• Journal of The Geomorphological Association of Korea
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• v.26 no.4
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• pp.141-145
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• 2019

This study investigated Quaternary sand deposits in the process of surveying Quaternary deposits distributed in Yonghan-ri, Heunghae-eup, Pohang city. Field geological surveys were conducted and OSL dating samples were taken. The altitude of the Quaternary sand deposits layer is about 15m, and there are two upper and lower sand dune layers, and a peat layer is developed between them. The sampling point are just above the peat layer, and the altitude level is about 13.4m (YHO-1) and about 13.7m (YHO-2). OSL dating was performed for YHO-1 and YHO-2 and the results were 69 ± 6 ka and 62 ± 5 ka, respectively. The date analyzed are interpreted as MIS 4. On the other hand, the formation time of the peat layer at an altitude of about 13.2 to 13.7m can be compared with the results of the OSL dating of the above sandy deposits. The peat layer can be inferred to have formed during MIS 5a or earlier.

• The Korean Journal of Quaternary Research
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• v.20 no.1 s.26
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• pp.28-38
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• 2006

Since the radioactivity of U was discovered by Becquerel in 1896, a number of radiometric dating techniques based on radioactive decay have been developed with the help of precise and accurate instruments. Among them, radiocarbon dating was introduced as the most effective method in archeology in Korea. However, though the radiocarbon methods have contributed greatly to the development of archeology in Korea, it is limited to organics in a matrix of soil and sediment, including organic carbon, charcoal, bone and so on. If there are no organics in some paleolitic sites, other methods are required for dating. Therefore, we introduced OSL (Optically Stimulated Luminescence) dating method in this paper. The method is mainly based on quartz grains or other particles. The aim of this paper is to discuss about sampling method and the limitation of its application in archeology.

• The Journal of the Petrological Society of Korea
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• v.23 no.3
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• pp.187-195
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• 2014

In this paper, we report new OSL ages of the marine terrace sediments at Suryum fault site, using single grains of quartz, and briefly discuss their chronological implications on the timing of terrace formation along the southeastern coast of Korea. Of 1200 grains measured, 93 quartz grains were found to have OSL properties suitable for dating, the equivalent dose ($D_e$) values of which varied significantly, ranging from 50 Gy to 610 Gy with the overdispersion of $30{\pm}4%$. Applied to the Central Age Model (CAM) and Minimum Age Model (MAM), these quartz grains showed the OSL ages of $83{\pm}4ka$ and $60^{+3}{_{-7}}ka$, respectively, both of which are stratigraphically inconsistent with the previously reported OSL ages of lower $2^{nd}$ terrace (MIS 5a; ~80 ka). However, Finite Mixture Model (FMM) revealed that a small fraction of the measured quartz grains ($6{\pm}4%$) were of the ages ($194{\pm}24ka$) corresponding to MIS 7. Conclusively, based on single grain OSL ages, it would be prudent not to exclude the possibility that the marine terrace sediments at Suryum fault site have formed during MIS 7. Further, our single grain OSL ages imply that multiple grain(single aliquot) OSL dating methods are not applicable to the marine sediments at Suryum fault site.

• Journal of the Mineralogical Society of Korea
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• v.23 no.4
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• pp.357-365
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• 2010

Optically stimulated luminescence (OSL) of quartz is commonly applied to the age dating of Quaternary sediments. However, one of the issues is that some of the quartz samples are not suitable to OSL dating. Mineralogical analysis of the quartz samples with diverse OSL signals are required to strengthen the reliability and applicability of the OSL dating. We analysed the OSL signal characteristics of sedimentary quartz samples from diverse geological environments and measured their trace element contents using laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Quartz samples could be grouped into ones suitable to OSL dating and ones unsuitable on the basis of their OSL signal characteristics. The average trace element contents ranged from 73 to 260 ppm (Al), and from 61 to 248 ppm (Ti) with minor Li, Mg, Cr, Mn, and Fe contents below 40 ppm. We did not find any significant variation of trace element contents of quartz samples consistent with their OSL signal characteristics. This indicates unknown mineralogical factors causing diverse OSL characteristics which should be confirmed by further analysis of sufficient set of samples.

• The Journal of the Petrological Society of Korea
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• v.10 no.3
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• pp.202-211
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• 2001

Luminescence is a physical phenomenon exhibited by many non-conducting, crystalline materials, such as quartz and feldspar. Within the crystals, energy absorbed from ionising radiation frees electrons to move through the crystal lattice and some are trapped at defects in the lattice. Observable luminescence is produced by electrons, released from traps by stimulation by absorption of light, which recombine with lattice defects which act as luminescence centers - optically stimulated luminescence (OSL). In a similar way to thermoluminescence(TL) dating, controlled measurement of the OSL signal can provide a means of determining the time since the last exposure of a layer of sediment to sunlight, the age of the sediment. However, whereas in the thermoluminescence dating of sediment only part of the latent thermoluminescence signal is bleached by sunlight as the sediment is deposited and allowance must be made during the laboratory measurements for the light insensitive component, optically induced luminescence dating has the advantage of working only with light sensitive traps in the crystal. Determination of the time since deposition of Quaternary sediment samples from the OSL of quartz grains using blue light was performed. A series of experiments and recent developments relating OSL dating are described, beginning by identifying the features which make OSL signals suitable for the development of dating method. Additionally, there are suggestions as to future research for obtaining reliable ages and a comment on current best practice on procedures, with the dating results of Quaternary sediment.

• Journal of Conservation Science
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• v.34 no.6
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• pp.481-492
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• 2018

We conducted TL/OSL dating for the earthenware kilns in the Bongsan-ri archaeological site, Osong, which was occupied from the late nineteenth to the late twentieth century. With the SAR-TL/OSL method, paleodose was determined from the equivalent dose during the burial period($ED_{burial}$), the background dose($ED_{BG}$), the fading correction factor(f), and the overestimation correction factor(C). The annual dose rates and their provenance were evaluated from the measurement of natural radionuclides $^{238}U$, $^{232}Th$, and $^{40}K$. Because the comprehensive absolute age was provided by combining the resulting TL/OSL and radiocarbon data, we concluded that, for the absolute chronology of a modern archaeological site, TL/OSL dating and radiocarbon dating must be carried out together and summed. The construction and occupation of earthenware kilns in the Bongsan-ri site had changed from stage I (No.5, 6 kilns), to stage II (No.1, 2, 3 kilns), to stage III (No.4) in chronological order. When Bayesian statistics were applied, we found that the absolute ages of occupation for stages I, II, and III correspond to AD $1910{\pm}23$, AD $1970{\pm}10$, and AD $1987{\pm}4$. These results were in good agreement with the archaeological context or chronology.

• Analytical Science and Technology
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• v.29 no.6
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• pp.269-276
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• 2016

Gosan-ri site is known as the early Neolithic cultural heritage, in which an archaic plainware, called as the Gosan-ri-type pottery, was excavated regarding as the first pottery manufactured in Korea. In this study, OSL dating was carried out to five soil layer samples collected in stratigraphic cross-section for evaluating the formation and occupation of the Gosan-ri site. Paleodose of each soil sample was calculated using the single aliquot regenerative dose (SAR) method with preheat of $220^{\circ}C$ and finally determined using maximum age model, considering its deposition process. The OSL age was determined from the ratio of paleodose to annual dose rate. From the resultant OSL ages and the related 14C dates, it was concluded that the Gosan-ri site was formed after 9,000 BC and a variety of cultural feature including the Gosan-ri-type pottery were occupied ranging from the early Neolithic to the middle of 4,000 BC. Finally, the Gosan-ri site was discarded in the middle of 4,000 BC and has been arrived at present through natural deposits.

• Journal of Radiation Protection and Research
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• v.36 no.2
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• pp.52-58
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• 2011

OSL dating for three hearths having the sequence of use and discard in No. 29 and 29-1 dwelling sites at Sogol cultural site was carried out. Resulting from the deconvolution of natural CW-OSL decay curve and thermal zeroing test, it was turned out that OSL signal was entirely composed of the heat- and light-sensitive fast component with high photoionization cross-section and all quartz OSL signals were thermally bleached under $300^{\circ}C$ which is the minimum temperature related to heating and cooking in Bronze age. After dose recovery test and plateau test, paleodose of each hearth sample was evaluated by using SAR method, and OSL age was determined from the ratio of paleodose to annual dose rate. For the purpose of the precision improvement of OSL age, Bayesian statistics was applied to each hearth's age and the archaeological sequence information. Finally, it could be concluded to the accurate use period of each hearth from the resultant OSL ages.

• Journal of The Geomorphological Association of Korea
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• v.28 no.2
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• pp.59-70
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• 2021

This study aims to determine the sunlight exposure according to depositional environment to improve the accuracy of optically simulated luminescence (OSL) dating. Sufficient sunlight exposure during transportation of sediment is a basic assumption of the OSL dating, and if the process does not occur enough, the results may be overestimated compared to the actual depositional age. Therefore, the main purpose of this study is to establish a correction method by determining residual or unbleachable dose after sunlight exposure in the actual deposition process, not in the laboratory measurement. Four samples from two sites were collected according to the depositional environment from rivers and coasts, and various OSL signals, including the size of residual dose, degree of dispersion between grains, and OSL signal sensitivity, were measured. As a result, it was confirmed that sediments formed under temporarily high energy environments, such as floods and surges, had relatively high residual dose or large dispersion of residual dose between particles. In further studies, the OSL signal characteristics of river sediments by flow velocity will be identified and the relationship between energy and OSL signal characteristics will be identified in more detail. Moreover, a method of reconstructing the paleo-environment at the time of deposition for existing sediments will be devised. It is expected to provide important information for the frequency of disaster recurrence and prediction of future climate change.

• Journal of The Geomorphological Association of Korea
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• v.24 no.2
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• pp.1-13
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• 2017

Massive coastal sand dunes are distributed in Ui-island, Shinan-gun. The sand dunes in Ui-island is worth studying, in terms of preserving natural environment without anthropogenic impacts. In this study, we surveyed geomorphological processes of the sand dune based upon measuring of geometric properties, grain size analysis, and OSL(Optically Stimulated Luminescence) age dating. The sediments of the dune consist mainly of well sorted medium sand with about 250$\mu$m. Based on spatial distribution of sand dunes, we found that they are formed by northwest monsoon during winter, and sands are supplied from Seongchon area in northern UI-island. According to OSL age dating, the sand dunes were deposited from $0.07{\pm}0.01ka$ to $0.17{\pm}0.04ka$. This result shows that the transformation of the dune due to the sand movement by wind was active during the last 100-200 years. The aerial photograph indicates that the dimension of the largest sand dune has decreased since 1945. Further research is needed to get more detailed information on geomorphic changes of sand dunes in UI-island.