• Ocean and Polar Research
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• 제24권2호
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• pp.167-175
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• 2002

Sediment from six piston cores from the East Sea (Sea of Japan) was analyzed for evidence of paleoceanographic changes and paleoclimatic variation. A distinct geochemical boundary is evident in major element concentrations and organic carbon content of most cores near the 10-ka horizon. This distinctive basal Holocene change is interpreted to be largely the result of changing sediment sources, an interpretation supported by TiO_2/Al_2O_3$ ratios. Organic carbon and carbonate contents also differ significantly between the Holocene and glacial intervals. The C/N ratio of organic matter is greater than 10 during the glacial period, but is less than 10 for the Holocene, suggesting that the influx of terrigenous organic matter was more volumetrically important than marine organic matter during glacial times. The chemical index of weathering (CIW) is higher for the Holocene than the glacial interval, and changes markedly at the basal Holocene geochemical boundary. Silt fractions are higher in the glacial interval, suggesting a strong effect of climate on silt particle transportation: terrigenous aluminosilicates and continental organic carbon transport were higher during glacial times than during the Holocene. Differences in sediment composition between the Holocene and glacial period are interpreted to have been climatically induced.

• 한국제4기학회지
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• 제22권1호
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• pp.28-36
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• 2008

The present study has focused on the environmental changes and evidences for sedimentation in the Lake Khuvsgul catchment during the Holocene period, inferred from short core sediment (BO03) from the eastern shore of Borsog Bay, which were analyzed in order to review records of the Holocene climatic evolution and Holocene history in Northern Mongolia. For the purpose of reconstruction of natural phenomenon that occurred in the lake catchment system during the Holocene, physical and chemical properties including HCl-soluble material, biogenic silica, organic matter and grain size distribution of minerals in the core sediments have been analyzed in this study. The vertical variations in composition for these properties show distinctly that five lines of paleoenvironmental evidence occurred in the lake catchment during the Holocene. A modified age model resulting from AMS carbon dating for the BO03 core sediment shows timings of these environmental events at 9.5 Kyr BP, 8.0 Kyr BP, 5.6 Kyr BP and 3.2 Kyr BP, respectively. Paleoenvironmental changes in the Lake Khuvsgul catchment system during the Holocene highlight distinctive features of the hydrological regime and geomorphologic evolution in the lake catchment due to regional landscape and global climatic changes corresponding with the Holocene optimum and thermal optimum. In particular, the change of hydrologic regime based on the sedimentological evidence has been caused by not only overland flow due to melting water, but also base flow due to thick permafrost around Khuvsgul region.

• 한국지형학회지
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• 제23권1호
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• pp.61-75
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• 2016

This study aims to reconstruct sea level change and paleogeomorphology since the middle Holocene by diatom analysis and 14C-dating from the sedimentary facies of three trenches on alluvial plain of Taehwa River, Taehwa-dong, Ulsan-si, South Korea. The Taewha-dong area was a narrow bay located between Bangeojin and eatuary of Taehwa River was a narrow bay which has been detached from the open sea during middle Holocene. Taewa-dong area at bay area was developed into alluvial plain by the sediments had been come from the Taewa river basin. The sea level change during the middle Holocene effected on the development of Taewha-dong alluvial plain and its information is included in the sediment facies.

• Journal of Astronomy and Space Sciences
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• 제31권4호
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• pp.335-340
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• 2014

There have been many suggestions and much debate about climate variability during the Holocene. However, their complex forcing factors and mechanisms have not yet been clearly identified. In this paper, we have examined the Holocene climate cycles and features based on the wavelet analyses of $^{14}C$, $^{10}Be$, and $^{18}O$ records. The wavelet results of the $^{14}C$ and $^{10}Be$ data show that the cycles of ~2180-2310, ~970, ~500-520, ~350-360, and ~210-220 years are dominant, and the ~1720 and ~1500 year cycles are relatively weak and subdominant. In particular, the ~2180-2310 year periodicity corresponding to the Hallstatt cycle is constantly significant throughout the Holocene, while the ~970 year cycle corresponding to the Eddy cycle is mainly prominent in the early half of the Holocene. In addition, distinctive signals of the ~210-220 year period corresponding to the de Vries cycle appear recurrently in the wavelet distribution of $^{14}C$ and $^{10}Be$, which coincide with the grand solar minima periods. These de Vries cycle events occurred every ~2270 years on average, implying a connection with the Hallstatt cycle. In contrast, the wavelet results of $^{18}O$ data show that the cycles of ~1900-2000, ~900-1000, and ~550-560 years are dominant, while the ~2750 and ~2500 year cycles are subdominant. The periods of ~2750, ~2500, and ~1900 years being derived from the $^{18}O$ records of NGRIP, GRIP and GISP2 ice cores, respectively, are rather longer or shorter than the Hallstatt cycle derived from the $^{14}C$ and $^{10}Be$ records. The records of these three sites all show the ~900-1000 year periodicity corresponding to the Eddy cycle in the early half of the Holocene.

• 대한지리학회지
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• 제48권6호
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• pp.837-855
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• 2013

낙동강 하구로부터 약 70km 떨어진 창녕 비봉리 신석기시대 유적에서 목선, 패각층, 도토리 구덩이 등 해양과 관련된 유구와 유물이 출토되었다. 유적의 발굴 과정에서 출토된 도토리 구덩이와 패각층의 특성, 퇴적상, 연대측정 및 규조분석 결과를 바탕으로 해수면변동 곡선을 복원하였다. 패각층과 도토리구덩이는 해수의 영향을 받은 유적지 유구로서 신석기 초기동안 지속적으로 조성되었으므로 해수면에 대한 정보를 제공한다. 퇴적상은 기반암, 기저역층, Holocene 충적층(해성층, 육성층, 배후습지성 퇴적층)으로 구분된다. Holocene 중기 동안 해수면은 상승과 하강을 반복하였으며, 울산 세죽리와 경기도 평택의 해수면변동 경향과 조화를 이룬다. 비봉리 지역의 해수면은 Holocene 중기인 7,000년 BP 경 현재 수준에 도달했으며, 5,000년 BP 경 김해지역의 현재 평균고조위보다 약 1m 정도 높았고, 4,000년 BP까지 안정된 상태를 유지하였다.

• 대한지리학회지
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• 제32권4호
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• pp.403-420
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• 1997

道垈川은 牙山灣으로 流入되는 小河川이다. Holocene 中期에 있어서 이 流域盆地의 堆積環境變化를 살펴보기 위하여 boring조사, 硅藻${\cdot}$花粉分析, carbon dating 등을 실시했다. 道垈川 流域의 Holocene 堆積層은 土炭層과 靑灰色 실트層이 互層을 이루고 있으며, 많은 硅藻와 花粉化石을 포함하고 있다. 硅藻와 花粉의 分析 결과에 의하면 靑灰色 실트층이 퇴적될 때는 相對的으로 海進의 경향이 있었고, 土炭層이 퇴적될 때는 相對的인 海面의 安定 내지 海退의 경향이 있었다. 後氷期 海岸線은 약 7,000년 BP 경에 현 도대천 하류부에 도달하였고, 그 후 6,000년 BP 까지 몇 차례 小海進과 海退를 거듯하였다. 약 7,000년 BP 경에 해면(평균고조위)은 약 3m에 이르렀고, 미상승과 하강을 거듭하면서 6,000년 BP 경에 약 5m 까지 上昇하였다. 西海岸에서는 海岸低濕地性 土炭地는 약 7,000년 BP 경에서 3,000년 BP 경까지 주로 형성되었고, 이들의 分布高度는 대부분 현재의 平均海面보다 2~6m 높은 위치에 분포하고 있다. 西海岸 土炭地는 대개 高潮位 海面과 관련된 內灣 鹽生濕地性 土炭地이므로, 潮差가 작은 東海岸의 堤間濕地(swale)에서 형성된 土炭地에 비하여 形成時期가 앞서고 分布高度가 높다.

• Ocean and Polar Research
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• 제27권3호
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• pp.289-297
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• 2005

The change in global climate and Asian monsoon patterns during the mid-Holocene, 6000 years before present (6 ka), is simulated by a climate model at spectral truncations of T170 with 18 vertical layers, corresponding to grid-cell sizes of roughly 75km. The present simulation is forced with the observed monthly data of sea surface temperatures, and the specified concentration of atmospheric carbon dioxide, while in the mid-Holocene experiment, orbital parameters such as obliquity, precession, and eccentricity are changed to the 6ka conditions. Under such conditions, the precipitation associated with the summer monsoon is enhanced over a wider zonal band from the Middle East to Southeast Asia, while no significant alteration takes Place in winter. The monsoonal wind also increases over the Arabian Sea, showing the enhanced southwesterly wind during summer and northeasterly wind during winter. Overall, the showing of the Asian monsoon is enhanced during the mid-Holocene, especially in summer, which is consistent with the proxy estimates and other previous model simulations.

• 한국제4기학회지
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• 제3권1호
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• pp.1-15
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• 1989

남해 대륙붕에서 채취된 70개의 표층퇴적물과 130개의 해수시료를 대상으로 하여 이 환경에서의 표층퇴적물 분포, 표층퇴적물과 해저지형 및 부유물질 분포에 대하여 연구하였다. 이토(mud)는 남해 대륙붕 수심 약 40m인 연안 및 내대륙붕 해역에서 우세하나 대륙붕 지역의 대부분은 조립물질인 모래가 우세하여 일부 지역에 따라 자갈 또는 패각 모래가 발달한다. 이와 같은 분포경향은 현세 (Holocene)해수면 상승(변동)과 그에 따른 수력학적인 조건에 의한 것으로 해석된다. 현세 간빙기의 최초기 즉, 현세 간빙기 직전의 빙기 (Wisconsin 혹은 Wurm) 후기에 위치하였던 해수면(약 18000y.B.P.)에 관련된 퇴적상과 그 당시의 연안해저지형의 특징이 본 연구결과의 하나로서 규명되었다.

• 한국지형학회지
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• 제28권4호
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• pp.31-39
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• 2021

Gaemok, the place name of Uihang-ri, Sowon-myeon, Taean-gun, Chungnam, indicates a tombolo. This study estimated the Holocene sea level change and development process of the coastal landforms of the Gaemok and Hwanyeong Tombolos in the Uihang coast. The tombolos seemed to form at approximately 3.4 ka and the average sea level at that time was estimated to be higher than that of the present by ca. 1 m. The Gaemok area was a separated island from the Taean peninsula during the Holocene Climatic Optimum. At approximately 3.4 ka when the sea level rose again after the fall, the Gaemok area was tied to the land by formation of the Gaemok and Hwanyeong Tombolos. The falling or fluctuating sea levels after 3.4 ka have shaped the present coastal landforms.

• Ocean and Polar Research
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• 제26권3호
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• pp.531-537
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• 2004

In this study we discuss some problems that emerged from paleolimnological and paleontological investigations of terrestrial Holocene ecosystems on King George Island (South Shetland Islands) conducted by an Argentine-Polish research group. Biological and geochemical markers commonly used in standard analytical procedures are considered insufficient in tracing overlapping records of past environmental changes preserved in peat banks, lake sediments and ornithogenic remnants. Records that might be explained by predictable natural events (related to glacio-isostatic uplift of land), roughly predictable events (ecological succession), or unpredictable events (volcanic eruptions or accidental destruction of aquatic moss) may overlap or interfinger one with another providing that signals of regional and/or global climatic changes, are hardly identifiable. A more sophisticated and more selective methods are recommended to do discrimination between records of local and regional/golbal processes in studies on Holocene climatic history of the South Shetland Islands.