scholarly journals Investigating the resetting of OSL signals in rock surfaces

2011 ◽  
Vol 38 (3) ◽  
pp. 249-258 ◽  
Author(s):  
Reza Sohbati ◽  
Andrew Murray ◽  
Mayank Jain ◽  
Jan-Pieter Buylaert ◽  
Kristina Thomsen
Keyword(s):  
Potential Method ◽  
Luminescence Dating ◽  
Rock Surface ◽  
Solar Simulator ◽  
Luminescence Signal ◽  
Thermal Transfer ◽  
Two Samples ◽  
Small Doses ◽  
Inner Parts ◽  
Partial Bleaching

Abstract There are many examples 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 samples 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 >100 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 samples. These indicate that, for instance, bleaching at a depth of 2 mm into these samples occurs at about ∼28% of the rate at the surface. We conclude that it should be possible to derive meaningful burial doses of >1 Gy from such cobbles; younger samples would probably require a correction for incomplete bleaching.

scholarly journals Identifying the degree of luminescence signal bleaching in fluvial sediments from the Inner Mongolian reaches of the Yellow River

2018 ◽  
Vol 45 (1) ◽  
pp. 82-96 ◽  
Author(s):  
Fuqiang Li ◽  
Baotian Pan ◽  
Zhongping Lai ◽  
Hongshan Gao ◽  
Xianjiao Ou
Keyword(s):  
Sediment Load ◽  
Yellow River ◽  
Coarse Grained ◽  
The Yellow River ◽  
Fluvial Sediments ◽  
Luminescence Signal ◽  
Particle Size Fractions ◽  
Signal Characteristics ◽  
High Sediment ◽  
Partial Bleaching

Abstract The partial bleaching of the luminescence signal prior to deposition results in age overestimation, and can be a problem in delineating fluvial evolution within an OSL chronological framework. The Inner Mongolian reaches of the Yellow River are characterised by a high sediment load and complex sources of sediments. To test the incomplete bleaching occurring in this type of environment, the residual doses and the luminescence signal characteristics of different particle size fractions from 14 modern fluvial sediment samples were investigated. Furthermore, 26 OSL ages derived from drilling cores were compared with 11 radiocarbon ages. Our results show that the residual equivalent doses principally range between 0.16 and 0.49 Gy for silt grains, and between 0.35 and 3.72 Gy for sand grains of modern samples. This suggests that medium-grained quartz has been well bleached prior to deposition, and is preferable to coarse-grained quartz when dating fluvial sediments in this region. The results also show that the De values of coarse-grained fractions display a stronger correlation with distance downstream. In addition, a comparison of OSL and radiocarbon ages from drilling cores establishes further confidence that any initial bleaching of these sediments was sufficient. As a result, we believe that the studied fluvial samples were well bleached prior to deposition.

scholarly journals Luminescence Dating of Fluvial Deposits from the Weser Valley, Germany

2015 ◽  
Vol 42 (1) ◽  
Author(s):  
Julia Roskosch ◽  
Sumiko Tsukamoto ◽  
Manfred Frechen
Keyword(s):  
Late Pleistocene ◽  
Luminescence Dating ◽  
Marine Isotope Stage ◽  
Coarse Grained ◽  
Performance Tests ◽  
Luminescence Signal ◽  
Fluvial Deposits ◽  
Fine Grained ◽  
Infrared Stimulated Luminescence ◽  
Off Time

Abstract Luminescence dating was applied on coarse-grained monomineralic potassium-rich feld-spar and polymineralic fine-grained minerals of five samples derived from fluvial deposits of the Riv-er Weser in northwestern Germany. We used a pulsed infrared stimulated luminescence (IRSL) single aliquot regenerative (SAR) dose protocol with an IR stimulation at 50°C for 400 s (50 μs on-time and 200 μs off-time). In order to obtain a stable luminescence signal, only off-time IRSL signal was rec-orded. Performance tests gave solid results. Anomalous fading was intended to be reduced by using the pulsed IRSL signal measured at 50°C (IR50), but fading correction was in most cases necessary due to moderate fading rates. Fading uncorrected and corrected pulsed IR50 ages revealed two major fluvial aggradation phases during the Late Pleistocene, namely during marine isotope stage (MIS) 5d (100 ± 5 ka) and from late MIS 5b to MIS 4 (77 ± 6 ka to 68 ± 5 ka). The obtained luminescence ages are consistent with previous 230Th/U dating results from underlying interglacial deposits of the same pit, which are correlated with MIS 7c to early MIS 6.

Direct dating of lithic surface artefacts using luminescence and application potential in geomorphology

2020 ◽  
Author(s):  
Michael Meyer ◽  
Luke Gliganic ◽  
Jan-Hendrik May
Keyword(s):  
Significant Proportion ◽  
Luminescence Dating ◽  
Rock Surface ◽  
Sediment Layer ◽  
Southern Tibet ◽  
Stratigraphic Sequence ◽  
Transport Pathways ◽  
Stone Materials ◽  
Glaciofluvial Deposits ◽  
Application Potential

<p>Lithic surface artefacts are anthropogenically formed stone materials (stone tools and spall generated during knapping) resting atop or being semi-embedded into the uppermost sediment layer of a stratigraphic sequence on a given landform. Such surface artefacts lack a secure stratigraphic context are encountered worldwide and often comprise a significant proportion of the archaeological record. Yet, direct absolute dating techniques for constraining the age of lithic surface scatters are currently not available.</p><p> </p><p>Promising recent work has shown the potential of using the optically stimulated luminescence (OSL) signal from rocks to date the emplacement of gravel pavements and blocks in both, archaeological and geological contexts (e.g. Sohbati et al., 2015; Jenkins et al., 2018). We build on this work and introduce a novel way of directly dating lithic surface artefacts using OSL-rock surface burial dating. We use this approach to date a surface lithic artefact scatter site, in southern Tibet. By calculating spatially resolved OSL burial ages for slices at 1 mm increments into each artefact’s buried surface we (i) infer the timing of artefact discard by humans at the site, (ii) demonstrate that most artefacts are not in-situ but were transported downslope and/or flipped and (iii) for some samples constrain the timing and number of cycles of artefact burial and re-exhumation.</p><p> </p><p>This is the first time that the OSL signal is used to date sunlight exposure of artefacts. The method is not limited to archaeological contexts but can be applied to other surface clasts that yield a reasonable OSL signal too. OSL rock surface burial dating of surface clasts and artefacts thus holds great potential to (i) constrain manufacture and artefact discard by humans and (ii) detect and reconstruct post-depositional disturbances and transport pathways. We discuss the application potential of this approach in archaeology and geomorphology. </p><p> </p><p>References:</p><p>Jenkins, G.T.H., Duller, G.A.T., Roberts, H.M., Chiverrell, R.C., Glasser, N.F., 2018. A new approach for luminescence dating glaciofluvial deposits – High precision optical dating of cobbles. Quaternary Science Reviews 192, 263-273.</p><p>Sohbati, R., Murray, A.S., Porat, N., Jain, M., Avner, U., 2015. Age of a prehistoric Rodedian cult site constrained by sediment and rock surface luminescence dating techniques. Quaternary Geochronology 30, 90–99.</p>

scholarly journals Damage Model and Numerical Experiment of High-Voltage Electro Pulse Boring in Granite

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 727 ◽  
Author(s):  
Changping Li ◽  
Longchen Duan ◽  
Songcheng Tan ◽  
Victor Chikhotkin ◽  
Wenpeng Fu
Keyword(s):  
Shock Wave ◽  
High Voltage ◽  
Geometric Model ◽  
Damage Model ◽  
Wave Model ◽  
Potential Method ◽  
Rock Breaking ◽  
Particle Flow Code ◽  
Rock Surface ◽  
Rock Breakage

High-voltage electro pulse boring (EPB) has the advantages of high rock-breaking efficiency and good wall quality, and is a new and efficient potential method of rock breaking. The EPB process is defined as random because it is affected by many factors. At present, there is no suitable physical and mathematical model to describe the process and results of rock breakage in EPB, and the conclusions reached regarding rock-breakage mechanisms are not uniform. In this study, a complete damage model of high voltage EPB in granite is established, which includes a shock wave model and a damage model of high voltage EPB in granite. The damage model is based on the Particle Flow Code two-dimensional program. Use of a damage model of EPB accommodates the complete process of high voltage EPB, from discharge to production of a shock wave, and so rock-breaking via electro pulse can be simulated and calculated. The time-varying waveforms of shock waves with different electrical parameters are simulated and calculated on the basis of the model. Different shock wave forms are loaded into the surface and internal rock in the damage geometric model of EPB granite. Then, the breakage process of the rock surface and internally, and the mechanism of rock breakage using EPB are analyzed. This study provides a scientific basis for the quantitative expression and prediction of rock fragmentation in EPB in order to improve the drilling efficiency and reduction of energy loss in the process of EPB.

User Guide for Luminescence Sampling in Archaeological and Geological Contexts

2015 ◽  
Vol 3 (2) ◽  
pp. 166-177 ◽  
Author(s):  
Michelle S. Nelson ◽  
Harrison J. Gray ◽  
Jack A. Johnson ◽  
Tammy M. Rittenour ◽  
James K. Feathers ◽  
...  
Keyword(s):  
Dose Rate ◽  
Target Material ◽  
Luminescence Dating ◽  
Background Information ◽  
Sample Collection ◽  
Luminescence Signal ◽  
Accuracy And Precision ◽  
Thermal Bleaching ◽  
Selection Of

AbstractLuminescence dating provides a direct age estimate of the time of last exposure of quartz or feldspar minerals to light or heat and has been successfully applied to deposits, rock surfaces, and fired materials in a number of archaeological and geological settings. Sampling strategies are diverse and can be customized depending on local circumstances, although all sediment samples need to include a light-safe sample and material for dose-rate determination. The accuracy and precision of luminescence dating results are directly related to the type and quality of the material sampled and sample collection methods in the field. Selection of target material for dating should include considerations of adequacy of resetting of the luminescence signal (optical and thermal bleaching), the ability to characterize the radioactive environment surrounding the sample (dose rate), and the lack of evidence for post-depositional mixing (bioturbation in soils and sediment). Sample strategies for collection of samples from sedimentary settings and fired materials are discussed. This paper should be used as a guide for luminescence sampling and is meant to provide essential background information on how to properly collect samples and on the types of materials suitable for luminescence dating.

Luminescence dating of the last glaciation maximum in the southern Black Forest, Germany: Preliminary results

2021 ◽  
Author(s):  
Felix Martin Hofmann ◽  
Alexander Fülling ◽  
Frank Preusser
Keyword(s):  
Last Glacial Maximum ◽  
Luminescence Dating ◽  
Black Forest ◽  
North West ◽  
Terminal Moraine ◽  
Last Glacial ◽  
Ice Cap ◽  
Last Glaciation ◽  
The Alps ◽  
Partial Bleaching

<p>During the last glaciation maximum, an ice cap and its more than 20 kilometres-long outlet glaciers covered the highest summit of the Black Forest, the Feldberg (1493 m above sea-level), and the surrounding region (Hofmann et al., 2020). This event is tentatively correlated with the global last glacial maximum (at ca. 22-19 ka). However, this hypothesis has never been tested by applying up-to-date geochronological techniques to glacial deposits or landforms. Due to the lack of significant topographic control, the climate probably mainly controlled the mass balance of the ice cap. Dating its last maximum extent may thus have important implications for the reconstruction of atmospheric circulations patterns during the Pleistocene. A last glaciation maximum out of phase with the Alps would strengthen the hypothesis that a meridional atmospheric circulation prevailed over Europe during the last glaciation maximum in the Alps (at ca. 25 ka).</p><p>We aim at filling this gap by re-investigating a well-preserved multi-ridged terminal moraine complex several kilometres north-west of the Feldberg. Since the beginning of the twentieth century, this landform is undisputedly assigned to the last glaciation maximum. As units of sorted sediments occur in two sections on one ridge of the terminal moraine complex, luminescence dating was deemed a suitable technique to infer the age of the landform.</p><p>Luminescence dating was applied to both feldspar and quartz for suitable comparison, as these dosimeters have different drawbacks. Since quartz from crystalline source areas often shows no or only a relatively weak luminescence signal, we anticipated that this also applies to the sampled sediments from the crystalline part of the Black Forest. Optically-stimulated luminescence (OSL) measurements revealed a bright signal in quartz as well as equivalent doses in the order of 200 Gy considerably below the saturation level. We did not observe any obvious signs for partial bleaching, but this possibility has to be confirmed via further OSL measurements, since the sampled sediments were not transported over large distances. Component analysis will also be performed.</p><p>Infrared-stimulated luminescence (IRSL) measurements on feldspar revealed higher preliminary luminescence ages. It is expected that anomalous fading and partial bleaching will be two major future challenges. To overcome the first problem, post-infrared IRSL dating will be applied. As resetting of this signal is more difficult when compared to IRSL and OSL signals, problems associated with incomplete bleaching may arise in future work.</p><p>Our preliminary quartz OSL ages tentatively suggest that the last glaciation maximum in the southern Black Forest preceded the last glaciation maxima in other formerly glaciated uplands in Central Europe and the global last glacial maximum. This result needs to be evaluated by luminescence dating of other ice-marginal landforms correlative with the last glaciation maximum. Other geochronological techniques, such as <sup>10</sup>Be cosmic-ray exposure dating, will also be applied to reveal their age.</p><p> </p><p><strong>Reference</strong></p><p>Hofmann, F. M., Rauscher, F., McCreary, W., Bischoff, J.-P., and Preusser, F.: Revisiting Late Pleistocene glacier dynamics north-west of the Feldberg, southern Black Forest, Germany, E&G Quaternary Science Journal, 69, 61–87, https://doi.org/10.5194/egqsj-69-61-2020, 2020.</p><p> </p><p> </p><p> </p>

scholarly journals Testing feldspar luminescence dating of young archaeological heated materials using potshards from Pella (Tell Tabqat Fahl) in the Jordan valley

2017 ◽  
Vol 44 (1) ◽  
pp. 98-110 ◽  
Author(s):  
Sahar Al Khasawneh ◽  
Andrew S. Murray ◽  
Stephen Bourke ◽  
Dominik Bonatz
Keyword(s):  
Iron Age ◽  
Luminescence Dating ◽  
Jordan Valley ◽  
Luminescence Signal ◽  
Systematic Uncertainties ◽  
Infrared Stimulated Luminescence ◽  
Recent Developments ◽  
Age Range ◽  
Multiple Samples ◽  
Osl Age

Abstract Recent developments in the use of more stable feldspar signals in the luminescence dating of sediments offer the possibility of obtaining accurate feldspar luminescence ages for ceramic artefacts; this is especially interesting in locations which do not provide suitable quartz extracts. Here we examine the application of the stable infrared stimulated luminescence signal measured at elevated temperature (in this case 290°C; pIRIR290) after stimulation at about room temperature to Levantine pottery samples. A total of 52 potsherds were collected from three superimposed iron-age units at Pella (Jordan); based on 14C dating, typology and seriation these units were deposited between 700 and 900 BCE. Sand-sized quartz extracts were unsuitable, and there was insufficient sand-sized feldspar, and so polymineral fine grains were chosen for dating. Various tests for reliability were undertaken (dose recovery, dependence of De on first stimulation temperature etc.). The pIRIR signals are weak, and 14 potsherds were rejected on this basis. Of the remainder, 3 were confidently identified as outliers. Based on those sherds for which IR signals were sufficiently intense, we use the ratio of the IR50 to pIRIR290 signals to argue that these outliers do not arise from incomplete resetting during manufacture. The ages from each layer are considerably over dispersed (typically by ∼25%) but average ages for each unit are consistent with each other and with the expected age range. The average OSL age for the site is 2840 ± 220 years (n = 35), with the overall uncertainty dominated by systematic uncertainties; this average is consistent with the range of 14C ages from 970–1270 BCE reported from across the destruction horizon. We conclude that the pIRIR290 signal is delivering accurate ages, but that the variability in age from shard to shard is much greater than would be expected from known sources of uncertainty. This demonstrates the need for site ages to be based on multiple samples; individual shard ages are unlikely to be sufficiently accurate.

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