• 한국광물학회:학술대회논문집
• /
• 한국암석학회.한국광물학회 2000년도 공동학술발표회 논문집
• /
• pp.24-24
• /
• 2000

We studied about petrological characteristics of the Bangeujin granite belongs to porphyritic biotite granite, petrogenesis of the enclaves in the granite and contact metamorphism of the sedimentary rock around the granite. The enclaves in the granite are concentrated in the eastern part of the Mipo fault but in the western part, these are rare. The enclaves can be divided into three types according to the petrographical characteristics. These three types are: (1) enclaves having few phenocrysts and fine grained igneous texture and ellipsoid is predominant; (2) enclaves similar In petrographical characteristics and having many phenocrysts considered as being originated from the granitic host rock; and (3) enclaves corresponding to granite in mode composition, having large phenocrysts and of which the matrix is corresponding to fine granular. First two types are correspond to mafic micro granular enclaves and the third is corresponds to felsic microgranular enclaves. In addition, the felsic microgranular enclaves capture the mafic microgranular enclaves. The fact that the compositions of biotite and plagioclase in the enclaves are nearly identical with those of biotite and plagioclase in the granitic host rock is considered as the results of supporting magma mingling. The major elements show well the linear variations as the SiOz$.$ content increases. The rare earth elements content decrease with increasing SiOz content, interpreted as the results of magma mingling. Therefore, we can conclude that the Bangeujin granite captured the felsic microgranular enclaves formed by collapse of early chilled margin during the crystallization and there was magma mingling by the injection of the mafic magma after that time. In addition, these aspects are predominant in the eastern part of the Mipo fault is considered as related to the fault movement.vement.

• 한국석유지질학회:학술대회논문집
• /
• 대한자원환경지질학회/한국석유지질학회/한국암석학회 2000년도 추계공동학술발표회 초록집
• /
• pp.68-68
• /
• 2000

• 암석학회지
• /
• 제25권4호
• /
• pp.349-360
• /
• 2016

부남암주(면적 $29.5km^2$)는 조립질 화강암, 석영몬조섬록암, 화강섬록암과 세립질 화강암 등의 4개 암상으로 분류되는 심성암 복합체이다. 세립질 화강암을 제외한 3개 암상은 석영몬조섬록암을 중심으로 화강섬록암과 조립질 화강암 순으로 동심원상 누대분포를 나타내며, 암상 간에는 매우 불규칙한 경계를 가지고 점이적 조성변화를 나타낸다. 또한 화강섬록암에서는 둥근 모양의 고철질 미립상 포유체(MME)를 흔하게 산출한다. 얼마의 MME는 경계가 들쭉날쭉하고 모양이 수평면에서 원상이지만 수직벽에서 상하로 긴 타원상이며 입도가 대개 세립질이지만 극세립질 냉각연변대를 가진다. 이러한 모양과 입도는 부분적으로 결정질인 규장질-고철질 마그마의 동시성 흐름과 혼화작용을 지시한다. 즉 MME는 규장질 마그마 속으로 주입하는 고철질 마그마가 방울로서 과냉각됨으로 타원체 모양을 이루며 어두운 극세립질 연변대를 나타내는 것이다. 부남암주에서 관찰되는 동심원상 누대분포, 불규칙한 경계 및 점이적 조성변화, 화강섬록암에서 MME의 산출과 타원체 배열 및 냉각연변대 등의 야외관계들에 의하면 두 개의 단구성원은 규장질 마그마에 의한 조립질 화강암과 고철질 마그마에 의한 석영몬조섬록암이고, 혼성암은 포유체를 함유하는 화강섬록암이라는 것이 증명된다. 그리므로 이들은 규장질 마그마 속으로 고철질 마그마가 주입할 때 중간에 혼합작용이 일어남으로써 고철질 단구성원을 중심으로 동심원상 누대를 나타내는 것이다. 여기서 석영몬조섬록암은 화강암질 마그마챔버 속으로 운반되는 고철질 마그마의 고기 화도를 나타내는 것으로 볼 수 있다. 고철질 마그마는 마그마 혼합작용에 효과적인 환경으로서 화도를 통해 상승하였던 것이다. 이러한 모든 특징은 부남암주에서 칼크알칼리 마그마의 혼합과정에 의해 만들어졌음을 암시해준다.

• 자원환경지질
• /
• 제19권3호
• /
• pp.179-192
• /
• 1986

In the Bupyeong district, Mesozoic pyroclastic rocks, intrusive breccia, granites and felsic porphyries comprise a volcano-plutonic complex, overlying and intruding the Precambrian Gyeonggi gneiss complex. pyroclastic rocks, consisted mainly of rhyolitic welded tuffs, form a topographic circular structure about 10 kilometers in diameter. Granites and felsic porphyries which intruded the pyroclastic rocks are distributed in the inner side and also along the outer margin of the circular structure. K-Ar ages of two granite bodies(biotite), 162 and $148{\pm}7$ Ma, and that of the intrusive rhyolite (whole rock), $121{\pm}6$ Ma indicate that a series of volcano-plutonic igneous activity occurred between Jurassic and early Cretaceous age. Petrochemical characteristics suggest that the pyroclastic rocks, granites and felsic porphyries were originated from the comagmatic source. From the evidences of field occurrence, petrochemical and geochronological characteristics of igneous rocks and the geologic structures, it is believed that the igneous rocks in the Bupyeong district were formed during a Jurassic to early Cretaceous resurgent caldera evolution.

• 자원환경지질
• /
• 제30권6호
• /
• pp.603-612
• /
• 1997

경상누층군이라 불리는 백악기 육성퇴적암-화산쇄설물들은 백악기 말-제3기초의 화강암류에 의해 관입 되어 있다. 의성-신령지역의 화강암류는 다양한 암상과 화학조성을 갖는다 : 반려암; 46.9, 섬록암; 58.3, 흑운모 화강암; 66.3~69.3, 장석 반암; 71.0 wt.% $SiO_2$. 화산암류는 화학적으로 금성산 칼데라에서는 안산암질 성분이 결여 된 현무암-유문암의 bimodal 유형과 선암산-화산 칼데라에서는 안산암-유문암의 felsic 유형으로 나뉜다. 대부분의 화성암류는 비알칼리 계열에 속하고, 칼크-알칼리 마그마의 분화 경로를 따른다. 화강암류는 높은 Zr/Y비에 의해 화산암류와 잘 구별된다. 화산암류에서 Zr/Y와 K/Y비의 차이는 맨틀기원 및 분별작용에서 불균질로 설명될 수 있다. 콘드라이트로 균질화된 희토류 원소량은 화강암류에서 Th와 K이 결핍되어 있고, 금성산 칼데라의 유문암에서 Sr와 Ti의 결핍되어 있다. 선암산-화산 칼데라의 유문암은 Rb, La 및 Ce이 부화되어 있다. $Rb-SiO_2$와 Rb-Y+Nb의 관계도는 화강암류와 화산암류가 화산호 환경이었음을 암시한다. K-Ar 연대는 4회의 심성활동 (섬록암; 89 Ma, 화강암; 64~62 Ma, 화강암/반암류; 55~52 Ma, 반려암; 52~45 Ma)으로 나뉘고, 금성산 칼데라의 bimodal 유형 (71~66 Ma)과 선암산-화산 칼데라의 felsic 유형 (61~54 Ma)으로 특징지워지는 화산활동이 수반되었다. 지화학 및 연대측정 자료들은 화성암류가 백악기말-제3기초 동안 다양한 지질학적 에피소드의 결과로 형성되었슴을 암시한다.

• 자원환경지질
• /
• 제33권3호
• /
• pp.217-228
• /
• 2000

We use spectral correlation method to analyze gravity and magnetic anomalies of Euiseong Sub-basin for distribution of rock facies and gelogic structures. The analysis reveals distinct polarity between gravity and magnetic anomaly correlation ; intermediate to mafic intrusives, extrusives, and the Tertiary basin shows positive gravity (+G) and positive magnetic (+M) correlation. Granitic gneiss and felsic volcanics negative gravity 9-G) and negative magnetic (-M) correlation. The Palgongsan granite, felsic to mafic extrusives and Mesozoic granites are characterized by -G and + M correlation. +G and -M correlations in the sedimentary formations are interpreted by uplift of pre-Cretaceous basement rocks . The + G and + M correlation characteristics in northeastern part of Euiseong Sub-basin including the Tertiary sedimentary basin result from the uplift of crustal materials. Major axes of spectrally correlated amomalies have mostly NW-SE or NE-SW directions. The former is due to the intrusives along strike-slip faults, and the latter which is observed in sedimentary formations is related to geological structures of basement associated new insight into the boundary between Euiseong and Milyang Sub-basin.

• 자원환경지질
• /
• 제19권spc호
• /
• pp.175-191
• /
• 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.

• 자원환경지질
• /
• 제19권1호
• /
• pp.35-55
• /
• 1986

The area of this study is located in the Sang dong district, Youngwol Gun, Kangwon Do, where the Ogcheon fold belt comes into contact with the Ryongnam massif. The area is covered by the Precambrian metasedimentary rocks of Yulri Group in the south from the line of Ungyosan-Maebongsan-Jansan-Taebaegsan Mountains and by the Cambro-Ordovician sedimentary rocks of Choseon Supergroup in the north. The Choseon Supergroup unconformably overlies the Yulri group. Several granitic intrusives occur in the Precambrian and Cambro-Ordovician terrain. The purpose of this study is to clarify the geochronology, mineralogical composition, geochemical characteristics, petrogenesis and tectonic settings of the Precambrian granitic rocks, and to evaluate the P.T. conditions of granitic intrusions. The K/Ar ages obtained from the muscovite of Nonggeori Granite, Naedeogri granite and pegmatite intruded into the Yulri Group are Early Proterozoic ($1805{\pm}18Ma$ to $1642{\pm}23Ma$), and those from the migmatitic pegmatite are Late Carboniferous ($305{\pm}4Ma$), respectively. The Precambrian granitic rocks are characterized by the presence of muscovite, tourmaline and grey feldspar with faint lineation of mafic minerals. In terms of mineralogical and chemical composition, the granitic rocks are felsic, calc-alkalic, peraluminous and S-type (ilmenite-series). The geochemical characteristics of major and trace elements indicate that the granitic rocks belong to syn-collision setting at the compressional plate margin. They were formed by progressive melting of relatively homogeneous crustal materials under 1~3kb and $670^{\circ}{\sim}720^{\circ}C$ in aqueous fluid conditions, and the Naedeogri granite was more fractionated than the Nonggeori granite. During the Taebaeg disturbance, Nonggeori granite, Naedeogri granite and pegmatite were intruded and emplaced into the Yulri Group. Migmatitic pegmatite occurring in the southwestern area, however, gave much younger muscovite age than the pegmatite intruded into the Yulri Group in rest of the area did, that might be due to the regional metamorphism of the Post-Choseon disturbance. The Geodo granitic mass and the Imog granite were intruded during the Bulgugsa disturbance.

• 보존과학회지
• /
• 제35권2호
• /
• pp.131-144
• /
• 2019

서산 검은여는 충남 서산시 부석면의 천수만에 있던 암초로, 현재는 육지에 노출되어 있다. 이 일대의 고지도에는 검은여가 표기되어 있으며, 지역의 명칭인 부석과 부석사가 여기에서 유래되었다고 한다. 검은여를 구성하는 암석은 초염기성암복합체와 이를 관입한 규장질화성암류이다. 이들은 위치에 따라 다양한 산출상태를 보이며 관입과 변질 등의 지질학적 작용을 받은 여러 특징들이 관찰된다. 초염기성암복합체는 크게 조립질 초염기성암과 중립질 염기성암으로 구분할 수 있다. 두 암석 모두 휘석과 각섬석으로 구성되어 있으며, 전반적으로 휘석암, 휘록암 및 황반암의 암상을 보인다. 규장질화성암은 담홍색중립질화강암, 반정질각섬석화강암 및 반화강암 등이며, 광물조성은 암석에 따라 차이가 있다. 검은여는 천수만 일대의 유일한 초염기성암복합체로 지질학적 및 경관적 차별성과 상징성이 충분하여 잠재가치가 뛰어난 것으로 판단하였다. 따라서 이를 보존하기 위한 학술적 연구와 편의 및 보호시설 등에 대한 보완을 통해 지정문화재로의 검토와 추진이 필요하다. 또한 검은여를 지역의 명소로 생각하던 선조들의 인식을 현대적으로 계승한다는 점에서 독특한 지방문화를 간직한 해양유산으로 평가되어야 할 것이다.

• 암석학회지
• /
• 제8권1호
• /
• pp.46-55
• /
• 1999

Fluid inclusions in granite and hydrothermal quartz indicate that three fluids have affected the Sannae granite. The earliest fluid is represented by three-phase aqueous fluid inclusions with high salinity (38 to 46 wt.% NaCl equiv.). It was exsolves from a crystallizing melt and trapped at a relatively high-pressure condition. The secong fluid is represented by two-phase aqueous fluid inclusion with low entectic temperatures (< $-40^{\circ}C$). low- to moderate salinity (3 to 24.0 wt.% NaCl equiv.) and high homogenization temperatures$ ($309^{\circ}C$$473^{\circ}C$)($. This fluid was trapped at higher pressures than 300-500 bars and precipitated molybdenite and wolframite in quartz veins. It was probably generted by fluid-host rock interactions since they show a wide range of salinity within a narrow range of homogenization temperatures. The final fluid is represented by an aquenous fluid boiling that separated into high-salinity (34-38 wt.% NaCl equiv.) and low-salinity fluid (0 to 8.7 wt.%) at $303-376^{\circ}C$ and 50-150 bars. These boiling fluids precipitated euhedral quartz in miarolitic cavities. The compositions of the final fluid was rather complex in the $H_2$O-NaCl-KCI-$FeCl_2$ system. The Sannae granite was a locus for repeated fluid events including magmatic fluids during the final stage of crystallization, the convection of hydrothermal fluids causing a fluid ascending, fluid boiling, and the local W-Mo mineralization and formation of miarolitic cavities due to thermal, tectonic and compositional properties of the felsic granite.