• 제목/요약/키워드: geoscience

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물리탐사 기술의 지반침하지역 공동탐지 적용성 연구 (Application of Geophysical Methods to Cavity Detection at the Ground Subsidence Area)

  • 김창렬;김정호;박영수;박삼규;이명종;손정술;임형래;정지민
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2005년도 춘계 학술발표회 논문집
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    • pp.376-383
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    • 2005

  • In this study, we conducted geophysical investigations for the organization of integrated geophysical methods to detect underground cavities of ground subsidence area at the field test site, located at Yongweol-ri, Muan-gun. We examined the applicability of geophysical methods such as electrical resistivity, electromagnetic, and microgravity to cavity detection with the aid of borehole survey results. Underground cavities are widely present within the limestone bedrock overlain by the alluvial deposits in the area of the test site where the ground subsidences have occurred in the past. The limestone cavities are mostly filled with groundwater and clays in the test site. Thus, cavities have low electrical resistivity and density compared to the surrounding host bedrock. The results of the study have shown that the zones of low resistivity and density correspond to the zones of the cavities identified in the boreholes at the site, and that the geophysical methods used are very effective to detect underground cavities. Furthermore, we could map the distribution of cavities more precisely with the test results incorporated from the various geophysical methods. It is also important to notice that the microgravity method is a very promising tool since it has rarely used for the cavity detection in korea. Beyond the investigation of underground cavities, the geophysical methods are required to provide useful information for the reinforcement design for the ground subsidence areas. It is, therefore, necessary to develop integrated geophysical technique incorporating different geophysical methods to precisely map underground cavities and image the subsurface of the ground subsidence areas.

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지질자원 세부기술별 성과특성 분석 - 한국지질자원연구원 기본사업 성과분석을 중심으로 - (Research Outcomes in Geoscience and Technology; A Case for the Fundamental Research Program of the Korea Institute of Geoscience and Mineral Resources)

  • 김성용;안은영;이재욱;이옥선;김유정
    • 자원환경지질
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    • 제41권1호
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    • pp.133-144
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    • 2008

  • 본 연구는 한국지질자원연구원에서 3년간(2004-2006) 수행된 기본사업 성과를 투입연구비 및 투입인력 둥의 변수로 분석하였다. 세부분야 기술별 성과의 특성을 기술통계적으로 분석한 결과, 실험 및 개발 분야가 상대적으로 논문 및 특허가 많이 생산되는 것을 보여주고 있다. SPSS을 이용하여 회귀분석을 실시한 결과, 투입 연구인력 수가 많아지면 연구비 규모가 커지고, 연구 성과량도 증가하는 것으로 나타났다 다만, 연구비가 증가한다고 연구 성과량이 증가하지는 않는 것으로 나타났다.

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The characteristics of zircon as the evidence for post-magmatic remobilization of REE and HFSE in the northern Motzfeldt alkaline igneous complex, southern Greenland

  • Kim, Eui-Jun;Yang, Seok-Jun;No, Sang-Gun;Park, Sung-Won;Lee, Seung Ryeol;Kim, You-Dong;Jo, Jinhee
    • Geosciences Journal
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    • 제22권6호
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    • pp.921-938
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    • 2018

  • The Motzfeldt intrusions in the Gardar Province, southern Greenland, split into syenitic plutonic and hypabyssal rocks, in which the latter include ring dykes and sheet intrusions. Sheet intrusions, considered as the source for rare earth elements (REE) and high field strength elements (HFSE), comprise sheets of peralkaline microsyenite (SPM), syenitic pegmatite (SP), and peralkaline microsyenite (PM). SP exhibits extremely high concentrations of REE and HFSE, which are positively correlated with increasing alkalinity from early towards late intrusion, caused by magmatic processes. In contrast, some of the SPM and PM are also significantly enriched in REE and HFSE, caused by post-magmatic fluids. The REE- and HFSE-rich phases in SP consist mainly of zircon and allanite with smaller amounts of pyrochlore in pseudomorph from the inferred eudialyte, whereas some of the PM and SPM consist of pyrochlore, REE-carbonate, and zircon in the matrix. The zircon grains in the Motzfeldt Sø Formation (MSF) syenite occur in interstitial spaces, exhibiting an association with magnetite and a bipyramidal form in texture. They are characterized by a highly fractured and embayed rim. Zircons from PM and SP are clearly enriched in Fe, Al, Ca, Na, Y, P, Hf, Y, P, Nb, Ta, and REE, and are depleted in Zr and Si in comparison with magmatic zircon. They also show a clear trend of higher LREE/HREE and $Eu/Eu^{\star}$ ratios, and lower $Ce/Ce^{\star}$ ratios, which define them as typical hydrothermal zircons. In contrast, zircons from the MSF syenite show a relatively lower LREE/HREE ratio and Eu and Ce anomalies of a similar magnitude compared with those from SP and PM. The occurrence and mineral composition of the zircon suggest that post-magmatic fluids have played an important role in the remobilization of REE and HFSE as well as the primary concentration of REE and HFSE, caused by magmatic processes.

  • https://doi.org/10.1007/s12303-018-0003-6 인용 KSCI