제주도 동부 알칼리 현무암내 스피넬-레졸라이트 포획체의 연구

윤성효,고정선,안지영,Yun, Sung Hyo,Koh, Jeong Seon,Anh, Ji Young 대한자원환경지질학회 1998 자원환경지질 Vol.31 No.5

The spinel Ihelzolite of ultramafic xenoliths are found in the alkali basalt from eastern part of the Cheju island, Korea. The xenolith is are mainly composed of olivine, orthopyroxene, clinopyroxene and spinel. Based on the chemical compositions of the constituent minerals, the ultramafic xenolith belong to upper mantle peridotite. Each minerals have a protogranular texture. Olivine with kink band texture partly shows undulatory extinction. Some clinopyroxenes have spongy textured rims. Brown spinels occur in the interstices between olivine and pyroxene grains. Olivine is mostly forsterite $(Fo_{89-90})$. Orthopyroxene is enstatite $(Wo_{1.3}En_{88.4}Fs_{10.3})$ with 3.87~5.25 wt% $Al_{2}O_{3}$. Clinopyroxene is diopside $(Wo_{48.0}En_{46.2}Fs_{5.8})$ with 6.75~5.03 wt% $Al_{2}O_{3}$. Spinel has the Mg value of 75.9 and its Cr-number is 10.2. According to the PoT estimations for the mantle xenoliths, equilibrium temperatures of the xenoliths range from 1023 to $1038^{\circ}C$ and pressure is 18 kbar. Spinellhelzolite from this area, which is characterized by lower Cr-number (10.2) and homogeneous chemical compositions, supports that these ultramafic xenoliths are derived from the upper mantle.

경상분지 동북부 보경사화산암체의 암석학적 연구

윤성효,이문원,고정선,김영라,한미경,Yun, Sung-Hyo,Lee, Moon-Won,Koh, Jeong-Seon,Kim, Young-La,Han, Mi-Kyeong 한국지구과학회 2000 한국지구과학회지 Vol.21 No.5

This study has been designed to elucidate the petrography and geochemical characteristics of the volcanic rocks and focused on petrogenesis and tectonic environment of the Bokyeongsa volcanics in the northeast Gyeongsang Basin. The Bokyeongsa volcanics consist of the Naeyeonsan tuff which include rock fragment plagioclase, quartz and hornblende and pumice showing welded structures, and felsite. According to the petrochemical data, the Naeyeonsan tuff and felsite are in the range of 68${\sim}$71wt% and 77wt% SiO$_2$ content respectively. The Naeyeonsan tuff belongs to dacite/rhyodacite, and felsite to rhyolite. These volcanics rocks belong to the calc-alkaline rock series on the TAS diagram and the AFM diagram. The variations of major elements of the volcanic rocks show that contene of TiO$_2$, Al$_2$ O$_3$, FeO$^T$, MnO, MgO, CaO are inversely proportional to those of SiO$_2$, but contents of K$_2$O are positively. They represent differentiation trend of calc-alkaline rocks series. In spider disgram of MORB-normalized trace element partterns, contents of K, Rb, Th and Ta are relatively high, but those of Nb, Zr, Hf, Ti, Y and Yb are nearly similar to MORB. In the chondrite-normalized REE patterns, light REEs are more enriched than heavy REEs. The trace element composition and REE patterns suggest that they are typical island-arc calc-akaline volcanic rocks formed in the tectonomagmatic environment of subduction zone under continental margin.

중국 북동부 대흥안령 지역 중생대 화산암류에 대한 암석화학적 특성 연구

윤성효,원종관,이문원,임강,Yun, Sung-Hyo,Won, Chong-Kwan,Lee, Moon-Won,Lin, Qiang 한국지구과학회 2000 한국지구과학회지 Vol.21 No.1

We studied petrological and geochemical characteristics of the Mesozoic volcanic rocks in the Da Hinggan Ling area northeast China, and discussed tectonic settings and origin of the Mesozoic volcanic rocks in northeast Asia. Volcanic rocks in Da Hinggan Ling area are composed of alkaline to subalkaline basalt-basaltic andesite-andesite-dacite-rhyolite, showing typical BAR(basalt-andesite-rhyolite) association. However, most of the volcanic rocks are basaltic and rhyolitic in composition, and andesitic rocks are relatively rare, which shows bimodal characteristics. Rb, Ba, Th and other incompatible element contents in the volcanic rocks are enriched, but the contents decrease with increasing the compatibility. REEs are fractionated and REE patterns of volcanic rocks are characterized by a high LILE/HFSE. On the tectonomagmatic discriminant diagram of Hf-Th-Nb, they fall into the fields for subduction-related destructive plate margin basalts and its differentiates. We suggest that the tectonomagmatic setting of Da Hinggan Ling area was located at the continental margin arc related with subduction environment during the Mesozoic time or may be derived from mantle plume contaminated geochemically from subducting slabs, although it is, at present within the Asia continent.

포항분지(浦項盆地) 북부(北部)(칠포(七浦)-월포(月浦)일원)에 분포(分布)하는 화산암류(火山岩類)에 대한 암석학적(岩石學的)·층서적(層序的) 연구(硏究)

윤성효,Yun, Sung Hyo 대한자원환경지질학회 1988 자원환경지질 Vol.21 No.2

The purpose of this study is to determine the stratigraphy of the volcanic rocks in the Chilpo-Weolpo area, the north of Pohang basin, based on field survey and lithological properties of the rocks. The volcanic pile(Chilpo tuff) overlies the Cretaceous sedimentary formation and is unconformably overlain by the Miocene Yeonil Group. The Chilpo tuff comprises a thick sequence(>200m) of pyroclastic flow deposits. Five members are distinguished, each representing separate flow units, comprising none(or weakly) to densely welded rhyolite tuff. The Chilpo tuff consists of, in ascending order, greenish weakly welded tuff, volcanic conglomerate, alternation of tuff breccias and fine tuffs, greenish none to densely welded tuff and red-brownish densely to weakly welded vitric tuff. This study revealed that the volcanic rocks in this area were formed by 4 volcanic stages. On the basis of K-Ar age($44.7{\pm}1.1\;Ma$) and lithologic data, geological age of the Chilpo tuff may be Eocene.

전남(全南) 고흥반도(高興半島)에 분포(分布)하는 화산암류(火山岩類)의 화산층서(火山層序) 및 암석학적(岩石學的) 연구(硏究)

윤성효,황인호,Yun, Sung Hyo,Hwang, In Ho 대한자원환경지질학회 1988 자원환경지질 Vol.21 No.4

The author aimed to describe the volcano-stratigraphy and petrology of the volcanic mass in the Koheung peninsula, South Cheolla province. The volcanic mass is composed of the volcanics and intrusives of late Cretaceous which extruded the Pre-cambrian metamorphic(Jirisan gneiss complex) and the early Cretaceous sedimentary(Duwon Formation) basement. The volcanic pile consists of, in ascending order, Bibongsan andesite, Koheung tuff and breccia, and Palyeongsan welded tuff, and are intruded by ring intrusives( intrusive breccia, andesite porphyry, intrusive rhyolite and fine-grained quartz-diorite) and central pluton(diorite, quartz monzodiorite, biotite granite and micrographic granite). Bibongsan andesite mainly consists of andesite tuff and lava. Koheung tuff consists of alternation of fine tuff, coarse tuff and lapilli tuff, and Palyeongsan welded tuff which overlies Koheung tuff, comprises K-feldspar and quartz phenocrysts, elongated brown fiamme, lithic fragments in matrix of devitrified brown glass shards, and mainly consists of rhyodacite to rhyolite vitric ash-flow tuff. The results of petrochemical studies of the igneous rocks suggest that the rocks were a serial differentiational products of fractional crystallization of calc-alkaline magma series. This study reveals that the volcanic mass in this area is inferred to the remnant of the resurgent cauldron, measuring 30 by 25 km in diameter. The cauldron block was lowered at least 1,000 m by ring fault displacement.

백두산 부석의 물리적 특성

윤성효(Sung-Hyo Yun) 한국암석학회 2015 암석학회지 Vol.24 No.4

백두산 산정부의 강하부석층의 부석에 대한 물리적 특성을 분석하였다. 백두산 천지 칼데라 외륜산 주변의 강하부석층은 주로 흰색 부석으로 구성되지만 이들 중에는 흑색, 회색의 부석이 함께 산출된다. 흰색 부석은 주로 유문암질(SiO₂ 71.1% 내외)이며, 흑색 부석은 조면암질(SiO₂ 64.8% 내외), 회색 부석은 이들의 중간 성분에 해당하는 조면암질로 SiO2 68.0% 내외이다. 이들 부석을 형성한 마그마의 평균밀도는 무수 마 그마의 경우 2.45 g/㎤, 함수 마그마의 경우 2.33 g/㎤로 계산되었다. 백두산 천지 칼데라 남단 와호봉(2,566 m)과 관면봉(2,526 m) 부근에서 채취한 암색을 달리하는 3 종류의 부석에 대하여 물리적 성질 중 밀도와 발포도를 측정하였다. 황색 부석은 평균 밀도가 0.74 g/㎤, 흑색 부석은 0.75 g/㎤, 회색~백색 부석은 0.73 g/㎤로 측정되었으며, 부석의 색깔에 무관하게 부석의 밀도는 평균 0.75 g/㎤로 거의 일정하였다. 부석의 발포도는 67.8~69.4%로 계산되어 높은 정도의 발포도를 가진 부석으로 분류될 수 있다. Pumices from the summit area of the Mt. Baekdu was analysed with respect to the physical characteristics. Fallout pumice deposits around the somma of the Cheonji caldera, Mt. Baekdu consist mainly of white pumices, but black pumices and gray pumices are also displayed together. White pumices are mainly rhyolitic(SiO₂ 71.1%) and black pumices are trachytic(SiO₂ 64.8%) in composition, and gray pumices are intermediate composition(SiO₂ 68.0%) between white pumices and black pumices. Average density of felsic magma formed the Mt. Baekdu pumices is 2.45 g/㎤ in anhydrous magma and 2.33 g/㎤ in hydrous magma, respectively. We determined the density and calculated the vesicularity of three different coloured pumices, which collected in the vicinity of the Waho-bong(2,566 m) and Gwanmyeonbong(2,526 m) of southern somma of the Cheonji caldera, Mt. Baekdu. Average density of the yellow pumices was measured as 0.74 g/㎤, black pumices as 0.75 g/㎤, and gray t0 white pumices as 0.73 g/㎤. Average density regardless of the colour of pumices was nearly constant at 0.75 g/㎤. Vesicularity of pumices is calculated to be 67.8~69.4% and these pumices can be classified as a highly vesicular according to classification of vesiculation characteristics.

제주도 산방산 용암돔(Lava Dome)의 구성암석에 대한 화산암석학적 연구

윤성효(Sung-Hyo Yun) 한국암석학회 2019 암석학회지 Vol.28 No.4

제주도 남서부에 위치하는 산방산 용암돔에 대하여 암석학적 연구를 수행하였다. 산방산 용암돔의 형태를 용암분출 방식에 따라 분류하면, 화구내의 하부로부터 상부로 계속적인 마그마 주입에 의하여 서서히 밀면서 상승 팽창한 ‘내부 기원형’에 해당하며, 용암돔 외곽부에 발달하는 테일러스 에이프런은 대부분 침식 제거되고 그 내부의 용암류의 냉각에 의한 수직절리가 발달하고 있는 ‘낮은 용암돔형’에 해당한다. 산방산을 구성하는 암석을 화산암 TAS 분류도에 적용하여 분류하면, Cox et al.(1979) 분류도에서 일부 벤모리아이트 영역에 도시되나 대부분이 조면암의 영역에 도시되며, 최근 사용하는 Le Maitre et al.(2002)의 분류도와 Zr/TiO₂-Nb/Y 분류도에서는 모두 조면암의 영역에 도시된다. 그러므로 산방산 용암돔을 구성하는 암석을 ‘조면암질 안산암’이라고 설명한 표현은 마땅히 ‘조면암’으로 수정되어야 할 것이다. 산방산 용암돔을 구성하는 화산암은 노옴 석영을 함유하는 조면암으로 SiO₂ 59.75-63.46 wt.%의 범위에서 일정한 분화 경향을 보인다. Abstract: Petrological studies were performed on the Sanbangsan lava dome, located in the southwest of Jeju Island Volcanic Field. According to the lava ejection method, it is ‘an internal primitive form’ that is gradually pushed up and expanded by continuous magma injection from the bottom to the top of the vent and it corresponds to the ‘low lava dome’. The rocks are partly plotted in the field of benmoreite, but mostly plotted in the field of trachyte of the Cox et al.(1979) classification diagram, and also mainly plotted in the field of trachyte of Le Maitre et al.(2002) and Zr/TiO₂-Nb/Y classification diagram. Therefore, the expression that described the rock of Sanbangsan lava dome as ‘trachy-andesite’ should be corrected to ‘trachyte’. The volcanic rocks that consists in the Sanbangsan lava dome are trachyte containing normative quartz and shows differentiation trend in the range of 59.75-63.46 wt.% SiO₂.

역사시대에 분화한 백두산 화산재의 화학 성분

윤성효(Sung-Hyo Yun),고정선(Jeon Seon Koh),장철우(Cheolwoo Chang) 한국암석학회 2018 암석학회지 Vol.27 No.1

백두산에서 역사시대에 분화한 화산재의 시료에 대하여 다양한 방법으로 주성분과 미량성분을 분석하였다. 화산재의 주성분 원소 함량은 SiO₂ 58.8~71.1 wt.%, Al₂O₃ 9.6~16.8 wt.%, Fe₂O₃<SUP>T</SUP> 4.5~6.9 wt.%, MgO 0.1~1.7 wt.%, CaO 0.3~1.6 wt.%, Na2O 5.2~6.3 wt.%, K₂O 4.3~5.9 wt.% 그리고 TiO₂ 1.2 wt.%이하로 분석되었다. Ba, Cu, Cr. Co, Ni, Sr, V, Zn와 Zr을 포함하는 32개 미량원소가 분석되었는데, 이들 화산재는 일부 미량원소와 경희토류 원소의 부화정도에 따라 두 그룹(그룹 A, 그룹 B)으로 구분되며, 그룹 A에는 1천년 전의 밀레니엄 분화물, 1668년과 1903년 분화물이, 그룹 B에는 1702년 분화물이 해당된다. 중금속원소인 Cu, Co, Zn, Mn 등은 소량 함유되어 나타난다. 백두산 화산재는, 섭입대 기원의 일본 사쿠라지마 화산의 화산재와 비교하여, 미량성분원소 중 Y, Nb, Pb, U, Sc, V, Ni 그리고 Cu 함량은 낮게 나타나며, Zr, Ba, Hf, Cr, Co, Zn 그리고 희토류(Eu제외) 등은 높은 함량을 나타낸다. Volcanic ash samples of historical eruptions from Mt. Baekdu were analyzed for major oxides, trace and rare earth elements by a variety of analytical techniques. The results indicate that the ashes consist of approximately 58.8~71.1 wt.% SiO₂, 9.6~16.8 wt.% Al₂O₃, 4.5~6.9 wt.% Fe₂O₃<SUP>t</SUP>, 0.1~1.7 wt.% MgO, 0.3~1.6 wt.% CaO, 5.2~6.3 wt.% Na₂O, 4.3~5.9 wt.% K₂O and less than 1.2 wt.% TiO₂. Thirty two trace metals including Ba, Cu, Cr. Co, Ni, Sr, V, Zn, and Zr were analyzed. The ashes can be divided two groups: group A(1 ka Millennium pumice, 1668 and 1903 pumice) and group B(1702 pumice) according to the relative enrichment of HREEs. The abundances of heavy metals such as Cu, Co, Mn, and Zn were relatively low. As compared to the Sakurajima volcanic ash, Baekdusan volcanic ash has low concentrations of Y, Nb, Pb, U, Sc, V, Ni and Cu and high concentrations of Zr, Ba, Hf, Cr, Co, Zn and rare-earth (except Eu).

백두산의 홀로세 화산활동의 마그마 성인

윤성효(Sung-Hyo Yun),고정선(Jeon-Seon Koh),장철우(Cheolwoo Chang) 대한지질학회 2015 대한지질학회 학술대회 Vol.2015 No.10

浦項盆地 北部(七浦-月浦일원)에 分布하는 火山岩類에 대한 岩石學的ㆍ層序的 硏究

Sung Hyo Yun(尹成孝) 대한자원환경지질학회 1988 자원환경지질 Vol.21 No.2

The purpose of this study is to determine the stratigraphy of the volcanic rocks in the Chilpo-Weolpo area, the north of Pohang basin, based on field survey land lithological properties of the rocks. The volcanic pile(Chilpo tuff) overlies the Cretaceous sedimentary formation and is unconformably overlain by the Miocene Yeonil Group. The Chilpo tuff comprises a thick sequence(200m) of pyroclastic flow deposits. Five members are distinguished, each representing separate flow units, comprising none(or weakly) to densely welded rhyolite tuff. The Chilpo tuff consists of, in ascending order, greenish weakly welded tuff, volcanic conglomerate, alternation of tuff breccias and fine tuffs, greenish none to densely welded tuff and red-brownish densely to weakly welded vitric tuff. This study revealed that the volcanic rocks in this area were formed by 4 volcanic stages. On the basis of K-Ar age(44.7±1.1 Ma) and lithologic data, geological age of the Chilpo tuff maybe Eocene.