oak and pine charcoals provided complementary rainfall estimates for September-December and January-August, respectively. The results reveal aridity changes throughout the Holocene in the western Mediterranean. Past spring-summer precipitation was consistently higher than at present. In contrast, autumn and early winter precipitation showed stronger fluctuations, particularly during the first millennium BC, and often exhibited values below those of the present. The high contribution of autumn precipitation to the annual water budget, typical of the present Mediterranean climate, was definitively established at the beginning of the current era. This study shows how a combination of species holding complementary environmental signals can contribute to a wider knowledge of local precipitation dynamics. © 2011 John Wiley & Sons, Ltd.


Architectonic and structural forms, both preserved and ruined, are studied in this paper, as well as constructive customs and decorative solutions, in a group of tufa-stone pendentive domed churches from Álava, La Rioja and Burgos provinces. In a first step buildings are analyzed; secondly, decorative and constructive production is studied; and finally, datation of High Middle Age complex-between second half of the Ninth Century and the beginning of Tenth Century-is discussed since obtained data. These architectonic, constructive and decorative systems imply the existence of various productive groups which define a singular ensemble during the period of time and for the place in which this ensemble was active. © 2015 CSIC.


Pinto-Llona A.C.,Institute Historia
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2013

Cave bears Ursus spelaeus are known from many limestone caves throughout the European Pleistocene. Despite the enormous quantities of fossils unearthed, many aspects of the cave bear ecology are still little known. Cave bear remains appear almost always with an array of variously sized tooth punctures, and the evidence from tooth mark types and sizes at several cave bear sites studied here indicates that cave bears themselves were responsible for the scavenging modifications recorded at these cave bear-only sites. Anatomical evidence for cave bear diet indicates that they had a tough-plant based diet and in addition, their powerful front legs suggest an enhanced digging capability that has sometimes been thought to relate to digging for tubers. Dental microwear analysis (DMA) approaches fossil and extant diets by comparing tooth wear for animals of known diet with that shown by fossils. Scanning electron microscope micrographs were prepared and the microwear features were measured. The results show differences in wear patterns between brown bears and cave bears from several locations and chronologies across northern Spain. There is no indication that these cave bears ate tubers or any food contaminated by soil; but the dental microwear observed indicates that they had a greater degree of bone consumption compared with brown bears. © 2012 Elsevier B.V.


Abel-Schaad D.,Institute Historia | Lopez-Saez J.A.,Institute Historia
Vegetation History and Archaeobotany | Year: 2013

Human impact is a key factor in the evolution of landscape since the mid-Holocene. In this work landscape changes in a mountainous area in central Spain are examined through the analysis of pollen at Peña Negra mire (Cáceres), since its formation during the transition period between the third and second millennium cal. b. c. The study focuses on anthropogenic dynamics linked to the effects of livestock husbandry and the use of fire for forest clearance, as the mire is located close to a natural pass across the Bejar Range. With this aim, non-pollen palynomorphs and charcoal accumulation rate are useful indicators to assess the increasing role of human influence on vegetation. Grazing activities are continuously detected from the base of the profile, with maxima in the last millennium, while the use of fire is more pronounced from 3000 to 1000 cal. b. p. The discontinuous presence through the profile of forest species like chestnut, walnut, beech, elm or yew has also been analyzed. © 2012 Springer-Verlag.

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