• 한국광물학회지
• /
• 제22권1호
• /
• pp.13-22
• /
• 2009

연구지역은 울산시 울주군의 양산단층대를 통과하는 터널(복안터널) 구간으로서 터널 상부에 경부고속도로와 국도 35호선이 위치한다. 기존의 조사결과 양산단층대 통과 터널 구간은 최대 폭 100 m에 이르는 단층비지와 단층각력암이 넓게 분포한다. 연구결과 양산단층 동측부에는 셰일로 대표되는 퇴적암이 분포하는데 이들은 기계적인 파쇄작용이나 열수변질작용의 영향을 거의 받지 않았다. 양산단층 서측부에는 데사이트질응회암이 분포하며, 양산단층의 영향으로 기계적 파쇄작용과 열수변질작용이 진행되었다. 양산단층 구간은 단층운동과 관련된 기계적 파쇄작용과 녹니석화작용, 견운모화작용, 고령석화작용으로 대표되는 열수변질작용이 복합적으로 작용하여 폭 $50{\sim}130m$에 이르는 단층대가 발달한다. 기계적 파쇄작용과 열수변질작용의 특징에 의해 양산단층대는 지질공학적으로 비변질대, 변질대, 변질.파쇄대, 단층비지대 등 4개의 구간으로 구분된다. 이들 구간은 기계적 파쇄작용과 변질작용의 정도 및 양상을 달리하며, 공학적 특성을 달리한다.

• 자원환경지질
• /
• 제24권3호
• /
• pp.233-244
• /
• 1991

청양지역의 각섬석편마암을 구성하는 흑운모는 심한 변질작용을 받아 녹니석화 및 질석화되어있다. 흑운모와 변질작용의 산물들에 대한 체계적인 전자현미분석은 이들 변질작용의 진행과정에서의 화학적 변화양상에 대한 중요한 정보를 제공해 준다. K와 Ti의 이탈작용은 두 변질작용에서 모두 나타나는 공통된 현상이지만, 흑운모의 사변체화 팔면체에서의 치환양상은 두 작용에서 전혀 다르게 나타난다. 그러나, 두 작용은 모두 층간의 전기적 균형을 이루려는 치환양상을 보이고 있다. 녹니석화 작용에서는 사면체내의 Si수가 일정하게 유지되며, 팔면체내에서의 Fe 및 Mg에 대한 Al의 치환양상이 두드러지게 나타난다. 이와는 달리, 질석화작용의 경우, 초기에는 일반적인 변질작용의 경향과 일치하는 dioctahedral화 되는 치환작용, 즉, Al의 팔면체에 대한 치환도가 증가하는 경향을 보이지만, 후기에서는 Al의 사면체로의 치환과 Fe의 팔면체 치환이 두드러지게 나타나는데, 이는 Fe의 양의 증가와 산화작용에 의한 결과로 생각된다. 두 변질작용은 모두 하나의 흑운모 구조가 곧바로 하나의 녹니석 및 질석으로 변화하는 과정과 두개의 흑운모 구조가 하나의 녹니석 및 질석으로 변화하는 과정이 제시되어 있는데, 현미경관찰 결과 및 화학적인 변화양상 등을 고려하여 볼 때, 녹니석화작용의 경우는 후자의 변화과정이 우세하였을 가능성이 높으며, 이 작용에 의해 변질과정이 요구되는 Al의 자체공급도 가능할 수 있다. 반면에 질석화 작용은 전자의 변화과정이 우세하였을 것으로 보이는데, 후기의 치환작용에서 요구되는 Fe의 증가는 보다 드물게 병행된 두개의 흑운모층이 하나의 질석으로 되는 작용의 결과로 생각할 수 있다. 질석화작용은 Fe의 전하상태가 매우 중요한 역할을 하는 것으로 보이는데, 이에 대한 해석을 위하여 몇가지 가정하에서 구조식을 재계산하여 보았다. 그 결과 질석에 적절한 구조식이 되기 위해서는 상당량의 Fe의 산화를 요구하게 되는 것으로 나타났다. 산화작용의 시기는 확실하지는 않지만, 치환작용변화가 일어난 질석화작용의 후기일 가능성이 높다.

• 자원환경지질
• /
• 제25권3호
• /
• pp.297-316
• /
• 1992

The Daebong gold-silver deposits is located in 8 km southwest of Cheongyang, Chungcheongnam-Do, Republic of Korea. The gold-silver-bearing hydrothermal quartz veins was formed within the Precambrian metasediments of Gyeonggi massif. Ore minerals occur as mainly of pyrite, sphalerite (0.78~6.19 wt.% Cd), galena, pyrrhotite and minor amounts of chalcopyrite, arsenopyrite, magnetite, ilmenite, chalcocite, electrum (55.00~89.55 wt.% Au) and argentite. The gangue minerals are quartz, calcite, chlorite, K-feldspar, biotite. Wall-rock alterations such as chloritization, silicification, pyritization, carbonatization and sericitization can be observed near the quartz veins. According to the mineral paragenetic sequence based on vein structure and mineral assemblages, three stage mineralizations can be recognized. Fluid inclusion, sulfur isotope and thermodynamic data show that the ore minerals were dominantly deposited at the between 388 and $204^{\circ}C$ from fluids with salinities of 8.1~0.3 wt.% equivalent NaCl, and sulfur isotope value 4.84 to 6.40 per mil of sulfides indicates igneous sources of sulfur in the hydrothermal system and fluid inclusion salinity data suggest that thermal fluids may have magmatic origin with some degree mixing of meteoric water.

• Ocean and Polar Research
• /
• 제23권1호
• /
• pp.11-21
• /
• 2001

K-Ar ages of the altered rocks from the Barton Peninsula are belows; altered tuffaceous andesite from southwestern part is 42 Ma, altered rocks contacted with quartz vein from southern part are 28 and 33 Ma, and advanced argillic altered andesite from northeastern part are 33 and 35 Ma. Those K-Ar ages are 10 My younger than granitic rocks of the Barton Peninsula. Hydothermal alteration of the Barton Peninsula was originated from mixing of magmatic water from parent magma of granitic rocks with meteoric water. The Al content in the hostrock is relatively constant during hydrothermal alteration, on the contrary the Mg content is in proportion to total alkali. The variation of total alkali and Mg contents in hydrothermal alteration indicates that those elements was washed out during hydrothermal alteration. The sequences of hydrothermal alteration of the Barton Peninsula is chloritization of amphiboles, sericitization of feldspars and kaolitization of sericite.

• Geomechanics and Engineering
• /
• 제20권3호
• /
• pp.233-241
• /
• 2020

Alkali-silica reaction (ASR) is among one of the most important damaging mechanisms in concrete, depending primarily on aggregates which contain reactive minerals. However, expansion in concrete may not directly relate to the reactive minerals. This study aims to investigate the influence of ASR and the expansion of mortar bars depending on aggregate type containing various components such as quartz, clay minerals (montmorillonite and kaolinite) and micas (muscovite and biotite). In this study, the accelerated mortar bar tests (AMBT) were performed in two conditions (mortar bars in the same and sole NaOH solutions). Petrographic thin section studies, X-ray diffraction (XRD) analysis (Rietveld method), scanning electron microscopy (SEM) and chemical analyses were carried out. This study showed that quartzite bars led to increase in expansion values of mortar bars in diabase-1 and andesite when these were in the same NaOH solution. However, three samples (basalt, quartzite and claystone) were found having ASR expansion based on the AMBT when the special molds were used for each sample. SEM study revealed that samples which exhibit highest expansions according to AMBT had a generally rough surface and acicular microstructures in or around the micro-cracks. Basalt and quartzite showed more variable in major oxides than those of other samples based on the chemical analyses, SEM studies and AMBT. This study revealed that the highest expansions were observed to source not only from reactive aggregates but also from alteration products (silicification, chloritization, sericitization and argillisation), phyllosilicates (muscovite, biotite and vermiculite) and clays (montmorillonite and kaolinite).

• 자원환경지질
• /
• 제27권6호
• /
• pp.537-548
• /
• 1994

The Weolyu gold-silver deposits at Hwanggan, Chungcheongbukdo, is of a late Cretaceous $(74.24{\pm}1.63Ma)$ epithermal vein-type, and is hosted in the quartz porphyry of late Cretaceous age. Based on mineral paragenetic sequence interpreted from vein structure and mineral assemblages, three stages mineralization were distinguished. A variety of ore minerals occurs including pyrite, sphalerite, chalcopyrite, galena with small amount of electrum, native silver, argentite, pearceite, sb-pearceite, argyrotite. The gangue minerals are quartz, rutile, calcite, apatite, fluorite and rhodochrocite. Wall-rock alteration such as pyritization, chloritization, sericitization, silicification is observed near the quartz veins. Au-Ag minerals were crystallized at middle and late stage of the two mineralization sequences. Results from the analysis of fluid inclusion and thermodynamic calculation indicate that Au-Ag mineral deposits were formed primarily by cooling and dilution of hydrothermal fluids($165{\sim}313^{\circ}C$, 0.4~2.4wt.% equivalent NaCl) with some degree mixing of meteoric water.

• 자원환경지질
• /
• 제23권2호
• /
• pp.161-181
• /
• 1990

The lead-zinc-silver-iron deposits from the Janggun mine are of hydrothermal-metasomatic origin, characterized by the marked hydrothermal alteration of the wallrocks, such as hydrothermal manganese enrichment of carbonate rocks, silicification, chloritization, sericitization, montmorillonitization and argillic alteration. The ore deposits have been emplaced within the Janggun Limestone of Cambro-Ordovician age at the immediate contacts with apophyses injected from the Chunyang Granite plutons of Late Jurrasic age. They have been structurally controlled by fractures in the carbonate rocks and the irregular intrusive contacts of granitic rocks, and are closely associated with hypogene manganese carbonate deposits. In the mine nine seperate orebodies are being mined. On the basis of the petrological study, hydrothermal alteration zone of this mine may be divided into the following four zones from wallrock to orebody. (I) Primary calcite and dolomite zone${\rightarrow}$(II) dolomitic limestone zone${\rightarrow}$(III) dolomitic zone${\rightarrow}$(IV) rhodochrosite zone${\rightarrow}$ orebody. There was not recongnized Mn and Fe elements in the primary calcite and dolomite zone. But, in the dolomitic limestone and dolomite zone, calcite and dolomite were subjected to weak hydrothermal manganese enrichment and the grade of the manganese enrichment increase oreward. By means of electron probe microanalysis, it was found that manganoan dolomite occured between primary dolomite grains, cross the cleavage of the primary dolomite and around the dolomite grains. Above these result supports that the Janggun manganese carbonate deposits are of hydrothermal metasomatic origin.

• 자원환경지질
• /
• 제6권3호
• /
• pp.133-170
• /
• 1973

The metamorphosed belt on cherty and andesitic rocks of the Gyeongnam province area has been well known as the most important copper matallogenetic province in Korea and locally has been investigated by several geologists. This report is summarized about geology, occurrence of ore deposits, the study of the present status of mine developments and exploitations and the suggestions of future proposed of copper mine developments and harmoniously and reseonably planning of demands and supply of copper ore. For convenience of study the writer divided the survey region as 4 areas, according to the conditions of mine location. They are (1) Goseong copper area (2) Gunbuk-Haman copper area (3) Masan-Changwon copper area (4) Tongrae-Ilgwang copper area. The geology of the above 4 areas consits of Cretaceous Gyongsang System, which is divided into Silla series, Nakdong Series and Bulguksa Series. The former has intrusive and extrusive andesite and sedimentary formation, and the latter has dioritic and hornblende granite. Ore deposits which is mostly vein types are confined mostly in the andesite and cherty rocks of Silla and Nakdong Series. It is observed slight hydrothermal alteration, i. e. propylitization, chloritization, saussuritization and silicification. It seems that the ore was formed by hydrothermal solution and secondary enrichement. The ore minerals are mainly chalcopyrite and pyrite, with small amounts of malachite, azurite, chalcocite, cuprite, galena, and sphalerite, magnetite, tetrahedrite and etc.. The efficient plan of copper mine developments in surveyed region are as following; (a) Gyeongnam Copper districts are divided in 4 area as mentioned above. (b) Each area would be likely developed as group-working as one unit. For the sufficiently supplying a demand of electric copper, the importations of high grade copper ore in foreign country are invitable at present status of copper mine developments and exploitations.

• 자원환경지질
• /
• 제2권3호
• /
• pp.58-67
• /
• 1969

Songgwang lead zinc mine is located in about 12km to the north-east of Jeonju City. Geology of the mine and its visinity is consisted of Jeonju series belonged to so-called Okcheon system, Seodaesan tuff formation, Silla series, and the quartz porphyry intruded into these formations. Jeonju series comprising 3 formations; that is, of Sadaeri, Sindong, and Girinbong. Jeonju series is generally distributed in southern part of the area, striking NNW, and diping NE $30^{\circ}$, or NW $30^{\circ}$. It is deformed to form synclinorium and anticlinorium plunging to the north with low angle. In the northern part of the area, Jeonju series was cut by Sinpeongri-fault of NEE direction near Sinpeongri. In the north side of the fault, it is overturned and shows NEE or NWW strikes and NW $60^{\circ}$ dips. At the west of Songgwangri, it is cut by 3 thrusts; the two are almost parallel each other, and the third oneis manifested by the fact that the lower black shale zone thrusted over the upper limestone. Songgwangri thrust, so named, is a post-mineral fault and its plane represents a premineral slip plane. Enrichment of are took place along the bedding plane or fissure parallel to it, as seen in adit No. 1 or No. 2 along the floor of the thrust, and along the sheared zone or the brecciated zone oblique to the plane near the thrust in crystalline limestone of Sindong formation as observed in the underground levels of inclined slope. Ore minerals are chiefly zincblende, galena, pyrrhotite, arsenopyrite, acompanied pyrite and chalcopyrite, and contain Au and Ag. In earlier stage of mineralization, the limestone was recrystalized, and sulphide minerals were enriched in the· permiable zone said above by pyrometasomatism, and in later stage the limestone was affected chloritization and sericitization. However hydrothermal replacement was weak, so that enrichment did not took place. It seems that minerallizing materials came up through the premineral slip plane and injected, and replaced the limestone in permiable zone said above with sulphide are minerals. Then Songgwangri thrust took place and, the lower black shale zone thrusted upon crystalline limestone.

• 자원환경지질
• /
• 제22권3호
• /
• pp.237-252
• /
• 1989

The Inseong gold-silver mine is located 3Km northwest of Suanbo, Choongcheongbugdo, Republic of Korea. The mine occurs in the shear zone formed by tension fractures within the Hwanggangri Formation of the Ogcheon metamorphic belt. Ore minerals found in the gold-silver bearing hydrothermal quartz vein composed mainly of pyrite, arsenopyrite, sphalerite, galena and minor amount of chalcopyrite, pyrrhotite, stannite, bismuthininte, native bismuth, chalcocite, electrum and tellurian canfieldite(?). The gangue minerals are quartz, calcite, chlorite and rhodochrocite. Wallrock alterations such as chloritization, silicitication, pyritization, carbonitization and sericitization can be observed in or around the quartz vein. According to the paragenetic sequence, quartz vein structure and mineral assemnlages, three different stages of ore formation can be recognized. The physico-chemical environment of ore formation in this deposit shows slight variation from stage to stage, but the condition of main ore deposition can be summarized as follows. Fluid inclusion, S-istope geothermometry and geothermometry based on mineral chemistry by use of arsenopyrite and chlorite show the ore was formed at temperature between 399 and $210^{\circ}C$ from fluids with salinities of 3.3-5.8 wt.% equivalent NaCl. It indicates that pressure during the mineralization is less than 0.6 Kb corresponding to a depth not greater than 1Km. S-isotope data suggests that thermal fluid may have magmatic origin wit some degree of mixing with meteoric water. In coclusion, the Inseong gold-silver deposit was formed at shallow depth and relatively high-temperature possibly with steep geothermal gradient under xenothermal condition.