Chung-Ryul Ryoo

• Dr.
• Korea Institute of Geoscience and Mineral Resources

We analyzed the structural characteristics of faults that cut unconsolidated conglomerates on three construction slopes in Geumsan-ri, Yangsan-si. This outcrop is located approximately 0.6 km north of the Gasan site, where Quaternary faulting has been previously reported. The six faults observed in Geumsan-ri have N14o-32oE strikes; the dip of thre...

Integration of geological and geophysical data is essential to elucidate the configuration and geometry of surface and subsurface structures, as well as their long-term evolution. The NNW–SSE-striking incised valley and parallel mountain range in the southeastern margin of the Korean Peninsula, extending 50 km from Gyeongju to Ulsan cities, are tog...

The Ulsan Fault Zone (UFZ) of NNW trend is developed in the Gyeongsang Basin, the southeastern part of the Korean Peninsula, and the Quaternary faults have been found around the UFZ. The faults generally thrust the Bulguksa igneous rocks of Late Cretaceous-Early Tertiary upon the Quaternary deposits or are developed within the Quaternary deposits....

The BophiVum massif in northwestern Myanmar mainly consists of peridotite, mafic intrusive, and mafic volcanic rocks, oceanic sediments, and chromitites. Small chromitite open pits are randomly distributed in the eastern lowland of the massif. In this study, we interpret the origin of the chromitite and suggest exploration guidelines for hidden ore...

The NNE–SSW-striking Yangsan Fault in southeastern Korea has been regarded as one of the most prominent seismogenic structures in the Korean Peninsula on the basis of instrumental and historical seismicity, and paleoseismic records along the fault zone. Its seismic behavior is, however, still uncertain due to long recurrence intervals of strong ear...

The main fault zone of the Yangsan Fault, located in the southeastern part of the Korean peninsula, is newly found at the Cheonjin-ri, Dudong-myeon, Ulju-gun, Ulsan, Korea. About 100 wide fault zone exposed along the Guryangcheon stream strikes N-S and dips over 70° toward east. The main fault zone is composed of N-S-striking gouge and breccia laye...

Based on the preliminary surveys for the occurrences of the Muwellut chrome-nickel mineralized zone (800 km2) in northwestern Myanmar, Bophivum area was selected as the detailed exploration area after considering data source, geological potential, metallogenic province, necessity of resource development on target mineral, exploration activity, grad...

This study describes a large recumbent fold, which occurs at the north entrance slope of the Batjae tunnel, Pyeongchang-gun, Gangwon-do, and interprets its formation mechanism. The several-hundred-meter scale fold, developed in the Jeongseon Limestone of the Paleozoic Joseon Supergroup, has a nearly horizontal axial plane and its head is facing nor...

Pseudotachylytes, produced by frictional heating during seismic slip, provide information that is critical to understanding the physics of earthquakes. We report the results of occurrence, structural characteristics, scanning electron microscopic observation and geochemical analysis of pseudotachylytes, which is presumed to have formed after the La...

Tsogttsetsii area, an intrusive complex associated with Cu mineralization, is located in the South Gobi, Mongolia. We performed the cross geochemical and extended exploration survey in Tsogttsetsii area. Cu mineralization in Tsogttsetsii area is porphyry Cu type related with alkali granite intruded in Late Carboniferous to Early Permian. In the con...

Since the 1970s, several prospective areas for copper mineralization have been recognized in Mongolia, stimulating further prospecting activities. The following types of copper ore formations are recognized in Mongolia: volcanic hosted Cu deposit, sediment hosted Cu deposit, skarn Cu deposit, epithermal replacement Cu-Ag and porphyry Cu-Au-Mo depos...

Tsogttsetsii area, an intrusive complex associated with Cu porphyry mineralization, is located in the Gurvansaikhan island arc terrane of the Central Asian Orogenic belt, Southern Mongolia. We performed a reconnaissance survey in Tsogttsetsii area. Cu mineralization in Tsogttsetsii area is porphyry Cu type related with alkali granite intruded in Pe...

The new rocks of the oceanic crust, like basalt, are created in the mid-oceanic ridge, and the magnetic polarities of the rocks are supposed to be oriented as following the Earth`s magnetic field. An extensive magnetic survey of total field at sea level reveals mainly unusual north-south magnetic stripes parallel to the axis of the mid-oceanic ridg...

Around Harar in the northeastern part of the Ethiopia, the Precambrian granitic gneiss and gabbro bodies are developed with several pegmatites. The rock bodies in this area have been deformed by ductile and brittle deformations developing fold and ductile shear structure, and thrust and fault.

Around Harar in the northeastern part of the Ethiopia, the Precambrian granitic gneiss and gabbro bodies are developed with several pegmatites. The rock bodies in this area have been deformed by ductile and brittle deformations developing fold and ductile shear structure, and thrust and fault.

Precambrian granitic gneisses and Cambrian meta-sedimentary rocks are prevalently distributed in the eastern part of the Taebaegsan region, and biotite granitic batholith of the Jurassic period (?) is found in the southern part of Uljin-si. But small scale leucocratic granitic stocks which commonly found here and there have been rather neglected in...

The Korean Peninsula is located in the intraplate regime of the Eurasian plate, and numerous historical and instrumental earthquakes have been recorded. Among these, the largest earthquakes were recorded in and around the Gyeongju and Ulsan areas in the southeastern part of the Korean Peninsula. We recently reexamined faults in Jinhyun and Jintee,...

The Yeongam mineralized zone is located in the southwestern part of the Korean peninsula, including the Sangeun, Eunjeok and Baramjai mines. This zone is located in the northeastern part of the Mokpo-Haenam-Yeongam volcanic circular structure. The 13 sites of quartz vein with mineralization are developed in the Sangeun-Eunjeok-Baramjai area, within...

Fe-Ti ore bodies occur in the western part of the Sancheong anorthosites around Banggok-ri, Sancheong, Korea. Within ore bodies, a several centimetric size of anorthositic breccia are enclaved by ore-bearing mafic part and deformed strongly as a sigmoidal form by ductile shearing. The ore bodies have a general N-S trending foliations with westward...

Fe-REE deposits occurred in Jaeunri, Hongcheon formed by carbonatitic melts consist of 3 parts such as northern, middle and southern ore bodies showing discontinuous distribution, and extension shape of ore bodies can be figured through field survey and geometric analysis. Foliations in gneiss around northern and middle ore bodies represent NNE, wh...

The tectonic evolution of the Central Ogcheon Belt has been newly analyzed in this paper from the detailed geological maps by lithofacies classification, the development processes of geological structures, microstructures, and the time-relationship between deformation and metamorphism in the Ogcheon, Cheongsan, Mungyeong Buunnyeong, Busan areas, Ko...

An Epithemal Au-Ag mineralized zone is developed in the Moisan area of Hwangsan-myeon, Haenam-gun, Jeol-lanam-do, Korea, which is located in the southwestern part of the Ogcheon metamorphic zone. It is hosted in the Hwangsan volcaniclastics of the Haenam Formation of the Late Cretaceous Yucheon Group. This research investigated the characteristics...

Fe-Ti ore bodies and mafic granulite occur in the Sancheong anorthosites, south Korea. In order to determine their petrogenetic relationship and to classify the Fe-Ti ore bodies, we have synthetically analyzed characteristics in the field, such as distribution and occurrence, and petrologic features through detailed outcrop sketches. The ore bodies...

Kinematical and fractal analyses were conducted on a fracture network in a well-exposed granite outcrop in SE Korea. The objective of this study is to examine the temporal and spatial evolution of the fracture network. From the orientation and abutting relationships of fracture sets, six fracturing events and their relative ages were established, s...

The Cotabamba cluster of porphyry centers is part of and lies at the heart of an emerging prolific porphyry copper gold province, the Andahuaylas-Yauri Belt. Several deposits in the belt are currently in the state of intensive pre-development and feasibility work(Las Bambas by Xstrata, Los Chancas by Grupo Mexico, Constancia by Norsemont). Tintaya...

A large number of mafic and felsic dykes occur pervasively within the Sancheong anorthositic rocks. Based on the orientations of intrusion planes and cross-cutting relationships, the dykes are classified into four mafic (M-55, M-30, M-10, M-NW) and two felsic (F-NE, F-NW) dyke swarms and they have intruded as M-55 F-NE M-30 M-10 M-NW F-NW in order...

In this paper, a Quaternary fault is described, which is developed in the mid-eastern part of Ulsan Fault Zone, near the southern Gaegok-ri, Oedong-eub, Gyeongju, Korea. The Gaegok 6 fault is developed along the contact between Early Tertiary granite and Quaternary gravel deposit overlying unconformably the granite. The fault strikes and dips to th...

The main fault of Yangsan Fault Zone (YFZ) and Quaternary fault were found in a trench section with NW-SE direction at an entrance of the Sinheung village in the northern Eonyang, Ulsan, Korea. We interpreted the movement history of the southern part of the YFZ from the geometric and kinematic characteristics of basement rock's fault of the YFZ (Si...

Hydrothermal deposits in the Gyeongsang Basin show the genetic relationship with igneous activity from Late Cretaceous to Early Tertiary in the spatial and temporal viewpoints. Many hydrothermal Au-Ag-Cu-Pb-Zn and clay deposits are dominantly distributed within the Gyeongsang Basin. The Gyeongsang Basin is divided into seven metallogenic provinces...

Two half circular structures are developed in the northern and southern blocks which divided by the WNW-trending lineament around Uiryeong-Haman area, southern part of the Gyeongsang basin. By displacing one half circular structure to the other one about 750 m, a perfect circular structure is reconstructed. Thus the WNW-trending lineament is a left...

The Gilan area in the central-northern part of Uiseong Block of Cretaceous Gyeongsang Basin is composed of Precambrian metamorphic rocks, Triassic Cheongsong granite, Early Cretaceous Hayans Group, and Late Cretaceous-Paleocene igneous rocks. In this area, the faults of various directions are developed: Oksan fault of trend, Gilan fault of NW trend...

We describe three Quaternary faults occurring in the eastern-central part of the Ulsan Fault Zone near Bulguk-sa, Gyeongju, Korea. The fault occur along the contact between the late Cretaceous-early Tertiary granite and the Quaternary gravel deposit which overlies unconformably the granite. They are named from NNW to SSE as Tabgol, Singye and Hwals...