임지현 Ji Hyeon Im , 추창오 Chang Oh Choo , 장윤득 Yun Deuk Jang

DOI: Vol.24(No.3) 151-162, 2011

Mineralogical and petrological characteristics were investigated on matrix of dense gray, vesiculate gray pumice, brown and black pumice in Ulleung Island by using XRD, FT-IR, XRF, SEM and thermal analysis. According to the analysis, most of pumice matrix are amorphous and include very small amount of sanidine and anorthoclase. Since the adsorption moistures, which commonly observed as O-H peak in FT-IR spectrum, are not identified in thermal analysis, it seems reasonable to conclude that content of the adsorption moisture has very low level. Although pumice has a large specific surface area, with long time elapsed after eruption, pumice matrix shows very low degree of hydration alteration due to the low level of water content. In SEM images, most surfaces of pumice show morphological characteristics such as various shapes of vesicle with wrinkled and thin walls resulted from ductile coalescence. Dense gray pumice formed in the initial stage includes small vesicles less than 15 μm in size with subangular to angular shapes, free of ovoid vesicle. These characteristics are interpreted to have related to the hydrous environment derived from phreato-plinian eruption. Submicron particles observed as amorphous alumina silicate assemblages in vesicle surface are considered as particles sticked to the matrix surface through rapidly cooling process during ascent of alkali phonolitic magma. It indicates that these particles coexisted partly with crystallized alkali feldspar.

울릉도, 부석, 기질, 알칼리장석, 기공, 수화프리니언 분출, Ulleung Island, pumice, matrix, alkali feldspar, vesicle, phreato-plinian eruption

손병국 Byeong Kook Son

DOI: Vol.24(No.3) 165-178, 2011

The potential of petroleum generation was investigated by clay mineralogical changes of illite-smectite on the sedimentary basins: Tertiary Pohang basin and Cretaceouls Gyeongsang basin on land, and offshore basins east and west of Korea. Only disordered illite-smectite mixed layer minerals occur in the Pohang sediment, where petroleum generation cannot be expected due to low temperatures below 100℃. By contrast, the Gyeongsang basin is characterized by the occurrence of illite and high temperatures above 200℃ which are obtained by illite crystallinity. The high temperatures indicate that the Gyeongsang sediment has already passed through the oil generation stage. The change of disordered illite-smectite to R=1 ordered illite-smectite is shown in the sediment of the East Sea continental shelf area at a depth of 2,500 m. Therefore, the oil generation can be expected in the sediments below the depth of 2,500 m. The sequential change of disordered illite-smectie to R=3 ordered illite-smectite through R=1 ordered illite-smectite occurs in the sediments of West Sea continental shelf area with burial depth which shows the favorable condition for oil and gas generation. The temperatures of sediments measured by illite-smectite indicate that hydrocarbon potential is very low in the onland basins but high in the continental shelf areas.

포항분지, 경상분지, 대륙붕, 일라이트-스멕타이트, 점토광물, 석유생성, Pohang basin, Gyeongsang basin, illite-smectite, clay mineral, petroleum generation

최헌수 Hun Soo Choi , 공기수 Gee Soo Kong , 김지훈 Ji Hoon Kim , 엄인권 In Kwon Um

DOI: Vol.24(No.3) 179-188, 2011

In order to investigate absolute age of marine sediment in the KR5 region, northeastern Pacific, we measured the Be isotope (10Be and 9Be) of box core (BC08-02-13) sediment with depth. Core sediment is divided into three sedimentary facies (FaciesⅠ, FaciesⅡ, FaciesⅢ). FaciesⅠ mainly consists of brown to dark brown (10YR4/3) homogeneous mud with high water content. FaciesⅡ shows brownish yellow (10YR6/6) color. The unconformity is recognized at the boundary between FaciesⅠ and FaciesⅡ, FaciesⅢ consists of very dark brown (10YR2/2) mud. Many bioturbated burrows are observed at FaciesⅡ and FaciesⅢ. Based on Be dating results, FaciesⅢ and FaciesⅡ had been deposited before 3.7 Ma and 2.3 Ma, respectively. After 2.3 Ma, the upper part of FaciesⅡ was eroded due to the change of sedimenary environment. FaciesⅠ has been deposited since 1.8 Ma. The unconformity located at the boundary between FaciesⅠ and FaciesⅡ may be driven by the envrionmental change due to the migration of Intertropical Convergence Zone.

Be 연대측정, 해저퇴적물, 북동태평양, 퇴적환경, Be age-dating, marine sediment, NE Pacific, sediment environment

정두희 Doo Hee Jeong , 유용재 Yong Jae Yu

DOI: Vol.24(No.3) 189-194, 2011

Martian satellite missions indicate that Martian equatorial plains are covered by ferric iron oxide. As a non-destructive technique, low-temperature treatment of remanent magnetization is effective in identifying magnetic minerals in rocks. In the present study, four sets of ferric iron oxides were prepared by aqueous alteration of ferrihydrite at warm conditions and four others by dehydration of goethite. As the amount of aluminous trivalent cations increases, crystallographic lattice parameters and N?el temperatures decrease. Such declines originate from lattice distortion as the smaller aluminous trivalent cations substitue the larger ferric irons. Whilst high remanence memory was observed for aqueously produced ferric iron oxide, low remanence memory was observed for dehydrated ferric iron oxide. In the future, magnetic remanence memory would be powerful in diagnosing the origin of ferric iron oxide.

3가철 산화물, 적철석, 화성, 잔류자화기억도, 모린변환온도, Ferric iron oxide, hematite, mars, remanence memory, morin transition

황길찬 Gil Chan Hwang , 김영호 Young Ho Kim

DOI: Vol.24(No.3) 195-204, 2011

Exsolution intergrowth of ilmenite and hematite was studied by the Rietveld refinement method. According to the analysis on these two structural analog minerals, it was found that octahedron (M2) of Ti in ilmenite is in the least deformation, then that (M1) of Fe in ilmenite is deformed next, and octaheron deformation of Fe in hematite is between M1 and M2. High pressure compression experiment was performed up to 5.8 GPa, where two minerals` XRD peaks merged completely. Ilmenite shows normal compression behavior, whereas hematite shrinks in very small amount. This kind of abnormal behavior might be due to the differential response to the applied pressure corresponding to the different compressibilities of the minerals each other.

용출, 티탄철석, 적철석, 리트벨트 법, 압축성, 이상거동, Exsolution, ilmenite, hematite, Rietveld refinement, compression, abnormal behavior

조현구 Hyen Goo Cho , 김순오 Soon Oh Kim , 이희일 Hi Il Yi , 신경훈 Kyung Hoon Shin

DOI: Vol.24(No.3) 205-214, 2011

Mineral compositions of 69 southeastern Yellow Sea surface sediments collected at the Korea Ocean Research and Development Institute (KORDI) cruise in 2010, were determined using the quantitative X-ray diffraction analysis. Southeastern Yellow Sea surface sediments are composed of major minerals (quartz 49.1%, plagioclase 13.0% and alkali feldspar 9.3%), clay minerals, calcite, and aragonite. Illite (9.4%) is the most abundant clay mineral, chlorite (4.6%) is the second, and kaolinite (0.8%) is few. Quartz and alkali feldspar contents are high in coarse-grained sediments, whereas amphibole and clay mineral contents are high in fine-grained sediments. Quartz, plagioclase, alkali feldspar, chlorite, and kaolinite contents are higher, and illite content is lower in mud zone 1 corresponding to south margin of Central Yellow Sea Mud than in mud zone 2, a part of Southeastern Yellow Sea Mud. Difference of mineral composition between two mud zone suggests that source of fine sediment may be different in two mud zone and Southeastern Yellow Sea Mud might be largely supplied from the Keum and Youngsan rivers in southern part of the west coast in the Korean Peninsula.

정량X선회절분석, 표층 퇴적물, 황해 남동 니질대, 황해 중앙 니질대, 일라이트, 점토광물, 근원지, Quantitative X-ray diffraction analysis, surface sediment, Southeastern Yellow Sea Mud,Central Yellow Sea Mud, illite, clay mineral, provenance

이승엽 Seung Yeop Lee , 오종민 Jong Min Oh , 백민훈 Min Hoon Baik

DOI: Vol.24(No.3) 217-224, 2011

Removal of dissolved selenium by D. michiganensis, a iron-reducing bacterium, and effects of dissolved metal elements such as iron, sulfate, and copper were investigated. Selenide that was reduced from selenite (2 mM) by D. michiganensis was gradually removed from the aqueous medium. As the reduced selenide was combined with aqueous iron, it was precipitated as a nanoparticulate iron-selenide. Sulfate and copper negatively affected the microbial selenite reduction, and the copper was especially toxic to the bacterium, inhibiting a microbial removal of dissolved selenite. These results show that it should be carefully biotreated for a selenium-contaminated site considering in situ sulfate or copper distribution and concentration. Consequently, the formation of iron-selenide by bacteria will be an important measure for preventing a long-distance migration of selenium in the subsurface environments.

철환원 박테리아, 미시가넨시스, 셀레늄, 환원, 철-셀레나이드, Iron-reducing bacterium, D. michiganensis, selenium, reduction, iron selenide

정기영 Gi Young Jeong , 최호정 Ho Jeong Choi , 권석기 Seok Ki Kwon

DOI: Vol.24(No.3) 225-234, 2011

The mineralogy and mixing state were investigated by the high resolution scanning electron microscopy combined with energy-dispersive X-ray analysis on particles of the total suspended solid (TSP) samples collected during the Asian dust event, spring, 2009. Relatively large particles were dominated by quartz, plagioclase, K-feldspar, amphibole, biotite, muscovite, chlorite, and calcite. Clay minerals usually occur as thin coatings on the coarse minerals or as aggregates. Calcite nanofibers are often admixed with clay platelets in the clay coatings and aggregates. Dust particles were classified on the basis of their main minerals. The single-particle mineralogy and mixing state of the TSP sample are consistent with those of PM10 samples in previous studies.

황사, 주사전자현미경, 혼합상태, 석영, 사장석, 점토광물, 방해석, Asian dust, scanning electron microscopy, mineralogy, mixing state, clay mineral, calcite

유재영 Jae Young Yu , 고현진 Hyun Jin Koh , 송홍규 Hong Gyu Song

DOI: Vol.24(No.3) 235-244, 2011

A batch experiment of pyrite oxidation was performed and the surfaces of the reacted pyrite were regularly observed with the scanning electron microscope (SEM) together with the chemical compositions of the solution to help understand the oxidation mechanisms of pyrite by Acidithiobacillus ferrooxidans (Af). The dissolved Fe concentrations clearly indicated that Af experiences the lag and then exponential growth phase. An Af cell was observed to be attached to the surface of pyrite during the lag, implying that a direct leaching by the microbe really happens for the period. It is not certain, however, whether the main mechanism of pyrite oxidation during that time was the direct leaching or not, because there were just a few cells confirmed to be attached and most of the dissolved Fe was Fe(III). The dissolved Fe concentration stayed almost constant from the mid-lag phase to just before the onset of the exponential phase, suggesting that Af needs an adaptation time to switch its oxidation mechanism from one to the other whichever it is during that stage of growth. The moment of Af`s cell division was observed by SEM on the surface of pyrite during the lag phase. The corrosion outline around the dividing cell was quite similar to the shape of the cell itself, which implies that the rate of the microbial oxidation is very uneven and the rate when the cell metabolizes should be much faster than that calculated from the concentration variation of the dissolved Fe. The number of etch holes by Af is much higher on the inoculated surfaces, indicating the average rate of pyrite oxidation is also much faster than that of abiotic oxidation. The microbial etch holes on pyrite surface are small and deep, which may influence the transition of the growth phases of Af from lag to exponential.

애씨디싸이오바실러스 페로악시댄스, 황철석 산화, 황철석 표면, 주사전자현미경, Acidithiobacillus ferrooxidans, pyrite oxidation, pyrite surface, SEM

고상모 Sang Mo Koh , 이길재 Gill Gae Lee , 유병운 Byoung Woon You

DOI: Vol.24(No.3) 245-252, 2011