• The Korean Journal of Ecology
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• 제28권5호
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• pp.245-254
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• 2005

This paper presents a paleoenvironmental study on Hoya Rincon do Parangueo, a maar lake in Valle de Santiago in Central Mexican Bajio. Maar lake sediments have been widely used for high-resolution reconstruction of paleoenvironment. Many different paleoenvironmental proxy data such as stable isotopes, pollen, sediment chemistry, and dung fungus spore were produced in this study. The pine-oak ratio, stable isotopes, and sediment chemistry help to reveal paleoenviromental changes throughout the whole period covered by sediment materials from this study site. The evidence I found indicates that during ca. 9,500 $\sim$ ca. 8,300 cal yr B.P. there was dry climate; during ca. 8,300 $\sim$ ca. 6,300 cal yr B.P. it was wetter; during ca. 6,300 $\sim$ ca. 4,000 cal yr B.P. drier and cooler; during ca. 4,000 $\sim$ ca. 1,100 cal yr B.P. milder and wetter. The presence of Chupicuaro culture between ca. 2,500 $\sim$ 1,100 cal yr B.P. is implied by the high frequencies of Amaranthaceae and Zea mars. It seems that man left this lake around 1,100 cal yr B.P. due to a dry climate after 1,300 cal yr B.P. Spanish arrival around 400 cal yr B.P. is implied by the fact that fe3 mars reappears and Sporormiella spp. become significant around 120 cm, whereas Poaceae drops sharply.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.882-887
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• 2006

Sedimentological, geochemical, geophysical and micropaleontological analyses of 10 borehole cores were carried out to understand depositional environment and sequence stratigraphy of late Quaternary sedimentation in the estuary of the Nakdong River. Holocene Formation in study area is classified into five sedimentary units. Early Holocene freshwater lower pebbly sandy deposit(Unit I), lower muddy deposit(Unit II), middle thin sandy deposit(Unit III), upper muddy deposit(Unit VI), and upper sandy deposit(Unit V), in ascending order contolled by global sea-level change since interglacial period(about 15,000 yrs B.P.). Unit I deposited in erosional environments before marine trangression. Unit II and Unit VI composed of clay were deposited in cold and worm currents for marine trangression., respectively.

• 한국제4기학회지
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• 제11권1호
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• pp.25-38
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• 1997

한국서남해안에 위치한 해남만의 조수 퇴적층(체)에 관한 층서 설정이 제4기후기 (late Quaternary)의 시간범위로 가능하였다. 즉 현재의 해남만에 분포하고 있는 조간대층은 지난 중기와 후기 현세(middle to late Holocene)동안에 형성된 퇴적지층단위(depositional sequence unit)이며 이 지층단위는 선현세(late Pleistocene)조간대 퇴적지층단위 disconformity 의 부정합 관계로 피복하고 있다 본연구에서는 전자를 Unit I(8-10m 내외의 두께)이라 칭하고 후자를 Unit II(10m 내외의 두께)라고 구분 명명하였다, 그런데 Unit II는 암상(lithofacies)의 특징에 근거하여 상부(upper part)와 하부(lower part)로 나누어진다. 상 부는 약 3-4m 의 두께를 가지고 있으며 황갈색을 분명히 나타내며 게 구멍 화석과 동토구 조(cryogenic structure)그리고 매우 높은 값의 전단응력을 나타낸다, 그러나 하부는 회색을 띄며 낮은 전단응력 값을 나타내 상부와 뚜렷이 구분된다 이러한 Unit II의 상부가 나타내 는 암상적 특징은 지난 간빙하기(Eemian interglacial time)에 형성된 오늘과 같은 조간대층 이 18,000년 전후의 최대 빙하기(last glacial maximum : LGM) 동안의 지배하에 노출되었 고 오랜동안 토양형성 과정이 풍화작용을 받은 증거를 나타내고 있다, 따라서 이지층의 층 서학적 단위 설정과 부정합 (disconformity) 적인 경계의미는 우리나라 제4기 층서(late Quaternary stratigraphy)를 규정하는데 매우 중요하다고 제안하는 바이다.

• 한국지형학회지
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• 제24권4호
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• pp.1-12
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• 2017

This study tried to reconstruct paleovegetation environments during the late Holocene with pollen analysis from archeological trenches at the right bank of Geumgang in Sejong-si. The lower hills was dominantly covered with pine trees, while alder trees and hygrophytes extended on the floodplain since 2,000yr BP. The pollen composition of Alnus dominance in the floodplain during the times is different from the general charateristics of Korean peninsula. Such a phenomenon is thought to be influenced by the fluvial process on the floodplain in the middle reaches of Geumgang around Sejong-si. Mihocheon and some tributaries join to Geumgang around Sejong-si, and the channel of Geumgang becomes narrow around the boundary between Sejong-si and Gongju-si. This narrow channel could attribute to the formation of extensive floodplain around Sejong-si. Moreover, human impacts such as agriculture appear continuously since 1,800yr BP.

• 한국지형학회지
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• 제24권1호
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• pp.51-62
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• 2017

Liao River with the largest basin area in the northeastern part of China has constructed huge floodplain along the lower reach. Especially a vast marsh was developed around estuaries and coastline near Liaodong Bay. The marsh was called as Yotaek(or Liaoze) before the modern time, which is meaningful for understanding human life since prehistorian times. By the analysis of historical documents and geomorphic data, it can be assumed that the height of Yotaek of landward boundary reached 20~30m from Heishan to Liaoyang during Han dynasty. The shoreline of 7,000 yr BP is estimated to coincide with the contour line between 20m and 30m at present. And the ancient shoreline during Christ era indicates 10m.a.s.l., which is corresponding to the seaside boundary of the Yotaek. The shoreline of Liaodong Bay was progressed seaward 30km/ka during 1000~1100 AD, while 10~40km/ka during late 19 century ~ early 20 century.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.85-85
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• 2022

The world's most extensive and active deltas, Louisiana's wetlands, are deteriorating rapidly due to multiple stressors such as the discharge of the Mississippi River, sea-level rise, and coastal retreat, the substantial but spatially and temporally variable impacts. However, the ecological and anthropogenic histories, the mode of environmental changes on a multi-millennial timescale have not been thoroughly documented. This study, a palynology-based multiproxy analysis, investigates hydrological, geological, geochemical, and anthropogenic impacts on southern Louisiana wetlands and a variety of external forcing agents influencing ecological succession. Sediment cores extracted from a small pond on a mangrove-dominate island near Port Fourchon, Louisiana, USA yielded a 4,000-year record. The site has been transformed from freshwater to saline water environments, to a mangrove dominant island over the late Holocene. The multivariate principal component analysis identified the relative strength of external drivers responsible for each ecological shift. The Mississippi River delta cycle (lobe switching) was the dominant driver of ecosystem changes during the late Holocene, while relative sea-level rise, tropical cyclones, climate, and anthropogenic effects have been the main drivers late in the site's history.

• 한국제4기학회지
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• 제17권2호
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• pp.167-168
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• 2003

The Upo wetland, the largest natural wetland in Korea, is located in Changnyeong-gun, Gyeongsannam Province ($35^{\circ}33'$ N, $128^{\circ}25'$ E), and 70 km upstream from the Nakdong River estuary. Unlike most other Korean wetlands that have been destroyed under the name of economic development, the Upo wetland has been able to preserve its precious ecosystem throughout the years. Thanks to increased public awareness about natural wetlands and environmental conservation, the Korean Ministry of Environment designated the Upo wetland an 'Ecological Conservation Area' on July 26th, 1997. On March 2nd of the following year, the Upo wetland (8.54 $\textrm{km}^2$) was designated a 'Protected Wetland' in accordance with the international Ramsar Treaty. A 4.49m long (from 9.73 to 5.24 m in altitude) UP-1 core ($35^{\circ}33'05"N$, $128^{\circ}25'17"E$), recovered in the marginal part of the Upo wetland, is divided into eight buried paleosol units of different ages on the basis of the abundance of color mottles and vertical color variations (Aslan et al., 1998). Radiocarbon datings suggested that the paleosol profile represent the last 5700 years. The entire section of the core was more or less subjected to pedogenetic processes, and shows very weak to moderate soil profile development. These Holocene paleosols are therefore regarded as synsedimentary soils of deluvium (deposits formed by floods) origin (Sycheva et al., 2003). Unit 1 to 5 paleosols are generally silt-rich and exhibit moderate profile development. The boundaries between the units are somewhat distinguishable, but not so clear cut. This is due to variable repeated combination of accumulation, denudation and soil forming processes within various periods. Mottle textures gradually decrease in abundance with increasing clay content in Unit 6, which results in weak profile development. The lower boundary of Unit 6 lies around about 2000 yrBP, the beginning of Subatlantic in Korea (Kim et al., 2001). Abrupt sediment textural change is detected in Unit 7, which is interpreted to indicate the human activities on the Upo wetland. Unit 8 represents the recent soil forming processes. The preliminary results of this ongoing study imply the primary factor for pedogenetic processes is the water table fluctuations related to the sedimentary textures like grain size distributions, and the geomorphological stability of the Upo wetland.o wetland.

• 한국제4기학회지
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• 제17권2호
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• pp.17-23
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• 2003

In Korea terrestrial fluvial sequences can be used as pedological and sedimentological markers indicating a millenium-scale environmental and climatic changes imprinted in fluvial sub-environments, which in turn are represented by the cyclicity of fluvial sands, backswamp organic muds, and flooding muds intercalations of frostcracked or dessicated brown paleosols. Post LGM and Holocene fluvial and alluvial sedimentary sequences of Korea are formed in such landscapes of coastal, floodplain, backswamp and hillslope areas. Among them, the most outstanding depositional sequences are fluvial gravels, sands and organic mud deposits in coastal, fluvial, or alluvial wetlands. The aim of this study is to explain the sedimentary sequences and palynofloral zones since the last 15,000years, on the basis of organic muds layers intercalated in fluvial sand deposits. Jangheung-ri site of Nam river, Soro-ri site of Miho river, Youngsan rivermouth site in Muan, Oksan-ri site of Hampyeong and Sanggap-ri site of Gochang are illustrated to interpret their sedimentary facies, radiocarbon datings, and palynofloral zonation. Up to the Middle to Late Last Glacial(up to 30-35Ka), old river-bed, flooding, and backswamp sequences contain such arboreal pollens as Pinus, Abies, and Picea, and rich in non-arboreal pollens like Cyperaceae, Gramineae, Ranunculaceae, and Compositae. During the LGM and post-LGM periods until Younger Dryas, vegetation has changes from the sub-alpine conifer forest(up to about 17-11Ka), through the conifer and broad-leaved deciduous forest, or mixed forest (formed during 16,680-13,010yrB.P), to the deciduous and broad-leaved forest (older than 9,500yrB.P). In the Earliest Holocene flooding deposits, fragments of plant roots are abundant and subjected to intensive pedogenic processes. During Holocene, three arboreal pollen zones are identified in the ascending order of strata； Pinus-Colyus zone(mixed conifer and deciduous broad-leaved forest, about up to 10Ka), Alnus-Quercus forest (the cool temperate deciduous broad-leaved forest, about 10Ka-2Ka), and Pinus forest (the conifer forest, about after 2Ka), as examplified in Soro-ri site of Cheonwon county. The palynological zonations of Soro-ri, Oksan-ri, Sanggap-ri, Youngsan estuary, and Gimhae fluvial plain have been recognized as a provisional correlation tool, and zonations based on fluvial backswamp and flooding deposits shows a similar result with those of previous researchers.

• 한국수산과학회지
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• 제20권2호
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• pp.166-174
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• 1987

본 조사해역 퇴적물의 퇴적양상은 서측의 세립질 퇴적물과 남부의 조립질 퇴적물, 그리고 이 지역외에 세립질과 조립진 퇴적물이 혼합된 지역인 세부분으로 나눌 수 있다. 퇴적물의 분포상태는 서측이 주로 mud이고 남동측은 sandy mud와 muddy sand로 이루어져 있는 반면 최남부에는 사립질의 sand가 분포하는데, 이는 대체로 조류와 해류의 유속 및 유향과 지형적인 특성에 많은 영향을 받는것으로 보인다. 삼천포와 육지도 주변의 왜도가 negative skewness인 것은 강한 조류의 영향 때문인 것으로 생각된다. 욕지도 안쪽과 섬진강하구 퇴적물을 C-M diagram에 plot해 본 결과 섬진강하구와 육지도 동쪽을 제외하고는 대부분 pelagic suspension의 형태로 운반 되었으나, 창선도와 삼천포 사이의 수로에서는 예외적인 현상이 나타나는데 이는 강한 조류때문에 나타나는 winnowing효과 때문으로 생각된다. 조직 표준치의 상관계수가 $0.76\~0.92$ 로서 매우 양호한 음의 상관관계를 가진다.

• 한국광물학회지
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• 제27권3호
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• pp.159-168
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• 2014

동해 후포분지의 고환경을 규명하기 위해 HB 13-2 코어를 대상으로 퇴적물의 입도 분석 및 XRD, XRF를 통한 광물 분석을 실시하였다. HB 13-2 코어 퇴적물은 0.4 mbsf를 기준으로 엽리가 미약하고 생교란작용이 나타나는 퇴적상과 생교란작용이 하부로 갈수록 강해지는 두 개의 퇴적상으로 구분된다. 0-0.82 mbsf 구간에서의 비응집성 실트(sortable silt) 함량의 갑작스러운 증가와 상부층준에서의 민감입도 요소의 변화는 대마난류의 영향이 증가하였음을 보여준다. 퇴적물의 주 구성광물은 석영, 미사장석, 정장석, 알바이트와 더불어 녹니석, 캐올리나이트, 일라이트와 같은 점토광물이 포함되어 있으며 이들은 시료의 깊이 및 입도와 크게 연관성이 없는 것으로 나타나는데 이는 코아시료의 퇴적기간 동안 수문학적 변화는 크지 않았음을 시사한다. 1.4 mbsf부터 점토광물의 결정도가 감소하고 S/I 피크가 증가하는 현상은 온난다습한 기후의 영향으로 판단된다.