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Sedimentological, paleobiological, mineralogical, and geochemical analyses of a sediment core retrieved on the seafront of Cartagena Bay were performed after high-resolution sampling. A wide series of dates obtained through radiocarbon and amino acid racemization proved that the Holocene record on the analyzed core began at ca. 7300 yr cal BP. Reinterpretation of the marine seismic profiles indicated that the beginning of this transgression was channeled along erosive paleochannels excavated on a coastal plain of, at least, MIS5c age. The Holocene paleoenvironmental evolution consisted of a first period marked by marine conditions with strong inputs from a fan delta linked to the reorganized fluvial network that occurred after the sudden rise of the base level, which caused a growing sedimentary prism. Later, the full marine environment was reflected in the development of a Posidonia - Cymodocea meadow hosting a rich biodiversity of marine species (mollusks, foraminifera, ostracoda). Around 3800 yr cal BP, the area underwent a profound change and a silting process started to alter the conditions, turning the area into a paucispecific brackish marsh environment in which mud deposition was dominant. Since Carthaginian times, arrangement works locally affected the record, allowing the arrival of some marine species due to port work (dredging) undertaken to gain depth and showing anthropic influence. [ABSTRACT FROM AUTHOR]

We reconstructed the palaeoenvironmental conditions of Cartagena Bay during the Holocene after a multidisciplinary study to identify natural variations and the anthropic processes of this coastal area. A total of 119 samples were recovered for amino acid racemization dating, 3 for radiocarbon dating (14C), and four sets of 80 samples for sedimentological and palaeontological determination, mineralogical content, biomarker and trace elements quantification. Two natural scenarios were identified from the variations of n -alkane indices and palaeobiological content. The first period (6650–5750 yr cal BP) was marked by the development of euhaline marine conditions with strong inputs from aquatic macrophytes and high biodiversity. After a hiatus, the area underwent a profound change, becoming a paucispecific brackish marsh environment with increasing inputs from land plants, with possible episodes of emersion with a greater presence from terrestrial gastropods (3600–300 cal yr BP). By combining trace element abundance and stanol distributions, our study also provides a novel approach to identify the predominant influence of anthropogenic factors in the last three millennia in the coastal record of Cartagena Bay. Findings confirmed that Pb mining and metallurgy began during the Bronze Age, with considerable inputs of this heavy metal into the atmosphere during Phoenician, Punic and particularly Roman times compared to the Middle Ages. Pollution by Cu and Zn was also observed during Punic and Roman times, and was first documented in the Middle Ages. In addition, faecal stanols, such as coprostanol, derived mainly from humans, and 24-ethylcoprostanol from herbivores were present, thereby indicating for the first time a continuous presence of human populations and significant pollution input since 3600 yr cal BP, this being greater in the late Bronze Age and Phoenician, Punic and Roman times than during Late Antiquity and the Middle Ages, when the city was in decline. [Display omitted] • Euhaline marine conditions and high biodiversity occurred at 6650–5750 yr. • A paucispecific brackish marsh environment occurred at 3400–300 yr after an hiatus. • Faecal sterols revealed pollution from herbivores and humans since Bronze Age. • Pb–Zn–Cu linked to regional mining-metallurgy since Bronze Age to Middle Ages. [ABSTRACT FROM AUTHOR]

In this paper we present a review of the available Holocene pollen records from the Spanish Central System (113 sites and 150 14 C dates). Palynological data obtained from pollen analyses of peat-bogs, lakes and archaeological sites, as well as radiocarbon dating, were used to infer the human impact on vegetation and landscape during the last 9 millennia. The Neolithic contribution to the configuration of landscape is scarce, limited to the valleys, while Chalcolithic settlements and their related activities (agriculture and grazing) represent the first evidence of significant human impact on the high-mountains. The pollen record has allowed us to relate two cultural periods of changing, the Copper Age–Early Bronze Age and Late Bronze Age–Early Iron Age transitions, to abrupt climate disruptions, the so-called 4.2 and 2.8 ka cal BP events respectively. From the Iron Age to the Early Middle Ages, anthropic activities were still sporadic, mainly located in the lowlands, but from the Feudal Period onwards, when La Mesta transhumance system takes place, high-mountain landscapes changed dramatically. Late Modern Period brings a further intensification of human pressure, especially related to forestry, with widespread pinewood afforestation. [ABSTRACT FROM AUTHOR]

A new record from a long sediment core (S3) in Navamuño (1505 m asl, western Iberian Central System) provides the reconstruction of the vegetation history and environmental changes in the region between 15.6 and 10.6 ka cal BP, namely during the Late Glacial and the early Holocene, using a multiproxy analysis (pollen-based vegetation and climate reconstruction, sedimentary macrocharcoals, loss-on-ignition, magnetic susceptibility and X-ray fluorescence (XRF) measurements). The results are then compared with other sequences from the Iberian Central System and the whole Iberian Peninsula in order to better understand the past dynamics of the main forest constituents. The pollen record shows a shift from open pine forests ∼15.6–14.7 ka cal BP (Oldest Dryas) to mixed open pine-birch woodlands ∼14.7–14.0 ka cal BP (Bølling). Woodlands were succeeded by a steppe-like landscape until ∼13.4 ka cal BP (Older Dryas), which was replaced again by high-mountain pine forests and riparian woodlands ∼13.4–12.6 ka cal BP (Allerød). A great development of cold steppe grasslands linked to the decline of birch woodlands is documented ∼12.6–11.7 ka cal BP (Younger Dryas). The early Holocene (11.7–10.6 ka cal BP) was characterized by a progressive reforestation of the study area by pine and birch forests in the highlands and oak woods in the lowlands. Temperate tree taxa (Carpinus betulus , Castanea sativa , Corylus avellana , Fraxinus , Juglans , Tilia , and Ulmus) were also common but likely at lower elevations. Pollen of Fagus sylvatica was already recorded during the Late Glacial and the early Holocene. The marked increasing local fire activity during the warmer and wetter Allerød oscillation could be related to a rise in tree cover, supporting the climatically driven character of these fires. Nevertheless, the strong increase in fire activity during the Younger Dryas would probably be related to growing tree and shrub mortality, as well as to the wet/dry biphasic structure of this stadial. The standard "Modern Analogue Technique" has been also applied to the Navamuño sequence to provide quantitative climate estimations for the Late Glacial and the early Holocene periods. This record is one of the few continental archives that show the climatic trend between the Late Glacial and the early Holocene in central Iberia, agreeing with many other regional records from the Western Mediterranean. • The Navamuño record provides one of the few continental records of the entire Late Glacial-early Holocene periods in central Iberia showing the strongest vegetation and environmental changes yet published. • Our study involves the first documentation of beech and hornbeam in glacial refugia in the centre of the Iberian Peninsula. • Results show significant contribution of the IACP and the 11.4 ka cal BP and a biphasic structure of the Younger Dryas. • Our study is one of the few palaeoclimatic and palynological reconstructions carried out at high resolution in SW Europe. [ABSTRACT FROM AUTHOR]