Search results for "Holocene"

2020

Abstract. A compilation of the published literature on dust content in terrestrial and marine sediment cores was synchronized with pollen data and speleothem growth phases on the Greenland Ice Core Chronology 2005 (GICC05) time axis. Aridity patterns for eight key areas of the global climate system have been reconstructed for the last 60 000 years. These records have different time resolutions and different dating methods, i.e. different types of stratigraphy. Nevertheless, all regions analysed in this study show humid conditions during early Marine Isotope Stage 3 (MIS3) and the early Holocene or deglaciation, but not always at the same time. Such discrepancies have been interpreted as reg…

Climate and structure of the 8.2 ka event reconstructed from three speleothems from Germany

2020

Abstract The most pronounced climate anomaly of the Holocene was the 8.2 ka cooling event. We present new 230Th/U-ages as well as high-resolution stable isotope and trace element data from three stalagmites from two different cave systems in Germany, which provide important information about the structure and climate variability of the 8.2 ka event in central Europe. In all three speleothems, the 8.2 ka event is clearly recorded as a pronounced negative excursion of the δ18O values and can be divided into a ‘whole event’ and a ‘central event’. All stalagmites show a similar structure of the event with a short negative excursion prior to the ‘central event’, which marks the beginning of the …

Drivers of change and ecosystem status in a temperate lake over the last Post-Glacial period from 14.5 kyr

2020

AbstractUnderstanding the long-term dynamics of ecological communities on the centuries-to-millennia scale is important for explaining present-day biodiversity patterns. Placing these patterns in a historical context could yield reliable tools for predicting possible future scenarios. Paleoarchives of macro+ and micro-fossil remains, and most importantly biomarkers such as fossil pigments and ancient DNA present in various sedimentary deposits, allow long term changes in ecological communities to be analysed. We use recent compilations of data including fossil pigments, metabarcoding of sedimentary ancient DNA and microfossils together with data analysis to understand the impact of gradual …

Aportaciones hidrogeológicas al estudio arqueológico de los orígenes de la Edad del Bronce de La Mancha: la cueva monumentalizada de Castillejo del B…

2014

Estudios recientes indican que las motillas, asentamientos de la Edad del Bronce de La Mancha, pudieron ser las más antiguas captaciones de agua subterránea en la Península Ibérica. Pero ¿por qué no existen motillas en el Campo de Montiel, territorio ubicado tradicionalmente en esta área cultural? En Castillejo del Bonete, sitio arqueológico situado en esa comarca, existe una cueva que fue utilizada y sellada durante la Prehistoria Reciente. Se presenta ahora la primera investigación paleohidrogeológica interdisciplinar en La Mancha, que ha analizado manantiales y niveles de agua subterránea del acuífero de Campo de Montiel, así como el interior de la sima de Castillejo del Bonete. Las conc…

Holocene millennial-scale productivity variations in the Sicily Channel (Mediterranean Sea)

2008

This study analyzes coccolithophore abundance fluctuations (e.g., Emiliania huxleyi, Gephyrocapsa specimens, and Florisphaera profunda) in core MD01-2444 sediment strata retrieved at the Iberian Margin, northeastern Atlantic Ocean. Coccolithophores are calcareous nannofossils, a major component of the oceanic phytoplankton, which provide information about past ecological and climatological variability. Results are supported by data on fossil organic compounds (sea surface temperatures, alkenones, and n-hexacosan-1-ol index) and geochemical analyses (benthic ?13Ccc and planktonic ?18Occ isotopes). Three scenarios are taken into account for this location at centennial-scale resolution over th…

Data for: Accumulation of metals and changes in the composition of freshwater lake organic sediments during the Holocene

2020

Distribution of metals in freshwater sediment strata formed during the Holocene in the territory of Latvia has been studied rather insufficiently. Considering the large volume of accumulated organic matter in sediments, studies of the content of metal elements in sediments can help to determine the peculiarities of metal accumulation process in limnic systems and biogeochemical cycling of metals. Lake Pilvelis, located in the eastern part of Latvia (the northern part of Europe), was selected as the study site. Lake Pilvelis is a small lake of a glacial origin, and more than 90% of its depression is filled with organic-rich sediments, such as gyttja or freshwater sapropel, with an average th…

Data from: Exposing the structure of an Arctic food web

2016

How food webs are structured has major implications for their stability and dynamics. While poorly studied to date, arctic food webs are commonly assumed to be simple in structure, with few links per species. If this is the case, then different parts of the web may be weakly connected to each other, with populations and species united by only a low number of links. We provide the first highly resolved description of trophic link structure for a large part of a high-arctic food web. For this purpose, we apply a combination of recent techniques to describing the links between three predator guilds (insectivorous birds, spiders, and lepidopteran parasitoids) and their two dominant prey orders …

Explotació dels mamífers i economia de les darreres comunitats caçadores-recol·lectores del vessant mediterrani ibèric durant la transició Tardiglaci…

2015

En el presente trabajo se realiza el estudio zooarqueológico de los vertebrados terrestres explotados por los grupos humanos de los niveles tardiglaciares de los yacimientos de Santa Maira (boca Oeste) y Nerja (sala del Vestíbulo). A partir de los datos obtenidos para las facies culturales Magdaleniense / Epipaleolítico / Mesolítico se caracterizan las tendencias de cambio en los modelos económicos de las últimas comunidades cazadoras-recolectoras de la península ibérica. Estas secuencias se contextualizan así mismo en la zona biogeográfica mediterránea peninsular. Entre los resultados obtenidos cabe destacar la definición y caracterización de un modelo económico "tardiglaciar", donde el mo…

Variations in Sediment Yield from the Upper Doubs River Carbonate Watershed (Jura, France) since the Late-Glacial Period

1999

AbstractThe Upper Doubs River Valley is a 910-km2watershed feeding into Lake Chaillexon. The lake was formed by a natural rockfall at the end of the Bølling Chronozone (around 14,250 cal yr B.P.) and since then has trapped material eroded from the watershed. The filling process and variations in sediment yield have been investigated by mechanical coring, seismic surveys, and electric soundings. The detrital sediment yield of the upstream watershed can be calculated by quantifying the sedimentary stocks for each climatic stage of the Late-Glacial period and Holocene Epoch and estimating the lake's entrapment capacity. This enables us to determine the intensity of the erosion processes in rel…

The formation of alluvial fans and young floodplain deposits in the Lieser catchment, Eifel Mountains, western German Uplands: A study of soil erosio…

2011

This study deals with the exploration and spatiotemporal quantification of the young Holocene, nearly skeleton-free floodplain sediments of the Lieser River, a tributary of the Mosel River in the Eifel Mts. The deposits are primarily a consequence of anthropogenic-triggered soil erosion in the catchment. To observe the phenomenon of corresponding soil erosion on multiple levels two small alluvial fans of tributary catchments were investigated. For comparison, one location in the neighboring Salm valley was described. The results were compared with those of other streams. With extensive fieldwork more than 100 drillings and pits were made at 12 locations. For dating the sediments OSL dating…