Luminescence dating of Romanian loess using feldspars

This work investigates the potential of optically and infrared stimulated luminescence signals (OSL and IRSL, respectively) from polymineral silt-sized grains to establish sedimentation chronologies for Romanian loess. The incentive for the study was the observation that various grain sizes of quartz yielded significantly different OSL ages, a behaviour that remains to be understood; feldspar also has the potential to date older deposits. The samples used in this study were taken from the loess/palaeosol sequence near Mircea Vodă, and all luminescence measurements were made using a single-aliquot regenerative-dose (SAR) protocol. A conventional approach, in which stimulation with IR was at 50°C and the detection window in the blue, was found to be compromised by thermal instability of the signals and/or initial sensitivity changes. A double-SAR approach – involving successive stimulation of the polymineral fine grains with IR and blue light, and detection of the resulting IRSL and post-IR OSL signals in the UV – was also tested. Although both signals exhibited significantly different fading rates, the corrected ages are mutually consistent and in agreement with OSL ages for purified silt-sized quartz. This indicates that it may not be necessary to isolate pure quartz to obtain reliable ages for Romanian loess. Owing to the limitations of the fading-correction method, however, the approach is limited to samples from the last glacial period. Finally, a post-IR IRSL protocol was tested, in which a first stimulation at 50°C was followed by a second stimulation at 225°C, and detection was in the blue. The post-IR IR225 signal appears not to suffer from anomalous fading, and yields ages entirely consistent with both OSL ages for silt-sized quartz and independent age control over four interglacial/glacial cycles. The overall conclusion is that post-IR IR dating of polymineral fine grains is very promising. The obtained age results urge the long-established chronostratigraphical framework for Romanian loess to be revised; the two uppermost well-developped palaeosols can no longer be thought of as interstadial soils that developed during the Last Glacial, but have formed during MIS 5 and MIS7, respectively

Chronology of loess-palaeosol sequences in SE Romania: insights from quartz-based SAR-OSL dating and high-resolution sampling strategies

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IRSL dating of Romanian loess using polymineral fine grains

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Investigations on the reliability of SAR-OSL equivalent doses obtained for quartz samples displaying dose response curves with more than one component

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Luminescence dating of archaeological materials and sediments in Romania using quartz

Luminescence dating exploits the dosimetric properties of mineral grains found in archaeological and geological materials of interest. The use of luminescence dating in archaeometry stretches back more than half a century, starting with thermoluminescence (TL) dating of heated artifacts. The subsequent development of optically stimulated luminescence (OSL) dating and protocols such as the single aliquot regeneration protocol (SAR) have increased the accuracy and precision of luminescence dating significantly. Quartz-based SAR-OSL dating is now generally considered as a reliable chronological tool, and it is increasingly used in a wide variety of (geo)archaeological studies. Optical dating of quartz has recently been implemented at Babes-Bolyai University (Cluj-Napoca, Romania). This paper documents the instruments and methods as used in this newly-established state of the art luminescence dating laboratory