• Title/Summary/Keyword: 지자기역전

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Extinction, Flood Basalts, and Geomagnetic Field (멸종, 범람 현무암과 지구자기장)

  • Yu, Yong-Jae
    • 한국지구물리탐사학회:학술대회논문집
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    • 2008.10a
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    • pp.33-36
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    • 2008
  • For the past 300 Ma, massive extinctions are associated with major flood basalt eruptions. The geomagnetic Superchrons (Cretaceous Normal Superchron, Kiaman Long Reversed Superchron, Moyero Long Reversed Superchron) precede the major flood basalt eruptions and massive extinctions. It is likely that upswing of mantle plumes is responsible for the generation of continental flood basalt. Eruption of flood basalts results in a catastrophic climate change as well as a massive genus depletion.

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Case studies for modeling magnetic anomalies with COMSOL Multiphysics® (콤솔 멀티피직스를 활용한 지자기장 모델링 사례 연구)

  • Ha, Goeun;Kim, Seung-Sep
    • Journal of the Geological Society of Korea
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    • v.54 no.6
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    • pp.677-682
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    • 2018
  • Magnetic anomalies are sensitive to magnetic properties present in deep Earth and near surface structures. Such geophysical characteristics often can be quantified by numerical analyses. In this study, we developed a finite element method (FEM) approach to compute magnetic anomalies using COMOL $Multiphysics^{(R)}$. This FEM approach was verified by comparing its numerical results with the previously known analytic solution for a uniformly magnetized sphere. Then, we used the method to compute magnetic reversal patterns near mid-ocean ridge with various faulting scenarios. This COMSOL-based approach can be incorporated into advanced multi-physical numerical models to understand the Earth.

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.