• Title/Summary/Keyword: 제 4기 후기

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Unconformity and Stratigraphy of late Quaternary Tidal Deposits, Namyang Bay, West Coast of Korea (한국 서해 남양만 조수 퇴적분지의 제 4기 퇴적층서와 부정합)

  • 박용안;최진용
    • 한국해양학회지
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    • v.30 no.4
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    • pp.332-340
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    • 1995
  • To study stratigraphy of tidal basin deposits, related unconformity and source of late Holocene tidal sediments in Namyang Bay, west coast of Korea, total 8 vibracore sediments have been analyzed. The uppermost stratigraphic sequence of the late Holocene Namyang intertidal deposit overlies three different stratigraphic sequences (1) oxidized reddish brown muddy deposit (Yongduri Member), (2) oxidized yellow deposit (Kanweoldo Formation) and (3) the pre-Cambrian gneiss complex unconformably. Accordingly, three unconformities between those different sequences are recognized. The Namyang tidal deposits (late Holocene) with several meter thickness are mostly coarsening upward sequence suggesting transgressive phase during a continuous rise of sea level. The tidal deposit vibracored down to 4.5 m in depth contains clastic glauconite sands (2% in average) from 2.5 m to the vibracore bottom. These glauconite sands are considered to be transported to the site of Namyang Bay tidal sedimentation from offshore continental shelf of the Yellow Sea along the course of late Holocene sea-level rise.

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Late Quaternary Sequence Stratigraphy in Kyeonggi Bay, Mid-eastern Yellow Sea (황해 중동부 경기만의 후기 제4기 순차층서 연구)

  • Kwon, Yi-Kyun
    • Journal of the Korean earth science society
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    • v.33 no.3
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    • pp.242-258
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    • 2012
  • The Yellow Sea has sensitively responded to high-amplitude sea-level fluctuations during the late Quaternary. The repeated inundation and exposure have produced distinct transgression-regression successions with extensive exposure surfaces in Kyeonggi Bay. The late Quaternary strata consist of four seismic stratigraphic units, considered as depositional sequences (DS-1, DS-2, DS-3, and DS-4). DS-1 was interpreted as ridge-forming sediments of tidal-flat and estuarine channel-fill facies, formed during the Holocene highstand. DS-2 consists of shallow-marine facies in offshore area, which was formed during the regression of Marine Isotope Stage (MIS)-3 period. DS-3 comprises the lower transgressive facies and the upper highstand tidal-flat facies in proximal ridges and forced regression facies in distal ridges and offshore area. The lowermost DS-4 rests on acoustic basement rocks, considered as the shallow-marine and shelf deposits formed before the MIS-6 lowstand. This study suggests six depositional stages. During the first stage-A, MIS-6 lowstand, the Yellow Sea shelf was subaerially exposed with intensive fluvial incision and weathering. The subsequent rapid and high amplitude rise of sea level in stage-B until the MIS-5e highstand produced transgressive deposits in the lowermost part of the MIS-5 sequence, and the successive regression during the MIS-5d to -5a and the MIS-4 lowstand formed the upperpart of the MIS-5 sequence in stage-C. During the stage-D, from the MIS-4 lowstand to MIS-3c highstand period, the transgressive MIS-3 sequence formed in a subtidal environment characterized by repetitive fluvial incision and channel-fill deposition in exposed area. The subsequent sea-level fall culminating the last glacial maximum (Stage-E) made shallow-marine regressive deposits of MIS-3 sequence in offshore distal area, whereas it formed fluvial channel-fills and floodplain deposits in the proximal area. After the last glacial maximum, the overall Yellow Sea shelf was inundated by the Holocene transgression and highstand (Stage-F), forming the Holocene transgressive shelf sands and tidal ridges.

Effects of Extracellular $Ca^{2+}$ and $Ca^{2+}$-Antagonists on Endothelium-Dependent Relaxation in Rabbit Aorta (토끼 대동맥 평활근의 내피세포 의존성 이완에 미치는 $Ca^{2+}$$Ca^{2+}$ 길항제의 효과)

  • Suh, Suk-Hyo;Goo, Yong-Sook;Park, Choon-Ok;Hwang, Sang-Ik;Kim, Ki-Whan
    • The Korean Journal of Physiology
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    • v.24 no.1
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    • pp.91-102
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    • 1990
  • The effects of extracellular $Ca^{2+}$ and various $Ca^{2+}$ antagonists on endothelium-dependent relaxation to acetylcholine were studied in the isolated rabbit thoracic aorta in order to elucidate the control mechanism of endothelium derived relaxing factor (EDRF) release. Endothelium was removed from aortic strips by gentle rubbing with cotton ball. The effect of hemoglobin on basal tension was also observed with hemolysate. The results obtained were as follows: 1) Endothelium-dependent relaxation (EDR) to acetylcholine (ACh) showed biphasic pattern; the initial rapid relaxation phase and the late slow relaxation phase. 2) With the depletion of the extracellular $Ca^{2+}$, EDR was gradually suppressed, especially the late slow relaxation. 3) Verapamil, nifedipine, $Mn^{2+}$ and $Cd^{2+}$ had not any effect on EDR, while $La^{3+}$ and $Co^{2+}$ suppressed EDR completely. 4) The resting tension of the strips with rubbed endothelium was not altered by the addition of hemoglobin. That of the strips with intact endothelium, however, was enhanced and EDR to ACh was completely blocked From these results, we suggest that extracellular $Ca^{2+}$ is necessary for ACh-induced slow relaxation while $Ca^{2+}$ antagonists have not any effect on EDR.

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The Late Quaternary Pollen Analysis of Gokgyo River Basin in Asan-City, Korea - Focused on Vegetation and Climate Environment between the Last Glacial Maximum and the Late Glacial - (충남 아산 곡교천 유역의 제4기 후기 화분분석 - 최종빙기 최성기~만빙기 식생 및 기후환경에 주목하여 -)

  • PARK, Ji-Hoon;KIM, Sung-Tae
    • Journal of The Geomorphological Association of Korea
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    • v.20 no.1
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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.

The Elevation of Paleo-shoreline and Formation Age of the 1st Marine Terrace in Dadaepo, Busan, South Korea (부산 다대포 지역 해안 단구 제1면의 구정선 고도와 형성 시기)

  • Shin, Jae-Ryul;Hong, Yeong-Min;Hong, Seong-Chan
    • Journal of The Geomorphological Association of Korea
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    • v.26 no.4
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    • pp.67-79
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    • 2019
  • This study documents the level of paleo-shoreline and the timing of formation of the lowest marine terrace (1st terrace) distributed in Dadaepo, Busan, South Korea. In the study area, the elevation of paleo-shoreline of the 1st terrace is clearly identified as 5 meters above mean high tide based on the elevation of wave-cut platforms and the elevation of boundary between marine and terrestial sediments. This is well consistent with the fact that are found along the Southern coast of the Korean Peninsula including Daepo-dong, Sacheon-si. The timing of formation of the 1st terrace in Dadaepo is confirmed to have been deposited around 70,000~80,000 years BP (MIS 5a) according to OSL and IRSL dating ages. However, because the formation age of the 1st terrace in Sacheon-si Daepo-dong (Southerm coast) and Pohang-si Umok-ri (Eastern coast) previously identified as about 90,000~100,000 years BP (MIS 5c), further discussion of what is needed. Possibly, it can be interpreted that the sub-interglacial (MIS 5a and 5c) sea-level records during the last interglacial period are likely to be selective on land depending on regions.

Expression and Role of Trypsin-Like Enzyme Involved in Hatching of Preimplantation Mouse Embryos (생쥐 배아의 부화에 관여하는 Trypsin 유사 효소의 발현과 역할)

  • Kim, Soo-Kyung;Kang, Hee-Kyoo;Jun, Jin-Hyun;Choi, Kyoo-Wan;Kim, Moon-Kyoo
    • Development and Reproduction
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    • v.5 no.1
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    • pp.17-21
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    • 2001
  • This study was conducted to investigate the expression pattern of Trypsin-like enzyme and the effect of a trypsin inhibitor(benzimidine) on hatching process during in-vitro culture of mouse preimplantation embryos. The Trypsin-like enzyme was identified by rhodamine-conjugated Trypsin substrate probe. The expression of trypsin-like enzyme was firstly detected at the late morula stage, and the enzyme was uniformly localized in the trophectoderm of late blastocysts. Especially, intense fluorescence was observed in the blebbing area of hatching blastocysts. Bisbenzamidine, contained in culture media, did not alter embryonic development from 4-cell stage to the expanded blastocyst but decrease the hatching rate in ImM concentration (15.8% vs 89.7%, p<0.02). In the treatment of bisbenzimidine (5mM) for 12 hours according to the embryonic stage of mouse, the hatching rate of control (83.0%) and treatment in late blastocysts (8.7%) were significantly (p<0.01) different. From these results, we suggested that the hatching enzyme having trypsin-like activity was localized from the late morula stage, and the hatching process by this enzyme was activated in the late blastocyst stage of mouse embryos.

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Mineralogy and Geochemistry of Quaternary Fault Gouges in the Southeastern Korean Peninsula (한반도 동남부 제4기 단층 비지의 광물학적 및 지구화학적 연구)

  • 손승완;장태우;김영규
    • Journal of the Mineralogical Society of Korea
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    • v.15 no.2
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    • pp.85-94
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    • 2002
  • XRF, XRD, EPMA have been used to investigate microstructures and mineralogical changes caused by the faulting and fluids associated with faulting in the Quaternary fault gouge zones at the Sangchon, Ipsil and Wangsan faults located at the southeastern part of the Korean Peninsula. The chemical compositions of faulted rocks and protoliths analyzed by XRF show that the fault gouges are relatively enriched in TiO$_2$, P$_2$O$_{5}$, MgO, and Fe$_2$O$_3$) compared with protoliths, indicating that the fluids associated with faulting were highly activated. XRD results show that the fault gouges predominantly consist of quartz, feldspar, calcite and clay minerals. Clay minerals formed in the gouge zones are mainly composed of smectite characterized by a dioctahedral sheet. Based on EPMA analyses various kinds of sulfide, carbonate, phosphate minerals were identified in the gouge zones and protoliths. Xenotime of grey fault gouge of the Sangchon fault and sulfide minerals of contact andesitic rock of Ipsil fault and contact grey andesitic rock of Wangsan fault were probably formed by inflow of hydrothermal solution associated with faulting prior to the Quaternary. Carbonate minerals of contact andesitic rock and gouge zone of the Ipsil fault were formed by inflow of fluid associated with faulting prior to the Quaternary. They are heavily fractured and have reaction rim on their edge, indicating that faultings and inflow of fluids were highly activated after carbonate minerals were formed. Calcites of Wangsan fault seemed to be formed in syntectonic or posttectonic Quaternary faulting.g.

The comparison and chronology of the lower marine terraces in the mid-eastern coast of Korean peninsula (韓反島 中部東海岸 低位海成段丘의 對比와 編年)

  • ;Choi, Seong-Gil
    • Journal of the Korean Geographical Society
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    • v.30 no.2
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    • pp.103-119
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    • 1995
  • This Paper aims to compare the lower marine terraces distributed from Muckho to Gangneung in the mid-eastern coast of Korean peninsula by the geomorphic method of using characteristies of terrace features and terrace deposits, paleosol, and fossil cryogenic structures, and to estimate the age of the lower marine terraces on the basis of the comparisons of those with the characteristics of thalassostatic terrace in adjacent rivers. The 1ower marine terraces in this area can be classified into two levels, i.e., lower marine terrace I and II surfaces, in desending order, according to the difference of former shoreline altitude. The former shoreline heights of the lowerm marine terrace I and II surfaces are 18m and 10m, respectiveiy. The width of the I surface is broader and distributed more continuousiy than that of II surface. Daejin I surface in Muckho coast, and Myeongju and Anin terrace in Gangneung coast could be classified into the lower marine terrace I surface, and Daejin II surfaCe into II surface. The Surface of ancient shore platform of the lower marine terrace I and II surfaces were weathered, and the color of the terrace deposit ranges from red to reddish brown. And this terrace deposit is covered with slope deposit of Last Glacial or fossil periglacial structures (platy structure and vecicle) of Last Glacial are formed in terrace deposit. These facts indicate that the lower marine terrace I and II surfaces had been formed before the Last Glacial, and then affected by chemical weathering under warm environment, finally followed by cold period. But the deposit of the lower marine terrace I surface is more weathered than that of II surface. And pseudogleyed red soil, which is developed in I but not in II surface, could be judged to have been formed in the Last Interglacial culmination stage (Oxygen isotope stage 5e). Therefore, in terms of the degree of weathering of the terrace deposit and the existence of pseudogleyed red soil, the age of both terrace is thought to be a little different. And the characteristics of the above mentioned II surface are accord with those of thalassostatic terrace formed in middle or late period of the Last Interglacial (5e or 5a). Thus on the basis of above all points, the lower marine terrace I and II surfaces in this area could be seen to have formed in the Last Interglacial culmination stage and middle or late period of the Last Interglacial, respectively. Because the lower mamine terrace I surface is broadry distributed in the eastern coast of Korea nPeninsula, the surface could be used to be a key surface in studying Quaternary marine terraces.

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Effects of Sowing Date and Cutting Time on Feed Value of Rye in Paddy Field (파종기와 예취시기가 답리작 호밀의 동료가치에 미치는 영향)

  • ;Je-Cheon Chae
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.39 no.6
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    • pp.519-525
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    • 1994
  • This experiment was conducted to investigate the effects of sowing date and cutting time on feed value of rye in paddy field at Yesan from Oct. 1990 to June 1991. The field experiment was sown 5 times at 10 day intervals from Oct. 5. The content of crude protein, digestible protein, total digestible nutrient(TDN), minerals(P, K, Ca, Mg), and energy(ENE, NEL, NEM, NEG) were decreased due to earlier sowing, while the content of acid detergent fiber (ADF) and neutral detergent fiber(NDF) increased. On the other hand, the yields per unit area for crude and digestible protein, TDN, minerals, and energy increased due to earlier sowing, but there was no significant difference among the plots sown on Oct. 5 through Oct. 25. The highest yield of crude protein was shown at late flowering stage, digestible protein and net energy gain (NEG) at heading stage and TDN at milk stage respectively.

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Physiological Studies on Injuries of Cool Weather in Rice Plant I. Effect of Heading Date and Physiological Characteristics of Boron and Phosphorus Application Under the Cold Water Temperature in Rice Plant (수도의 냉해에 대한 생리학적 연구 제1보 저수온하에서 붕소 및 인산시용이 수도의 출수 및 생리적 특성에 미치는 영향)

  • Cho, D.S.;Heu, H.
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.28 no.1
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    • pp.76-80
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    • 1983
  • In order to investigate the effect of boron and phosphorus for reduction of cold injury of rice, this experiment was undertaken by pot trial. Two levels of phosphorus and 6 levels of boron were applied once at the three stages such as tillering, panicle formation and meiosis stage. Cold water was irrigated to maintain cool temperature ranging 15 to $18^{\circ}C$ from panicle formation stage. It was shown a tendency that three to seven days of early heading were resulted by the 3, 5 and 10kg of boron application per 10 are. The ripening ratio and physiological root activity was rather slightly increased in the above boron levels.

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