• Journal of Conservation Science
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• v.37 no.3
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• pp.245-254
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• 2021

In this study, organic materials in Dancheong specimens were analyzed to establish a Dancheong preparation method in Unhangak Hall of Hwaryeongjeon Shrine, Suwon. IR and pyrolysis/GC/MS were applied to a Zuhong specimen and a gilded one. The IR spectra showed absorption peaks corresponding to C-O, C=O, OH, although they were different from those of animal glue, Asian lacquer, and drying oil. The Pyrolysis/GC/MS after the on-line methylation revealed Asian lacquer-derived components, such as methyl 7-(2,3-dimethoxyphenyl)heptanoate, and drying oil-derived components, such as nonanedioic acid, dimethyl ester. Based on these results, we estimated that Asian lacquer and drying oil were used in the Dancheong preparation. Small amounts of 3-methyl-1H-pyrrole were also detected, which could possibly originate from animal glue. The radiocarbon age of the specimens appeared to be between the late 17^th to the early 20^th century. This study potentially reports the first case of Asian lacquer detection in a Dancheong specimen in Korea.

• Journal of The Geomorphological Association of Korea
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• v.17 no.1
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• pp.39-48
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• 2010

This is a case study to research the environmental changes that occurred during the Latter Half of the postglacial age around the Basin of Onyang River in Asan, Korea. In line with this purpose, the author performed a pollen analysis and a radiocarbon dating on the deposits of alluvial fan around the upper Geumgok River, a tributary of Onyang River. Sampling point was at the altitude of about 67.5 meters, which belongs to the central zone of the cool temperate forest. The followings are the results of the study. The study area has passed through SC-I (the coniferous forest period in which Pinus was dominant), SC-II (the deciduous broad-leaved forest period in which Quercus and Castanea were dominant) and SC-III (the mixed conifer and deciduous broad-leaved forest period, in which Pinus, Quercus and Ulmus/Zelkova were dominant) respectively since about 3,000 yrB.P. SC-I period and SC-II period are presumed to be between about 3,000 and 2,000 yrB. P., and SC-III period to begin after 2,000 yrB.P. In comparison with the nationwide pollen zone during the postglacial age, SC-I and SC-II periods are contrasted with the R-IIIa zone and also the SC-III zone with the RIIIb zone. In addition, it is assumed that Pinus densiflora forest luxuriated there since 2,000 yrB.P. due to the destruction of forests, and that a lot of Fagopyrum pollen appeared; altogether, it was the so-called human interference period, from which forests began to be markedly destroyed. It is concluded that in those days inhabitants leaded agricultural life.

• Analytical Science and Technology
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• v.22 no.1
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• pp.51-56
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• 2009

The samples from coastal sand dune stratum in Chollipo were dated by Optically Stimulated Luminescence (OSL) with modified Single Aliquots Regeneration (SAR) method. It is possible to choose the OSL signals by thermal treatments such as preheat and cut-heat in SAR procedure. Preheat and cut-heat of $260^{\circ}C$ for 10 sec $-220^{\circ}C$ for 0 sec, and $270^{\circ}C$ for 10 sec $-270^{\circ}C$ for 10 sec were applied for estimation of equivalent dose of the samples. The OSL signals from different thermal treatment were used for OSL dating. Equivalent dose were estimated with 4 fractionated grain distributions with $75{\mu}m$, $150{\mu}m$ and $200{\mu}m$ sieves with above heating treatments. Consequently, the estimated dose were differently valued in sample sizes and applied heating treatments, different stratum ages were calculated. The ages from radiocarbon dating were compared with the OSL ages. The ages varying with grain sizes produce that the site sampled were formed with mixed soil sources.

• Journal of The Geomorphological Association of Korea
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• v.18 no.2
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• pp.25-37
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• 2011

The purpose of this study is to investigate the history of phenomenon(hereinafter called mass-movement) of movement of inorganic material originated from hillslope by denudation of hillslope surrounding the watershed during Holocen period in the Chaamgol watershed(hereinafter called study watershed) uppermost stream of Maegokcheon Cheonan-si Chungnam. To do this, for the object of allivium distributed in valley bottom of study watershed, facies analysis, radiocarbon dating and grain size analysis were conducted and geomorphological analysis on study watershed conducted together. The result is like the following. It was confirmed that over around 9,100yrBP~to recent due to a few times of mass-movement occurred in time scale of 10²~10³ years, a large quantity of inorganic material is mixed in organic material layer originated from wetland formed in valley bottom of study watershed or exists between organic material layers. And it was found that in study watershed, mass-movement occurred in instable period of hillslope after the Early Holocen existed at least 8 times (M1 period~M8 period) and wetland environment formed in the stable period of hill slope existed total 4 times (W1 period~W4 period). This analysis result will be used in the future as basic material in research of Holocen climate change of Maegokcheon watershed and in restoration of denudation process of hillslope following this.

• Korean Journal of Heritage: History & Science
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• v.57 no.3
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• pp.56-67
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• 2024

This study aims to characterize the material of the finishing materials used in the No.1 stone chamber tomb of the Baekje-era tumuli in Songjeri, Naju with mineralogical, chemical, and physical analyses. The finishing material is a mixture of white lumps and fragments, presumed to be shells, that remain on the surface and between the gaps of the stone walls inside the tomb. The analysis results revealed that the main constituent mineral of the finishing material is calcite. Infrared spectroscopy showed peaks due to calcium carbonate, and thermal reaction decarbonation in the 700~800℃ range, high calcium content, and loss on ignition were confirmed. Therefore, the main material of the finishing materials was determined to be lime, and since no aggregates such as sand or gravel were found, it was identified as lime paste. The shell fragments mixed into the lime paste appear dark blue or grayish-white in color, with no original shape remaining. The surface has a layered structure, and microscopic observations revealed prismatic layers with a columnar structure and nacreous layers with a consistent orientation, suggesting that the shells are from bivalve mollusks. Additionally, X-ray imaging of the shell fragments showed holes and tunnels caused by boring marine organisms both on the surface and inside, and radiocarbon dating results confirmed that the dating of the shells was consistent with the construction period of the tomb. It is concluded that the finishing material used in Tomb No. 1 in Songje-ri, Naju, was lime paste mixed with shell fragments, and the lime was made using the shells of bivalve mollusks as the raw material.

• The Korean Journal of Quaternary Research
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• v.16 no.2
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• pp.9-21
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• 2002

In Korea, many open-air upper palaeolithic sites are located at the river valley, particularly exposed in gently rotting terrain along the river course. They are situated at an altitude less trail 30 m above present river bottom, and covered with the blankets of slope deposits of several meters in thickness. The purpose of this research is to eluridate depositional and vegetational environment of the alluvial upper palaeolithic Jangheung-ri sites on the basis of analytical properties of grain size population, chronology, palynology, soil chemistry and clay mineralogy and magnetic susceptibility of the Jangheung-ri Quaternary formations. The lithostratograpy of Jangheung-ri sit is subdivided into 3 layers based on the depositional sequence and radiocarbon ages. From bottom to top, they are composed of slope deposits with lower paleosol layers, young fluvial sand and gravel with backswamp organic muds, and upper paleosol layers. The upper paleosol was formed under rather dry climatic condition between each flooding period. Dessication cracks were prevalent in the soil solum which was filled with secondarily minuted fragments due to pedogenetic process. The soil structure shows typical braided-typed cracks in the root part of cracking texture, and more diversified pattern of crackings downward. The young fluvial sand gravel were formed by rather perennial streams after LGM. The main part of organic muds was particularly formed after 15Ka. Local backswamp were flourished with organic muds and graded suspension materials in the flooding muds were intermittently accumulated in the organic muds until ca. 11Ka. This episode was associated with migration of Nam River toward present course. Organic muds were formed in backswamp or local pond. Abies/Picea-Betula with Ranunculaceae, Compositae, Cyperaceae were prevalent. This period is characterized with B$\Phi$lling, Older Dryas, Allerod, and Younger Dryas (MIS-1). Stone artefacts were found in the lower paleosol layers formed as old as 18Ka-22Ka. Based on the artefacts and landscape settings of the Jangheung-ri site, it is presumed that settlement grounds of old people were buried by frequent floodings of old Nam River, the river-beds of which were heavily fluctuated laterally and river-bed erosions were activated from south to north in Jangheung-ri site until the terminal of LGM9ca 17Ka).

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.1
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• pp.1-7
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• 2009

This study has been focused on determining the chemical composition of $^{14}C$ - in terms of both organic and inorganic $^{14}C$ contents - in reactor coolant from 3 different PWR's reactor type. The purpose was to evaluate the characteristic of $^{14}C$ that can serve as a basis for reliable estimation of the environmental release at domestic PWR sites. $^{14}C$ is the most important nuclide in the inventory, since it contributes one of the main dose contributors in future release scenarios. The reason for this is its high mobility in the environment, biological availability and long half-life(5730yr). More recent studies - where a more detailed investigation of organic $^{14}C$ species believed to be formed in the coolant under reducing conditions have been made - show that the organic compounds not only are limited to hydrocarbons and CO. Possible organic compounds formed including formaldehyde, formic acid and acetic acid, etc. Under oxidizing conditions shows the oxidized carbon forms, possibly mainly carbon dioxide and bicarbonate forms. Measurements of organic and inorganic $^{14}C$ in various water systems were also performed. The $^{14}C$ inventory in the reactor water was found to be 3.1 GBq/kg in PWR of which less than 10% was in inorganic form. Generally, the $^{14}C$ activity in the water was divided equally between the gas- and water- phase. Even though organic $^{14}C$ compound shows that dominant species during the reactor operation, But during the releasing of $^{14}C$ from the plant stack, chemical forms of $^{14}C$ shows the different composition due to the operation conditions such as temperature, pH, volume control tank venting and shut down chemistry.

• Journal of the Korean earth science society
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• v.29 no.6
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• pp.454-465
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• 2008

Benthic foraminiferal assemblage and AMS radiocarbon dating of core sediments from the northern shelf of the East China Sea were analyzed in order to understand the paleoenvironment and sedimentary environmental changes around the Korean marginal seas since the last glacial maximum (LGM). The core sediments, containing continuous records of the last 16,000 years, reveal a series of well-defined vertical changes in number of species (S), P/T ratio and species diversity (H) as well as foraminiferal assemblage. Such down-core variations display a sharp change at a core depth of approximately 240 cm, which corresponds to ca. 10,000 year B.P. The sediments of the lower part of the core (240${\sim}$560 cm, Zone I), including the well-developed tide-influenced sedimentary structures, are characterized by high abundances of Ammonia beccarii and Elphidium clavatum (s.l.) and low values in number of species, P/T ratio and diversity. These tide-influenced signatures and foraminiferal assemblage characters suggest that the sediments of Zone I were deposited in a coastal environment (water depths of 20${\sim}$30 m) such as tidal estuary with an influence of the paleo-rivers (e.g., old-Huanghe and Yangtze rivers) during the early phase of the sea-level rise (ca. 16,000 to 10,000 years) since the LGM. In contrast, the upper core sediments (0${\sim}$240 cm, Zone II) are characterized by abundant Eilohedra nipponica and Bolivina robusta with a minor contribution of A. ketienziensis angulata and B. marginata. and high values in number of species, P/T ratio and diversity. Based on relative abundance of these assemblage, Zone II can be divided into two subzones (IIa and IIb). Zone IIa is interpreted to be deposited under the inner-to-middle shelf environment during the marine transgression in the early Holocene (after ca. 9,000 yr B.P.) when sea level rapidly increased. The sediments of zone IIb most likely deposited after 6,000 yr B.P. under the outer shelf environment (80${\sim}$100 m water depth), which is similar to modem depositional environments. The muddy sediments of zone IIb were probably transported from the old-Huanghe and Yangtze Rivers during the late Holocene. We suggest that the present-day oceanographic conditions over the Yellow and the East China Seas have been established after ca. 7,000${\sim}$6,000 yr B.P. when the Kuroshio Current began to influence this area.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.3
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• pp.152-163
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• 2001

Based upon the sedimentological, geochemical and micropaleontological analyses of two sediment cores from the Antarctic Peninsula (AP), three distinct lithological units can be recognized: (1) ice-proximal an/or ice-distal diamictons in the lower part of the cores, accumulated just seaward of the grounding line of the ice shlef until 11,000 yrs BP; (2) diatomaceous mud between 6,000 and 2,500 yrs BP in the middle part, resulted from a large influx of organic materials by enhanced production of open marine condition; (3) diatomaceous sandy mud since 2,500 yrs BP, characterized by an increase in sand content and decrease in TOC and diatom abundance in the lower layers, which reflects the formation of more extensive and seasonally persistent sea ice. Based on the C-14 radiocarbon dating, the sub-ice shlef deposition of the diamicton on the AP western shelf completed around 11,000 yrs BP. Colder condition was reinstated between 12,800 and 11,600 BP with a dropin TOC content and diatom abundance, which is coincident with the Younger Dryas event in the North Atlanticregion. At this time, the ice shelf, that is now absent in the study area, appears to advance as evidenced by an abrupt increase in sea-ice taxa. A climatic optimum is recognized between 9,000 and 2,500 BP, coincide witha mid-Holocene climatic optimum 'Hypsithermal Warm Period' from the other Antarctic sites. During this time, diatomaceous mud accumulated by a large influx of organic materials by enhanced production occurred in openmarine condition. Around 2,500 BP, diatomaceous sandy mud reflects the formation of more extensive and seasonally persistent sea ice, coincident with the onset of the Neoglacial in the Antarctic. Our results provide evidence of climatic change from the Antarctic Peninsula`s western shelf that helps in determining the existence and timing of Holocene milennial-scale climatic events in the Southern Hemisphere.

• Economic and Environmental Geology
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• v.43 no.4
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• pp.333-341
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• 2010

Fluvial sediments are widely distributed in present and old river-beds of the mid-Keum River, the tributaries of which are the Yugu and Jeongan Rivers. The basement of the mid-Keum River area consists of Mesozoic granites which are easily eroded compared to Precambrian gneisses, which are exposed in the upper-Keum River area. The provenance of the fluvial sediments includes both the Precambrian gneisses and Mesozoic granites, which occur in the catchment of the mid-Keum River. The coarse-grained sediments were probably transported from the river-beds and the overbank floodings of the main Keum River and its tributaries when the climate was warm and wet. The oldest mud deposits were dated at ca. 9,400 yr BP by the radiocarbon method. It has been estimated that the sand deposits below the dated muds were formed in a period from the Late Pleistocene to the Early Holocene. However we have revealed that the major part of the present river-bed sediments was formed at ca. 3,000-6,000 yr BP, i.e., in the mid- to late Holocene, when summer monsoon was very strong due to climatic changes. We have calculated fluvial sedimentation rates of 0.12-0.16 cm/yr and 0.02-0.09 cm/yr for borehole KJ-29 river-bed sediments and borehole KJ-28 floodplain deposits, respectively. We conclude that the sedimentation rate is higher near the present stream channel than near the floodplain.