• Journal of The Geomorphological Association of Korea
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• 제20권1호
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• pp.11-20
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• 2013

The pollen analysis was performed targeting the valley plain alluvium of Jangjae-ri, Asan area in order to clarify the climate and vegetation environment of the Last glacial maximum and the Late glacial in terms of Gokgyo River Watershed In Asan-City, Korea. The sample collection point gets included in the current deciduous broadleaf forest zone (south cool temperate zone). The results are as follows. (1) The vegetation environment of about 19,300-14,100yrB.P. at the investigation area is mainly classified into YJ-I period and YJ-II period while YJ-Ia period is classified once again into YJ-Ia period and YJ-Ib period. YJ-Ia period (19,300-17,500yrB.P.) is correlated with the Last Glacial Maximum while the vegetation at the time has relatively a little wide distribution area of grassland compared to the forest and the forest vegetation of this time period is the mixed conifer and deciduous broad-leaved forest. YJ-Ib period (15,400-14,750yrB.P.) is correlated with the Late glacial (or the Last Glacial Maximum) and the distribution area of grassland became wider compared to the forest. While the forest vegetation of this time period is the mixed conifer and deciduous broad-leaved forest, a difference exists in terms of the dominant tree species. YJ-II period (about 14,650-14,100yrB.P.) is correlated with the Last glacial while the distribution area of grassland became even wider than the forest compared to the YJ-Ib in case of the vegetation at the time and the forest vegetation of this time period is the coniferous forest. (2) Both YJ-I period and YJ-II period were relatively cold and dry compared the End of Late Glacial (about 12,000-10,000yrB.P.)~Early Holocene (10,000-8,500yrB.P.), Also, YJ-II period was relatively colder than the YJ-I period and the YJ-Ib period was relatively more humid than the YJ-Ia period.

• Journal of Conservation Science
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• 제12권1호
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• pp.26-30
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• 2003

We examined the species of charcoals excavated at the late paleotithic site of Suyanggae. Suyanggae is located on the riverbed of Han river near Banyans, central Korea. The charcoals belong to the post-glacial period (radiocarbon dates: $18,630\~16,400\;BP$). Only two species were identified. Most of samples (139 among 142) examined were Pinus spp. (diploxylon). The other 3 samples were Picea spp. The results suggest the upper layer at $235\~245\;cm$ below the ground level was formed during dry and warm post glacial period, predominated by two needle pines and lower layer at 270 cm below the ground layer during the last glacial maximum period, predominated by spruces.

• Ocean and Polar Research
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• 제28권4호
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• pp.451-457
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• 2006

Hole 1124 of ODP Leg 181 was located in the Rekohu sediment drift off eastern New Zealand in the southwest Pacific Ocean. Mean gain sizes of sortable silt were measured in two drilled cores (1124A and l124B). Chronostratigraphy of core 1124 was correlated with the well-dated nearby core S931, resulting that the age of core 1124 covers the late Pleistocene spanning about MIS (Marine Isotope Stage) 5. Mean grain size of sortable silt seemed to be relatively large during the glacial period, whereas that of the interglacial period was smaller, although several tephra layers contain some coarse-grained pyroclatic particles. The variation in mean grain size of sortable silt in Rekohu sediment drift during the late Pleistocene indicates that the intensity of Deep Western Boundary Current (DWBC) might have been enhanced during the glacial period as a result of increased production of Antarctic Bottom Water (AABW).

• The Korean Journal of Quaternary Research
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• 제17권2호
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• pp.13-14
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• 2003

It is generally well known that Quaternary is characteristic geologically in terms of glacial and interglacial repeats and their associated unconformity formation. This paper deals with the first finding of the characteristic and significant meaningful unconformity between Holocene and late Pleistocene, which implies submergence and emergence of the tidal sedimentary basin along the western coastal zone of Korea during interglacial stage(IOS-5e) and glacial time(IOS-2). The stratigraphy of intertidal deposits in the Haenam Bay, western coast of Korea shows two depositional sequence units (Unit I of Holocene and Unit II of late Pleistocene) bounded by an erosional surface of disconformity. The disconformity is related to the latest Pleistocene sea-level lowstands (probably during the LGM). The Unit II is interpreted as intertidal deposit showing tidal sedimentary structures and crab burrow ichnology and has two parts (the upper part and the lower part) showing different lithology and character. The upper part of Unit II shows characteristic subaerial exposure features (emergence) and its related lithology. Such subaerially exposed upper part (more or less 4m to 5m in thickness) is characterized by yellow-brownish sediment color, cryoturbat-ed structure, crab burrow ichnofacies and high value of shear strength. Geochemical and clay mineral analyses of the upper part sediments also indicate subaerial exposure and weathering. In particular, very high value of magnetic susceptibility of the upper part in comparison to that of the lower part is interpreted as pedogenetic weathering during the subaerial exposure period.

• Journal of Plant Biology
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• 제25권1호
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• pp.37-53
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• 1982

Pollen analysis from lake districts, Youngnangho, Wolhamji and Bangeojin, revealed vegetational patterns in Korea. The pollen stratigraphy was divided into five zones, zone L, I, II, IIIa and IIIb for the past 15,000 years. During zone L (earlier than 10,500 yr BP), late-glacial period, Youngnangho was vegetated with a coniferous forest dominated by spruce, larch, haploxylon pine and fir with considerable amount of herbs. Zone I(10,500~7500 yr BP) was predominantly herbaceous vegetationj with significant amount of oak and diploxylon pine. It suggests that the overall environment became milder and drier than late-glacial period. Zone II(7,500~4,000 yr BP), hypsithermal period, showed significant warming condition, indicated by high pollen concentrations of oak, diploxylon pine and hornbeam, and by more diverse flora of deciduous broad-leaved trees than before. Herbs were not an important part of vegetation. Zone III$^a$(4,000~1,500 yr BP) had pine and oak as main elements. Birch increased slightly while hornbeam decreased in this time. It indicates cooling condition. Zone III$^b$(1,5000-present) which can be called pine period showed obvious human interference. Following forest clearance, agriculture was intensified. The beginning of logging and agriculture was discernible by a sudden decline of arboreal species and by considerable amount of rice, buckwheat, sorrel and plantain. Numerous charcoal fragments were observed in zone I and zone III$^b$.

• Economic and Environmental Geology
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• 제36권6호
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• pp.545-556
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• 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.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• 제9권1호
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• pp.1-12
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• 2004

Sedimentary facies and high-resolution echo facies were analyzed to elucidate sedimentation pattern of the late Quaternary glacial-marine deposits in the northern continental margin of the South Shetland Islands. Six sedimentary facies are classified, based on grain texture and sedimentary structures in gravity cores. The high-resolution (3.5 ㎑) echo characters are classified into 6 echo facies on the basis of clarity, continuity, and shape of bottom and subbottom echoes together with seafloor topography. Distribution of the echo and sedimentary facies suggest that there was a significant change in sedimentation pattern between the Last Glacial Maximum (LGM) and subsequent glacier-retreating period. When the grounded glaciers extended to the present shelfbreak during LGM, coarse-grained subglacial tills were widespread in the shelf area, and deep troughs in the shelf were carved beneath the fast-flowing ice steam. As the glacial margin retreated landward after LGM, dense meltwater plumes released from the retreating ice-front were funneled along the glacier-carved troughs, and accumulated channel- or cannyon-fill deposits in the shelf and the upper to mid slope. At that time, slope sediments seem to have been reworked by slope failures and unsteady contour currents, and further transported by fine-grained turbidity currents along the South Shetland Trench. After the glacial retreat, sediments in the shelf and slope areas have been mainly introduced by persistent (hemi) pelagic settling, and fine-grained turbidity currents frequently occur along the axis of the South Shetland Trench.

• Journal of the Korean Geographical Society
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• 제47권2호
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• pp.159-178
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• 2012

Since the suggestions on the paleo-glacial landforms in and around the northern high mountains of Korean Peninsula by some western and Japanese scientists in the early 1900s, the likelihood of the glacier existence in the Baekdusan over the Quaternary glacial period has been had in common among most of the Korean geomorphologists. In the other meaning, some have cast doubt on the likelihood the paleo-glacier in the Baekdusan because there has been no unequivocal evidences for the glacier such as striation, moraines, except morphologic characteristic landforms possibly related to glacier. Here we show some evidences for the existence of the glacier in the Baekdusan and their cosmogenic $^{36}Cl$ exposure ages over the late Quaternary and would put forward a model on the Quaternary landscape evolution of the Baekdusan, with a focus on the relationship of 1000 AD explosive eruption and the glacial landforms. The exposure ages constrained by cosmogenic $^{36}Cl$ abundances of the col surface of the western slope located below the glacier yield 46~26 ka, which is inphase with the last glacial period. Given all the evidences above, we can draw a conclusion that the glacier existed on the Baekdusan over the late Quaternary and the style of glaciation changed from extensive ice cap through valley glacier to restricted cirque.

• The Korean Journal of Quaternary Research
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• 제12권1호
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• pp.77-88
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• 1998

한반도의 제4기 지층을 암층서 및 단구층서를 기준으로 전기, 증기 및 후기 플라이 스토신 지층(Ear-ly Middle late Pleistocene Deposits)으로구분할 수 있다. 제 3기와 제4기 의 경계는 고지자기층서 해석에 의하여 한반도에서는 Gauss와 Matuyama chron 경계인 약 2.6Ma를 기준으로 설정할수 있다. 전기 플라이스토신 지층(Early Pleistocene Deposits)은 지형고도상 조구조 운동이 배제된 지역에서는 80m 이하에서의 계곡 사이에서 나타난다. 증 기 플라이스토신 지층(Middle Pleistocene Deposits)은 약0.8Ma부터 약 125ka까지이다. 중기 플라이스토신은 제4기 초깁터 발달하기 시작하였던 주요 계곡들이 현재와 비슷한 형태로 넓 고 깊어지기 시작했던 시기이다. 하천과 해안에는 일련의 단구지형을 잘발달시키지 시작했 고 단구이 형성은 현재보다 해수면이 더 높았던 마지막간빙기까지 계속되었다. 후기 플라이 스토신 지층(late Pleistocene Deposits)은 약 125Ka부터 10Ka까지이며 마지막 간빙기(Last Inter-glacial)와 마지막빙하기(Last Glacial)가 포함된다, 마지막간빙기 동안에는 제 2 하안 및 제 2 해안단구역층이 잘 발달하여 있다 마지막 빙하기 동안에는 해수면의 하강이 극심했 으며 특히 산사면에서 지형경사면을 따라 하부이동된 사면붕적층이 한반도의 전역에 널리 발달했던 시기였다.

• Journal of the korean society of oceanography
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• 제34권3호
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• pp.151-166
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• 1999

Both benthic and planktonic foraminifera from Core 97-02 obtained in the northern East China Sea are quantitatively analyzed for reconstructing the paleocenography of late Quaternary. Since the earliest time of the core sediment (last not older than 18000 yr B.P.), the paleo-water depth has changed from less than 20 m to near 100 m at present, which is reflected by the benthic foraminiferal assemblages: before 14000 yr B.P., the water depth was shallower than 20 m; from 14000 to 7500 yr B.P., water depth was 20-50 m; and after 7500 yr B.P., water depth was 50-100 m. The foraminiferal fauna also disclose the water mass history: during the last glacial maximum, the water that dominated the study area might be the coastal water; at the end of the last glacial maximum(14000-9500 yr B.P.), the Yellow Sea Cold Water mostly affected this area; then it gave way to the Yellow Sea Warm Current after 9500 yr B.P.; and finally, the warm water has dominated this area since 9500 yr B.P. because of the westward shift and enhancement of the Kuroshio Current.