• Journal of The Geomorphological Association of Korea
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• v.24 no.4
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• pp.13-25
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• 2017

To reconstruct the paleo-temperature quantitatively and to overcome limitation of traditional qualitative pollen analysis, this study was performed pollen analysis using the modern surface soil at Yulha-dong, Gimhae-si of southeastern part of Korean peninsula. Canonical Correspondence Analysis(CCA) was done to identify the most important environment variable about composition of modern surface pollen sample. Also, Weighted Average-Partial Least Square(WA-PLS) was analyzed to obtain modern surface pollen-temperature transfer function. The transfer function was applied to the results of qualitative fossil pollen analysis at Yulha-dong, Gimhae-si, Sampyung-ri, Ulsan-si and Taewha-dong, Ulsan-si. Therefore, the paleo-temperature was reconstructed during the Holocene since 6,200 yr BP. According to the results of the research, it is $1{\sim}2^{\circ}C$ lower than the current average annual temperature at the study area in 6,200 yr BP, since then it increased to the same level to the current temperature and decreased again until 2,600 yr BP. From the 2,600 yr BP, the temperature was fluctuated to the present.

• Ocean and Polar Research
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• v.29 no.1
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• pp.1-8
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• 2007

A series of long chain unsaturated ketone (alkenone) was identified in the particulate organic matter sampled from surface water of the eastern South Sea, Korea. The seawater temperature based on the $C_{37}$ alkenone was calculated by using several different equations of unsaturation index(${U^{K'}}_{37}$), compared with in situ CTD temperature. Among the previously reported equations, the equation(0.044T-0.204) which was proposed by Sawada et al.(1996) seems to be the most useful for the calculation of $C_{37}$ alkenone temperature, showing average $0.51^{\circ}C$ difference between ${U^{K'}}_{37}$ temperature and in situ CTD temperature. This result suggest that alkenone should be a useful molecular biomarker for reconstructing paleo-environmental change in the South and East Sea, Korea. However, it is required to establish more reliable equation for the calculation of $C_{37}$ alkenone temperature.

• Journal of the Korean Geographical Society
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• v.43 no.4
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• pp.477-494
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• 2008

Stable isotope analyses on lake or wetland sediments are useful to reconstruct paleoclimate. Organic and inorganic carbonates obtained from lake sediment are isotopically analyzed to get oxygen and carbon isotopic ratios. Oxygen isotope ratios can be used to quantitatively and qualitatively reconstruct paleo-temperature or humidity while carbon isotope ratios be used to reveal environmental changes around the lake or human impacts on the area. Peat mosses in peat bogs are nice samples for the carbon isotope analysis, which derives paleo-temperature and paleo-atmospheric $CO_2$ changes. In coastal area, the reconstruction of past sea-level is possible because terrestrial originated organic matter is carbon isotopically different from marine originated organic matter. Also, scientists can do research on Asian Monsoon based on the fact that $\delta^{13}C$ of C3 plants and C4 plants are consistently different each other and that they are distributed differently with respect to salinity. In Korea, paleoenvironmental studies using stable isotopes are not popular yet because of low academic interests on the methodology and difficulties of obtaining proper sediment samples. Interesting results can be produced to answer paleoenvironmental questions of Korea if scientists isotopically analyze sediment cores from a paleo-lake such as Hanon in Jeju island, peat bogs such as Mujechi-Neup and Yong-Neup, and coastal wetlands.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.22 no.2
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• pp.45-55
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• 2017

Long chain alkyl diols (LCDs) have been reported in sediments from various marine environments. Rampen et al. (2012) introduced the paleo-sea surface temperature (SST) proxy, Long chain Diol Index (LDI) based on the relative abundance of $C_{30}$ 1,15-diol, $C_{28}$ 1,13-diol, and $C_{30}$ 1,13-diol. In general, CP-Sil5CB and DB-5ms columns have been used for the quantitative and qualitative analysis of LCDs with a GC-MS. In this study, we examined the effect of three different columns (CP-Sil5CB, HP-5ms and DB-5) on the quantitative analysis of LCDs using marine sediments from the East Sea of Korea and the western Arctic Ocean. In general, our study showed that the results of CP-Sil5CB differed significantly from those of HP-5ms and DB-5. However, the differences of the LDI-derived SSTs among three columns were $0.1-0.2^{\circ}C$ for the East Sea and $0.2-0.7^{\circ}C$ for the western Arctic Ocean, which were well within the calibration error range (${\pm}1{\sigma}$). Accordingly, our study showed that the use of different columns resulted in significant differences of LCDs concentrations, but its effect on the LDI was relatively insignificant. Therefore, it appears that the different columns can be used for the paleo-SST reconstruction in the East Sea and the western Arctic Ocean using the LDI proxy.

• Journal of Conservation Science
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• v.25 no.1
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• pp.101-114
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• 2009

Potsherds and kilns of the AD 3th century excavated from Gundong and Majeon sites, Korea were studied to investigate the production techniques and provenance of potsherds and kilns on the pastes. For potsherds, kilns blocks and in-situ paleo-soils, provenance of raw materials were estimated through mineralogy and geochemistry, while production technique and thermal feature of kilns were investigated through observation of textures and compositions as well as firing experiment on paleo-soils. As a result of study, potsherds and kilns were found to have similar mineralogical compositions as the neighboring paleo-soils and to have same evolution path with that of geochemistry. The potsherds were divided into 3 groups according to firing temperature and production technique. Group 1 consists of reddish stamped pattern pottery with loose textures, which has many pores and contains many iron oxides. Its temper is less than about 0.5mm, and was probably fired between 700 to $800^{\circ}C$. Group 2 contains ash to grayish blue stamped pattern pottery, which has vitrified texture and few pores. Its temper is less than about 0.5mm, and was probably fired from 900 to $1,000^{\circ}C$. However, some potsherd belongs to the group 2 in terms of features for temper and pastes, but it was probably fired over $1,100^{\circ}C$. Group 3 contains reddish and grayish stamped pattern pottery. It has vitrified matrix, few pores and temper consists of polycrystalline quartz and feldspar over 2mm, and it was probably fired around $1,000^{\circ}C$. The kiln had experienced temperature from 600 to $700^{\circ}C$ on the wall, from 900 to $1,000^{\circ}C$ on the bottom, suggesting the function of high temperature firing.

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.55-61
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• 2003

In the year 2000 we culminated a successful five year investigation of climate change by completing a preliminary east-west transect across Mongolia. An earlier tree-ring study at Tarvagatay Pass, Mongolia indicated unusual warming during the 20th century similar to other paleo-investigations of the northern hemisphere. This record had represented one of the few tree-ring records for central Asia. New data from several sites in western Mongolia confirmed the preliminary temperature. The highest twenty-year growth period for the composite record is from 1973-1994. The western Mongolian record was significantly correlated with the Taimyr Peninsula and two northern hemisphere temperature reconstructions reflecting large-scale temperature patterns while showing some important regional differences. These differences should prove useful for climate models. We have also developed a millennial length temperature-sensitive record at the Solongotyin Davaa site (formerly Tarvagatay Pass) using relict wood and living trees. Conspicuous features over the last 1000 years are a century scale temperature decline punctuated by the end of the Little Ice Age in the late-1800s and 20th century warming. The record also shows a cold period early in the 12th century and warm intervals late in the 10th, early in the 15th and at end of the 18th centuries. Despite a limited sample size before 900 AD, the long Solongotyin Davaa record is useful in indicating severe cold events and suggests some cold intervals nearly as severe. These tree ring series, spanning much of the circumpolar northern treeline, have been compiled to create a long-term reconstruction of the Earth's temperature over centuries. The new chronology, in addition to its value as a detailed record of Mongolian climate, provides independent corroboration for such hemispheric and global reconstructions and their indications of unusual warming during the 20th century.

• Economic and Environmental Geology
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• v.26 no.3
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• pp.267-278
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• 1993

Serpentinite rocks which are composed mainly of olivine, serpentine and clinopyroxene, cropped out in the anorogenic Kyongsang sedimentary basin of South Korea. The serpentinites contain high content of MgO (36.87~41.99%) and 47~67 ppm Co, 1185~2042 ppm Ni and 979~3582 ppm Cr, which are quite similar to those of ultrabasic rocks such as peridotite and dunite. Isotopic compositions of serpentinites range from -95.5 to -105.7‰ in ${\delta}D$ and +1.7 to 7.1‰ in ${\delta}^{18}O$ corresponding to the continental antigorite type. A wide variation of oxygen isotopic values and $H_2O^+$ content of serpentinites reflect the different water/rock ratios during serpentinization processes. Formation temperature of serpentine minerals are estimated to be unusually high temperature of $488{\sim}646^{\circ}C$ by serpentine-magnetite isotopic fractionation, which belong to continental antigorite type. Calculated ${\delta}^{18}O$ value of serpentinized fluid during serpentinization is suggested that the hydrothermal fluid responsible for serpentinization be originated from the magmatic fluid with a minor influx of paleo-meteoric water in this area.

• Economic and Environmental Geology
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• v.56 no.1
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• pp.55-63
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• 2023

Variations in geochemical and mineralogical properties of the ferromanganese(Fe-Mn) crust reflect environmental changes. In the present study, geochemical and mineralogical analyses, including micro X-ray fluorescence and X-ray diffraction, were utilized to reconstruct the paleo-ocean environment of western Pacific Magellan seamount cluster. Samples of the Fe-Mn crust were collected using an epibenthic sledge from the open seamount XX (151° 51.12' 7.2" E and 16° 8.16' 9.6" N, 1557 meters below sea level) in the Western Pacific Magellan Seamount. According to the structure and phosphating status, the Fe-Mn crust of the OSM-XX can be divided into the following: phosphatizated (L4-L5), massive non-phosphatizated (L3), and porous non-phosphatizated (L1-L2) portions. All ferromanganese layers contain vernadite, and owing to the presence of carbonate fluorapatite (CFA), the phosphatizated portion (L4-L5) is rich in Ca and P. The massive non-phosphatizated section (L3) contains high Mn, Ni, and Co, whereas the porous non-phosphatizated portion (L1-L2), which comprises detrital quartz and feldspar, is rich in Fe. Variations in properties of the Fe-Mn crust from the OSM-XX reflect changes in the nearby marine environment. The formation of this crust started at approximately 51.87 Ma, and precipitation of the CFA during the global phosphatization event that occurred at approximately 36-32 Ma highlights an elevated sea level and low temperature during the associated period. The high Mn, Ni, and Co concentrations and elevated Mn/Fe ratios of samples from the massive phosphatizated portion indicate that the oxygen minimum zone (OMZ) was enhanced, and reducing conditions prevailed during the crust formation. The high Fe and low Mn/Fe ratios in the porous portion indicate a weak OMZ and dominantly oxidizing conditions. These data reflect environmental changes following the end of the Mi-1 glacial period in the Miocene-Oligocene boundary. Subsequently, Mn/Fe and Co/Mn ratios increased slightly in the outermost part of Fe-Mn crust because of the enhanced bottom current and OMZ associated with the continued cooling from approximately 9 Ma. However, the reduced carbonate dissolution rate in the Pacific Ocean from approximately 6 Ma decreased the growth rate of the Fe-Mn crust.

• Ocean and Polar Research
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• v.30 no.3
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• pp.351-359
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• 2008

In an effort to develop high-resolution sea surface temperature (SST) proxies for mid-latitude regions, two massive reef-building coral species, Alveopora and Favia, were collected from Jeju and Tsushima Islands, respectively. Their skeletons were subsequently analyzed for annual growth banding, Sr/Ca and Mg/Ca ratios. Hermatypic corals are thinly distributed in the waters of Jeju Island, where Alveopora japonica was the only dominant coral species. A higher diversity of hermatypic corals were observed in the waters of Tsushima Island, where Favia sp. was the most common coral species and even forming an about 6-m-high reef structure. Both Alveopora and Favia showed annual growth layers consisting of couplets of high- and low-density bands. Sr/Ca ratio of both species and Mg/Ca ratio of Alveopora also showed seasonal variation, likely reflecting SST variation. These results suggest the possibility that Alveopora and Favia species can be used as potential SST proxies. However, this study also highlights the potential growth disturbance of middle latitude corals due to high rainfall during monsoon and low SST during winter. This possibility should be taken into account in the investigation of Sr/Ca(Mg/Ca)-SST relationships.

• Journal of Conservation Science
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• v.29 no.2
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• pp.111-125
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• 2013

This study focused on making technique and usage of potteries from Proto-Three Kingdom to Baekje Kingdom in Balanri Site. The potteries were divided into four groups, Jungdo type I, Jungdo type II, Tanalanmun type and the Baekje type on the basis of the shape and physical properties. The Jungdo type potteries were used as kitchen wares, showing mostly yellowish brown color. The Tanalanmun type potteries were used as storages, showing gray green color. Firing temperature of the Jungdo type and the Baekje type potteries were presumed to be fired at 900 to $940^{\circ}C$, whereas the Tanalmun type potteries were fired at around 900 to $1,100^{\circ}C$. This is indicated that the firing condition was adjusted according to the purposes of the potteries. On the one hand, the Balanri potteries were made of paleo-soil which was collected in very near place from the site based on geochemical characteristics of the pottery clays and the soil.