• 암석학회지
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• 제23권2호
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• pp.119-138
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• 2014

활화산을 감시하는 방법은 육안으로 직접 관찰하는 방법, 과거의 분화 기록 문건을 참조하는 방법, 직접적으로 관측 장비를 동원하여 화산체를 감시하는 방법 등이 있다. 이 중 관측 장비를 이용하여 화산체를 감시하는 방법 중 가장 기본적인 것은 지진활동도의 감시이며, 이외에도 지진계에 기록된 지진활동 중 인위적인 노이즈를 걸러내는 데 효과적인 공진 관측, 그리고 정밀수준기, 전자거리측정기, 경사계, GPS, InSAR 관측법을 통한 지표변형의 감시, 화산가스 감시, 수문학적/기상학적 감시, 기타 지구물리학적 감시 등의 방법이 있다. 이러한 감시 기법을 통해 화산의 활동을 효과적으로 감시하고 이를 통해 지하 마그마방에서의 마그마 거동을 파악함으로써 미래의 화산 분화를 보다 정확하게 예측하고 조기 경보하여 그에 따른 재해의 피해를 경감하고 최소화 할 수 있다.

• 자원환경지질
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• 제11권2호
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• pp.47-57
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• 1978

The study focused on the petrology and petrochemistry of the so called "Ganghwa syenitic rocks" which intruded into metasediment of basement in southeastern part of Ganghwa Island. The geologic sequence of the mapped area was shown in table 1, 10 model analyses and 7 chemical analyses on the rock samples taken from the Ganghwa syenitic rocks and Manisan granite have been used to discuss the nomenclature of the rocks and petrological relationship between rock types. The petrograpical and petrochemical features based on, the analyses are as follows: 1) Ganghwa syenitic rocks consist of Ganghwa alkali syenite and Ganghwa diorite porphyry which based on the classification of the subcommision on systematics of igneous of IGUS. Ganghwa diorite porphyry which occured as dike forms are intruded into Ganghwa alkali syenite. The rock forming minerals of Ganghwa alkali syenite are composed of perthite, plagioclase, quartz, hornblend and chlorite in major, and zircon, apatite, sericite and magnetite in minor. Ganghwa diorite porphyries consist of plagioclase, biotite, hornblend, orthoclase and chlorite, with, porphyritic texture. 2) In silica-oxides variation (Fig. 2) and AMF diagram (Fig_ 3), the Ganghwa alkali syenite is similar to the trend of Daly's average basalt-andesite-dacite-rhyolite than Skaergaard which shows the trend of the fractional crystallization of magma, and equivalent to the alkali rock series by Peacock. 3) The general trend of data points shift to plagioclase, and are superimposed on the alkali rich terminal part of the granodiorite province of SW Finland in normative Q-Kf-Pl(Fig. 4) and Or-Ab-An diagram respectively. The above-mentioned evidences suggested that the Ganghwa syenitic rocks are the differential products resulted by assimilation of intermediated magma and metasedment rock under relatively rapid cooling condition.

• 자원환경지질
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• 제47권2호
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• pp.97-105
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• 2014

청송 주왕산 화산암체의 최하부층인 대전사 현무암에서 산출되는 페퍼라이트는 화성활동과 퇴적작용의 동시성을 보여준다. 본 연구에서는 야외 조사와 이미지 분석, 편광현미경 분석, XRD 같은 실내 조사를 통해 주왕산 페퍼라이트의 형태를 분류하고 형성과정을 유추함으로써 반응 메커니즘과 고환경을 연구하였다. 야외 조사 결과, 하부에서는 구형, 중부에서는 아각형, 상부에서는 불규칙형 페퍼라이트가 대표적으로 나타나며, 노두 규모에서 페퍼라이트 영역은 판상형, 유동형 그리고 공급통로형의 특징적인 구조로 산출된다는 것을 알 수 있다. 페퍼라이트의 형태는 마그마 또는 용암과 퇴적물의 종류에 의해 좌우된다고 연구되어 왔지만, 동일한 공급물에도 불구하고 다양한 형태로 페퍼라이트가 산출되는 것은 형성과정이 단일 메커니즘으로 이루어진 것이 아니라 여러 메커니즘의 복합적인 결과임을 나타낸다. 상하부에 따른 변화 중 가장 뚜렷한 변화를 보이는 퇴적물비로부터 생성 당시 모퇴적물의 공급량이 페퍼라이트의 형성과정에 영향을 미쳤을 것으로 추정한다.

• 자원환경지질
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• 제26권1호
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• pp.55-65
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• 1993

Udo Island, some 3 km off the coast of Sungsan Peninsula at the eastern promontory of Cheju Island, occurs in such a regular pattern on the sequences which reprent an excellent example of an eruptive cycle. The island comprises a horseshoe-shaped tuff cone, a nested cinder cone on the crater floor, and a lava delta which extends over northwest from the moat between two cones. The volcanic sequences suggest volcanic processes that start with emergent Surtseyan eruption, progress through Strombolian eruption and end with lava effusion followed by reworking of smooth tephra on the tuff cone. Eruptive environment and hydrology of vent area in the Udo tuff cone are poorly constrained because the stratigraphic units under the tuff cone are unknown. It is thoughl, however, that the tuff cone could be mainly emergent because the present cone deposits show no evidence of marine reworking, and standing body of sea water could play a great role. The emergent volcano is characterized by distinctive steam-explosivity that results primarily from a bulk interaction between rapidly ascending magma and a highly mobile slurry. The sea water gets into the vent by flooding accross or through the top or breach of tephra cone. Udo tuff cone was constructed from Surtseyan eruption which went into with tephra finger jetting activities in the early stage, late interspersed with continuous uprush activities and proceeded to only continuous uprush activities in the last. When the enclosure of the vent by a long-lived tephra barrier would prevent the flooding and thus allow the vent to dry out, the Surtseyan eruption ceased to transmit into Strombolian activities, which constructed a cinder cone on the crater floor of the tuff cone. The Strombolian eruption ceased when magma in the conduit gradually became depleted in gas. In the case of Udo, the last magmatic activity was Hawaiian-type (and/or fountain) which accumulated basalt lava delta. And then the loose tephra of the tuff cone reworked over the moat lava and the northeastern flank.

• 자원환경지질
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• 제12권3호
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• pp.115-126
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• 1979

The Jecheon granite mass has turtle-shape exposure of about $190km^2$ at vicinity of Jecheon-eup, and is elongated in the direction of NEE-SWW. It discordantly intrudes the Bakdalryong metamorphic rocks and the great limestone series(Samtaesan and Hungwolri formation) which belong to the pre-Cambrian and Ordovician, respectively. The mass is composed of five facies of different grain size; texture and charecteristic minerals. The five facies are (1) coarse grained biotite granodiorite, (2) fine grained hornblende biotite granodiorite, (3) coarse grained pink feldspar granodiorite (4) leucogranite, and (5) porphyritic biotite granite. The mutual relationship between each facies is intrusion in (1)-(2) and (2)-(3), but unknown in (3)-(4) and (4)-(5). 22 modal analyses and and 10 chemical analyses on more than a hundred of representative samples taken from the mass are listed as tables. Triangular plot of modal and normative Q-Kf-Pl of this mass show a continuous differentiation products from certain common magma by change of chemical composition and anorthite contents in plagioclase. The metamorphic facies of contact aureole in surrounding rocks adjacent to the granite body are corresponded to hornblende hornfels facies with mineral assemblages of wollastonite-diopside-calcite in calcareous rocks, and of quartz-biotite-muscovite-cordierite in argillaceous rocks. Variation of silica versus oxides of major elements shows that the mass is similar to the trend of Daly's average basalt-andesite-dacite-rhyolite which shows the trend of the fractional crystallization of magma, and is equivalent to the calc-alkali rock series by Peacock. AMF diagram shows that Jecheon granite mass is equivalent to normal diffentiation products such as skaergaard intrusion. The above evidences suggest that the Jecohon granite mass is normal differentiation products formed by fractional crystallization under relatively slow cooling condition.

• 자원환경지질
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• 제27권4호
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• pp.335-343
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• 1994

The Eonyang amethyst deposits are composed of vug quartz emplaced in the Eonyang granites of Mesozoic Cretaceous age. The Eonyang granites are composed of biotite granite, porphyritic biotite granite, aplite and miarolitic granite. The petrochemical data of the Eonyang granites show the trend of subalkaline magma, calc-alkaline magma, I-type granitoid and magnetite series. The vug quartz show the characteristic growth zoning (white quartz-smoky quartz-amethyst) from wall side. Generally fluid inclusions in the vug quartz can be divided into four main types based on compositions (I-type: gas inclusion, II-type: liquid inclusion, III-type: polyphase inclusion, IV-type: liquid $CO_2$-bearing inclusion). Solid phase of polyphase inclusions are halite(NaCl), sylvite(KCl), hematite ($Fe_2O_3$) and unknown anisotropic solid. Homogenization temperatures inferred from the fluid inclusion study ranges from $440^{\circ}C$ to $485^{\circ}C$ in white quartz, from $227^{\circ}C$ to $384^{\circ}C$ in smoky quartz, from $133^{\circ}C$ to $186^{\circ}C$ in amethyst, respectively. Salinities of fluid inclusions in each mineralization stages ranges from 40 wt.% to 58 wt.% in white and smoky quartz, from 1.0 wt.% to 8.7 wt.% in amethyst respectively. A consideration of the pressure regime during vug quartz deposition based on the boiling evidence suggests lithostatic pressure of less than 72 bars. This range of pressure indicate that vug quartz lay at depth of 750 m below the surface at the during mineralization.

• 한국광물학회지
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• 제21권4호
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• pp.373-382
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• 2008

제주도 동북사면에서 발견된 선흘리 스피넬 페리도타이트 맨틀포획 암의 지화학적 특성은 처음보고 되는 것으로 제 4기 제주도 동북사면 하부에 위치한 상부맨틀의 화학 조성, 평형 온도, 마그마 정체 시간에 관한 일련의 정보를 제공하여 준다. 감람석($Fo_{89-90}$)을 포함한 스피넬 페리도타이트 내 구성광물들의 화학 조성은 일정하며 광물 중심부와 연변부의 화학 조성 차이 또한 크지 않다. 사방휘석-단사휘석 지온계를 이용하여 얻은 평형 온도 범위(약 $951{\sim}1035^{\circ}C$)는 기존 제주도 다른 지역에서 산출되는 맨틀포획암에서 얻어진 온도 범위와 유사하다. 스피넬 페리도타이트가 모마그마에 포획되어 정체된 시간은 확산방정식과 감람석 내 칼슘 농도 변화를 이용하여 계산하여 본 결과 약 42일이다.

• 암석학회지
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• 제26권4호
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• pp.341-352
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• 2017

영덕 서부에서 산출되는 지품화산암층은 하부로부터 유문암질 화성쇄설암, 층회암, 안산암질 유리쇄설암, 유문암 용암, 응회질 역암, 안산암 용암 순으로 구성되는 층서단위이다. 유문암질 화성쇄설암은 SHRIMP U-Pb 연대측정에 의해 $68.5{\pm}1.6Ma$로 측정되었다. 이 층서단위는 이 무렵에 대부분 유문암질 화산작용에 의해 형성되었으며 국부적이지만 다른 화구로부터 안산암질 화산작용에 의해 추가되었다. 유문암질 화산작용은 먼저 수증기마그마성 폭발작용으로 인해 화성쇄설층을 형성시켰고, 나중에 유문암질 화산작용이 재개되어 기존 화구로부터 용암 분류작용으로 유문암질 용암돔을 형성하였다. 1차 및 2차 유문암질 화산작용 사이에 화산 말단부의 낮은 저지는 침수되어 층회암층이 퇴적되었고 연이어 다른 화구에서 안산암질 화산작용이 일어나 흘러나온 용암이 호수물과의 접촉에 의해 급냉파쇄작용으로 유리쇄설암을 형성하였으며, 마지막으로 다시 안산암질 용암이 재차 흘러들어와 지품화산을 얇은 안산암 용암층으로 덮었다.

• 자원환경지질
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• 제31권2호
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• pp.149-158
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• 1998

Volcanic rocks including rhyolitic tuff, rhyolite and welded tuff in the Bupyeong silver mine area form a topographic circular structure known as a resurgent caldera. Granitic rocks are emplaced inside and outside area of the circular structure. K-Ar dating and Nd-Sr isotope studies were carried out to invesitigate the origin and petrogenetic evolution of the rhyolitic and granitic magma in the Bupeong silver mine area. Whole rock K-Ar age ranges from 208 to 131 Ma for rhyolitic rocks. Radiometric ages for the granitic rocks are 167.6 Ma for pink feldspar biotite granite from inside granitic pluton of the circular volcanic body, 178.8 Ma for the Kimpo hornblende biotite granite and 111.8 Ma for the Songdo foliated granite from outside granitic plutons of the volcanic body. The radiometric age data indicates that the volcanic activities which are partly overlapped by granite plutonic activities in the Bupyeong mine area had recorded early Jurassic and early Cretaceous in age. Initial Sr and Nd isotopic ratios of the rhyolitic rocks ($^{87}Sr/^{86}Sr$=0.710~0.719 and $^{143}Nd/^{144}Nd$=0.5115~0.5118) are similar to those of granitic rocks ($^{87}Sr/^{86}Sr$=0.709~0.716 and $^{143}Nd/^{144}Nd$=0.5115~0.5116) from inside granite stock. This means that similar source materials of felsic magma responsibles for the Bupyeong volcanic rocks and inside plutonic rocks. Based on the Nd and Sr isotopic compositions, rhyolitic and granitic magmas in the Bupyeong area originated from the partial melting of the old continental crust which has Nd model age ranging from 1500 to 2900 Ma. This is analogous to those of the other Jurassic granitoids in South Korea.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권2호
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• pp.25-37
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• 2014

The volcanic type of geothermal water is linked intimately to active or potentially active volcanoes and takes place near the plate boundaries. In contrast to the volcanic type, the geothermal water in Korea has a non-volcanic origin. Korea's geothermal water is classified into the residual magma (RM) type and deep groundwater (DG) type according to the criterion of $35^{\circ}C$. This study reviewed the relationship between the physical and chemical features of the 281 geothermal water sources in South Korea in terms of the specific capacity, water temperature, and chemical compositions of two different basements (igneous rock and metamorphic rock) as well as the geological structures. According to the spatial relationship between the geothermal holes and geological faults, the length of the major fault is considered a key parameter determining the movement to a deeper place and the temperature of geothermal water. A negligible relationship between the specific capacity (Q/s) and temperature was found for both the RM type and DG type with the greater specific capacities of the RM- and DG-igneous types than the RM- and DG-metamorphic types. No relationship was observed between Q/s and the chemical constituents ($K^+$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$, $Zn^{2+}$, $Cl^-$, $SO_4{^{2-}}$, $HCO_3{^-}$, and $SiO_2$) in the DG-igneous and DG-metamorphic types. Furthermore, weak relationship between temperature and chemical constituents was found for both the RM type and DG type.