AMS radiocarbon dating of annually laminated sediments from Lake Holzmaar, Germany (original) (raw)
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The …, 2012
The annually laminated record of Lake Belau offers an exceptional opportunity to investigate with high temporal resolution Holocene environmental change, aspects of climate history and human impact on the landscape. A new chronology based on varve counts, 14 C-datings and heavy metal history has been established, covering the last 9400 years. Based on multiple varve counting on two core sequences, the easily countable laminated section spans about 7850 varve years (modelled age range c. 9430 to 1630 cal. BP). Not all of the record is of the same quality but approximately 69% of the varves sequence is classified to be of high quality and only c. 5% of low quality. The new chronology suggests dates generally c. 260 years older than previously assumed for the laminated section of the record. The implications for the vegetation and land-use history of the region as well as revised datings for pollen stratigraphical events are discussed. Tephra analysis allowed the identification of several cryptotephra layers. New dates for volcanic eruptions are presented for the Lairg B event (c. 6835 cal. BP, 2s range 6832-6615 cal. BP), the Hekla 4 event (c. 4396 cal. BP, 2s range 4417-4266 cal. BP), and Hekla 3 eruption (c. 3101 cal. BP, 2s range 3120-3068 cal. BP).
The Holocene, 2012
The annually laminated record of Lake Belau offers an exceptional opportunity to investigate with high temporal resolution Holocene environmental change, aspects of climate history and human impact on the landscape. A new chronology based on varve counts, 14C-datings and heavy metal history has been established, covering the last 9400 years. Based on multiple varve counting on two core sequences, the easily countable laminated section spans about 7850 varve years (modelled age range c. 9430 to 1630 cal. BP). Not all of the record is of the same quality but approximately 69% of the varves sequence is classified to be of high quality and only c. 5% of low quality. The new chronology suggests dates generally c. 260 years older than previously assumed for the laminated section of the record. The implications for the vegetation and land-use history of the region as well as revised datings for pollen stratigraphical events are discussed. Tephra analysis allowed the identification of sever...
Multi-proxy dating of Holocene maar lakes and Pleistocene dry maar sediments in the Eifel, Germany
Quaternary Science Reviews, 2013
During the last twelve years the ELSA Project (Eifel Laminated Sediment Archive) at Mainz University has drilled a total of about 52 cores from 27 maar lakes and filled-in maar basins in the Eifel/Germany. Dating has been completed for the Holocene cores using 6 different methods (210 Pb and 137 Cs activities, palynostratigraphy, event markers, varve counting, 14 C). In general, the different methods consistently complement one another within error margins. Event correlation was used for relating typical lithological changes with historically known events such as the two major Holocene flood events at 1342 AD and ca 800 BC. Dating of MIS2eMIS3 core sections is based on greyscale tuning, radiocarbon and OSL dating, magnetostratigraphy and tephrochronology. The lithological changes in the sediment cores demonstrate a sequence of events similar to the North Atlantic rapid climate variability of the Last Glacial Cycle. The warmest of the MIS3 interstadials was GI14, when a forest with abundant spruce covered the Eifel area from 55 to 48 ka BP, i.e. during a time when also other climate archives in Europe suggested very warm conditions. The forest of this "Early Stage 3 warm phase" developed subsequently into a steppe with scattered birch and pine, and finally into a glacial desert at around 25 ka BP. Evidence for Mono Lake and Laschamp geomagnetic excursions is found in two long cores. Several large eruptions during Middle and Late Pleistocene (Ulmener Maar e 11,000 varve years BP, Laacher See e 12,900 varve years BP, Mosenberg volcanoes/Meerfelder Maar 41e45 cal ka BP, Dümpel Maar 116 ka BP, Glees Maar e 151 ka BP) produced distinct ash-layers crucial for inter-core and inter-site correlations. The oldest investigated maar of the Eifel is 40 Ar/ 39 Ar dated to the time older than 520 ka BP.
A Younger Dryas varve chronology from the Rehwiese palaeolake record in NE-Germany
Quaternary Science Reviews, 2012
The first 1400-year floating varve chronology for northeastern Germany covering the late Allerød to the early Holocene has been established by microscopic varve counts from the Rehwiese palaeolake sediment record. The Laacher See Tephra (LST), at the base of the studied interval, forms the tephrochronological anchor point. The fine laminations were examined using a combination of micro-facies and mXRF analyses and are typical of calcite varves, which in this case provide mainly a warm season signal. Two varve types with different sub-layer structures have been distinguished: (I) complex varves consisting of up to four seasonal sub-layers formed during the Allerød and early Holocene periods, and, (II) simple two sub-layer type varves only occurring during the Younger Dryas. The precision of the chronology has been improved by varve-to-varve comparison of two independently analyzed sediment profiles based on well-defined micro-marker layers. This has enabled both (1) the precise location of single missing varves in one of the sediment profiles, and, (2) the verification of varve interpolation in disturbed varve intervals in the parallel core. Inter-annual and decadal-scale variability in sediment deposition processes were traced by multi-proxy data series including seasonal layer thickness, highresolution element scans and total organic and inorganic carbon data at a five-varve resolution. These data support the idea of a two-phase Younger Dryas, with the first interval (12,675e12,275 varve years BP) characterised by a still significant but gradually decreasing warm-season calcite precipitation and a second phase (12,275e11,690 varve years BP) with only weak calcite precipitation. Detailed correlation of these two phases with the Meerfelder Maar record based on the LST isochrone and independent varve counts provides clues about regional differences and seasonal aspects of YD climate change along a transect from a location proximal to the North Atlantic in the west to a more continental site in the east.
Radiocarbon, 1992
Laminated sediments of Gościaż Lake can be used as an independent source of material for calibrating the radiocarbon time scale. The varve chronology is based on three long cores from the deepest part of the lake, with one additional core from the second deepest part. From pollen andCladoceraspectra and stable isotope and chemical content sequences, we have determined the Allerød(AL)/Younger Dryas(YD) and Younger Dryas/Preboreal(PB) boundaries in the three long cores with relatively good accuracy, and have tentatively defined the AL/YD boundary in the fourth core. The Younger Dryas period contains at least 1520 varves, with 980 varves in fragments well replicated in all four cores. The duration of the Younger Dryas as recorded in sediments of Gościaż Lake corresponds well to the duration derived from230Th/234U and14C dates on Barbados corals, but disagrees with estimates from Soppensee, Lake Holzmaar and Swedish varves. Two AMS dates of terrestrial macrofossils from the PB and YD pe...
Bio- and chronostratigraphy of the lateglacial in the Eifel region, Germany
Quaternary International, 1999
In recent years enormous success has been achieved in varve counting of the Eifel maar lakes, but a detailed correlation with the biostratigraphy has been missing. In this paper, we present new palynological results of the Lateglacial sequences from Holzmaar Lake and Meerfelder Maar Lake based on annually laminated sediments. In particular, the Meerfelder Maar has great potential, because, in contrast to the Holzmaar, the sequence between the Ulmener Maar Tephra (11 000 varve years BP) and the Laacher See Tephra (12 880 varve years BP) including the Younger Dryas is undisturbed and complete. Therefore, we currently use the Meerfelder Maar chronology (Brauer et al., 1999b) as an independent varve calendar for the biostratigraphy of the Lateglacial. The palynological signals of both maar lakes are in good agreement and can easily be correlated with one another and with type sections/type regions in northwestern Germany and Jutland. The sequences of the Eifel maar lakes have the quality of hypostratotypes with regional biozones based on an absolute time scale.
Quaternary International, 1999
Due to its high accumulation rate, the loess sequence of Nu{loch (Rhine Valley, Germany) is well suited to a high-resolution study of continental paleoenvironmental changes over the last climatic cycle for northwestern Europe. As carbon isotope ratios of plants depend on environmental variations, C of loess-derived organic matter constitute reliable paleoclimatic proxies. We present here a new chronology of Nu{loch loess sequence based on several C and TL-dates. Our data show high correlations with global climate e!ects (Vostok-[CO ]) or semi-global (GISP2-O) and thus o!er, in this way, a new approach to establish accurate chronologies in continental sequences. Furthermore, using a deconvolution of the C signal would provide a quantitative proxy of moisture supply and permit paleoprecipitation reconstructions.
Multi-method study of the Middle Pleistocene loess–palaeosol sequence of Köndringen, SW Germany
E&G Quaternary Science Journal
Loess-palaeosol sequences (LPSs) remain poorly investigated in the southern part of the Upper Rhine Graben but represent an important element to understand the environmental context controlling sediment dynamics in the area. A multi-method approach applied to the LPS at Köndringen reveals that its formation occurred during several glacial-interglacial cycles. Field observations, as well as colour, grain size, magnetic susceptibility, organic carbon, and carbonate content measured in three profiles at 5 cm resolution, provide detailed stratigraphical information. Only minor parts of the LPS are made up of loess sediment, whereas the major parts are polygenetic palaeosols and pedosediments of varying development that are partly intersected, testifying to a complex local geomorphic evolution. The geochronological framework is based on 10 cm resolution infrared-stimulated luminescence (IRSL) screening combined with 18 multi-elevated-temperature post-IR IRSL ages. The luminescence ages indicate that two polygenetic, truncated Luvisols formed during marine isotope stages (MISs) 9(-7?) and MIS 5e, whereas unaltered loess units correspond to the last glacial (MISs 5d-2) and MIS 8. The channel-like structure containing the two truncated Luvisols cuts into > 2 m thick pedosediments apparently deposited during MIS 12. At the bottom of the LPS, a horizon with massive carbonate concretions (loess dolls) occurs, which may correspond to at least one older interglacial. Kurzfassung: Löss-Paläoboden-Sequenzen (LPS) sind im südlichen Teil des Oberrheingrabens bisher nur unzureichend untersucht, obwohl sie ein wichtiges Element für das Verständnis der Umweltbedingungen darstellen, welche die Sedimentdynamik in diesem Gebiet gesteuert haben. Die Anwendung eines Multi-Methoden-Ansatzes auf die LPS in Köndringen enthüllt, dass diese während mehrerer glazialinterglazialer Zyklen entstanden ist. Die Feldansprache dreier Profile und Laboranalysen in 5 cm Auflösung (Farbe, Korngröße, magnetische Suszeptibilität, organischer Kohlenstoff-und Karbonatgehalt), geben detaillierte Informationen über deren stratigraphischen Aufbau. Nur geringe Teile des LPS bestehen aus Löß, der teilweise durch Hangabschwemmungen geschichtet ist, während der größte Teil aus polygenetischen Paläoböden und Pedosedimenten unterschiedlicher Ausprägung besteht, die sich teilweise überschneiden und von einer komplexen lokalen geomorphologischen Entwicklung zeu-Published by Copernicus Publications on behalf of the Deutsche Quartärvereinigung (DEUQUA) e.V. 2 L. Schwahn et al.: Middle Pleistocene loess-palaeosol sequence of Köndringen, SW Germany gen. Der geochronologische Rahmen basiert auf Screening mittels Infrarot-Stimulierter Lumineszenz (IRSL) mit einer Auflösung von 10 cm in Kombination mit 18 Altern, die mit dem Multi-Elevated-Temperature post-IR IRSL Verfahren bestimmt wurden. Die Lumineszenzalter deuten darauf hin, dass die beiden polygenetischen, gekappten Luvisole während der marinen Isotopenstadien (MIS) 9(-7?) und MIS 5e entstanden sind, während die Lösseinheiten dem letzten Glazial (MIS 5d-2) und MIS 8 entsprechen. Die rinnenartige Struktur, welche die beiden gekappten Luvisole enthält, schneidet in > 2 m mächtige Pedosedimente ein, die offenbar während MIS 12 abgelagert wurden. An der Basis des LPS findet sich ein Horizont mit großen Karbonatkonkretionen (Lößkindl), die mindestens einem älteren Interglazial entsprechen könnten.