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  • 1. Dehnert, Andreas
    et al.
    Kracht, Oliver
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Akcar, Naki
    Kemna, Hans Axel
    Kubik, Peter W.
    Schlüchter, Christian
    Cosmogenic isotope burial dating of fluvial sediments from the Lower Rhine Embayment, Germany2011In: Quaternary Geochronology, ISSN 1871-1014, E-ISSN 1878-0350Article in journal (Refereed)
    Abstract [en]

    Cosmogenic isotope burial dating, using 10Be and 26Al, was applied to PlioePleistocene fluvial successionsfrom the Lower Rhine Embayment, Germany. The approach consists of three principal steps: (1)measurement of cosmogenic nuclides in depth profiles, (2) modelling of hypothetical nuclide concentrationsbased on a first-order conceptualisation of the geological context and the principal succession ofdepositions and subsequent erosional and burial phases, and (3) using parameter estimation to identifyvalues for the a priori unknown model parameters (burial age, initial nuclide concentrations, terraceerosion rates) that result in minimal disagreement between hypothetical and measured nuclideconcentrations.

  • 2. Fritz, Michael
    et al.
    Wetterich, Sebastian
    Schirrmeister, Lutz
    Meyer, Hanno
    Lantuit, Hugues
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Pollard, Wayne H.
    Eastern Beringia and beyond: Late Wisconsinan and Holocene landscape dynamics along the Yukon Coastal Plain, Canada2012In: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 319, p. 28-45Article in journal (Refereed)
    Abstract [en]

    Terrestrial permafrost archives along the Yukon Coastal Plain (northwest Canada) have recorded landscape development and environmental change since the Late Wisconsinan at the interface of unglaciated Beringia (i.e. Komakuk Beach) and the northwestern limit of the Laurentide Ice Sheet (i.e. Herschel Island). The objective of this paper is to compare the late glacial and Holocene landscape development on both sides of the former ice margin based on permafrost sequences and ground ice. Analyses at these sites involved a multi-proxy approach including: sedimentology, cryostratigraphy, palaeoecology of ostracods, stable water isotopes in ground ice, hydrochemistry. and AMS radiocarbon and infrared stimulated luminescence (IRSL) dating. AMS and IRSL age determinations yielded full glacial ages at Komakuk Beach that is the northeastern limit of ice-free Beringia. Herschel Island to the east marks the Late Wisconsinan limit of the northwest Laurentide Ice Sheet and is composed of ice-thrust sediments containing plant detritus as young as 16.2 cal ka BP that might provide a maximum age on ice arrival. Late Wisconsinan ice wedges with sediment-rich fillings on Herschel Island are depleted in heavy oxygen isotopes (mean delta O-18 of -29.1 parts per thousand); this, together with low d-excess values, indicates colder-than-modern winter temperatures and probably reduced snow depths. Grain-size distribution and fossil ostracod assemblages indicate that deglaciation of the Herschel Island ice-thrust moraine was accompanied by alluvial, proluvial. and eolian sedimentation on the adjacent unglaciated Yukon Coastal Plain until similar to 11 cal ka BP during a period of low glacio-eustatic sea level. The late glacial-Holocene transition was marked by higher-than-modern summer temperatures leading to permafrost degradation that began no later than 11.2 cal ka BP and caused a regional thaw unconformity. Cryostructures and ice wedges were truncated while organic matter was incorporated and soluble ions were leached in the thaw zone. Thermokarst activity led to the formation of ice-wedge casts and deposition of thermokarst lake sediments. These were subsequently covered by rapidly accumulating peat during the early Holocene Thermal Maximum. A rising permafrost table. reduced peat accumulation, and extensive ice-wedge growth resulted from climate cooling starting in the middle Holocene until the late 20th century. The reconstruction of palaeolandscape dynamics on the Yukon Coastal Plain and the eastern Beringian edge contributes to unraveling the linkages between ice sheet. ocean, and permafrost that have existed since the Late Wisconsinan.

  • 3. Fuchs, Margret C.
    et al.
    Boehlert, Ralph
    Krbetschek, Matthias
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Egli, Markus
    Exploring the potential of luminescence methods for dating Alpine rock glaciers2013In: Quaternary Geochronology, ISSN 1871-1014, E-ISSN 1878-0350, Vol. 18, p. 17-33Article in journal (Refereed)
    Abstract [en]

    Rock glaciers contain valuable information about the spatial and temporal distribution of permafrost. The wide distribution of these landforms in high mountains promotes them as useful archives for the deciphering of the environmental conditions during their formation and evolution. However, age constraints are needed to unravel the palaeoclimatic context of rock glaciers, but numerical dating is difficult. Here, we present a case study assessing the potential of luminescence techniques (OSL, IRSL) to date the inner sand-rich layer of active rock glaciers. We focus on the signal properties and the resetting of the signal prior to deposition by investigating single grains. While most quartz shows low signal intensities and problematic luminescence characteristics, K-feldspar exhibits much brighter and well-performing signals. Most signals from plagioclases do not show suitable properties. Luminescence signals far below saturation indicate distinct but differential bleaching. The finite mixture model was used to determine the prominent populations in the equivalent dose distributions. The luminescence ages represent travel times of grains since incorporation into the rock glacier and hence, minimum ages of rock glacier formation. Luminescence ages between 3 ka and 8 ka for three rock glaciers from the Upper Engadine and Albula region (Swiss Alps) agree well with independent age estimates from relative and semi-quantitative approaches. Therefore, luminescence seems to have the potential of revealing age constraints about processes related to the formation of rock glaciers, but further investigations are required for solving some of the problems remaining and reducing the dating uncertainties.

  • 4. Gaar, Dorian
    et al.
    Lowick, Sally E.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    PERFORMANCE OF DIFFERENT LUMINESCENCE APPROACHES FOR THE DATING OF KNOWN-AGE GLACIOFLUVIAL DEPOSITS FROM NORTHERN SWITZERLAND2014In: Geochronometria, ISSN 1733-8387, E-ISSN 1897-1695, Vol. 41, no 1, p. 65-80Article in journal (Refereed)
    Abstract [en]

    Luminescence properties of two samples taken from sand lenses in proglacial outwash deposits of a piedmont glacier that reached the Swiss midlands during the Last Glacial Maximum are investigated in detail. Deconvolution of CW-OSL decay curves shows that the fast component dominates the OSL signal of quartz. The chemistry of single feldspar grains, in particular the K content in different grains, is determined using wavelength dispersive spectrometry (electron microprobe), revealing an average 12.9 wt.% K of the grains contributing to the IRSL signal. D-e distributions are investigated in order to gain insights into partial bleaching, and agreement is found for quartz OSL and feldspar IR50 and pIRIR(225) ages for small aliquots and single grains when applying the Minimum Age Model. These ages are also consistent with independent age control. For one sample, ages determined using the Central Age Model result in highly overestimated ages for both feldspar and quartz.

  • 5. Gaar, Dorian
    et al.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Luminescence dating of mammoth remains from Northern Switzerland2012In: Quaternary Geochronology, ISSN 1871-1014, E-ISSN 1878-0350, Vol. 10, no SI, p. 257-263Article in journal (Refereed)
    Abstract [en]

    Remains of at least two individuals of woolly mammoths (Mammuthus primigenius) were discovered after blastings in a limestone quarry located on the southern slope of the Jura Mountains, northern Switzerland. During the subsequent excavation two blocks were taken for luminescence dating from the sediment surrounding the remains; the deposits are interpreted to represent the filling of a karst hole. Luminescence dates on the polymineral and purified quartz fine grain fraction are compared to those obtained for single grains of quartz and small aliquots of quartz as well as feldspar coarse grains. All approaches give ages consistent within the dating uncertainties and are interpreted to prove the robustness of the dating results. The age of the sediment of ca. 63 ka indicates deposition during Marine Isotope Stage (MIS) 4, thus, during a time when Switzerland experienced rather cold climatic conditions. These are some of the oldest numerically dated woolly mammoth remains of Europe.

  • 6. Gennari, Giordana
    et al.
    Rosenberg, Thomas
    Spezzaferi, Silvia
    Berger, Jean-Pierre
    Fleitmann, Dominik
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Al-shanti, Mahmoud
    Matter, Albert
    Faunal evidence of a Holocene pluvial phase in Southern Arabia with remarks on the morphological variability of Helenina anderseni2011In: Journal of Foraminiferal Research, ISSN 0096-1191, E-ISSN 1943-264X, Vol. 41, p. 248-259Article in journal (Refereed)
    Abstract [en]

    Although foraminifera have been found living in inlandsaline lakes isolated from the sea, this phenomenon has rarelybeen recognized in the fossil record. This study documents theoccurrence of benthic foraminifera in Holocene lake sedimentslocated nearly 500 km inland from the Red Sea, in theAl-Mundafan region of southern Saudi Arabia. The lakeformed during a regional pluvial period, 10,500–6000 yr BP.The presence of foraminifera and brackish charophytes in thestudied section represent an interval when the lake wasslightly brackish due to high evaporation. The studiedsediments yielded a bispecific benthic foraminiferal faunacomprised of Helenina anderseni and Trichohyalus aguayoi,as well as the brackish charophyte genus Lamprothamnium.The benthic foraminifera are species characteristic ofmangrove swamps, salt marshes, and lagoons, which areenvironments currently widespread along the Red Sea coasts.Because the Al Mundafan area was never connected to the seaduring the Quaternary, wading birds must have been thevector that transported the foraminifera to the paleolake

  • 7. Greilich, S.
    et al.
    Gribenski, Natacha
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Mittelstrass, D.
    Dornich, K.
    Huot, S.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Single-grain dose-distribution measurements by optically stimulated luminescence using an integrated EMCCD-based system2015In: Quaternary Geochronology, ISSN 1871-1014, E-ISSN 1878-0350, Vol. 29, p. 70-79Article in journal (Refereed)
    Abstract [en]

    We report on the feasibility of assessing single-grain dose-distributions by using an EMCCD-based imaging system with complementary analysis software. Automated image-processing was successfully applied to compensate sample motion and for grain identification. Following a dose recovery test, 74% of the grains were recognized successfully, and 44% exhibited a suitable OSL dose response behavior to interpolate an equivalent dose value, and a central dose recovery ratio of 1.038 was obtained.

  • 8.
    Gribenski, Natacha
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Greilich, Steffen
    Huot, Sebastien
    Mittestrass, Dirk
    Investigation of cross talk in single grain luminescence measurements using an EMCCD camera2015In: Radiation Measurements, ISSN 1350-4487, E-ISSN 1879-0925, Vol. 81, p. 163-170Article in journal (Refereed)
    Abstract [en]

    Highly sensitive electron multiplying charges coupled devices (EMCCD) enable the spatial detection of luminescence emissions from samples and have a high potential in single grain luminescence dating. However, the main challenge of this approach is the potential effect of cross talk, i.e. the influence of signal emitted by neighbouring grains, which will bias the information recorded from individual grains. Here, we present the first investigations into this phenomenon when performing single grain luminescence measurements of quartz grains spread over the flat surface of a sample carrier. Dose recovery tests using mixed populations show an important effect of cross talk, even when some distance is kept between grains. This issue is further investigated by focusing just on two grains and complemented by simulated experiments. Creation of an additional rejection criteria based on the brightness properties of the grains is inefficient in selecting grains unaffected by their surroundings. Therefore, the use of physical approaches or image processing algorithms to directly counteract cross talk is essential to allow routine single grain luminescence dating using EMCCD cameras.

  • 9. Guralnik, B.
    et al.
    Ankjaergaard, C.
    Jain, M.
    Murray, A. S.
    Mueller, A.
    Waelle, M.
    Lowick, S. E.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Rhodes, E. J.
    Wu, T. -S
    Mathew, G.
    Herman, F.
    OSL-thermochronometry using bedrock quartz: A note of caution2015In: Quaternary Geochronology, ISSN 1871-1014, E-ISSN 1878-0350, Vol. 25, p. 37-48Article in journal (Refereed)
    Abstract [en]

    Optically stimulated luminescence (OSL) thermochronometry is an emerging application, whose capability to record sub-Million-year thermal histories is of increasing interest to a growing number of subdisciplines of Quaternary research. However, several recent studies have encountered difficulties both in extraction of OSL signals from bedrock quartz, and in their thermochronometric interpretation, thus highlighting the need for a methodological benchmark. Here, we investigate the characteristic OSL signals from quartz samples across all major types of bedrock and covering a wide range of chemical purities. High ratios of infrared to blue stimulated luminescence (IRSL/BLSL), an insensitive 'fast' OSL component, and anomalously short recombination lifetimes seen in time-resolved luminescence (TROSL), are often encountered in quartz from crystalline (magmatic and metamorphic) bedrock, and may hamper successful OSL dating. Furthermore, even when the desirable signal is present, its concentration might be indistinguishable from its environmental steady-state prediction, thus preventing its conversion to a cooling or heating history. We explore the saturation properties and the thermal activation parameters of various OSL signals in quartz to outline the capabilities and limitations for their use in low-temperature thermochronometry.

  • 10. Heiri, Oliver
    et al.
    Koinig, Karin A.
    Spoetl, Christoph
    Barrett, Sam
    Brauer, Achim
    Drescher-Schneider, Ruth
    Gaar, Dorian
    Ivy-Ochs, Susan
    Kerschner, Hanns
    Luetscher, Marc
    Moran, Andrew
    Nicolussi, Kurt
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Schmidt, Roland
    Schoeneich, Philippe
    Schwoerer, Christoph
    Sprafke, Tobias
    Terhorst, Birgit
    Tinner, Willy
    Palaeoclimate records 60-8 ka in the Austrian and Swiss Alps and their forelands2014In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 106, p. 186-205Article in journal (Refereed)
    Abstract [en]

    The European Alps and their forelands provide a range of different archives and climate proxies for developing climate records in the time interval 60-8 thousand years (ka) ago. We review quantitative and semi-quantitative approaches for reconstructing climatic variables in the Austrian and Swiss sector of the Alpine region within this time interval. Available quantitative to semi-quantitative climate records in this region are mainly based on fossil assemblages of biota such as chironomids, cladocerans, co-leopterans, diatoms and pollen preserved in lake sediments and peat, the analysis of oxygen isotopes in speleothems and lake sediment records, the reconstruction of past variations in treeline altitude, the reconstruction of past equilibrium line altitude and extent of glaciers based on geomorphological evidence, and the interpretation of past soil formation processes, dust deposition and permafrost as apparent in loess-palaeosol sequences. Palaeoclimate reconstructions in the Alpine region are affected by dating uncertainties increasing with age, the fragmentary nature of most of the available records, which typically only incorporate a fraction of the time interval of interest, and the limited replication of records within and between regions. Furthermore, there have been few attempts to cross-validate different approaches across this time interval to confirm reconstructed patterns of climatic change by several independent lines of evidence. Based on our review we identify a number of developments that would provide major advances for palaeoclimate reconstruction for the period 60-8 ka in the Alps and their forelands. These include (1) the compilation of individual, fragmentary records to longer and continuous reconstructions, (2) replication of climate records and the development of regional reconstructions for different parts of the Alps, (3) the cross-validation of different proxy-types and approaches, and (4) the reconstruction of past variations in climate gradients across the Alps and their forelands. Furthermore, the development of downscaled climate model runs for the Alpine region 60-8 ka, and of forward modelling approaches for climate proxies would expand the opportunities for quantitative assessments of climatic conditions in Europe within this time-interval.

  • 11. Hoffmann, Gösta
    et al.
    Rupprechter, Magdalena
    Rahn, Mirjam
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Fluvio-lacustrine deposits reveal precipitation pattern in SE Arabia during early MIS 32015In: Quaternary International, ISSN 1040-6182, E-ISSN 1873-4553, Vol. 382, p. 145-153Article in journal (Refereed)
    Abstract [en]

    On a global scale, Marine Isotope Stage (MIS) 3 (ca. 55-30 ka) was characterised by frequent and abrupt changes in climate. At the same time, humans may have dispersed out of Africa and populated the planet. For the Arabian Peninsula, a key region in both contexts, the paucity of suitable terrestrial records leaves our knowledge of the environmental conditions during this important period enigmatic. Here, we elucidate the environmental history for part of the Oman Mountains by analysing luminescence-dated fine-grained playa-like sediments from Wadi Mistal that formed in a landslide-dammed ephemeral lake. We identified 112 individual fining-upward sequences in the distal facies of the lake that are interpreted to represent major precipitation events during early MIS 3. The nature of sedimentation together with the presence of desiccation cracks and the absence of any faunal remains imply that the lakes had a temporary nature. It appears that the time of deposition was characterised by strong short-lived precipitation events, rather than continuous rainfall under a monsoonal regime. This points towards a climatic situation during early MIS 3 that was not so different from that of the present, at least in this part of Arabia.

  • 12. Juschus, Olaf
    et al.
    Pavlov, Maksim
    Schwammborn, Georg
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Fedorov, Grigory
    Melles, Martin
    Late Quaternary Lake-Level Changes of Lake El´gygytgyn, NE Siberia2011In: Quaternary Research, ISSN 0033-5894, E-ISSN 1096-0287, Vol. 76, p. 411-451Article in journal (Refereed)
    Abstract [en]

    Lake El'gygytgyn is situated in a 3.6 Ma old impact crater in northeastern Siberia. Presented here is areconstruction of the Quaternary lake-level history as derived from sediment cores from the southern lakeshelf. There, a cliff-like bench 10 m below the modern water level has been investigated. Deep-watersediments on the shelf indicate high lake levels during a warm Mid-Pleistocene period. One period with lowlake level prior to Marine Oxygen Isotope Stage (MIS) 3 has been identified, followed by a period of high lakelevel (10 m above present). In the course of MIS 2 the lake level dropped to −10 m. At the end of MIS 2 thebench was formed and coarse beach sedimentation occurred. Subsequently, the lake level rose rapidly to theHolocene level. Changes in water level are likely linked to climate variability. During relatively temperateperiods the lake becomes free of ice in summer. Strong wave actions transport sediment parallel to the coastand towards the outlet, where the material tends to accumulate, resulting in lake level rise. During coldperiods the perennial lake ice cover hampers any wave activity and pebble-transport, keeping the outlet openand causing the lake level to drop.

  • 13. Lomax, Johanna
    et al.
    Fuchs, Markus
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Fiebig, Markus
    Luminescence based loess chronostratigraphy of the Upper Palaeolithic site Krems-Wachtberg, Austria2014In: Quaternary International, ISSN 1040-6182, E-ISSN 1873-4553, Vol. 351, p. 88-97Article in journal (Refereed)
    Abstract [en]

    The loess section Krems-Wachtberg (Lower Austria) is well known for its Upper Palaeolithic find layer, which contains a double and a single infant burial. The layer containing the grave (archaeological horizon AH 4.4) was dated to 26,580 +/- 160 C-14 BP (Einwogerer et al., 2006), corresponding to ca. 31 ka cal BP and is embedded in an 8 m thick loess sequence. In order to provide a chronostratigraphy of the entire section, 38 samples for luminescence dating were taken at high resolution from below and above the find layer. The samples were dated using the quartz coarse grain fraction, the quartz fine grain fraction and/or the polymineral fine grain fraction. The resulting ages are in correct chronostratigraphic order and, in case samples were measured with different protocols, agree within errors with each other and with the radiocarbon age of the find layer. The polymineral fine grain ages are systematically slightly lower than the quartz ages, although no fading could be detected in laboratory experiments. Loess deposition at the site commenced ca. 40 ka ago and reaches up to ca. 22 ka. The ages indicate nearly continuous loess sedimentation throughout this time span. Short breaks in sedimentation probably exist but cannot be resolved due to the uncertainties of luminescence ages.

  • 14.
    Lowick, Sally
    et al.
    Univ Bern, Inst Geol, CH-3012 Bern, Switzerland .
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Trauerstein, Mareike
    Univ Bern, Inst Geol, CH-3012 Bern, Switzerland .
    Investigating age underestimation in the high dose region of optically stimulated luminescence using fine grain quartz2011In: Quaternary Geochronology, ISSN 1871-1014, E-ISSN 1878-0350, Vol. 6, p. 33-41Article in journal (Refereed)
    Abstract [en]

    The age range of the single-aliquot regenerative-dose (SAR) protocol applied to quartz optically stimulatedluminescence (OSL) has become the subject of debate as age underestimations for samples ofEemian age (ca. 125 ka) and older are increasingly reported. In order to investigate the origin of the ageunderestimation, the behaviour of fine grain quartz samples taken from two sites was compared.Sediment from both sites originates in the Alps, with those from Azzano Decimo, northeastern Italy,already displaying a significant age underestimation before reaching the Eemian, while ages for samplesfrom Niederweningen, northern Switzerland, agree with expected ages well beyond the Eemian. Estimateddose (De) values for both sets of samples are up to around 400 Gy, and all meet the usualperformance criteria for testing the reliability of the SAR protocol. De values determined using a sensitivity-corrected multiple aliquot regenerative-dose (MAR) protocol were within 10% of those determinedusing a SAR protocol for both sites, and so could not overcome the significant underestimation seen atAzzano Decimo. Lifetime calculations confirmed the stability of the signal well beyond the age rangerequired at both sites, for both the initial integral as well as that used for an early backgroundsubtraction. The relative percentage contribution of the fast and medium OSL components to the initialintegral remained constant in both the natural signal and similar sized laboratory generated doses. Thequartz OSL from both sites displayed similar characteristics under all analyses and no indication wasfound for the possible origin of the age underestimation seen at Azzano Decimo. In the comparisonsmade between the doseeresponse of both laboratory and naturally generated signals in these samples,no evidence was found to suggest that the presence of the high dose linear region is restricted to thelaboratory. The reliability of quartz OSL ages derived from this part of the curve however, remain inquestion, and require the support of independent age control until a performance criterion can be foundwith which to test it.

  • 15.
    Lukas, Sven
    et al.
    Institut für Geologie, Universität Bern, Baltzerstrasse 1þ3, 3012 Bern, Switzerland.
    Preusser, Frank
    Institut für Geologie, Universität Bern, Baltzerstrasse 1þ3, 3012 Bern, Switzerland.
    Anselmetti, Flavio S.
    Eawag, Departement of Surface Waters, Überlandstrasse 133, 8600 Dübendorf, Switzerland.
    Tinner, Willy
    Institute of Plant Sciences & Oeschger Centre for Climate Change Research, Universität Bern, Altenbergrain 21, 3013 Bern, Switzerland.
    Testing the potential of luminescence dating of high-alpine lake sediments.2012In: Quaternary Geochronology, ISSN 1871-1014, E-ISSN 1878-0350, Vol. 8, p. 23-32Article in journal (Refereed)
    Abstract [en]

    The potential of luminescence dating of high-alpine lacustrine sediments is tested on samples taken fromthree high-altitude moraine-bounded lakes in the Swiss Alps. Independent age control is provided byradiocarbon ages and detailed palynological data in all cases. All samples show good luminescencecharacteristics (no thermal transfer, good dose recovery and recycling), but two samples show rather lowquartz signals. Radioactive disequilibria in the uranium decay chain observed in one sample areaccounted for by using a dynamic modelling approach. Because all cores had largely dried out and watercontent had not been measured after sampling, we developed a modern limnological approach toretrospectively establish palaeo-water content. Applying average water content values from a dataset ofmodern sediments with similar characteristics to the samples investigated here we obtained ages thatmatch the independent age control. Whereas the low-signal quartz separates consistently underestimatethese ages, the polymineral samples more accurately match them, do not suffer from anomalous fadingand are thus considered reliable. This study demonstrates for the first time that applying luminescencedating to high-alpine, ice-proximal lacustrine sediments is a promising avenue to obtain a chronology forsuch depositional environments.

  • 16. Lüthgens, Christopher
    et al.
    Böse, Margot
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Age of the Pomeranian ice-marginal position in northeastern Germanydetermined by Optically Stimulated Luminescence (OSL) dating ofglaciofluvial sediments2011In: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 40, p. 598-615Article in journal (Refereed)
    Abstract [en]

    The Pomeranian ice margin is one of the most prominent ice-marginal features of the Weichselian glaciation innorthern Europe. Previous results of surface-exposure dating (SED) of this ice margin disagree with establishedchronologies and ice retreat patterns, i.e. are much younger than previously expected. We crosscheck the age of thePomeranian ice-marginal position in northeastern Germany using single-grain quartz Optically Stimulated Luminescence(OSL) dating of glaciofluvial sediments. OSL dating indicates an active ice margin between 20.11.6 kaand 19.42.4 ka forming outwash plains attributed to the Pomeranian ice-marginal position. On the basis of theseresults, we suggest a critical reassessment of previous SED data available for the Pomeranian ice-marginal positionwithin their respective regional geomorphological contexts. From a process-based point of view, SED ages derivedfrom glacigenic boulders document the stabilization of the landscape after melting of dead ice and landscapetransformation under periglacial conditions rather than the presence of an ice margin. SED indicates a firstphase of boulder stabilization at around 16.40.7 ka, followed by landscape stabilization within the area attributedto the recessional Gerswalder subphase around 15.20.5 ka. A final phase of accumulation of glaciolacustrine andglaciofluvial sediments at around 14.71.0 ka documents the melting of buried dead ice at that time.

  • 17. Madritsch, Herfried
    et al.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Fabbri, Olivier
    Climatic and tectonic controls on the development of the River Ognon terrace system (eastern France)2012In: Geomorphology, ISSN 0169-555X, E-ISSN 1872-695X, Vol. 151, p. 126-138Article in journal (Refereed)
    Abstract [en]

    The River Ognon in eastern France is the principal drainage of the southwestern Vosges Mountains. Its lowermost valley reach is oriented parallel to the northwestern front of the Alpine collision zone and is characterized by a well-developed terrace system. Geomorphological, sedimentological, and geochronological analyses were performed on this terrace system and associated deposits. The results allow for reconstructing the Pleistocene evolution of the river valley and for concluding on the processes that led to the formation of the terrace system. The lithological characterization of the terrace deposits by means of heavy mineral analyses indicates pronounced modifications of the river's drainage area. Optically stimulated luminescence dating suggests that the last significant catchment modification and associated sediment accumulation correlates with the last glacial advance in the Vosges Mountains. Despite the apparently strong impact of climatic processes on the evolution of the River Ognon, our investigation also indicates a mild tectonic influence on presently observed terrace distribution.

  • 18.
    Massuanganhe, Elidio A.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. Universidade Eduardo Mondlane, Moçambique.
    Berntsson, Annika
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Risberg, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Westerberg, Lars-Ove
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Christiansson, Marie
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Bjursäter, Stefan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Achimo, Mussa
    Palaeogeography and dynamics of the deltaic wetland of Save River, Mozambique2018In: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 489, p. 64-73Article in journal (Refereed)
    Abstract [en]

    Many mangrove wetland systems in deltaic environments are negatively affected by massive sedimentation fromriver inflows. In this paper we use the example of the Save River delta to assess the palaeogeographic distributionof mangrove wetlands and to analyze their dynamics. To track past occurrences of mangrove wetlands in thestudy area we have integrated sedimentological data with siliceous microfossil analysis combined with AMSradiocarbon and OSL dating. The results show a fine-grained deposit with an approximate thickness of 2 m,present at different sampling sites. In the upper deltaic plain, the deposit is interbedded between sand layers,while in the lower deltaic plain the deposit occupies the uppermost stratigraphic position. In most of thesampling sites the deposit shows a succession with brackish-marine diatoms at the bottom of the sequence whilethe upper part shows only scattered occurrences. Based on sedimentological and microfossil characteristics wehave interpreted the layer to represent a mangrove wetland deposit. The development of the deposit in the studyarea is suggested to have been initiated around 3100 cal. yr BP, induced by sea-level rise. Thereafter, the developmentfollowed the combined effect of a sea-level fall and delta progradation processes. In some areas,particularly in the proximal part of the delta, the mangrove deposit has developed progressively on top of thedelta-front. From around 1300 years ago (OSL) onwards, massive alluvial sedimentation impacted the mangroveecosystem. However, the retreat of mangrove wetland coincided with a regional fall of sea level. At the edges ofthe alluvial deposit, the current mangrove ecosystem has reclaimed the habitat in some sectors where gullyerosion has exposed the once extinct mangrove habitat.

  • 19.
    Massuanganhe, Elidio
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. Universidade Eduardo Mondlane, Moçambique.
    Westerberg, Lars-Ove
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Risberg, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Bjursäter, Stefan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Achimo, Mussa
    Geomorphology and landscape evolution of Save River delta, South-central MozambiqueManuscript (preprint) (Other (popular science, discussion, etc.))
    Abstract [en]

    The Save River delta has well-preserved geomorphological and sedimentological features with potential to reveal its evolution as well as past regional environmental changes, which are anticipated to integrate into other data at a global scale. In this study we mapped and integrated these features to understand the environmental processes that drove the late evolution of the delta. The results suggest that the present configuration of the delta was primarily dominated by a delta-front protruding into the sea, in a faulted coast section that may have favoured the formation of the depocenter. The development of the delta-front was initiated prior to c. 3100 cal. yrs BP, and around this age, fine-grained sediments started to accumulate on it forming a mangrove wetland deposit that expanded from the proximal sector of the delta to the current position shown in a geomorphological map. The results show successive dune ridges in the southern sector of the delta which indicate a series of consecutive shorelines over time as the delta prograded towards the current position. These dunes have created favourable conditions for accumulation of fine-grained sediments in the back-barrier sectors, contributing to the development of the mangrove wetland. An alluvial floodplain developed during the last millennium, probably a result of high precipitation the catchment area.

  • 20. Matter, Albert
    et al.
    Neubert, Eike
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Rosenberg, Thomas
    Al-Wagdani, Khalid
    Palaeo-environmental implications derived from lake and sabkha deposits of the southern Rub' al-Khali, Saudi Arabia and Oman2015In: Quaternary International, ISSN 1040-6182, E-ISSN 1873-4553, Vol. 382, p. 120-131Article in journal (Refereed)
    Abstract [en]

    Shallow lakes and sabkha deposits are evidence of past periods of higher groundwater table than today, and hence reflect increased humidity in the Rub' al-Khali, the large desert in the southern part of the Arabian Peninsula. Reported here are the observations made during four expeditions into this remote area in combination with luminescence dating constraining the age of the deposits. The results presented extend the spatial coverage of evidence and show that most of the deposits correlate to MIS 5 (ca. 130-70 ka) and the Early/Mid Holocene (ca. 11-5.5 ka). A single sample points towards potentially more humid conditions during the transition MIS 4/3 (ca. 65-55 ka). The presence of the mussel Unio in some of the deposits attributed to MIS 5 is indirect evidence for the presence of fish in the lakes, which must have supported a rich and diverse fauna (and probably also flora). Together with other evidence, this demonstrates that a number of small persistent lakes were spread across the Rub' al-Khali for at least some of the time. These lakes would not only have been a potential source of freshwater but could also have provided an additional and easy accessible food source via the fish for humans migrating through the area. The presented palaeoenvironmental data underlines that parts of MIS 5 represent a time window of opportunity for a potential expansion of modern humans across Arabia.

  • 21. May, Jan-Hendrik
    et al.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Gliganic, Luke Andrew
    Refining late Quaternary plunge pool chronologies in Australia's monsoonal 'Top End'2015In: Quaternary Geochronology, ISSN 1871-1014, E-ISSN 1878-0350, Vol. 30, p. 328-333Article in journal (Refereed)
    Abstract [en]

    Plunge pool deposits from Australia's 'Top End' are considered as important archives of past monsoonal activity in the region. The available chronology of these deposits was so far based on thermoluminescence (TL) dating and indicated maximum flood magnitudes during the Last Glacial Maximum in contrast with more arid conditions as deduced from other archives of the region. This study revisits plunge pool deposits at Wangi Falls by applying multiple and single-grain Optically Stimulated Luminescence (OSL) dating of quartz and high-resolution gamma spectrometry, supported by radiocarbon dating of organic material. The aim is to reappraise the existing chronology and investigate if the deposits are affected by partial bleaching, post-depositional mixing and/or problems related to annual dose determination. The latter seems to have a minor impact on the ages at most. Equivalent Dose (D-e) distributions are broad, in particular for single grains, but apparently hot result from partial bleaching or post-depositional mixing. Rather, microdosimetry caused by radiation hotspots in the sediment and zircon inclusions in the quartz grains is considered problematic for these sediments. The results presented here imply that the previous TL chronology overestimated the real deposition age of the sediments.

  • 22. May, Jan-Henrik
    et al.
    Zech, Jana
    Zech, Roland
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Angollo, Jaime
    Kubik, Peter W.
    Veit, Heinz
    Reconstruction of a complex late Quaternary glacial landscape in the Cordillera de Cochabamba (Bolivia) based on a morphostratigraphic and multiple dating approach.2011In: Quaternary Research, ISSN 0033-5894, E-ISSN 1096-0287, Vol. 76, p. 106-118Article in journal (Refereed)
    Abstract [en]

    Although glacial landscapes have previously been used for the reconstruction of late Quaternary glaciations inthe Central Andes, only few data exist for the Eastern Cordillera in Bolivia. Here, we present results fromdetailed morphostratigraphic mapping and new data of surface exposure dating (SED), optically stimulatedluminescence (OSL), and radiocarbon dating (14C) from the Huara Loma Valley, Cordillera de Cochabamba(Bolivia). Discrepancies between individual dating methods could be addressed within the context of a solidgeomorphic framework. We identified two major glaciations. The older is not well constrained by theavailable data, whereas the younger glaciation is subdivided into at least four major glacial stages. Regardingthe latter, a first advance dated to ~29–25 ka occurred roughly contemporaneous with the onset of the globallast glacial maximum (LGM) and was followed by a less extensive (re-)advance around 20–18 ka. The locallast glacial maximum (LLGM) in the Huara Loma Valley took place during the humid lateglacial ~17–16 ka,followed by several smaller readvances until ~10–11 ka, and complete deglaciation at the end of the EarlyHolocene.

  • 23. Plotzki, A.
    et al.
    May, J. -H
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Roesti, B.
    Denier, S.
    Lombardo, U.
    Veit, H.
    Geomorphology and evolution of the late Pleistocene to Holocene fluvial system in the south-eastern Llanos de Moxos, Bolivian Amazon2015In: Catena (Cremlingen. Print), ISSN 0341-8162, E-ISSN 1872-6887, Vol. 127, p. 102-115Article in journal (Refereed)
    Abstract [en]

    In the Bolivian Amazon several paleochannel generations are preserved. Their wide spectrum of morphologies clearly provides crucial information on the type and magnitude of geomorphic and hydrological changes within the drainage network of the Andean foreland. Therefore, in this study we mapped geomorphological characteristics of paleochannels, and applied radiocarbon and optically stimulated luminescence dating. Seven paleochannel generations are identified. Significant changes in sinuosity, channel widths and river pattern are observed for the successive paleochannel generations. Our results clearly reflect at least three different geomorphic and hydrological periods in the evolution of the fluvial system since the late Pleistocene. Changes in discharge and sediment load may be controlled by combinations of two interrelated mechanisms: (i) spatial changes and re-organizations of the drainage network in the upper catchment, and/or (ii) climate changes with their associated local to catchment-scale modifications in vegetation cover, and changes in discharge, inundation frequencies and magnitudes, which have likely affected the evolution of the fluvial system in the Llanos de Moxos. In summary, our study has revealed the enormous potential which geomorphic mapping and analysis combined with luminescence based chronologies hold for the reconstruction of the late Pleistocene to recent fluvial system in a large portion of Amazonia.

  • 24. Plotzki, A.
    et al.
    May, J. -H
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Veit, H.
    Geomorphological and sedimentary evidence for late Pleistocene to Holocene hydrological change along the Rio Mamore, Bolivian Amazon2013In: Journal of South American Earth Sciences, ISSN 0895-9811, E-ISSN 1873-0647, Vol. 47, p. 230-242Article in journal (Refereed)
    Abstract [en]

    Aerial photography and satellite imagery reveal manifold geomorphological evidence of a dynamic evolution of past and present rivers in the Bolivian Amazon. Comparison of oxbow lake and meander scar dimensions along an inactive meander belt of the Rio Mamore (Llanos de Moxos, north-eastern Bolivia) and its modern counterpart suggests significant regional paleohydrological variability. We used these features as geomorphological and sedimentary archives to enhance our understanding of longer-term variations of the fluvial system. Late Pleistocene to Holocene hydrological changes of the Rio Mamore are inferred from: (i) the analysis of satellite imagery, (ii) discharge estimates from meander morphology, (iii) stratigraphic, and (iv) chronological information based on luminescence and radiocarbon dating. The combined data from three oxbows indicate that the now abandoned meander belt - the paleo-Mamore - continued to be active at least until similar to 5 ka, and likely even postdating 3 ka. An up to threefold increase in discharge is estimated for the modern Rio Mamore versus the paleo-Mamore. The altered runoff regime may have triggered an avulsive shift towards the currently active Rio Mamore. The preceding increase in discharge in turn, was possibly related to a shift in climatic conditions, which changed markedly between the mid- and late Holocene in tropical South America. In addition, it may have been the indirect result of capturing the avulsive Rio Grande system to the east of the Rio Mamore. Alternative explanations for the differences in dimensions of the paleo versus the modern Rio Mamore, i.e. contemporaneous activity of both rivers or alteration of site factors such as the channel/floodplain relationship, are considered to be unlikely.

  • 25.
    Preusser, Frank
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Graf, Hans Rudolf
    Keller, Oskar
    Krayss, Edgar
    Schlüchter, Christian
    Quaternary glaciation history of northern Switzerland2011In: E&G Quaternary Science Journal, ISSN 0424-7116, Vol. 60, p. 282-305Article in journal (Refereed)
    Abstract [en]

    A revised glaciation history of the northern foreland of the Swiss Alps is presented by summarising field evidence and chronologicaldata for different key sites and regions. The oldest Quaternary sediments of Switzerland are multiphase gravels intercalated bytill and overbank deposits (‘Deckenschotter’). Important differences in the base level within the gravel deposits allows the distinguishingof two complex units (‘Höhere Deckenschotter’, ‘Tiefere Deckenschotter’), separated by a period of substantial incision.Mammal remains place the older unit (‘Höhere Deckenschotter’) into zone MN 17 (2.6–1.8 Ma). Each of the complexes containsevidence for at least two, but probably up-to four, individual glaciations. In summary, up-to eight Early Pleistocene glaciations ofthe Swiss alpine foreland are proposed. The Early Pleistocene ‘Deckenschotter’ are separated from Middle Pleistocene depositionby a time of important erosion, likely related to tectonic movements and/or re-direction of the Alpine Rhine (Middle PleistoceneReorganisation – MPR). The Middle-Late Pleistocene comprises four or five glaciations, named Möhlin, Habsburg, Hagenholz(uncertain, inadequately documented), Beringen, and Birrfeld after their key regions. The Möhlin Glaciation represents the mostextensive glaciation of the Swiss alpine foreland while the Beringen Glaciation had a slightly lesser extent. The last glacial cycle(Birrfeld Glaciation) probably comprises three independent glacial advances dated to ca. 105 ka, 65 ka, and 25 ka. For the last glacialadvance, a detailed radiocarbon chronology for ice build-up and meltdown is presented.

  • 26.
    Preusser, Frank
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Muru, Merle
    Rosentau, Alar
    Comparing different post-IR IRSL approaches for the dating of Holocene coastal foredunes from Ruhnu Island, Estonia2014In: Geochronometria, ISSN 1733-8387, E-ISSN 1897-1695, Vol. 41, no 4, p. 342-351Article in journal (Refereed)
    Abstract [en]

    Different post-IR Infrared Stimulated Luminescence (IRSL) approaches are applied to sediments from a Holocene coastal foredune sequence on Ruhnu Island in the eastern Baltic Sea. The comparison of D (e)-values and ages determined by the different approaches is complimented by fading and bleaching experiments. The fading experiments imply strong fading of IRSL (50A degrees C) signals and no fading of any of the post-IR IRSL signals, but this is not confirmed by the determined D (e)-values. In fact, post-IR IRSL (150A degrees C) D (e)-values agree within errors with those calculated for IRSL (50A degrees C). From the bleaching experiments it is inferred that the higher values observed for post-IR IRSL at more elevated stimulation temperatures (225A degrees C/290A degrees C) are likely related to either thermal transfer and/or slow-to-bleach components within the signal. For the dating of the Holocene foredune sequence of Ruhnu Island, the post-IR IRSL (150A degrees C) approach is preferred and these agree with the limited independent age control available from radiocarbon dating. Accordingly, the sequence formed between ca. 7.0 ka and 2.5 ka ago.

  • 27.
    Preusser, Frank
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Rufer, Daniel
    Schreurs, Guido
    Direct dating of Quaternary phreatic maar eruptions by luminescence methods2011In: Geology, ISSN 0091-7613, E-ISSN 1943-2682, Vol. 39, no 12, p. 1135-1138Article in journal (Refereed)
    Abstract [en]

    The suitability of quartz optically stimulated luminescence (OSL) and feldspar infrared stimulated luminescence (IRSL) for the direct dating of phreatic eruptions was tested on examples from the Eifel Volcanic Field, Germany. The mean IRSL age of 11.6 +/- 0.5 ka for Ulmener Maar Tephra is in excellent agreement with the independent age control (11 +/- 0.1 ka), but the mean OSL age of 14.2 +/- 0.6 ka overestimates the known age by 3 ka. For Meerfelder Maar Tephra, consistent IRSL (mean 74.9 +/- 5.0 ka) and OSL ages (74.9 +/- 5.5 ka) have been observed. The consistent results from Meerfelder Maar imply that the overestimation observed for Ulmener Maar quartz OSL might not be relative to the eruption age, but rather represents a small absolute offset. In samples taken from deposits of the eruption of Laacher See Volcano, no resetting of the OSL signal and highly scattered IRSL estimates were found. This implies that phreatomagmatic eruptions are less well suited for this dating approach compared to pure phreatic maar eruptions, where the effect of high-pressure shock waves probably dominates the process of resetting the luminescence signal.

  • 28. Rodrigues, Leonor
    et al.
    Lombardo, Umberto
    Fehr, Seraina
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Veit, Heinz
    Pre-Columbian agriculture in the Bolivian Lowlands: Construction history and management of raised fields in Bermeo2015In: Catena (Cremlingen. Print), ISSN 0341-8162, E-ISSN 1872-6887, Vol. 132, p. 126-138Article in journal (Refereed)
    Abstract [en]

    Recent archaeological research suggests that some parts of the Amazon Basin were significantly modified by pre-Columbian populations. One of the most impressive examples of such transformations is the raised fields of south-western Amazonia, in the Llanos de Moxos in the Bolivian Lowlands. Despite a growing interest in raised field agriculture, due to the important role it seems to have played in the development of pre-Columbian complex societies, very few field-based investigations have been performed in the Amazon Basin. As a result, there is limited knowledge of how these fields were constructed, managed and within which time-frame they were in use. This study provides a new interpretation of how pre-Columbian raised fields were managed and a chronological sequence of their utilisation and eventual abandonment. Fieldwork was carried out in the indigenous community of Bermeo, in the vicinity of San Ignacio de Moxos, where some of the best preserved fields in the Llanos Moxos are found. Magnetic susceptibility and the geochemistry of the sediments, combined with radiocarbon and optically stimulated luminescence dating, show that the raised fields were in intermittent use since as early as AD 570-770. The original surface on which the fields were built and distinct periods of construction and use have been identified. The data suggests that raised fields were built during a few separate construction events, probably linked to periods of more frequent and severe floods. The study challenges the most widely accepted theory that suggests that pre-Columbians were able to cultivate these fields on a continuous basis by transferring nutrient-rich sediments from the canals to the fields. We conclude that pre-Columbians built raised fields to overcome periods of increased flooding, with the main objective of improving drainage.

  • 29. Rosenberg, T. M.
    et al.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Fleitmann, D.
    Schwalb, A.
    Penkman, K.
    Schmid, T. W.
    Al-Shanti, M. A.
    Kadi, K.
    Matter, A.
    Humid periods in southern Arabia: Windows of opportunity for modern human dispersal2011In: Geology, ISSN 0091-7613, E-ISSN 1943-2682, Vol. 39, no 12, p. 1115-1118Article in journal (Refereed)
    Abstract [en]

    Arabia is a key area for the dispersal of anatomically modern humans (AMH, Homo sapiens) out of Africa. Given its modern hostile environment, the question of the timing of dispersal is also a question of climatic conditions. Fresh water and food were crucial factors facilitating AMH expansions into Arabia. By dating relict lake deposits, four periods of lake formation were identified: one during the early Holocene and three during the late Pleistocene centered ca. 80, ca. 100, and ca. 125 ka. Favorable environmental conditions during these periods allowed AMH to migrate across southern Arabia. Between ca. 75 and 10.5 ka, arid conditions prevailed and turned southern Arabia into a natural barrier for human dispersal. Thus, expansion of AMH through the southern corridor into Asia must have taken place before 75 ka, possibly in multiple dispersals.

  • 30. Rosenberg, Thomas M.
    et al.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Risberg, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Plikk, Anna
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Kadi, Khalid A.
    Matter, Albert
    Fleitmann, Dominik
    Middle and Late Pleistocene humid periods recorded in palaeolake deposits of the Nafud desert, Saudi Arabia2013In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 70, p. 109-123Article in journal (Refereed)
    Abstract [en]

    Present climate in the Nafud desert of northern Saudi Arabia is hyper-arid and moisture brought by north-westerly winds scarcely reaches the region. The existence of abundant palaeolake sediments provides evidence for a considerably wetter climate in the past. However, the existing chronological framework of these deposits is solely based on radiocarbon dating of questionable reliability, due to potential post-depositional contamination with younger C-14. By using luminescence dating, we show that the lake deposits were not formed between 40 and 20 ka as suggested previously, but approximately ca 410 ka, 320 ka, 200 ka, 125 ka, and 100 ka ago. All of these humid phases are in good agreement with those recorded in lake sediments and speleothems from southern Arabia. Surprisingly, no Holocene lake deposits were identified. Geological characteristics of the deposits and diatom analysis suggest that a single, perennial lake covered the entire south-western Nafud ca 320 ka ago. In contrast, lakes of the 200 ka, 125 ka, and 100 ka humid intervals were smaller and restricted to interdune depressions of a preexisting dune relief. The concurrent occurrence of humid phases in the Nafud, southern Arabia and the eastern Mediterranean suggests that moisture in northern Arabia originated either from the Mediterranean due to more frequent frontal depression systems or from stronger Indian monsoon circulation, respectively. However, based on previously published climate model simulations and palaecolimate evidence from central Arabia and the Negev desert, we argue that humid climate conditions in the Nafud were probably caused by a stronger African monsoon and a distinct change in zonal atmospheric circulation.

  • 31. Rosenberg, Thomas M.
    et al.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Wintle, Ann G.
    A comparison of single and multiple aliquot TT-OSL data sets for sand-sized quartzfrom the Arabian Peninsula2011In: Radiation Measurements, ISSN 1350-4487, E-ISSN 1879-0925, Vol. 46, no 6-7, p. 573-579Article in journal (Refereed)
    Abstract [en]

    The quartz OSL signal from dune sands from Saudi Arabia and Oman start to saturate at doses of about100 Gy. In order to try to date dune sands with greater expected doses, a previously published,single-aliquot, regenerative-dose protocol (SAR) for thermally-transferred optically stimulatedluminescence (TT-OSL) was tested. Dose recovery tests, recycling and recuperation ratios showed robustfunctioning and dose response curves demonstrated the potential to extend the dose range to beyond600 Gy. Multiple aliquot additive dose (MAAD) TT-OSL protocols were used to test for sensitivity changesin the SAR TT-OSL protocol up to doses of 1200 Gy. A strong dose dependent deviation of the SAR TT-OSLrelative to the MAAD TT-OSL dose response is observed. Comparison of the TT-OSL and OSL sensitivitydata obtained from the MAAD and SAR data sets shows a lack of proportionality between TT-OSL and OSLfor the SAR data which will result in a problem when SAR dose response curves are constructed usingmany regeneration points with doses above 300 Gy.

  • 32. Rufer, Daniel
    et al.
    Gnos, Edwin
    Mettier, Ralph
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Schreurs, Guido
    Proposing new approaches for dating young volcanic eruptions by luminescence methods2012In: Geochronometria, ISSN 1733-8387, E-ISSN 1897-1695, Vol. 39, no 1, p. 48-56Article in journal (Refereed)
    Abstract [en]

    The application of luminescence dating to young volcanic sediments has been first investigated over three decades ago, but it was only with the technical innovations of the last decade that such analyses became viable. While current analytical procedures show promise for dating late Quaternary volcanic events, most efforts have been aimed at unconsolidated volcanic tephra. Investigations into direct dating of lava flows or of non-heated volcanoclastics like phreatic explosion layers, however, remain scarce. These volcanic deposits are of common occurrence and represent important chrono- and volcanostratigraphic markers. Their age determination is therefore of great importance in volcanologic, tectonic, geomorphological and climate studies. In this article, we propose the use of phreatic explosion deposits and xenolithic inclusions in lava flows as target materials for luminescence dating applications. The main focus is on the crucial criterion whether it is probable that such materials experience complete luminescence signal resetting during the volcanic event to be dated. This is argued based on the findings from existing literature, model calculations and laboratory tests.

  • 33. Rufer, Daniel
    et al.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Schreurs, Guido
    Gnos, Edwin
    Berger, Alfons
    Late Quaternary history of the Vakinankaratra volcanic field (central Madagascar): insights from luminescence dating of phreatomagmatic eruption deposits2014In: Bulletin of Volcanology, ISSN 0258-8900, E-ISSN 1432-0819, Vol. 76, no 5, p. 817-Article in journal (Refereed)
    Abstract [en]

    The Quaternary Vakinankaratra volcanic field in the central Madagascar highlands consists of scoria cones, lava flows, tuff rings, and maars. These volcanic landforms are the result of processes triggered by intracontinental rifting and overlie Precambrian basement orNeogene volcanic rocks. Infrared-stimulated luminescence (IRSL) dating was applied to 13 samples taken from phreatomagmatic eruption deposits in the Antsirabe-Betafo region with the aim of constraining the chronology of the volcanic activity. Establishing such a chronology is important for evaluating volcanic hazards in this densely populated area. Stratigraphic correlations of eruption deposits and IRSL ages suggest at least five phreatomagmatic eruption events in Late Pleistocene times. In the Lake Andraikiba region, two such eruption layers can be clearly distinguished. The older one yields ages between 109 +/- 15 and 90 +/- 11 ka and is possibly related to an eruption at the Amboniloha volcanic complex to the north. The younger one gives ages between 58 +/- 4 and 47 +/- 7 ka and is clearly related to the phreatomagmatic eruption that formed Lake Andraikiba. IRSL ages of a similar eruption deposit directly overlying basement laterite in the vicinity of the Fizinana and Ampasamihaiky volcanic complexes yield coherent ages of 68 +/- 7 and 65 +/- 8 ka. These ages provide the upper age limit for the subsequently developed Iavoko, Antsifotra, and Fizinana scoria cones and their associated lava flows. Two phreatomagmatic deposits, identified near Lake Tritrivakely, yield the youngest IRSL ages in the region, with respective ages of 32 +/- 3 and 19 +/- 2 ka. The reported K-feldspar IRSL ages are the first recorded numerical ages of phreatomagmatic eruption deposits in Madagascar, and our results confirm the huge potential of this dating approach for reconstructing the volcanic activity of Late Pleistocene to Holocene volcanic provinces.

  • 34. Rupnik, Petra Jamsek
    et al.
    Benedetti, Lucilla
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Bavec, Milos
    Vrabec, Marko
    Geomorphic evidence of recent activity along the Vodice thrust fault in the Ljubljana Basin (Slovenia) - a preliminary study2013In: Annals of Geophysics, ISSN 1593-5213, E-ISSN 2037-416X, Vol. 56, no 6, p. S0680-Article in journal (Refereed)
    Abstract [en]

    We investigated two prominent, E-W trending scarps in Quaternary sediments, located close to the town of Vodice in the Ljubljana Basin (central Slovenia). By using detailed geomorphological analysis of the scarps, field surveying, and structural observations of deformed Quaternary sediments, we conclude that the scarps are the surface expression of a N-dipping thrust fault that has been active during the Quaternary. From Optically Stimulated Luminescence and Infrared Stimulated Luminescence dating of deformed Quaternary sediments we estimate a slip rate of 0.1 to 0.3 mm a(-1) in the last 133 ka. Using the published empirical fault-scaling relationships, we estimate that an earthquake of magnitude 5.9 to 6.5 may be expected on the Vodice thrust fault. The fault may, therefore, present a major seismic hazard for the densely populated and urbanised region of central Slovenia.

  • 35. Schmidt, C.
    et al.
    Rufer, D.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Krbetschek, M.
    Hilgers, A.
    THE ASSESSMENT OF RADIONUCLIDE DISTRIBUTION IN SILEX BY AUTORADIOGRAPHY IN THE CONTEXT OF DOSE RATE DETERMINATION FOR THERMOLUMINESCENCE DATING2013In: Archaeometry, ISSN 0003-813X, E-ISSN 1475-4754, Vol. 55, p. 407-422Article in journal (Refereed)
    Abstract [en]

    A combination of two autoradiography methods was applied to investigate the radionuclide distribution patterns in a range of different silices. We obtained greyscale images (-radiation) and -track patterns for qualitative assessment, and used a statistical approach to quantify the degree of uniformity of the radiation fields. It was found that almost all samples are poor in potassium, thorium and uranium, and that locally high concentrations are present only in dark-coloured veins and inclusions. Statistical analyses reveal evidence of radionuclide clustering in more than half of the 21 specimens. Concerning thermoluminescence dating of burnt lithics, such gradients should be taken into account to improve precision and accuracy in cases where the external radiation is not strongly dominating for the sample under consideration.

  • 36. Schmidt, Christoph
    et al.
    Pettke, Thomas
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Rufer, Daniel
    Kasper, Haino Uwe
    Hilgers, Alexandra
    Quantification and spatial distribution of dose rate relevant elements in silex used for luminescence dating2012In: Quaternary Geochronology, ISSN 1871-1014, E-ISSN 1878-0350, Vol. 12, p. 65-73Article in journal (Refereed)
    Abstract [en]

    Thermoluminescence (TL) is routinely used to date heated lithic artefacts which mostly consist of silex (a mixture of amorphous opal and microcrystalline chalcedony). Analytical investigations of bulk samples confirmed that these materials contain considerable concentrations of radioactive elements, generating an internal dose rate contribution. Common dosimetric models assume the latter to be homogeneous throughout the sample. If this assumption would prove invalid, this will result in systematic errors in the calculated age, especially in the course of so called 'hot spots' of alpha-emitters (and associated local changes in a-sensitivity) and the dose response characteristics of alpha-radiation. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of 22 silex samples are presented here, quantifying element concentrations at several tens analytical spots per sample. Along with radioactive elements (K, Rb, U, Th), another 21 major, minor and trace elements were measured in order to allow characterization of the impurities present in most of the samples. The dataset provides a detailed picture of the spatial distribution of radionuclides and hence of the uniformity of the internal alpha- and beta-dose rate. It is shown that the silex itself mostly contains low amounts of K (<0.1 wt.%), U (<1.0 mu g g(-1)) and Th (<0.4 mu g g(-1)), and dosimetrically negligible Rb concentrations. Systematically higher concentrations are obtained by ICP-MS measurements of the bulk samples. This matches with the finding that impurities (veins, inclusions) often yield significantly elevated radionuclide concentrations, up to two orders of magnitude higher than the silex values. These veins and inclusions, for example Ca or Mg carbonates and Fe-Mn-oxy-hydroxides, lead to steep gradients mainly in the internal alpha-radiation field. Alternative approaches are required to account for the non-uniform internal dose rate and improve the reliability of TL dates of problematic samples.

  • 37. Trauerstein, Mareike
    et al.
    Lowick, Sally E.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Schlunegger, Fritz
    Small aliquot and single grain IRSL and post-IR IRSL dating of fluvial and alluvial sediments from the Pativilca valley, Peru2014In: Quaternary Geochronology, ISSN 1871-1014, E-ISSN 1878-0350, Vol. 22, p. 163-174Article in journal (Refereed)
    Abstract [en]

    Infrared stimulated luminescence (IRSL) and post-IR IRSL are applied to small aliquots and single grains to determine the equivalent dose (De) of eleven alluvial and fluvial sediment samples collected in the Pativilca valley, Central Peru at ca. 10 S latitude. Small aliquot De distributions are rather symmetric and display over-dispersion values between 15 and 46%. Small aliquot g-values range between 4 and 8% per decade for the IRSL and 1 and 2% per decade for the post-IR IRSL signal. The single grain De distributions are highly over-dispersed with some of them skewed to higher doses, implying partial bleaching; this is especially true for the post-IR IRSL Measurements of a modern analog reveal that residuals due to partial bleaching are present in both the IRSL as well as the post-IR IRSL signal. The g-values of individual grains exhibit a wide range with high individual uncertainties and might contribute significantly to the spread of the single grain De values, at least for the IRSL data. Electron Microprobe Analysis performed on single grains reveal that a varying K-content can be excluded as the origin of over-dispersion. Final ages for the different approaches are calculated using the Central Age Model and the Minimum Age Model (NAM). The samples are grouped into well-beached, potentially well-bleached and partially bleached according to the evaluation of the single grain distributions and the agreement of age estimates between methods. The application of the MAM to the single grain data resulted in consistent age estimates for both the fading corrected IRSL and the post-IR IRSL ages, and suggests that both approaches are suitable for dating these samples.

  • 38. Trauerstein, Mareike
    et al.
    Lowick, Sally
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Rufer, Daniel
    Schlunegger, Fritz
    Exploring fading in single grain feldspar irsl measurements2012In: Quaternary Geochronology, ISSN 1871-1014, E-ISSN 1878-0350, Vol. 10, p. 327-333Article in journal (Refereed)
    Abstract [en]

    IR laser stimulated luminescence was used to determine the equivalent dose (De) for about 150 luminescent K-feldspar grains of two well-bleached aeolian sand samples, previously dated using quartz optically stimulated luminescence (OSL) and thermally-transferred OSL (TT-OSL). Fading tests were performed both on the entire single grain disc, using stimulation by IR LEDs, and on each grain individually, by stimulation with an IR laser. The single grain De distributions are highly over dispersed, even after applying rejection criteria, such as recycling ratio and recuperation. Fading rates determined with the IR LED stimulation do not represent the fading behavior of the IR laser stimulated signal and are therefore considered inappropriate for the fading correction of single grain D-e values. Fading rates of individual grains exhibit a wide range of values (0%-10% per decade) and plotting the single grain fading rates against the single grain De values reveals a negative relationship. Different approaches were taken to correct for fading, but the resulting ages tend to underestimate the reference ages.

  • 39. Trauerstein, Mareike
    et al.
    Norton, Kevin P.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Schlunegger, Fritz
    Climatic imprint on landscape morphology in the western escarpment of the Andes2013In: Geomorphology, ISSN 0169-555X, E-ISSN 1872-695X, Vol. 194, p. 76-83Article in journal (Refereed)
    Abstract [en]

    Because of competing forces and variations through time, the relative importance of geomorphic processes responsible for the long-term topographic evolution of a mountain range is not always obvious. Here we perform a space-for-time substitution with the western escarpment of the Andes between 10 and 20 degrees S to identify the mechanisms of plateau destruction over geological timescales. We use this setting to propose that variations in the precipitation rate play a primary role in setting hillslope relief in uplifted mountainous landscapes. We find that in dry climates local topographic relief grows with increasing precipitation, independent of the underlying lithology and given an overall uniform rock uplift history. We proceed by differentiating Andean landscapes with generally low precipitation rates (80-500 mm a(-1), Peruvian Andes 10-20 degrees S) where local relief correlates positively with precipitation, from those with higher precipitation rates (400-1400 mm a(-1), Chilean Andes 35-40 degrees S) where increases in precipitation lead to topographic decay. We suggest that these trends result from dominant bottom-up control (channel incision is faster than hillslope response) giving way to an increasing top-down control (hillslope lowering is faster than channel incision). With low precipitation, relief growth is controlled by stream incision and knickzone retreat into a largely undissected plateau. With higher precipitation rates, relief is set by the steepness of graded streams and the rates of sediment production and transport on hillslopes. Trends of topography can also be interpreted in temporal terms in which the higher precipitation results in shorter response times, such that the Peruvian Andes between 10 and 20 degrees S are still responding to Miocene uplift, while in the Chilean Andes between 35 and 40 degrees S, these knickzones have already propagated through the entire fluvial network. We anticipate that such changes also operate during the formation and destruction of other mountainous plateau landscapes.

  • 40. Tronchère, Hervé
    et al.
    Goiran, Jean-Philippe
    Schmitt, Laurent
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Bietak, Manfred
    Forstner-Müller, Irene
    Callot, Yann
    Geoarchaeology of an ancient fluvial harbour: Avaris and the Pelusiac branch (Nile River, Egypt)2012In: Géomorphologie, ISSN 1266-5304, no 1, p. 23-36Article in journal (Refereed)
    Abstract [en]

    The former city of Avaris is one of the biggest in the Nile delta. The city was the capital of the Hyksos kings who ruled Egypt during the Second Intermediate Period, around 1650-1550 BC. The city was built on the edge of the Pelusiac branch of the Nile River, in the middle of a complex anabranching river system. Historical sources mention the existence of a fluvial harbour in Avaris. This large town required a harbour complex to fulfil its economic and military role. Until recently, the precise location of Avaris' harbour basin was unclear. A pluridisciplinary project was set up in order to locate this harbour, by implementing various methods and tools. This project was part of a broader study of the palaeo-landscape of the whole city that provided us with a better knowledge of the palaeo-environment and its depositional processes. We were able to suggest the most likely area where a harbour could have been built. Extensive geomagnetic surveys backed the sedimentary boreholes analysis in order to get a precise image of the harbour basin, also helped by archaeological findings. The relationships between the basin and the Nile were also explored, especially a small channel linking the harbour to the main river as well as another one connecting it to a secondary channel of the Pelusiac branch at the south. We used OSL dating to reconstruct the history of the harbour, from the natural formation of a favourable geomorphologic site to its adaptation and maintenance by man during the apogee of the Hyksos capital.

  • 41. Veit, Heinz
    et al.
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Trauerstein, Mareike
    The Southern Westerlies in Central Chile during the two last glacial cycles as documented by coastal aeolian sand deposits and intercalating palaeosols2015In: Catena (Cremlingen. Print), ISSN 0341-8162, E-ISSN 1872-6887, Vol. 134, p. 30-40Article in journal (Refereed)
    Abstract [en]

    Changes in the position and intensity of the Southern Westerly Winds (SWW) and related causal processes during the Quaternary are controversial and not well understood. Here, we present a record from continental Central Chile, based on coastal aeolian sand and dunes with intercalated palaeosols, reaching back 190 ka in time. Sixteen samples for luminescence dating and additional samples for geochemical procedures were analysed from three locations in the Norte Chico (La Serena, Los Vilos, Las Ventanas). Besides the recent Bw-horizons, four palaeosols (Btb1, Btb2, Btb3, Btb4) are identified. They formed in periods with stable surface conditions and a relatively dense vegetation cover, whereas sand accumulation reflects increased aeolian activity under dry conditions and, in parts, glacial sea level lowering. Three of these soils are well bracketed by luminescence data to <14 ka (Bw), 59-47 ka (Btb4) and 135-125 ka (Btb2). The formation of Btb1 and Btb3 tentatively occurred at 190-160 ka and 107-95 ka. Btb-horizons are interpreted to reflect wetter conditions than modern ones (Bw-horizons). Since the only way to bring wetter conditions to the coastal area of the Norte Chico are the SWW, the documented changes should reflect changes in paleo atmospheric circulation. The more humid periods appear to show a periodicity, dominated by the obliquity cycle. Increased Antarctic sea-ice during austral winter combined with a weak South Pacific Anticyclone at subtropical latitudes, seem to have favoured winter incursions of humid air masses from the Westerlies.

  • 42. Vojtko, Ratislav
    et al.
    Marko, Frantisek
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Madaras, Jan
    Kovacova, Marianna
    Late Quaternary fault activity in the Western Carpathians: evidence from the Vikartovce Fault (Slovakia)2011In: Geologica Carpathica, ISSN 1335-0552, E-ISSN 1336-8052, Vol. 62, no 6, p. 563-574Article in journal (Refereed)
    Abstract [en]

    The Cenozoic structure of the Western Carpathians is strongly controlled by faults. The E-W striking Vikartovcefault is one of the most distinctive dislocations in the region, evident by its geological structure and terrain morphology.This feature has been assumed to be a Quaternary reactivated fault according to many attributes such as its perfectlinearity, faceted slopes, the distribution of travertines along the fault, and also its apparent prominent influence on thedrainage network. The neotectonic character of the fault is documented herein by morphotectonic studies, longitudinaland transverse valley profile analyses, terrace system analysis, and mountain front sinuosity. Late Pleistocene activityof the Vikartovce fault is now proven by luminescence dating of fault-cut and uplifted alluvial sediments, presentlylocated on the crest of the tilted block. These sediments must slightly pre-date the age of river redirection. Consideringthe results of both luminescence dating and palynological analyses, the change of river course probably occurred duringthe final phase of the Riss Glaciation (135 ± 14 ka). The normal displacement along the fault during the Late Quaternaryhas been estimated to about 105—135 m, resulting in an average slip rate of at least 0.8—1.0 mm · yr—1. The present resultsidentify the Vikartovce fault as one of the youngest active faults in the Central Western Carpathians.

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