• Economic and Environmental Geology
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• v.14 no.1
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• pp.1-25
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• 1981

This paper is a literature review on the following subjects: 1) relationships between porphyry molybdenum and copper systems; 2) hydrothermal environments of molybdenite depositions; 3) genetic significance of molybdenite polyforms; and 4) trace element patterns in molybdenite useful as an exploration guide. The geologic similarities between porphyry molybdenum (e. g. Climax) and porphyry copper (e. g. Bingham) systems exist, and similar techniques can be applied for exploring deposits of either type. Several features suggest that tungsten and tin may form porphyry-like systems (i. e. lowgrade, large tonnage). The clustering of porphyry-like systems in geophysically distinctive batholithic provinces is well documented and provides larger targets for reconnaissance exploration. Geochemical studies suggest that uranium should often occur in close proximity to molybdenum ores in igneous as well as sedimentary environments.

• Journal of the Mineralogical Society of Korea
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• v.19 no.2 s.48
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• pp.99-109
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• 2006

Igneous rocks occurring in the northwesern part of Keumsan area, Chungcheongnam-do were studied petrogeochemically. The geology of this area is composed mainly of the Precambrian biotite gneiss, age-unknown Ogchon supergroup, Jurassic biotite granite, and Cretaceous volcanic rocks, pink feldspar granite and quartz porphyry. The biotite granite is gradually changes to leucocratic nature by going from center to periphery of the rock mass. It shows variation, with distance from the center, in chemical components: $SiO_2,\;Na_2O\;and\;K_2O$ increase, whereas $Fe_2O_3,\;CaO,\;P_2O_5,\;MgO,\;and\;TiO_2$ decrease. Based on geochemical data, the biotite granite and quartz porphyry belong to subalkaline series and I-type. They show calc-alkaline differentiation trend. The biotite granite shows little negative Eu-anomaly pattern, whereas quartz porphyry show marked negative Eu-anomaly pattern, indicating that quartz porphyry was evolved further, when compared with biotite granite.

• Economic and Environmental Geology
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• v.49 no.3
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• pp.193-199
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• 2016

Constancia mine is a deposit developed within Andahuaylas-Yauri Cu-Mo-Au metallogenic belt, southeastern Peru and is located in the southwestern part of Abancay deformation zone structurally as the porphyry copper deposit type. Mineralized zone in Constancia mine are composed of leached zone, secondary enrichment zone(ca. 1% Cu), mixed zone, primary mineralized zone(ca. 0.5%), skarn zone(ca. 1.5% Cu) from the upper part. Main country rock is monzonitic porphyry. Leached zone are characterized by the precipitation of limonite and looks brown in the outcrop. Oxidized zone have green due to the occurrence of copper oxide and secondary enrichment zone are characterized by the occurrence of chalcocite. Skarn zone are characterized by the occurrence of magnetite and garnet. Now, Hudbay, Canadian mining company, have 100% share about Constancia mine and started to produce commercially from January, 2015.

• Economic and Environmental Geology
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• v.13 no.2
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• pp.69-79
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• 1980

Granitic rocks, from the Eonyang and the northwestern part of Ulsan area, were mainly studied from the petrochemical point of view. From field work, microscopic observation and the result of K-Ar ages, these granitic rocks are divided into six rock types of a, b, c, d, e and e', of which modal composition are given. Type a, c, e and e' are mainly granodiorite, type b is adamellite, and type d is granodiorite, adamellite and others (porphyritic rock, porphyry and felsitic rocks). Bulk chemical analyses of 22 samples of the granitic rocks are given. The petrographical and petrochemical characteristics of these rocks are discussed briefly. In the petrochemical compositions with their characteristic variation trends of several oxides and norm Or-Ab-An triangular diagram, type a, b and c show some similarity to that of San-yo granite of Japan and younger granite of Ogcheon geosynclinal zone, and then, type e and e', to San-in granite of Japan. But, some of granitic rock samples of type d are similar to San-yo granite and the others of type d to San-in granite because this type is composed of porphyritic rock, porphyry and felsitic rocks. According to the result of K-Ar ages (1976, Lee et al.) of rock samples from type a, b and care Cretaceous, on the otherwise, type d, e and e', are Tertiary granitic rocks. Judging from these evidences, granitic rocks in the area are correlated to the Cretaceous and Tertiary granitic rocks in the, southwestern Japan, that is, type a, band c are correlated to San-yo granite, and type d, e and e' to San-in granite.

• Economic and Environmental Geology
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• v.44 no.2
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• pp.109-122
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• 2011

The major Mo deposits in South Korea were formed during the Jurassic Daebo orogeny, the Late Cretaceous and the Tertiary post-orogenic igneous activities, and are characterized by a variety of genetic types such as pegmatite, greisen, skarn, porphyry and vein types. The Jangsu mine is a pegmatite-style deposit which is genetically related to the Jurassic ilmenite-series two-mica granite with the Mo mineralization age of $159.6{\pm}4.5$ Ma. The Geumseong mine occurs as a skarn/porphyry-style deposit associated with highly fractionated granite. Its age of Mo mineralization within aplitic cupola is about 96.5~l07.5 Ma. The Yeonil mine is a porphyry-style deposit, and the Geumeum mine is a veinlet-style deposit along the fracture zone with their mineralization ages of $58.4{\pm}1.6$ and $54.4{\pm}1.2$ Ma, respectively. The contrasts in the style of Mo mineralization in Korea reflect the different environment of the related magmatism. The Jurassic mineralization, being related to deep-seated granitoids, occurs as a pegmatite-style deposit, whereas the Cretaceous one, being related to subvolcanic granitoids, occurs as skarn/porphyry/vein-type ore deposits. The Tertiary Mo mineralization has a close relationship with the igneous activities associated with the Tertiary basin formation along the east coast, Korean peninsular.

• Economic and Environmental Geology
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• v.9 no.2
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• pp.85-106
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• 1976

The Bulgugsa acidic igneous rocks of the late Cretaceous age are largely distributed in Busan area, which is located in the southeastern corner of the Korean Peninsula. These igneous rocks comprise in ascending order, felsite, dacitic-rhyolitic welded tuffs, granite porphyry and granitic rocks. The former three members represent the early phase of volcanic activities, so that they are named as Jangsan volcanic rocks. The granitic rocks consist of granodiorite, hornblende biotite granite, Kumjongsan granite, fine grained granite, and Daebyen granite, represent the late phase of igneous activities. The Kumjongsan grainte, the largest pluton of the granitic mass, emplaced between two great vertical faults trending NNE. New chemical analyses of 33 rock samples of these acidic rocks are given. Their chemical compositions are generally similar to those of the late Mesozoic acidic igneous rocks of the northern Ashio mountains, and C-Zone granite group of the Ogcheon geosyncline, with their characteristic variation trends of several oxides. Their chemical compositions also show that $Al_2O_3$ is high value, and differentiation index is high, too. Systematically developing joints in Kumjungsan granite are divisible into two types at least. One is the NS-N $20^{\circ}E$ trendirig, $85^{\circ}{\sim}90^{\circ}$ dipping type of joint system which coincides with the trends of distribution of the granite mass and the dikes intruding this granite. Joints of this type may be cooling joints generated as tension cracks. The other is the $N60^{\circ}{\sim}70^{\circ}W$ or $N40^{\circ}{\sim}60^{\circ}E$ trending type of joint systems. It is considered that. joints belonging to this type may be shear joint occurring under the state of south-north tectonic couple acting at the east and west side of the granite mass. Igneous activities of the the Bulgugsa acidic igneous rocks in Busan area was taken place as. follows, formation of the magma reservoir, eruption and intrusion of felsite, consolidation of vents. and increasing vapor pressure in magma reservoir, eruption of pyroclastic flows, caldera collapse, intrusion of granite porphyry, and intrusion of granitic rocks at the latest stage.

• Journal of the Korean Geophysical Society
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• v.7 no.2
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• pp.113-120
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• 2004

Hydrochemical characteristics of deep groundwater at Surak-ri, Nonsan-gun, Chungnam Province was explained by major ion concentration, water type, and phase stability diagram. The area is composed of meta-sedimentary rock and quartz pophyry. The 5 boreholes where deep groundwater was sampled and analyzed are located on the meta-sedimentary rocks and drilling depth range of the wells is from 554 m to 928 m. pH, TDS, Na, and SiO2 values are high in the groundwater from meta-sedimentary area intruded by quartz pophyry, while Ca is high in the groundwater from meta-sedimentary area. K and Mg concentrations are low but F concentration is high both groundwater. The content of major anions is in the order of CO3(HCO3)>Cl>SO4(F) in both geology, while that of major cations shows the order of Na>Ca>K(Mg) in meta-sedimentary area intruded by quartz porphyry and a>Na>Mg>Na in meta-sedimentary area. Based on the phase equilibrium in the systems Na2O-Al2O3-SiO2-H2O and K2O-Al2O3-SiO2-H2O, the groundwater is saturated with respect to Quartz and more evolved compared with the natural mineral water. It is concluded that chemical evolution in the groundwater from meta-sedimentary area intruded by quartz porphyry, is nearly saturated with respect to feldspar, while the groundwater from meta-sedimentary area continue to proceed with increasing pH by reaction of feldspar.

• Economic and Environmental Geology
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• v.19 no.spc
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• pp.175-191
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• 1986

The Geodo granodiorite intruded into the Joseon Supergroup is fine-grained at the marginal part, and medium-grained and more leucocratic at the central part. The Quartz monzonite porphyry intruded inte Precambrian granite and Geodo granodiorite has abundant plagioclase phenocryst. The Imog granite intruded into the Yulri Group and the Joseon Supergroup is mediumgrained biotite granite with partly pinkish feldspar phenocryst. The K/Ar ages obtained from the biotite of the Geodo granodiorite and Imog granite are Early ($111{\pm}1{\sim}107{\pm}1$ Ma) and Late ($93{\pm}1{\sim}92{\pm}1$ Ma) Cretaceous, respectively. The K/Ar sericite age of the quartz-sericite zone of the lower Jangsan quartzite occuring in the western area gave much younger age (about 170 Ma) than that of the Jangsan quartzite, that might be reset due to the regional metamorphism of the Daebo orogeny. The granitic rocks of the area are felsic to mafic, metaluminous to peraluminous, calc-alkalic (alkali-lime index${\fallingdotseq}$ 57) and I-type (magnetite-series) based on the chemical data_ And they appear to have been fractionated at the order of Geodo granodiorite, Quartz monzonite porphyry and Imog granite. In terms of mineralogy, geochemistry and K/Ar biotite age, a rock suite of monzodiorite, quartz monzodiorite and quartz monzonite-granodiorite in the Geodo stock was fractionally differentiated from a magmatic body from its margin to inward.

• Economic and Environmental Geology
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• v.41 no.3
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• pp.335-344
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• 2008

The acid rock drainage (ARD) production potential of rock was assessed for a tunnel construction area, Kimhae and the damage reduction strategy was discussed based on the ARD risk evaluation. The geology of the studied area consisted of Mesozoic quartz porphyry, sandstone, tuff and granite. Sulfides occurred as a disseminated type in quartz porphyry and granite, and a vein type in sandstone. Quartz porphyry and sandstone with a high content of sulfide were classified as a potentially ARD forming rock. The drainage originated from those rocks may acidify and contaminate the surrounding area during the tunnel construction. Therefore, the drainage should be treated before it is discharged. A slope stability problem due to the ARD was also expected and the coating technology was recommended for the reduction of ARD generation before the application of supplementary work for enhancing slope stability such as shotcrete and anchor. From the ARD risk analysis, those rocks should not be used as aggregate and be used as bank fill material with the system for the minimum contact with rain water and ground-water.

• Economic and Environmental Geology
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• v.2 no.1
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• pp.13-33
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• 1969

The Mulkum mine, located in Mulkum-myon, Yangsan-Kun, Kyeongsang Province, is one of the biggest iron mine in Korea. The geology of this mine and its vicinity consists of Chusan andesitic rocks and Datae-dong andesite porphyry of the Kyeongsang System which were intruded by biotite granite widely distributed near the vicinity of Mulkum-ni. The ore deposits, embedded in Dotae-dong andesite porphyry, are fissure-filling vein type in origin. Up to present ore bodies of Main vein, No. 2 vein, Eastern No. 1, 2 vein and Western No. 1 vein are exploited. Generally the veins strike N 10-25 E and dip to 60-90 SE. The proved length of vein is more than 500 meters and its depth 150 meters in Main vein with 3-4 meters of thickness in average. Ore minerals are mainly magnetite and locally associated with small amounts of hematite, sphecularite and chalcopyrite. Gangue minerals are quartz, epidote, chlorite, pyroxene, and garnet, etc. The modes of occurrence of vein are as follow; 1. Branching and parallel vein patterns are observed around main shaft in -1 level. 2. Multiple cymoid loops and subrectangular vein patterns are observed around main shaft in -2 level. 2. Single vein patterns are observed in -3 and -5 level. The ore-shoots plunge northeasterly about 20-30 degrees. In conclusion, the tectonically fractured zone belongs to the poorly mineralized zone and shoots are formed as single vein type. The general trends of one-shoots must be applied the prospecting of the deep-seated ore body in the deposits.