ORCID Profile
0000-0003-0587-8077
Current Organisations
Ghent University
,
Technical University of Denmark
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Wiley
Date: 18-05-2016
DOI: 10.1111/BOR.12180
Publisher: Elsevier BV
Date: 03-2018
Publisher: Elsevier BV
Date: 10-2015
Publisher: Springer Science and Business Media LLC
Date: 07-03-2018
DOI: 10.1038/S41467-018-03329-2
Abstract: The International Commission on Stratigraphy (ICS) utilises benchmark chronostratigraphies to ide geologic time. The reliability of these records is fundamental to understand past global change. Here we use the most detailed luminescence dating age model yet published to show that the ICS chronology for the Quaternary terrestrial type section at Jingbian, desert marginal Chinese Loess Plateau, is inaccurate. There are large hiatuses and depositional changes expressed across a dynamic gully landform at the site, which demonstrates rapid environmental shifts at the East Asian desert margin. We propose a new independent age model and reconstruct monsoon climate and desert expansion/contraction for the last ~250 ka. Our record demonstrates the dominant influence of ice volume on desert expansion, dust dynamics and sediment preservation, and further shows that East Asian Summer Monsoon (EASM) variation closely matches that of ice volume, but lags insolation by ~5 ka. These observations show that the EASM at the monsoon margin does not respond directly to precessional forcing.
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 10-2021
Publisher: Walter de Gruyter GmbH
Date: 22-09-2011
DOI: 10.2478/S13386-011-0042-5
Abstract: A new measurement protocol has been tested on K-feldspars from Whanganui Inlet and Parengarenga Harbour, New Zealand. A Single Aliquot Regenerative (SAR) dose protocol, using two successive infrared (IR) stimulations (post-IR IR SAR protocol) is setup for these young ( years) coastal sediments. Significant anomalous fading (g2days=7 %/decade) is observed using the conventional IR signal measured at 50°C. In contrast, the fading rate of the IR signal measured at elevated temperature (150°C) after the IR stimulation at 50°C (a post-IR IR signal) is not significant (g2days≤ 1 %/decade). Surprisingly low residual infrared stimulated luminescence (IRSL) signals were observed for a surface s le, suggesting that accurate ages as young as ∼50 years can be obtained for these recent deposits. IRSL ages ranging between 48±6 years and 1050±50 years are obtained from six s les, indicating that sediment accumulation has occurred at the two sites during the last millennia, despite a falling trend in relative sea-level in Whanganui Inlet and a stable relative sea-level at Parengarenga Harbour.
Publisher: Springer Science and Business Media LLC
Date: 28-11-2017
DOI: 10.1038/S41467-017-01643-9
Abstract: Urbanism in the Bronze-age Indus Civilisation (~4.6–3.9 thousand years before the present, ka) has been linked to water resources provided by large Himalayan river systems, although the largest concentrations of urban-scale Indus settlements are located far from extant Himalayan rivers. Here we analyse the sedimentary architecture, chronology and provenance of a major palaeochannel associated with many of these settlements. We show that the palaeochannel is a former course of the Sutlej River, the third largest of the present-day Himalayan rivers. Using optically stimulated luminescence dating of sand grains, we demonstrate that flow of the Sutlej in this course terminated considerably earlier than Indus occupation, with ersion to its present course complete shortly after ~8 ka. Indus urban settlements thus developed along an abandoned river valley rather than an active Himalayan river. Confinement of the Sutlej to its present incised course after ~8 ka likely reduced its propensity to re-route frequently thus enabling long-term stability for Indus settlements sited along the relict palaeochannel.
Publisher: Wiley
Date: 09-07-2016
DOI: 10.1111/BOR.12179
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 06-2017
Publisher: Elsevier BV
Date: 04-2010
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 09-2016
Publisher: Wiley
Date: 05-2016
DOI: 10.1002/JQS.2848
Publisher: Elsevier BV
Date: 07-2012
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 09-2017
Publisher: Elsevier BV
Date: 05-2009
Publisher: Cambridge University Press (CUP)
Date: 07-2015
DOI: 10.1016/J.YQRES.2015.04.001
Abstract: We present a study based on four inland eolian locations in Eastern, Central and Southeastern Lithuania belonging to the northeastern part of the ‘European Sand Belt’ (ESB). Although there have been several previous studies of the ESB, this north-eastern extension has not been investigated before in any detail. The sedimentary structural–textural features are investigated and a chronology was derived using optically stimulated luminescence on both quartz and feldspar. The sedimentary structures and the rounding and surface characteristics of the quartz grains argue for a predominance of eolian transport. Additionally, some structural alternations and a significant contribution of non-eolian grains are interpreted as inherited local glacial/glaciofluvial-bearing lithologies. Three main (glaciolacustrine–) eolian phases are distinguished based on the position in the landscape and the luminescence ages: (1) An older eolian series around 15 to 16 ka, possibly correlated with the cold GS-2a event according to the GRIP stratigraphy, and (2) a younger eolian series around 14.0 ka, possibly representing the GI-1d and 1c events. The older eolian series is underlain by (3) a glaciolacustrine – eolian series for which the period of deposition remains uncertain due to the significant discrepancy between the ages based on quartz and feldspar.
Publisher: Elsevier BV
Date: 05-2009
Publisher: MDPI AG
Date: 03-09-2022
DOI: 10.3390/QUAT5030037
Abstract: This paper presents an updated geological reconstruction of the Quaternary evolution of the River Thames at its downstream extremities, close to the North Sea coast, based on new data from multi-disciplinary and citizen-science sources. In this area, the interaction of the Thames with the MIS 12 (Anglian) glaciation is an important part of the Quaternary archive. The Anglian ice sheet, which reached parts of north and east London, was responsible for erting the Thames southwards into its present course, although the footprint of the maximum ice sheet(s) does not reach the North Sea coast south of Hollesley, Suffolk. Further south, the coastal zone hosts pre-Anglian and early Anglian river-terrace deposits of the pre- ersion Thames system, superimposed upon which are products of later post-Anglian rivers, of both Middle and Late Pleistocene age. On the peninsula between the Stour and Blackwater–Colne estuaries, the lowest and most recent terrace of the pre- ersion Thames includes evidence directly pertaining to the glacial disruption event, for which geochronological data are reported here for the first time. The first post- ersion terrace of the Thames also reaches this peninsula, the river having essentially re-joined its original valley before crossing the alignment of the modern coastline. This terrace passes beneath Clacton-on-Sea, where it includes the type locality of the Clactonian Palaeolithic Industry. The area of interest to this paper, in NE Essex and southern Suffolk, includes a number of interglacial and Palaeolithic sites, the data from which assist in constraining the chronostratigraphy of the sequence. In some cases, there has been uncertainty as to whether these sites represent pre-Anglian environments and hominin occupations, part of the palaeo-Thames sequence, or whether they are the product of later post-Anglian streams, formed after the Thames had migrated southwards. This paper compiles evidence from a wide range of recent sources, including developer-funded archaeological appraisal and citizen-science activities, to explore and update the evidence from sites at Ipswich, Upper Dovercourt and Thorpe-le-Soken, as well as a number of localities associated with the Clacton Channel Deposits (host to the type-Clactonian), amongst others. The resulting new data are placed within the wider context of the Quaternary fluvial archives in southern Britain, with a discussion of how disparate sources of information, including the work of citizen scientists, have contributed.
Publisher: Editorial CSIC
Date: 13-05-2015
Publisher: Elsevier BV
Date: 08-2022
Publisher: Wiley
Date: 23-05-2018
DOI: 10.1111/BOR.12321
Publisher: Wiley
Date: 17-04-2014
DOI: 10.1111/BOR.12080
Publisher: Wiley
Date: 10-2016
DOI: 10.1002/JQS.2895
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 02-2016
Publisher: Elsevier BV
Date: 12-2014
Publisher: Walter de Gruyter GmbH
Date: 22-09-2011
DOI: 10.2478/S13386-011-0047-0
Abstract: Using a set of modern/young (0 to about 200 years old) dust s les collected from the Chinese Loess Plateau the bleachability of IRSL measured at 50°C (IR50) and post-IR50 elevated temperature IRSL (measured at 225°C and at 290°C) is investigated by measuring the apparent (residual) doses recorded by these signals. Doses recorded by quartz OSL are used as a reference. Allowing for differences in dose rates it seems that both IRSL and post-IR IRSL signals yield residual doses that are significantly larger than the doses measured in quartz. These residual doses can be largely explained by thermal transfer caused by preheating. Nevertheless, we advise against the use of a low temperature preheat ( °C) with IR50 to date loess s les because, as has been reported before, the signal appears to be thermally unstable. In general, we conclude that it may not be advisable to apply post-IR IRSL dating to Chinese loess s les where residuals of up to ∼20 Gy are a significant fraction of the total dose. However, these residuals quickly become unimportant when dating older s les, and this is the age range in which post-IR IRSL dating is likely to be most useful.
Publisher: Walter de Gruyter GmbH
Date: 22-09-2011
DOI: 10.2478/S13386-011-0043-4
Abstract: Recent work on infrared stimulated luminescence (IRSL) dating has focussed on finding and testing signals which show less or negligible fading. IRSL signals measured at elevated temperature following IR stimulation at 50°C (post-IR IRSL) have been shown to be much more stable than the low temperature IRSL signal and seem to have considerable potential for dating. For Early Pleistocene s les of both European and Chinese loess natural post-IR IRSL signals lying in the saturation region of the laboratory dose response curve have been observed this suggests that there is no significant fading in nature. As a contribution to the further testing of post-IR IRSL dating, we have used 18 s les from two Japanese loess profiles for which quartz OSL and tephra ages up to 600 ka provide age control. After a preheat of 320°C (60 s), the polymineral fine grains (4–11 μm) were bleached with IR at 50°C (200 s) and the IRSL was subsequently measured at 290°C for 200 s. In general, the fading uncorrected post-IR IRSL ages agree with both the quartz OSL and the tephra ages. We conclude that the post-IR IRSL signal from these s les does not fade significantly and allows precise and accurate age determinations on these sediments.
Publisher: Walter de Gruyter GmbH
Date: 2021
Abstract: In this study, we explored the potential of a NaI(Tl) scintillator-based gamma spectrometer for the accurate determination of burial dose rates in natural geological s les using a full spectrum analysis (FSA) approach. In this method, an iterative reweighted least-square regression is used to fit calibration standard spectra ( 40 K, and 238 U and 232 Th series in equilibrium) to the s le spectrum, after subtraction of an appropriate background. The resulting minimum detection limits for 40 K, 238 U, and 232 Th are 4.8, 0.4 and 0.3 Bq·kg −1 , respectively (for a 0.23 kg s le) this is one order of magnitude lower than those obtained with the three-window approach previously reported by us, and well below the concentrations found in most natural sediments. These improved values are also comparable to those from high-resolution HPGe gamma spectrometry. Almost all activity concentrations of 40 K, 238 U, and 232 Th from 20 measured natural s les differ by ≤5% from the high resolution spectrometry values the average ratio of dose rates derived from our NaI(Tl) spectrometer to those from HPGe spectrometry is 0.993 ± 0.004 (n=20). We conclude that our scintillation spectrometry system employing FSA is a useful alternative laboratory method for accurate and precise determination of burial dose rates at a significantly lower cost than high resolution gamma spectrometry.
Publisher: American Geophysical Union (AGU)
Date: 05-2012
DOI: 10.1029/2011GC004029
Publisher: Elsevier BV
Date: 11-2022
Publisher: Elsevier BV
Date: 11-2022
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 09-2012
Publisher: Oxford University Press (OUP)
Date: 18-05-2006
DOI: 10.1093/RPD/NCI518
Abstract: The reliability of equivalent doses (De) from Chinese loess, measured using isothermal thermoluminescence (ITL) is tested. Dose calculations use the single-aliquot regenerative-dose (SAR) procedure. Despite good reproducibility of laboratory-induced signals and negligible response at zero dose, a significant overestimation of De is observed, compared with OSL measurements. Measurement of a known laboratory dose administered after optical bleaching, but before any heating, demonstrates that the first heating during measurement of the natural signal causes a significant sensitivity change, undetected by SAR. Using the single-aliquot regeneration and added (SARA) dose procedure, which allows for initial sensitivity change, good agreement with OSL is obtained after allowance is made for initial incomplete bleaching. It is concluded that SAR-ITL, in its present form, is not a suitable method for dating Chinese loess it is very important to undertake a dose recovery test before any TL procedure is used to date sediments.
Publisher: Elsevier BV
Date: 08-2015
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 04-2017
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 04-2010
Publisher: Elsevier BV
Date: 2010
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 07-2013
Publisher: Elsevier BV
Date: 10-2019
Publisher: Copernicus GmbH
Date: 15-08-2022
DOI: 10.5194/GCHRON-4-517-2022
Abstract: Abstract. Mineral grains within sediment or rock absorb a radiation dose from the decay of radionuclides in the host matrix. For the beta dose component, the estimated dose rate must be adjusted for the attenuation of beta particles within the mineral grains. Standard calculations, originally designed for thermoluminescence dating of pottery, assume that the grain is embedded in a homogenous medium. However, most current applications of trapped-charge dating concern sand- or silt-sized dosimeters embedded in granular sediment. In such cases, the radionuclide sources are not homogeneous but are localised in discrete grains or held on grain surfaces. We show here that the mean dose rate to dosimeter grains in a granular matrix is dependent on the grain-size distributions of the source grains and of the bulk sediment, in addition to the grain size of the dosimeters. We further argue that U and Th sources are likely to be held primarily on grain surfaces, which causes the dose rate to dosimeter grains to be significantly higher than for sources distributed uniformly throughout grains. For a typical well-sorted medium sand, the beta dose rates derived from surface U and Th sources are higher by ∼ 20 % and ∼ 30 %, respectively, compared to a homogenous distribution of sources. We account for these effects using an expanded model of beta attenuation – including the effect of moisture – and validate the model against Monte Carlo radiation transport simulations within a geometry of packed spheres.
Publisher: Wiley
Date: 15-06-2016
DOI: 10.1111/BOR.12185
Publisher: Wiley
Date: 12-10-2011
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 11-2022
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 07-2012
Publisher: Wiley
Date: 23-02-2012
Publisher: Walter de Gruyter GmbH
Date: 19-06-2011
DOI: 10.2478/S13386-011-0029-2
Abstract: There are many ex les of buried rock surfaces whose age is of interest to geologists and archaeologists. Luminescence dating is a potential method which can be applied to dating such surfaces as part of a research project which aims to develop such an approach, the degree of resetting of OSL signals in grains and slices from five different cobbles/boulders collected from a modern beach is investigated. All the rock surfaces are presumed to have been exposed to daylight for a prolonged period of time (weeks to years). Feldspar was identified as the preferred dosimeter because quartz extracts were insensitive. Dose recovery tests using solar simulator and IR diodes on both K-feldspar grains and solid slices taken from the inner parts of the rocks are discussed. Preheat plateau results using surface grains and slices show that significant thermal transfer in naturally bleached s les can be avoided by keeping preheat temperatures low. Equivalent doses from surface K-feldspar grains were highly scattered and much larger than expected (0.02 Gy to Gy), while solid surface slices gave more reproducible small doses (mean = 0.17±0.02 Gy, n = 32). Neither crushing nor partial bleaching were found to be responsible for the large scattered doses from grains, nor did the inevitable contribution from Na-feldspar to the signal from solid slices explain the improved reproducibility in the slices. By modelling the increase of luminescence signal with distance into the rock surface, attenuation factors were derived for two s les. These indicate that, for instance, bleaching at a depth of 2 mm into these s les occurs at about ∼28% of the rate at the surface. We conclude that it should be possible to derive meaningful burial doses of Gy from such cobbles younger s les would probably require a correction for incomplete bleaching.
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 02-2019
Publisher: Copernicus GmbH
Date: 28-04-2021
DOI: 10.5194/GCHRON-3-229-2021
Abstract: Abstract. Statistical analysis has become increasingly important in optically stimulated luminescence (OSL) dating since it has become possible to measure signals at the single-grain scale. The accuracy of large chronological datasets can benefit from the inclusion, in chronological modelling, of stratigraphic constraints and shared systematic errors. Recently, a number of Bayesian models have been developed for OSL age calculation the R package “BayLum” presented herein allows different models of this type to be implemented, particularly for s les in stratigraphic order which share systematic errors. We first show how to introduce stratigraphic constraints in BayLum then, we focus on the construction, based on measurement uncertainties, of dose covariance matrices to account for systematic errors specific to OSL dating. The nature (systematic versus random) of errors affecting OSL ages is discussed, based – as an ex le – on the dose rate determination procedure at the IRAMAT-CRP2A laboratory (Bordeaux). The effects of the stratigraphic constraints and dose covariance matrices are illustrated on ex le datasets. In particular, the benefit of combining the modelling of systematic errors with independent ages, unaffected by these errors, is demonstrated. Finally, we discuss other common ways of estimating dose rates and how they may be taken into account in the covariance matrix by other potential users and laboratories. Test datasets are provided as a Supplement to the reader, together with an R markdown tutorial allowing the reproduction of all calculations and figures presented in this study.
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 12-2011
Publisher: Elsevier BV
Date: 04-2011
Publisher: Elsevier BV
Date: 08-2023
Publisher: Elsevier BV
Date: 04-2009
Publisher: Elsevier BV
Date: 07-2013
Publisher: Elsevier BV
Date: 07-2012
Publisher: Wiley
Date: 07-01-2013
DOI: 10.1111/BOR.12002
Publisher: Elsevier BV
Date: 03-2015
Publisher: Wiley
Date: 07-05-2015
DOI: 10.1111/BOR.12125
Publisher: Elsevier BV
Date: 04-2012
Publisher: Elsevier BV
Date: 06-2014
Publisher: Wiley
Date: 06-05-2011
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 05-2009
Publisher: Elsevier BV
Date: 09-2016
Publisher: Elsevier BV
Date: 04-2010
Publisher: Wiley
Date: 03-2012
Publisher: Cambridge University Press (CUP)
Date: 26-01-2023
DOI: 10.1017/QUA.2022.68
Abstract: This study uses luminescence and 14 C accelerator mass spectrometry procedures to date relevant glaciofluvial and glacial deposits from the south-central and southeastern Pyrenees (Andorra–France–Spain). We distinguish two types of end-moraine complexes: (1) those in which at least a far-flung moraine exists beyond a frequently nested end-moraine complex (the most common) and (2) those in which a close-nested end moraine encompasses at least two glacial cycles. Both types formed within six distinctive glacial intervals: (1) A penultimate glacial cycle during Marine Oxygen Isotope Stage (MIS) 6 and older glaciofluvial terraces occurred beyond the range of the luminescence dating method. (2) An early glacial advance in MIS 5d (~97 −15/+19 ka) was followed by glacial retreat during MIS 5c ( 91 ± 9 ka). (3) The last maximum ice extent (LMIE) was in early MIS 4 (~74 ± 4.5 ka). (4) Unexpectedly, glaciers thinned during the second half of MIS 3 (~39 −6/+11 ka). (5) During the MIS 3–2 transition, glaciers subsequently fluctuated behind the LMIE limits. (6) The global last glacial maximum (LGM) started as early as ~26.6 ± 0.365 ka b2k, and the corresponding end moraines were built behind the LMIE limits or merged with it, forming close-nested moraines.
Publisher: Elsevier BV
Date: 02-2017
Publisher: Elsevier BV
Date: 11-2017
Publisher: Wiley
Date: 20-01-2009
Publisher: Springer Science and Business Media LLC
Date: 28-10-2021
Publisher: Elsevier BV
Date: 05-2017
Publisher: Geological Society of America
Date: 20-07-2012
DOI: 10.1130/B30558.1
Publisher: Elsevier BV
Date: 11-2017
Publisher: Copernicus GmbH
Date: 12-06-2019
Abstract: Abstract. The Tibetan Plateau is of peculiar societal relevance as it provides freshwater from the so-called “Water Tower of Asia” to a large portion of the Asian population. However, future climate change will affect the hydrological cycle in this area. To define parameters for future climate change scenarios it is necessary to improve the knowledge about thresholds, timing, pace and intensity of past climatic changes and associated environmental impacts. Sedimentary archives reaching far back in time and spanning several glacial–interglacial cycles such as Nam Co provide the unique possibility to extract such information. In order to explore the scientific opportunities that an ICDP drilling effort at Nam Co would provide, 40 scientists from 13 countries representing various scientific disciplines met in Beijing from 22 to 24 May 2018. Besides paleoclimatic investigations, opportunities for paleomagnetic, deep biosphere, tectonic and paleobiological studies were discussed. After having explored the technical and logistical challenges and the scientific opportunities all participants agreed on the great value and need to drill this extraordinary archive, which has a sediment thickness of more than 1 km, likely covering more than 1 Ma.
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 2022
Publisher: Elsevier BV
Date: 10-2022
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 10-2015
Publisher: Wiley
Date: 05-2021
DOI: 10.1002/JQS.3317
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 12-2018
No related grants have been discovered for Jan-Pieter Buylaert.