• Journal of the korean society of oceanography
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• v.34 no.1
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• pp.43-48
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• 1999

The latest-Quaternary paleoceanographic history of the Ulleung Basin, the East Sea (the Sea of Japan) is reconstructed on the base of planktonic foraminifera, oxygen and carbon isotopes, and accelerator mass spectrometer radiocarbon (AMS-$^{14}$C) data from two cores. Sinistral populations of Neogloboquadrina pachyderma are dominant during the last glacial period while dextral forms of Neogloboquadrina pachydeyma are abundant in the Holocene. An abrupt increase in ${\delta}^{18}$O values in both cores that began about 11 ka B.P may indicate the Younger Dryas cooling episode. A low-salinity event, marked by light ${\delta}^{18}$O values (0-1 %), is observed before the Younger Dryas event. As previous works suggested, the low-salinity event is probably due to the freshening of surface water caused by fresh water input from Huang Ho river and/or the excess of precipitation over evaporation. The lowest salinity water in the Ulleung Basin was probably continued from approximately 18 ka B.P. to 15 ka B.P. The ${\delta}^{18}$O values have gradually decreased since the Younger Dryas as a result of the continuous inflow of the warm Tsushima Current into the East Sea.

• Asian review of World Histories
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• v.4 no.1
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• pp.35-81
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• 2016

The objective of this essay is to propose a cultural history of cosmography and cartography from the thirteenth to the sixteenth centuries. It focuses on some of the processes that characterized these fields of knowledge, using mainly western European sources. First, it elucidates the meaning that the term cosmography held during the period under consideration, and the scientific status that this composite field of knowledge enjoyed, pointing to the main processes that structured cosmography between the thirteenth century and the sixteenth century. I then move on to expound the circulation of cosmographic knowledge among Portugal, Venice and Lisbon in the fourteenth and fifteenth centuries. This analysis will show how cartography and cosmography were produced at the interface of articulated commercial, diplomatic and scholarly networks; finally, the last part of the essay focuses on the specific and quite distinctive use of cosmography in fifteenth-century European culture: the representation of "geo-political" projects on the world through the reformulation of the very concepts of sea and maritime networks. This last topic will be developed through the study of Fra Mauro's mid-fifteenth-century visionary project about changing the world connectivity through the linking of several maritime and fluvial networks in the Indian Ocean, Central Asia, and the Mediterranean Sea basin, involving the circumnavigation of Africa. This unprecedented project was based on a variety of sources accumulated in the Mediterranean Sea basin as well as in Asia and in the Indian Ocean over the course of several centuries.

• Journal of the korean society of oceanography
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• v.33 no.1-2
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• pp.8-17
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• 1998

Paleoceanographic history of the East Sea is reconstructed based on several environmental parameters (coarse fraction content, planktonic foraminifera/benthic foraminifera ratio, fragmentation and assemblages of planktonic foraminifera, and coiling ratio of Neogloboquadrina pa-chyderma, etc,) of the late Quaternary sediments obtained from the Ulleung Basin. N. pa-chydeyma and Globigerina bulloides are dominant species (greater than 90% in abundance)among the total planktonic foraminifera assemblages in the late Quaternary sediments. The benthic foraminifera rarely occurred throughout the cores. Sinistrally-coiled specimens of N. pa-chyderma representing cold water temperature are observed more abundantly than dextrally-coil-ed ones. In addition, the sinistrally-coiled N, pachydeyma showed more the amount at the lower part of the cores than at the upper part suggesting the restriction of the Tsushima Warm Current into the East Sea during glacial period. G. bulloides, a species representative of upwelling condition, shows more abundant occurrence in the sediments of Core 941013 than those of Core 941006. This implies that Core 941013 is more influenced by upwelling than Core 941006. The upper part of the two cores contain more fragmentation of planktonic foraminifera suggesting significant dissolution by corrosive bottom wafer. Ascending CCD also played an important role for the absence of planktonic foraminifera at the upper part of the cores.

• Journal of the Society of Disaster Information
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• v.13 no.2
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• pp.276-285
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• 2017

Studies on the North East Asian Black Death have been actively conducted, but the contents of the Yanbian region have been rarely mentioned. The purpose of this study was to investigate the preventive measures and effects of the pneumonic plague in the Tumen River basin (mainly the present Yanbian region) based on the study of Yanbian region based on the research of researchers related to the North East Asia Black Death. In particular, we will use historical sources to provide a review of mortality levels and international cooperation in the region, as well as an overview the causes of the pandemic prevention efforts.

• The Korean Journal of Quaternary Research
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• v.14 no.2
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• pp.125-135
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• 2000

The late Quaternary stratigraphy and basal unconformity (nonconformity) of the intertidal deposits (upper tidal flat) in the Banweol tidal basin in the Kyunggi Bay, west coast of Korea has been investigated and established. The Unit I (middle to late Holocene upper intertidal deposit) and Unit II (pre-Holocene fluvial to alluvial deposit) in descending order are classified and interpreted. The basement rocks of the Banweol tidal basin is dominantly preCambrian metamorphic rocks on which Unit II is overlying unconformably. In short, the late Quaternary stratigraphy and unconformity of the Banweol tidal flat deposits are established and interpreted in terms of sedimentology and sea-level fluctuation history during late Quaternary.

• Economic and Environmental Geology
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• v.7 no.1
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• pp.1-21
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• 1974

From the point of view of geological history, the land of South Korea is regarded as the subject of processes of the changes in formations of several geological blocks such as Kyonggi massif, Yeongnam massif, Taebaegsan basin, Kyungsang basin and so on. Through the long period of geological chronology, the present topography and geotectonics have been formed by the complicate interactions of epirogenetic movements, magmatism, orogenesis, differential vertical movements, metamorphism and sedimentation. The reason of the crust movements mentioned above, is suppossed that the Pacific and West Pacific plate have subducted directly or indirectly into the East Asia plate. This fact can be endorsed by the results of the studies on the heat flow, gravity anomaly, absolute age dating, tectonic lineation, lithofacies and the temperature of hot spring in South Korea. The formations of metal ore deposits as well as other geological processes can be determined by the mechanical control of the plates and be divided into several systematic patterns. The investigation of about 110 metal mines in South Korea shows the following results. (1) Plate boundary volcanic type is about 28% (2) Plate boundary plutonic type is about 44% (3) Intraplate sedimentary type is about 26% (4) Intraplate magmatic type is about 2%.

• The Korean Journal of Petroleum Geology
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• v.10 no.1_2 s.11
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• pp.34-39
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• 2004

This article discusses stratigraphy and geological history of continental shelf area covering of offshore San-in to Tsushima islands. Geological data from 5 wells and detailed seismic surveys indicate that sediments in the studied area are divided into 4 stratigraphic groups ranging from Oligocene to Tertiary in age, namely X, H, K, and D groups in ascending order. The oldest X group of Oligocene time comprises paralic sediments including volcanics deposited in the initial stage of basin-formation. N group of mainly lower Miocene time consists of deep marine sediment, representing the highest stage of transgression. Sediments of the K group of middle Miocene time show distinct off-lapping depositional pattern during the basinfilling stage. The youngest D group covers these older groups unconformably. Strong deformation of sediments prior to the deposition of the D group formed many anticlinal structures. Five exploratory wells were drilled at the selected structures, where only minor gas shows were encountered. The area provides the enough palaeotemperature to mature the source rocks at moderate depth.

• The Korean Journal of Quaternary Research
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• v.18 no.1 s.22
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• pp.31-39
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• 2004

The stable-unstable curve graph (S-U curve) and the ignition los curve graph (IL curve) for pollen composition and inorganic material content in three areas (namely, Kawadoi Basin, Moniwa-Takada moor, and Nenoshiroishi moor) were prepared to reconstruct the recurrence history of slope failure during the Holocene in Northeastern Japan. Through the S-U curve, a period with a high slope failure frequency of 5,600~4,670yrB.P. was identified in Kawadoi Basin, two of 6,390~5,070yrB.P. and 4,750~3,800yrB.P. in Moniwa-Takada moor, and three of 6,630~6,070yrB.P., 5,890~5,360yrB.P., and 5,000~4,650yrB.P. in Nenoshiroishi moor. Through the IL curve, a period with a high slope failure frequency of 5,600~5,140yrB.P. was identified in Kawadoi Basin, and two of 6,390~6,170yrB.P. and 4,750~2,840yrB.P. in Moniwa-Takada moor. Most of above-mentioned periods were included in the period of slope instability in precedent studies. However, the periods with high slope failure frequency in this study were rather different from those in precedent studies. The times and numbers associated with these periods in each study area also showed discrepancies. Accordingly, to achieve the above-mentioned purpose, more case studies must be performed to improve the reconstruction level of slope failure frequency, which could be explained through the analysis of pollen composition and inorganic material content.

• Journal of Wetlands Research
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• v.15 no.3
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• pp.367-380
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• 2013

In this study, sub-indicators, and thematic mid-indexes to evaluate the water use characteristics were selected through historical data analysis and factor analysis, and consisted of the subject approach framework. And the integrated index was developed to evaluate water use characteristics of the watershed. Using developed index, the water use characteristics were assessed for 812 standard basins with the exception for North Korea using data of 1990 to 2007 from the relevant agencies. A sensitivity analysis is conducted for this study to determine the proper way through various normalization and weighting methods. To increase the objectivity of developed index, the history of the damage indicators are excluded in the analysis. In addition, in order to ensure its reliability, results from index with and without consideration of the damage history were compared. Also, the index is also applied to real data for 2008 Gangwon region to verify its field applicability. Through the validation process this index confirmed the adequacy for the indicators selection and calculation method. The results of this study were analyzed based on the spatial and time vulnerability of the basin's water use, which can be applied to various parts such as priority decision-making for water business or policy, mitigations for the vulnerable components of the basin, and supporting measures to establishment by providing relevant information about it.

• Economic and Environmental Geology
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• v.42 no.1
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• pp.27-53
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• 2009

A 30-m-thick Middle Ordovician Jigunsan Shale exposed along the southern limb of the Backunsan (Baekunsan) Syncline, Taebacksan (Taebaeksan) basin, has been simply considered as a transgressive shale sequence onlapped the underlying Maggol platform carbonates. Results of this study, however, suggest that majority of the Jigunsan Shale be interpreted as a regressive shale sequence downlapped onto a thin (ca. 240 cm) marine stratigraphic unit consisting of organic-rich (>3 wt.% of TOC) black shales in the lower Jigunsan Shale, which was accumulated at the time of maximum regional transgression. Detailed stratigraphic analysis in conjunction with XRD, XRF, and ICP-MS as well as Rock-Eval pyrolysis allows the thin marine stratigraphic unit in the Jigunsan Shale to define a condensed section that was deposited in a distinctive euxinic zone formed due to expansion of pycnocline during the early highstand phase. As well, a number of stratigraphic horizons of distinctive character that may have sequence stratigraphic or environmental significance, such as transgressive surface, maximum flooding surface, maximum sediment starvation surface, and downlap surface, are identified in the lower Jigunsan Shale. In the future, these stratigraphic horizons will provide very useful information to make a coherent regional stratigraphic correlation of the Middle Ordovician strata and to develop a comprehensive understanding on stratigraphic response to tectonic evolution as well as basin history of the Taebacksan Basin.