• Economic and Environmental Geology
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• v.55 no.2
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• pp.171-181
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• 2022

The Geochang Au-Ag deposit is located within the Yeongnam Massif. Within the area a number of hydrothermal quartz and calcite veins were formed by narrow open-space filling of parallel and subparallel fractures in the granitic gneiss and/or gneissic granite. Mineral paragenesis can be divided into two stages (stage I, ore-bearing quartz vein; stage II, barren calcite vein) by major tectonic fracturing. Stage I, at which the precipitation of major ore minerals occurred, is further divided into three substages (early, middle and late) with paragenetic time based on minor fractures and discernible mineral assemblages: early, marked by deposition of pyrite with minor pyrrhotite and arsenopyrite; middle, characterized by introduction of electrum and base-metal sulfides with minor sulfosalts; late, marked by hematite with base-metal sulfides. Fluid inclusion data show that stage I ore mineralization was deposited between initial high temperatures (≥380℃ ) and later lower temperatures (≤210℃ ) from H₂O-CO₂-NaCl fluids with salinities between 7.0 to 0.7 equiv. wt. % NaCl of Geochang hydrothermal system. The relationship between salinity and homogenization temperature indicates a complex history of boiling, fluid unmixing (CO₂ effervescence), cooling and dilution via influx of cooler, more dilute meteoric waters over the temperature range ≥380℃ to ≤210℃. Changes in stage I vein mineralogy reflect decreasing temperature and fugacity of sulfur by evolution of the Geochang hydrothermal system with increasing paragenetic time. The Geochang deposit may represents a mesothermal gold-silver deposit.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.583-585
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• 2005

WebDAV 프로토콜은 웹상의 공동 저작활동을 지원하기 위한 IETF 표준으로써, 원거리에 있는 사용자들 간에 파일을 공동 편집하고 관리할 수 있도록 해주는 HTTP 프로토콜의 확장이다. 이것은 웹상에서 가상의 작업공간을 구성함으로써, 원격 사용자들 간에 새로운 방식으로 공동작업을 가능하게 한다. 무선 네트워크 기술과 무선 장치의 발달로 이동을 하면서 WebDAV 서버에 접속한 후 협업을 수행한다면 유선 환경보다 효율적인 협업을 할 수 있을 것이다. 본 논문에서는 .NET Compact Framework 환경에서 동작하는 PDA WebDAV 클라이언트를 설계하였다. 본 클라이언트는 무선 네트워크를 지원하는 환경에서 PDA를 이용하여 WebDAV 서버와 HTTP 요청을 통하여 서버 자원을 확인할 수 있다. 이러한 PDA WebDAV 클라이언트는 PDA 환경에 맞는 인터페이스를 가져야 하고, 또한 WebDAV 명세를 따라야 한다. PDA WebDAV 클라이언트는 공간의 제약을 받지 않는 PDA를 이용함으로써 자료의 효율적인 공유 및 교환을 통하여 능동적인 협업 환경을 구축 할 수 있다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.150-152
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• 2015

본 논문은 개발자에게 멀티플랫폼 지원을 위한 웹언어 기반의 하이브리앱 개발환경을 제안한다. 최근 웹 기술의 발달로 웹 언어 기반의 애플리케이션이 증가 하고 있다. 그러나 웹 언어로 구현된 모바일 애플리케이션의 경우 디바이스의 플랫폼에서 제공하는 고유의 자원들에 대한 사용이 어려우며, 애플리케이션 마켓에서 배포가 어려운 단점이 있다. 본 논문에서는 이러한 문제를 해결하기 위해 통합개발환경을 구현하여 개발자들이 웹언어로 다양한 플랫폼에서 애플리케이션을 개발할 수 있는 환경을 제공한다. 제안하는 통합개발환경은 안드로이드와 타이젠 운영체제를 지원하며, 브라우저 기반의 웹 에뮬레이터와 애플리케이션 패키징 인터페이스를 지원하여 개발되는 소스코드를 테스트할 수 있도록 한다. 또한, 웹 에뮬레이터에서 디바이스 고유의 리소스를 사용하기위한 API를 설계한다. 제안하는 방법의 검증을 위해 타이젠 기반의 IVI 디바이스와 안드로이드 스마트폰을 사용하여 웹 언어로 작성된 애플리케이션을 테스트 한다.

• Economic and Environmental Geology
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• v.45 no.3
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• pp.295-306
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• 2012

In this study, the Singal fault zone in the Gyeonggi massif is identified in the Kiheung area. Geotechnical investigations were carried out to locate and characterize of the Singal fault zone in the Kiheung reservoir area. The N-S striking Shingal fault is known to be a Riedel-type strike-slip fault within the Choogaryung rift. Along the fault zone, 62 bore holes were drilled and electrical resistivity survey of about 11km, and vibroseis seismic refraction and reflection survey of about 500m were done. From the result of investigations, it is found that the fault zone, consisting mainly of gouge and breccia, has maximum width of 300 meters with anastomosing geometry of secondary fractures developed subparallel to the fault zone. We interpret these geometric features to be the result of structural development of flower-structure type at the restraining band of strike-slip fault. However, there are uncertainties of this interpretation because there are virtually no outcrops in the area. Further investigation to understand geometric features and linkage style of the fault zone.

• Economic and Environmental Geology
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• v.46 no.3
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• pp.267-278
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• 2013

The East African Rift System(EARS) is known to be hosted epithermal Au-Ag deposits, and the best-known example is Main Ethiopian Rift Valley(MER) related to Quaternary bimodal volcanism. Large horst-graben system during rifting provides open space for emplacement of bimodal magmas and flow channel of geothermal fluids. In recent, large hydrothermally altered zones(Shala, Langano, and Allalobeda) and hot spring related to deeply circulating geothermal water have been increasing their importance due to new discoveries in MER and Danakil depression. The hot springs in Shala and Allalobeda occur as boiling pool and geyser on the surface, whereas some areas didn't observe them due to decreasing ground water table. The host rocks are altered to quartz, kaolinite, illite, smectite, and chlorite due to interaction with rising geothermal water. The hot springs in MER are neutral to slightly alkaline pH(7.88~8.83) and mostly classified into $HCO_3{^-}$ type geothermal water. They are strongly depleted in Au, and Ag, but show a higher Se concentration of up to 26.7 ppm. In contrast, siliceous altered rocks around hot springs are strongly enriched in Pb(up to 33 ppm, Shala), Zn(up to 313 ppm, Shala), Cu(up to 53.1 ppm, Demaegona), and Mn(up to 0.18 wt%t, Shala). In conclusion, anomalous Se in hot spring water, Pb, Zn, Cu, and Mn in siliceous altered rocks, and new discoveries in MER have been increasing potential for epithermal gold mineralization.

• Economic and Environmental Geology
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• v.50 no.2
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• pp.105-116
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• 2017

The purpose of this study is to provide the information on genesis of obsidian occurring in the southwestern part of Ulleung Island, Korea, and to discuss its implications for volcanic activity through volcanological and mineralogical properties of obsidian. Obsidian occurs locally at the lower part of the Gombawi welded tuff, showing various complex textures and flow banding. Though obsidian is mostly homogeneous, it is closely associated with alkali feldspar phenocrysts, reddish tuff, and greyish trachyte fragments. The obsidian occurs as wavy, lenticular blocks or lamination composed of fragments. Cooling fractures developed on obsidian glass are characterized by perlitic cracks, orbicular or spherical cracks, indicating that obsidian rapidly quenched to form an amorphous silica-rich phase. It is evident that hydration took place preferentially at the outer rim relative to the core of obsidian, forming alteration rinds. The glassy matrix of obsidian includes euhedral alkali feldspars, diopside, biotite, ilmenite, and iron oxides. Microlites in glassy obsidian are composed mainly of alkali feldspars and ilmenite. Quantitative analysis by EPMA on the obsidian glass part shows trachytic composition with high iron content of 3 wt.%. Accordingly, obsidian formed with complex textures under a rapid cooling condition on surface ground, with slight rheomorphism. Such results might be induced by collapse of lava dome or caldera, which produced the block-and-ash flow deposit and the transportation into valley while keeping high temperatures.

• Economic and Environmental Geology
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• v.30 no.1
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• pp.67-77
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• 1997

Seismic data from Lake Tanganyika indicate a complex tectonic, structural, and stratigraphic history. The Lake Tanganyika rift consists of half grabens which tend to alternate dip-direction along the strike of the rift. Adjacent half-grabens are separated by distinct accommodation zones of strike-slip motion. These are areas of relatively high basement, and are classified into two distinct forms which depend on the map-view geometry of the border faults on either side of the accommodation zone. One type is the high-relief accommodation zone which is a fault bounded area of high basement with little subsidence or sediment accumulation. These high-relief areas probably formed very early in the rifting process. The second type is the low-relief accommodation zone which is a large, faulted anticlinal warp with considerable rift sediment accumulated over its axis. These low-relief features continue to develop as rifting processes. This structural configuration profoundly influences depositional processes in Lake Tanganyika. Not only does structures dictate where discrete basins and depocenters can exist, it also controls the distribution of sedimentary facies within basins, both in space and time. This is because rift shoulder topography controls regional drainage patterns and sediment access into the lake. Large fluvial and deltaic systems tend to enter the rift from the up-dip side of half-grabens or along the rift axis, while fans tend to enter from the border fault side.

• Economic and Environmental Geology
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• v.25 no.2
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• pp.179-190
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• 1992

The Yeongchun area is located at the central part of the Danyang Coalfield, where Precambrian granitoids, Cambro-Ordovician Choseon Supergroup, Carboniferous-early Triassic Pyeongan Supergroup, middle Triassic-Jurassic Bansong Group and extrusive tuffs are exposed. The rocks in the area underwent four phases of deformation, which are (a) $D_1$ : Movement of the Okdong Fault, (b) $D_2$ : Formation of NW-SE trending folds and stretching lineations, (c) $D_3$: Movement of the Gagdong Thrust Fault and associated structures of NNE-SSW trending folds, and (d) $D_4$ : E-W trending strike-slip faults and folds. During the $D_3$-event, flexural slip deformation intensively affected rocks in the area. Strain measurements show relatively low strain intensity in the area. The types of strain ellipsoid are prolate in the hangingwall area and those near to the footwall area range from plane strain to weak oblate. The oblate type is developed in the region far from the footwall area.

• Economic and Environmental Geology
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• v.51 no.6
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• pp.579-587
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• 2018

Chungnam Basin has been known as one of the largest Mesozoic basins in Korea, filled mainly with so-called Daedong Supergroup. The basin has evolved as the Early to Middle Jurassic intra-arc volcano-sedimentary basin developed on top of the Late Triassic to Early Jurassic post-collisional basin in this area, recording evolutionary history of the Mesozoic tectonics in the southwestern Korean Peninsula. This study carries out the geometric interpretations of the Seongjuri syncline and its surroundings in the central part of the Chungnam Basin, based on detailed structural field survey. Based on its doubly-plunging fold geometry, the Seongjuri syncline could be subdivided into the southwestern and northeastern domains. On the down-plunge profiles of the southwestern domain of the Seongjuri syncline as well as the underlying Okma fold, the Okma fault shows typical geometry of a basement-involved reverse fault that propagated up to the sedimentary cover. The profiles illustrate that the Seongjuri syncline occurs in front of the tip of the Okma fault, likely implying its origin as a part of the fault-related fold system. The result of this study will provide better insight into the structural interpretation of the Chungnam Basin, and will further provide useful information for the Mesozoic orgenic events of the southwestern Korean Peninsula.

• Economic and Environmental Geology
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• v.50 no.1
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• pp.45-59
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• 2017

In this research, we have extracted historical records regarding the geotechnology from the Goryeosa and the Annals of the Joseon Dynasty which are rated as ancient books that have objective views in the Goryeo Dynasty and the Joseon Dynasty in order to understand the national awareness and the social situation of the past events. We used the Korean history database system of National Institute of Korean History (NIKH) and collected related records by searching specific keywords such as volcano, mining, hot spring, and meteorite. According to the historical records, geological events such as the volcano and meteorite were regarded as important issues which were enough to be recorded in annals and surveyed by the dispatched government officials to the fields of events. In case of the hot springs, government officials conducted explorations of hot springs at king's orders and developed the potential areas of hot springs. Among the historical records on mining, the contents of geotechnology including the contents about discovered minerals and its locations can be easily found from those ancient books. Especially, it is possible to understand the history of geotechnology such as an establishment of modern organizations and a capitalistic flow for development through the history of the mining in the late Joseon Dynasty.