• Title/Summary/Keyword: 암석자기

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Magnetic Susceptibility and Petrochemical Compositions of Mesozoic Granites in Korea (국내 중생대 화강암의 대자율 특성과 화학조성)

  • 홍세선
    • The Journal of the Petrological Society of Korea
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    • v.13 no.1
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    • pp.16-33
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    • 2004
  • By relating mineralogy, petrology and geochemistry to observed magnetic properties, an understanding of the geological factors that control magnetic signatures is obtained. Magnetic susceptibility measurements and geochemical analyses were carried out for 160 samples in the Jurassic to Cretaceous granitoids, which is distributed to Pocheon, Jipori, Geumsan, Namwon, Songnisan, Yongdam, Masan, Jindong, and Taebaeksan areas. The magnetic properties of igneous infusion in these granites reflect bulk rock composition, reduction-oxidation state, hydrothermal alteration which are controlled by tectonic setting, composition and history of the source region, depth of emplacement and nature of wall rocks.

On an Apparatus of Visualization for Magnetic Reversal and Magnetic Stripes (자기역전 시각화 장치와 지자기띠에 대하여)

  • Ryoo, Chung-Ryul
    • The Journal of the Petrological Society of Korea
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    • v.25 no.1
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    • pp.85-88
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    • 2016
  • The new rocks of the oceanic crust, like basalt, are created in the mid-oceanic ridge, and the magnetic polarities of the rocks are supposed to be oriented as following the Earth's magnetic field. An extensive magnetic survey of total field at sea level reveals mainly unusual north-south magnetic stripes parallel to the axis of the mid-oceanic ridge, especially in the Atlantic Ocean. From this stripes the Earth's magnetic field is considered as repeatedly 'flipped'(the N pole becoming the S pole, and vice versa) and many times over geological time. The discovery of stripes of alternately normal and reversed-magnetized rocks forming the ocean floor has been a key evidence for the sea-floor spreading, continental drift, and plate tectonics. This study introduces a simple apparatus to explain a possible mechanism of the magnetic reversal in the new oceanic crust, which makes a magnetic stripe adjacent to the mid-oceanic ridge. The apparatus shows a bar magnet effect of adjoined stripes to have a special magnetic polarity on the rocks in the center of the mid-oceanic ridge. The new magnetic stripe seems to be generated not only by Earth's magnetic field, but also by neighbored stripes in the mid-oceanic ridge, acting as a bar magnet.

The Effects of Project Learning on 'Strata and Rock' of Pre-service Teachers on Self Directed Learning Ability and Environmental Sensitivity (초등예비교사의 '지층과 암석'에 대한 프로젝트 학습이 자기주도적 학습능력 및 환경감수성에 미치는 효과)

  • Lee, Yongseob
    • Journal of the Korean Society of Earth Science Education
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    • v.9 no.2
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    • pp.233-242
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    • 2016
  • The purpose of this study was learning about the project 'stratum and the rock ' of pre-primary teachers to the effects of self-directed learning ability and environmental sensitivity. This study was set up experimental treatment period of 15 weeks from March 2016 to June, students who are B Education University of fourth grade the first semester participated, in the study, It was composed of 34 students of 1 class taking 'strata and rock' lecture. Experimental study group consisted of exploration activities on the field experience about strata and rock. Set the area they want to explore the site by teams. The results of this study are as follows. First. learning about the project 'stratum and the rock ' of pre-primary teachers was effective to self-directed learning skills. 2nd, Learning about the project 'stratum and the rock ' of pre-primary teachers was effective to environmental sensitivity. 3rd, The students showed a positive response and were interested in the project 'stratum and the rock ' of pre-primary teachers.

Control Weights On Supervised Kohonen Feature Map For Using Higher Order Neuron (고차 뉴런을 이용한 KOHONEN 자기 조직화 맵의 연결강도 특성)

  • Jung, Jong-Soo;Kim, Sung-Il;Jeon, Byung-Hoon
    • Proceedings of the KIEE Conference
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    • 2003.07d
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    • pp.2516-2518
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    • 2003
  • 본 논문은 고차 뉴런의 문제점으로 지적되고 있는 뉴런이 방대하게 증가하는 문제를 해결하고자, 최적의 뉴런을 생성하고 생성되어진 고차 뉴런 중 일정 비율로 뉴런의 연결강도를 도태시켜 감에 따라 네트워크상에 나타나는 특성을 비교하였다. 본 논문은 고차 뉴런을 이용한 Kohonen의 자기 조직화 맵의 고차 뉴런부에 일정 비율로 연결강도를 도태한 후 인식률을 얻는 형태로 시뮬레이션을 하였다. 특히, 종래 형태의 고차 뉴런을 이용한 Kohonen 자기 조직화 맵의 알고리즘을 변형없이 사용하였으며 중복되는 뉴런을 최대한 억제하기 위해 2차 뉴런만을 생성한 네트워크 구조 위에 입력 데이터의 특징을 유지하고 고차 뉴런의 특징을 더욱 활성화하기 위해 일정한 양의 연결강도를 도태시킴으로써 출력면에서 국소집중 반응에 의한 정확한 인식률 향상 등을 조사하는 시뮬레이션을 하였다. 본 제안 모델의 특성을 살펴보기 위해 60개의 데이터로 이루어진 금속 소나 음데이터와 암석 소나 음 데이터를 이용하여 금속인지 암석인지를 판별하는 시뮬레이션을 하였다.

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Paleomagnetic Studies in Korea (한국의 고지자기학 연구)

  • Suk, Dong-Woo;Lee, Youn-Soo
    • Economic and Environmental Geology
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    • v.39 no.4 s.179
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    • pp.385-402
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    • 2006
  • Paleomagnetic studies have made remarkable contributions to the understanding of many geological aspects of Korea for the last 40 years, such as the collisional processes of Korean Peninsula, the development of basins in relation with fault systems, the opening and evolution of the East Sea, and the reconstruction of paleogeographic configuration. These contributions have played an important role in the escalation of geology in Korea by elucidating the mechanisms on Processes of fragmentation and amalgamation of the Peninsula, mountain building, igneous activities, metamorphism, and folding and faulting based on the view of plate tectonics. This paper is intended to introduce and summarize the paleomagnetic research papers designed to decipher the tectonic processes of Korea, according to the geologic ages of the studied rocks.

Determination of Rock Cleavages Using AMS (Anisotropy of Magnetic Susceptibility): a Case Study on the Geochang Granite Stone, Korea (대자율이방성(AMS) 분석을 통한 석재 결의 파악: 거창 화강석에서의 사례 연구)

  • Cho, Hyeongseong;Kim, Jong-Sun;Kim, Kun-Ki;Kang, Moo-Hwan;Sohn, Young Kwan;Lee, Youn Soo;Jwa, Yong-Joo;Son, Moon
    • The Journal of the Petrological Society of Korea
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    • v.24 no.3
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    • pp.209-231
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    • 2015
  • In granite quarry, stones are generally quarried along easily separating planes called as 'rock cleavage'. Because orientation and characteristics of the rock cleavage are directly involved with easy quarrying, it is the most important factor on selecting a direction of digging. Using AMS (anisotropy of magnetic susceptibility), we attempt to interpret rock fabrics in Geochang Granite Stone (JS, SD, AR, GD, BW, MD quarry) and discuss about determination of rock cleavages and correlation between the rock fabrics and cleavages. Based on mean susceptibility, thermo-susceptibility curves, and hysteresis parameters, Ti-poor MD and/or PSD magnetites are the main contributor to AMS of the granite stones. The systematic magnetic foliations with sub-vertical dip angle are developed in the whole granite quarries. In most of the granite quarries, the magnetic foliations are significantly consistent with grain plane. In the BW quarry, which has higher $P_J$ values than the others, the magnetic foliations coincide exceptionally with rift plane. These results suggest that rock cleavages in granite stone are related to rock fabrics meaning shape and spatial arrangement of crystals. Magnetic fabrics analysis using AMS method, therefore, can be a quantitative and effective tool for determination of rock cleavages in granite quarry.