Extending the area of investigation of fine versus coarse quartz optical ages from the Lower Danube to the Carpathian Basin

Timar-Gabor, Alida; Constantin, Daniela; Marković, Slobodan B.; Jain, Mayank

doi:10.1016/j.quaint.2014.09.065

Cited by 38 publications

(15 citation statements)

References 48 publications

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“…It is important to note that, for all previously investigated samples with equivalent doses higher than~100e200 Gy, the equivalent doses obtained on coarse quartz were systematically higher than for the finer material; this is unexpected when considering that the natural dose rate to fine grains should be somewhat higher than that to coarser grains (mainly because of the alpha dose rate contribution to silt-sized grains), and implies that the cause of the discrepancy resides in the equivalent dose measurements. It is also important to note that for younger ages (with equivalent doses lying in the more linear part of the dose response curves) agreement has been found between the fine and coarse grain quartz ages Timar-Gabor et al, 2015).…”

Section: Introductionmentioning

confidence: 74%

On the importance of grain size in luminescence dating using quartz

Timar-Gabor

Buylaert

Guralnik

et al. 2017

Radiation Measurements

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h i g h l i g h t sDiscrepancy between quartz SAR-OSL ages obtained on fine and coarse grains. Dose response curve adequately fitted by a sum of two saturating exponentials. Isothermal decay fitted by a single exponential. Clear dependency between the saturation characteristics (D 0 s) and the quartz grain size. No correlation between the 2 D 0 value and the maximum attainable accurate equivalent dose. a r t i c l e i n f o a b s t r a c tThere are two major problems commonly encountered when applying Optically Stimulated Luminescence (OSL) dating in the high dose range: (i) age discrepancy between different grain sizes, and (ii) age underestimation. A marked and systematic discrepancy between fine-grain (4e11 mm) and coarse-grain (63e90 mm) quartz single aliquot regeneration protocol (SAR) ages has been reported previously for Romanian and Serbian loess >40 ka (D e of~100 Gy), generally with fine-grain ages underestimating the depositional age. In this paper, we show a similar age pattern for two grain size fractions from Chinese loess, thus pointing to a potential worldwide phenomenon. While age underestimation is often attributed to signal saturation problems, this is not the case for fine grain material, which saturates at higher doses than coarse grains, yet begins to underestimate true ages earlier. Here we examine the dose response curves of quartz from different sedimentary contexts around the world, using a range of grain sizes (diameters of 4e11 mm, 11e30 mm, 35e50 mm, 63e90 mm, 90e125 mm, 125e180 mm, and 180 e250 mm). All dose response curves can be adequately described by a sum of two saturating exponential functions, whose saturation characteristics (D 0 values) are clearly anticorrelated with grain diameter (4) through an inverse square root relationship, D 0 ¼ A/√4, where A is a scaling factor. While the mechanism behind this grain-size dependency of saturation characteristics still needs to be understood, our results show that the observation of an extended SAR laboratory dose response curve does not necessarily enable high doses to be recorded accurately, or provide a corresponding extended age range.

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Section: Introductionmentioning

confidence: 74%

On the importance of grain size in luminescence dating using quartz

Timar-Gabor

Buylaert

Guralnik

et al. 2017

Radiation Measurements

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“…This might also hint towards another process within quartz OSL measurements, which is not yet understood. Especially considering the differences between grains sizes (Timar-Gabor et al, 2015b;Timar-Gabor and Wintle, 2013) and differences between natural and laboratory growth curve shapes (e.g. Chapot et al, 2012;Timar-Gabor et al, 2015a), which both seem to start around 100-150 Gy, this problem becomes evident.…”

Section: Evaluation Of the Quartz Characteristicsmentioning

confidence: 99%

“…Loess samples consisting of fine grains of quartz are thought to be the ideal material for optically stimulated luminescence (OSL) dating (Roberts, 2008), but recent studies indicate that this is not necessarily correct. Timar-Gabor et al (2012, 2015b found varying dose response curve (DRC) shapes for different grain sizes of quartz that led to age discrepancies. Moreover, disagreements between natural and laboratory-induced DRCs (e.g.…”

Section: Introductionmentioning

confidence: 99%

New luminescence-based geochronology framing the last two glacial cycles at the southern limit of European Pleistocene loess in Stalać (Serbia)

et al. 2017

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Abstract:A new geochronology was established for the Stalać loess-paleosol sequence (LPS) in Serbia. The section is located in the interior of the Central Balkan region, south of the typical loess distribution, in a zone of paleoclimatic shifts between continental and Mediterranean climate regimes. The sampled sequence contains four well-developed paleosol and loess layers, a crypto tephra and one visible tephra layer. Optically stimulated luminescence measurements showed a strong dependency of preheat temperature on equivalent dose for one fine-grained quartz sample, which makes it unsuitable for dating. A firm chronology framing the last two glacial cycles was established using finegrained polyminerals and the post-infrared infrared stimulated luminescence (pIR 50 IR 290 ) protocol instead. The characteristics of dated paleosols indicate similar climatic conditions during the last interstadial and interglacial phases, which were different from the penultimate interglacial period. The tephra within the L2 loess, probably related to tephra layers also found in other sections in Southeastern Europe, was sandwich-dated. The results indicate an age between 118 ka and 141 ka. Furthermore, a weak pedogenic layer dated to between 126 ka and 148 ka gives a first numerical age to this soil formation in Southeastern Europe.

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“…A further problem when dating the quartz fraction may be different ages derived from different grain sizes. This was shown by various studies in the Lower Danube region and Carpathian Basin, in which contrasting luminescence ages were determined when dating the fine (4-11 lm) or coarse (63-125 lm) grain fraction of quartz in age ranges >40 ka (Timar-Gabor et al 2011, 2015bConstantin et al 2012Constantin et al , 2014. In these studies, the coarse grain ages appear to provide the more reliable ages, and the fine grain ages appear to be underestimated.…”

mentioning

confidence: 97%

“…This was shown by various studies in the Lower Danube region and Carpathian Basin, in which contrasting luminescence ages were determined when dating the fine (4–11 μm) or coarse (63–125 μm) grain fraction of quartz in age ranges >40 ka (Timar‐Gabor et al . , ; Constantin et al . , ).…”

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confidence: 99%

A luminescence‐based chronology for the Harletz loess sequence, Bulgaria

Lomax

Fuchs

Antoine

et al. 2018

Boreas

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The Harletz loess‐palaeosol sequence is located in northwestern Bulgaria and represents an important link between well‐studied loess sequences in eastern Romania and further sites to the west of the Carpathians (e.g. Serbia and Hungary). The aim of this study was to establish a chronostratigraphy of the deposits, using various methods of luminescence dating, together with basic stratigraphical field observations as well as magnetic properties. Luminescence dating was carried out using the quartz fine grain fraction and a SAR protocol, and the feldspar coarse grain fraction, applying the MET‐pIRIR protocol. Due to underestimation of the quartz fine grain fraction in the lower parts of the sequence, the resulting chronology is mainly based on the feldspar ages, which are derived from the stimulation temperature at 150 °C. A comparison with nearby sequences from Serbia, Hungary and Romania, and interpretations obtained through the stratigraphical and sedimentological signature of the sequence, supports the established chronology. Our data suggest that the prominent palaeosol (soil complex) in the upper quarter of the sequence was formed during MIS 5. It would follow that large parts of the Last Glacial loess overlying this palaeosol were probably eroded, and that the thick loess accumulation underlying this soil complex can be allocated to the penultimate glacial (MIS 6). A prominent MIS 6 tephra, which has been reported from other sequences in the area, is also present at Harletz.

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Extending the area of investigation of fine versus coarse quartz optical ages from the Lower Danube to the Carpathian Basin

Abstract: 14Despite the general satisfactory performance of quartz in the single aliquot regeneration protocol

Cited by 38 publications

References 48 publications

On the importance of grain size in luminescence dating using quartz

On the importance of grain size in luminescence dating using quartz

New luminescence-based geochronology framing the last two glacial cycles at the southern limit of European Pleistocene loess in Stalać (Serbia)

A luminescence‐based chronology for the Harletz loess sequence, Bulgaria

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