• Animal Systematics, Evolution and Diversity
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• v.13 no.2
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• pp.73-81
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• 1997

한국산 조류 중 박새속(genus Parus)에 속하는 4종 Parus major wladiwostokensis (박새), P. ater amurensis(진박새), P. palustrius hellmayri(쇠박새) 및 P. varius varius(곤줄 박이)를 대상으로 이들의 계통적 유연관계를 구명하기 위하여 mtDNA분석을 실시하였다. 6 base를 인지하는 10개의 제한효소를 처리하여 얻어진 mtDNA의 크기는 16.6~17.0Kb였으며 Pst I과 Pvu II는 종간 차이가 뚜렷하였다. 각 종간의 절편양상을 비교하여 Parus속의 종 간 분화정도를 비교한 결과 P. m. wladiwostokensis와 P. a. amurensis의 유전적 근연관계 가 가장 가까웠고(p=0.073, F=0.294) P. a. amurensis와 P. v. varius는 비교적 현저한 유전 적 차이를 보였다.(p=0.119, F=0.143). Brown 등 (1979)의 공식을 이용하여 박새속 4종의 분 화시기를 추정한 결과 이들은 후기 선신세(Pliocene)와 초기 홍적세(Pleistocene) 사이에 분 화된 것으로 추정되었다.

• The Korean Journal of Zoology
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• v.36 no.1
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• pp.28-35
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• 1993

한국과 일본에 분포하는 갈겨니(Z. temmincki)를 대상으로 유전적 변이를 조사한 결과 한국에 분포하는 갈겨니 A(mm)-type과 일본에 분포하는 B-type(Watanabe and Mizuguchl, 1988)은 유전적으로 매우 가까운 동일 종으로 나타났고 한국산 갈겨니 B (MS)-type과 일본산 갈겨니 A-type의 유연관계가 가장 멀게 나타났다. 따라서 한국 및 일본에 분포하는 갈겨니는 모두 3종이 존재하는 것으로 추정되며 일본과 한국에 각각 2종씩이 분포하는 것으로 나타났다. 이들 갈겨니의 분화시기는 홍적세시기(Pleistocene)에 이루어진 것으로 추정되었다.

• The Korean Journal of Zoology
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• v.38 no.1
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• pp.87-95
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• 1995

한국산 담수어류의 잉어목, 황어아과(Leuciscinae) 어류 2속 5종의 계통적 유연관계를 구명하기 위하여 mtDNA분석을 실시하였다 6 base를 인지하는 10개의 제한효소를 처리하여 얻어진 강tDNA의 크기는 16.5-17.5 Kb였으며 Bcl I, Bgl I, Bgl II, Hin dIII, Pvu II, Xba I 등은 종간 차이가 뚜렷하였다. 각종의 집단간 mtDNA분화정도는 매우 낮았으나(p=1% 미만) M. oxyephalus의 무주집단과 제주집단은 예리적으로 큰 차이를 보였다(p=5.3%) Moroco속의 종간 분화정도를 비교한 결과 M. oxycephafus와 M. lagowsk서 사이가 평균 f=7.2%로 근면관계가 제일 가까웠고 M. keumkang과 M. semotilus는 타종들과 근연관계가 제일 멀었다. Moroco속과 Phoxinus속간의 평균 유전적 분화정도는 f=13.7%로 현저한 차이를 보였다. Brown 등(1979)의 공식을 이용하여 이들 황어아과 2속 5종의 분화시기를 추정한 결과 이들은 후기 선신세(Pliocene)와 흥적세(Pleistocene) 사이에 분화된 것으로 추정되었으며 이 결과는 동위효소 연구에서 얻어진 결파(Yang and Min, 1989)와 잘 일치한다.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.80-81
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• 2003

The Swan Coastal Plain, on which the City of Perth (pop. 1.32 million) is situated, is formed of aeolian sands of Pleistocene-Recent age. The mainly unconsolidated sediments build a series of dune lines paralleling the coastline. The near-surface water-table sees expression in numerous shallow freshwater lakes and marshes in the interdunal depressions. The sands are highly permeable, and 〉 70% of the city’s total water supply is derived from this local aquifer. (omitted)

• 한국해양학회지
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• v.1
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• pp.16-24
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• 1971

Over 40 bottom sediment samples were collected from the southern sea of Korea. The detailed textural characteristic of the sediments, percent calcium carbonate and heavy and light mineralogy were determined. Seaward of these sediments is a nearly broad belt of sandy sediments. In a broad outline it is considered to constitute a near-shore deposits left from a Pleistocene time of eustatically lowered level of sea water, because the sediments on the outer half of the continental shelf are much coarser than that nearer shore. The carbonate content increases strongly to the southeast and northwest of Cheju Island. It is believed that the high calcium carbonate content can be largely attributed to the availability of carbonate materials.

• Journal of the Korean Geographical Society
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• v.30 no.1
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• pp.1-13
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• 1995

One of the oldest fossil of conifers and taxads in the Korean peninsula includes Elatocladus, Ullmannia, Walchia and dates back to the Permian period of the Palaeozoic era. The only conifer which successfully survived since the Cretaceous period is Pinus and still thrives in Korea. The extinction of Miocene conifers, such as Sciadopitys, Taxodiaceae, Metasequoia and Cryptomeria may due to the climatic deteriorations during the late Pleistocene period. However, the cryophilous conifers and taxads, e.g..Pinus, Juniperus, Abies, Picea, Cupressaceae, Larix and Taxus continued to exist from the Miocene to the late Pleistocene and became major vegetational elements in the mountainous areas of Korea. As the temperature ameliorates in the late Holocene period, thermophilous Pinus (Diploxylon) gradually had increased in numbers and became a dominant vegetation in the lowland and montane areas since 2,000 years B.P. in korea. Out of various Korean conifers and taxads, Pinus which surviving since the Cretaceous period of Mesozoic era, ranges spatially from southern coastal area to northern alpine belt of the Korean peninsula. Pinus which contains largest species number in conifers is one of the most well-adapted genus to the Korean environment. The next important conifer Juniperus dates back to the Miocene period of Cenozoic era and continuously maintains speciation and expansion of distributional range. Other major conifers and taxads of Korea include Picea, Abies, Lorix and Taxus. The restriction of distributional range of Cephralotaxus and Tsuga may due to the climatic deterioration during the Pleistocene period of Cenozoic era. The patterns of the temporal and spatial distribution of Korean conifers and taxads may provide invaluable informations for the better understanding of present-day distributional range and ecology.

• The Korean Journal of Petroleum Geology
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• v.6 no.1_2 s.7
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• pp.20-24
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• 1998

Expert system is one type of artificial intelligence softwares that incorporate problem-solving knowledges and experiences of human experts by use of symbolic reasoning and rules about a specific topic. In this study, an expert system, PLAYMAKER2, is used to interpret sedimentary facies and depositional settings of the sedimentary sequence. The original version of the expert system, PLAYMAKER, was developed in University of South Carolina in 1990, and modified into the present PLAYMAKER2 with some changes in the knowledge-base of the previous system. The late Cenozoic sedimentary sequence with maximum 10,000 m in thickness, which is located in the Korean Oil Exploration Block VI-1 at the southwestern margin of the Ulleung Basin, is analysed by the expert system, PLAYMAKER2. The Cenozoic sedimentary sequence is divided into two units-lower Miocene and upper Pliocene-Pleistocene sediments. The depositional settings and sedimentary facies of the Miocene sediments interpreted by PLAYMAKER2 in terms of belief values are: for depositional settings, slope; $57.4\%$, shelf; $21.4\%$, basin; $10.1\%$, and for sedimentary facies, submarine fan; $35.7\%$, continental slope; $26.3\%$, delta; $16.1\%$, deep basinplain; $6.1\%$ continental shelf; $3.2\%$, shelf margin; $1.4\%$. The depositional settings and sedimentary facies of the Pliocene-Pleistocene sediments in terms of belief values we: for depositional settings, slope; $59.0\%$, shelf; $22.8\%$, basin; $7.0\%$, and for sedimentary facies, delta; $24.1\%$, continental slope; $22.2\%$, submarine fan; $17.3\%$, continental shelf; $7.0\%$, deep basinplain; $4.8\%$, shelf margin; $2.6\%$. The comparison of the depositional settings and sedimentary facies consulted by PLAYMAKER2 with those of the classical interpretation from previous studies shows resonable similarity for the both sedimentary units-the lower Miocene sediments and the upper Pliocene-Pleistocene sediments. It demonstrates that PLAYMAKER2 is an efficient tool to interpret the depositional setting and sedimentary facies for sediments. However, to be a more reliable system, many sedimentologists should work to refine and add geological rules in the knowledge-base of the expert system, PLAYMAKER2.

• Economic and Environmental Geology
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• v.53 no.5
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• pp.585-596
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• 2020

The 2017 Pohang Earthquakes occurred near a drill site in the Pohang Enhanced Geothermal System. Water injected for well stimulation was believed to have reactivated the buried near-critically stressed Miocene faults by the accumulation of the Quaternary tectonic strain. However, surface expressions of the Quaternary tectonic activity had not been reported near the epicenter of the earthquakes before the site construction. Unusual, large-scale water-escaped structures were identified 4 km away from the epicenter during a post-seismic investigation. The water-escaped structures comprise Miocene mudstones injected into overlying Pleistocene coastal sediments that formed during Marine Isotope Stage 5. This indicates the vulnerable state of the mudstones long after deposition, resulted from the combined effects of rapid tectonic uplift (before significant diagenesis) and the development of an aquifer at their unconformable interface of the mudstone. Based on the detailed field analysis and consideration of all possible endogenic triggers, we interpreted the structures to have been formed by elevated pore pressures in the mudstones (thixotropy), triggered by cyclic ground motion during the earthquakes. This interpretation is strengthened by the presence of faults 400 m from the study area, which cut unconsolidated coastal sediment deposited after Marine Isotope Stage 5. Geological context, including high rates of tectonic uplift in SE Korea, paleo-seismological research on Quaternary faults near the study area, and historical records of paleoearthquakes in SE Korea, also support the interpretation. Thus, epicenter and surrounding areas of the 2017 Pohang Earthquake are considered as a paleoseismologically active area, and the causative fault of the 2017 Pohang Earthquakes was expected to be nearly critical state.

• Ocean and Polar Research
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• v.38 no.3
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• pp.195-207
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• 2016

Because the high latitude region in the North Pacific is characterized by high primary production in the surface water enriched with nutrients, it is important to understand the variation of surface water productivity and associated nutrient variability in terms of global carbon cycle. Surface water productivity change or its related nutrient utilization rate during the Northern Hemisphere Glaciation (NHG; ca. 2.73 Ma) has been reported, but little is known about such circumstances under gradual climate cooling since the NHG. Bulk nitrogen isotope (${\delta}^{15}N_{bulk}$) of sedimentary organic matter has been used for the reconstruction of nutrient utilization rate in the surface water. However, sedimentary organic matter experiences diagenesis incessantly during sinking through the water column and after burial within the sediments. Thus, in this study we examine the degree of nitrate utilization rate during the early Pleistocene (2.4-1.25 Ma) since the NHG, using the diatom-bound nitrogen isotope (${\delta}^{15}N_{db}$), which is known to be little influenced by diagenesis, from Site U1343 in the Bering slope area. ${\delta}^{15}N_{db}$ values range from ~0.5 to 5.5‰, which is lower than ${\delta}^{15}N_{bulk}$ values, but they vary with larger amplitude. Variation patterns between ${\delta}^{15}N_{db}$ values and biogenic opal concentration are generally consistent, which indicates that the nitrate utilization rate is closely related to opal productivity change in the surface water. A positive correlation between opal productivity and nitrate utilization rate was observed, which is different from the other high latitude regions in the North Pacific. The main reason for this contrasting relationship is that the primary production in the surface water at Site U1343 is influenced mostly by the degree of sea ice formation. Still, although concerns about diagenetic alteration have been avoided by using ${\delta}^{15}N_{db}$, the effects of the preservation state of biogenic opal and the species-dependent isotopic fractionation on ${\delta}^{15}N_{db}$ should be assessed in the future studies.

• The Korean Journal of Quaternary Research
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• v.1 no.1
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• pp.3-20
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• 1987

With regard to the Quaternary formations in the Korean Peninsula, very few studies have been done specially from a stratigraphic viewpoint. The alluvial sediments filling in the valleys have often been considered as the only formation of Quaternary age (more precisely of the Holocone) and so the Pleistocene was regarded as an erosional or nondepositional episode. This is apparently evident from a quick look at the general geological maps of the Peninsula, which show a lithological sequence of Mesozoic or Paleozoic substrata immediately overlain by Holocene alluvium. Likewise, the Pleistocene period was described in terms of unconformity in most local or regional stratigraphical successions of the Peninsula. Recently several different types of Quaternary formation, besides the so-called Holocene alluvium in the valley plain have been found around the Peninsula. They consist of coastal deposits, marine or fluviatile terrace deposits, ancient valley fill deposits or slope deposits. Some parts of the volcanic sediments in Jeju Is. are also known as the Quaternary sequence. Thus the Quaternary deposits in the Peninsula are far more developed than previously known to gelolgists. Moreover the importance of Quaternary research became recently apparent in Korea due to the shortage of raw materials and to the policy of an optimum land-use. Advanced constructions and land reclamation have required more precise engineering parameters of loose materials and an estimation of land stability. This does not imply only the engineering, or the structural properties of the loose material, but at the same time the basic study of the sediments from the stratigraphical and environmental viewpoints has been necessary. In this connection, Quaternary outcrops specially along the coastal fringe of the Peninsula have been mapped, profiled and sampled for sedimentological, clay-mineralogical and palaeomagnetic studies. All these results are compiled for the core of the Quaternary stratigraphy of the Peninsula.