• Analytical Science and Technology
• /
• v.22 no.2
• /
• pp.136-140
• /
• 2009

To improve the carbon recovery yield of chemical pretreatment in soil and sediment for $^{14}C$ age dating using AMS (Accelerator Mass Spectrometry), we have developed ultrasonic method in chemical pretreatment to replace with stirring method which has been generally used in each step of humic acid extraction for soil and sediment samples. Extraction conditions such as ultrasonic power, temperature and reaction time have been optimized. Six times higher carbon recovery yield could be obtained from low carbon content samples using ultrasonic method. We also compared the dating results by AMS obtained using ultrasonic method with the ages of samples treated by the stirring method. It was found that this new method could be applied to the pretreatment process of low carbon content samples for AMS age dating without effects on the dated ages, and with highly improved carbon recovery yields.

• Journal of The Geomorphological Association of Korea
• /
• v.18 no.1
• /
• pp.101-112
• /
• 2011

Coastal terrace was developed at 7.2m height near Shinchon village in Geoje Island. It is located on the east side of southern coast in Korean Peninsula, where sea-level changes caused by ebb and flow of the tide, embayment are relatively low. Due to the breccia layer by mass-movement, dark grayish clayey formation, marine origin's rounded gravel are deposited sequentially in a cross-section of coastal terrace, so it provides a good example which understand Holocene sea level changes to determine the effect on the various sedimentary environments. For the purpose of identifying the morphogenetic process, Grain size, Roundness, XRD, AMS dating analysis was attempted. As a result, after last glacial age, Holocene sea level rise to +5.6m(4,740±100yrs BP). At that time, various geomorphological features are considered to be formed.

• Journal of Conservation Science
• /
• v.28 no.4
• /
• pp.411-416
• /
• 2012

The purpose of this study was to analyze AMS radiocarbon dating, using wiggle match, of a charcoal column excavated from a fired dwelling site (ra-#8) at the Pungnaptoseong earthen wall made in Baekje era. The result of wiggle matching for 6 decadal single-ring samples of the charcoal produced ${\pm}2{\sigma}$ radiocarbon date (95.4% confidence interval) as A.D. 190~280. It indicated that the dwelling site (ra-#8) belonged to the early and middle of the 3rd century. Radiocarbon dating results confirmed the date speculated by archaeologists according to dwelling structure and pottery style.

• The Korean Journal of Quaternary Research
• /
• v.4 no.1
• /
• pp.27-40
• /
• 1990

$^{14}C$ age dating by AMS (accelerator mass spectrometry) technique was performed on twenty five small sized fossil shells and one peat taken from the sixteen piston cores in the southern and southeastern Korean Sea. AMS technique is available to date only a few milligram of amorphous carbons compare than conventional dating technique. It is described in detail of sample pre-treatment and experimental, and applied to the reconstruction of the sea level changes since the late Pleistocene in the Korean Sea. Dated age ranges from 520$\pm$100 to older than 33,500 years. Sedimentary facies in the study area represents a different environmental set which is affected by sea level fluctuation since the late Pleistocene.

• Analytical Science and Technology
• /
• v.7 no.3
• /
• pp.1069-1084
• /
• 1994

수 MV급 탄뎀형 가속기와 정전형, 자장형 질량분석기를 결합함으로써 존재비가 극히 작은 동위원소 측정이 가능해진다. 수 MeV로 가속이 되면 분해에 방해가 되는 모든 분자이온들이 제거되며, 탄뎀형 가속기에서는 음이온으로부터 가속이 개시되므로 몇몇 음이온을 형성하지 못하는 동중원소의 간섭으로부터 자유로워지기 때문에 고감도분석이 실현될 수 있다. 이외에 음이온을 형성하는 동중원소들은 주로 이온함인 최종 검출기에서의 유효 전하에 따른 에너지손실 차이를 이용하여 효과적으로 제거할 수 있다. 현재는 주로 장반감기 방사성동위원소인 $^{10}Be$, $^{14}C$, $^{26}Al$, $^{36}Cl$과 $^{129}I$ 등의 측정법이 확립되어 천연시료 중에서 동위원소 존재비 $10^{-12}$에서 $10^{-15}$까지의 정량이 가능하며, 원자수로 환산한 검출하한을 $10^5$개가 된다. 또한 해당 원소를 기준으로 소요 시료량은 대부분 mg 정도로 충분하다. 지금까지는 불가능했던 이러한 특징으로 인해 지난 수년간 AMS(Accelerator Mass Spectrometry)가 활용되어 온 연구분야는 지구과학(기후학, 우주화학, 빙하학, 수문학, 해양학, 퇴적학, 화산학 및 광물탐사), 인류 및 고고학(연대측정), 그리고 물리학(천체물리, 핵 및 입자물리) 등으로 다양하다. 이외에 생의학 및 재료과학 분야에서도 AMS를 활용하고자 하는 노력이 계속되고 있다. 본 해설에서는 가속기질량분석기술의 특징, 원리, 장치 및 활용분야 등을 소개하고자 하며, 이로써 관련 분야의 연구 활성화에 기여하고자 한다.

• Journal of Conservation Science
• /
• v.31 no.3
• /
• pp.279-285
• /
• 2015

The purpose of this study was to analyze radiocarbon dating, using wiggle match, of a wooden board from Yeongheung-do shipwreck excavated from Yeongheung-do in Incheon Ongjingun. The result of wiggle matching for 5 decennial tree-ring block samples of the hull bottom board produced ${\pm}2{\sigma}$ radiocarbon date (95.4% confidence interval) as A.D. 710~730 or A.D. 750~774. It indicated that the Yeongheung-do shipwreck belonged to the early or middle of the 8th century. Radiocarbon dating results confirmed the date speculated by archaeologists according to ship structure and pottery style.

• Journal of Conservation Science
• /
• v.33 no.4
• /
• pp.275-281
• /
• 2017

The purpose of this study was to carry out radiocarbon dating using a wiggle match, of wooden boards and grains from the Mado shipwreck No. 4, which was excavated from Mado in Taean-gun, Chungcheongnam-do. The result of the wiggle matching for four decennial tree-ring samples of the stern plank produced a ${\pm}2{\sigma}$ radiocarbon date (95.4% confidence interval) of A.D. 1337-1356 or A.D. 1412-1429. The grains produced a ${\pm}2{\sigma}$ radiocarbon date (95.4% confidence interval) of A.D. 1415-1455. This indicated that the Mado shipwreck No. 4 belonged to the early or middle of the 15th century. These radiocarbon dating results correlate with the date that was speculated by archaeologists according to the ship's structure and ceramic style.

• The Journal of the Petrological Society of Korea
• /
• v.14 no.3 s.41
• /
• pp.149-156
• /
• 2005

Ar-Ar, carbon AMS and OSL dating was carried out to clarify the age of the human footmarks on the Hamori Formation, Jeju Island, Korea. $^{40}Ar/^{39}Ar$ ages of trachybasalt from the Songaksan Tuff, which is underlain by the Hamori Formation, range between $10.6{\pm}19.9\;Ka$ and $11.7{\pm}26.3\;Ka$. Radiocarbon AMS ages of humin fractions extracted from sediment samples yielded the maximum limit age of the Hamori Formation as $15,161{\pm}70\;yr$ B.P. The OSL dating of the top and bottom layers of the Hamori Formation gave $6.8{\pm}0.3\;ka$ and $7.6{\pm}0.5\;ka$, respectively, suggesting that timing of the human footmarks formation can be constrained as between ca 6,800 yr B.P. and 7,600 yr B.P.

• Economic and Environmental Geology
• /
• v.36 no.6
• /
• pp.545-556
• /
• 2003

Detailed interdisciplinary investigations demonstrate that the Yeongsan River estuarine-filled sediments clearly record important paleoenvironmental changes during the Last Glacial and Holocene. The sediments from 18.9 m(20.5∼l.6m in depth) long core MW-1 are differentiated by changes in sedimentary textures and palynomorph assemblages. Chronology was provided by AMS$^{14}$C dating and regional pollen correlation. Three paleoenvironrnental phases are recognized: (1) The Last Glacial deposits consist mainly of fluvial sediments and paleosols, experienced deposition alternating with pedogenesis. The appearance of the paleosols suggests that the paleoclimate might be cold and humid. (2) The early and middle Holocene phase started abruptly in response to the rapid global climatic warming. and is characterized by abundant marine palynomorphs. (3) The late Holocene is marked by more cool conditions. The paleoenvironmental changes recorded in the sediments coincide not only with local but also with broad-scale, probably global climate changes.

• Journal of Conservation Science
• /
• v.34 no.5
• /
• pp.359-368
• /
• 2018

The purpose of this study was to analyze the wood species of the stern plank and persimmon seed from Daebudo shipwreck No.2 excavated from Daebudo, Danwon-gu, Ansan-si, and Gyeonggi-do by wiggle-matching of radiocarbon measurements. Results of the analysis showed that all the wooden boards of the hull were made from Pinus Hard Pine Group. The other parts of hull and wooden pegs were made from Pinus Hard Pine Group, Castanea spp., Quercus spp. sect. Lepidobalanus, Alnus spp., and Zelkova serrata Makino. Excavated wide-tooth wooden comb and fine-tooth bamboo comb were made from Acer spp. and Bambusoideae. Excavated rope was made from Pueraria thunbergiana Benth. The stern plank, wooden support, and persimmon stone showed ${\pm}2{\sigma}$ radiocarbon date(95.4% confidence interval) of AD 1151-1224. This indicated that the Daebudo shipwreck No.2 occurred during the early or middle 12-13th century. Our radiocarbon dating results confirmed the date speculated by archeologists based on the ceramic style.