• Title/Summary/Keyword: complex modes

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Petrology and petrochemistry of the Jurassic Daebo granites in the Pocheon-Gisanri area (포천 - 기산리 일대에 분포하는 쥬라기 대보화강암류의 암석 및 암석화학)

  • 윤현수;홍세선;이윤수
    • The Journal of the Petrological Society of Korea
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    • v.11 no.1
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    • pp.1-16
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    • 2002
  • The study area is mostly composed of Precambrian Gyeonggi gneiss complex, Jurassic Daebo granites, Cretaceous tonalite and dykes, and so on. On the basis of field survey and mineral assemblage, the granites can be divided into three types; biotite granite (Gb), garnet biotite granite (Ggb) and two mica granite (Gtm). They predominantly belong to monzo-granites from the modes. Field relationship and K-Ar mica age data in the surrounding area suggest that intrusive sequences are older in order of Gtm, Ggb and Gb. Gb and Ggb, major study targets, occur as medium-coarse grained rocks, and show light grey and light grey-light pink colors, respectively. Mineral constituents are almost similar except for opaque in Gb and garmet in Ggb. Gb and Ggb have felsic, peraluminous, subalkaline and calc alkaline natures. In Harker diagram, both rocks show moderately negative trends of $TiO_2$, MgO, CaO, $Al_2O_3$, $Fe_2O_3$(t), $K_2O$ and $P_2O_5$ as $SiO_2$ contents increase. Among them, $TiO_2$, MgO and CaO show two linear trends. From the trends and the linear patterns in AFM, Sr-Ba and Rb-Ba-Sr relations, it is likely that they were originated from the same granitic magma and Ggb was differentiated later than Gb. REE concentrations normalized to chondrite value have trends of parallel LREE enrichment and HREE depletion. One data of Ggb showing a gradually enriched HREE trend may be caused by garnet accompaniment. Ggb have more negative Eu anomalies than Gb, suggesting that plagioclase fractionation in Ggb have occurred much stronger than that in Gb. In modal (Qz+Af) vs. Op, Gb and Ggb belong to magnetite-series and ilmenite-series, respectively. From the EPMA results, opaques of Gb are magnetite and ilmenite, and those of Ggb are magnetite-free ilmenite or not observed. Bimodal distribution of magnetic susceptibility reveals two different granites of Gb (332.6 ${mu}SI$) and Ggb (2.3 ${mu}SI$). Based on the paleomagnetic analysis as well as modal analysis, the main susceptibilities of Gb and Ggb reside in magnetite and mafic minerals, respectively. They belong to S-type granite of non-magnetic granite by susceptibility value. In addition, $SiO_2$ contents, $K_2O/Na_2O$, A/CNK molar ratio and ACF diagram support that they all belong to S-type granites.

Perception of Undergraduate Environmental Education Program Students of Hangu University on Their Career Prospect and Career Preparation (항구대학교 환경교육과 학생들의 진로전망인식과 진로준비 고찰)

  • Ahn, Sun-Young;Lee, Yong-Hwan;Yang, An-Na;Kum, Ji-Hun
    • Hwankyungkyoyuk
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    • v.21 no.1
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    • pp.82-96
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    • 2008
  • The primary purpose of this research is to examine the career development of under-graduate environmental education program students. More specifically, it intends to understand how they perceive their career prospect, how they prepare for they career and what kind of career development assistance they receive from their school. For most of college students, a primary purpose for attending college is to prepare for a career, but often academic preparation in college is not enough to get the job they aspire. Career preparation becomes even more complex when their major does not dictate any specific career path or when the major does dictate a specific career path but it does not provide sufficient and quality job opportunities. Undergraduate environmental education programs are typical examples of the latter. To illuminate the understanding of the context surrounding undergraduate environmental education program students, semi-structured interviews were conducted through an instance message software program from August 17th, 2007 to August 20th, 2007. The subjects of this study consisted of 4 undergraduate students and 2 graduates of Hangu University (a tentative name). Each participant was interviewed once or twice for about 2 hours each interview. The findings of the study are as follow. First, they maintain a positive attitude regarding the career outlook and the career decision but it is not well founded. Second, career search and career preparation are conducted individually, and their school does not provide much systematic career assistance. Third, they did not see the relevance of the curriculum of their program to their future career. A few preliminary implications for practices related to career development may be drawn from the findings reported in this study. First, undergraduate students in environmental education programs appear to be in need of comprehensive career development assistance ranging from exploration of job opportunities related to majors, to development of job-seeking skills, to general issues of career preparation and choice. Experiential modes of career exploration seem to be helpful in clarifying their interest and aptitude in the area of environmental education. Second, career development assistance for these students should start at early college years. Third, these students may need help in exploring diverse opportunities related to their major as well as other academic areas. Finally, it is recommended to create more careers in the area of environmental education.

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