• The Journal of the Petrological Society of Korea
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• v.11 no.2
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• pp.65-73
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• 2002

The wavy extinction of quartz grains can be used as a good indicator to show the degree of rock deformation. To determine degree of the rock deformation, intensity of wavy extinction (IWE) of quartz grains was measured by using polarizing microscope, digital camera, and NIH image (or Scion Image). In this experiment, the measurement was performed along the line perpendicular to the subgrain boundary of wavy extinction. IWE was measured when a quartz grain shows maximum extinction in polarizing microscope. NIH image was represented in terms of 256 gray-scale brightness, which was associated with intensity of the wavy extinction. IWE was determined by the degree of brightness versus the measuring length of a quartz grain. IWE was analysed in the distribution chart with the collection unit of 5. Regarding the characteristics of data distribution, the median between the mode and the median of the histogram is defined as a representative value for the IWE, and this value is subdivided into the five levels of rock deformation zones (lowest- or non-, low-, medium-, high-, and highest deformation) with their respective indices (D1, D2, D3, D4, and D5). The correlation between the Eonyang Granite and the Yangsan Fault was investigated by using the indices. The results indicate that IWE values decreased away from the fault.

• The Journal of the Petrological Society of Korea
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• v.11 no.3_4
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• pp.250-258
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• 2002

The wavy extinction of quartz can be used as a standard indicator showing the degree of rock deformation. To determine the degree of rock deformation, the intensity of wavy extinction (IWE) of quartz was measured using petroggraphic microscope, digital camera, and NIH image. In this study, this method was applied to the Cheongsan porphyritic granite, Cheongsan two mica granite, and Baekrok granite to investigate the deformation intensity of Cheongsan area. NIH Image data show a high-grade deformation in the vicinity of the strike-slip fault (between Cheongsan granite and Baekrok granite) and the unconformity (between Cheongsan granite and Youngdong basin). Thus, the main deformation in these areas is most likely to be concentrated on the faults that generate Yeongdong basin and the strike slip faults between Cheongsan granite and Baekrok granite.

• The Journal of the Petrological Society of Korea
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• v.12 no.3
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• pp.101-109
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• 2003

The wavy extinction of quartz can be used as a standard indicator showing the degree of rock deformation. In determine the degree of rock deformation, the intensity of wavy extinction (IWE) of quartz was measured using polarizing microscope, digital camera, and NIH Image program. This method was applied to the granite of Pocheon-Gisanri area, which are divided three type; biotite granite (Gb), garnet biotite granite (Ggb) and two mica granite (Gtm). In this study, measurement of wavy extinction was proceeded Ggb in eastern part and Gb in western part based on the Pocheoneup. The result was that Gb shows low deformation degree below D2, and Ggb represents high deformation degree above D3, generally showing that increasing deformation degree from northwest to southeast in the studied area. It is suggested that the fault which penetrated Ggb in 1/250,000 geological map affected the deformation degree of Ggb.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.73.1-73.1
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• 2018

We investigated shock history of three achondrite meteorites: NWA 3117, a howardite from asteroid Vesta, NWA 2727, a breccia from the Moon, and NWA 856, a shergottite from Mars. Shock histories were evaluated from deformation of plagioclase feldspars. Feldspar grains were classified based on observations in cross-polarized light as undulatory, mosaic, mosaic-recrystallized or maskelynite. This sequence represents increasing deformation of original feldspar crystals. Undulatory crystals have wavy extinction, mosaic crystals have patchy extinction, and mosaic-recrystallized grains appear as if they were originally coarse-grained and have recrystallized to mosaics of small equant crystals. Maskelynite grains are isotropic, indicating transformation to glass. Based on feldspar deformation, the degrees of impact processing are NWA 856 > NWA 3117 > NWA 2727. The high deformation of NWA 856 is expected because this sample is from Mars, which is a large parent body and requires a powerful impact to accelerate a rock to escape velocity. In contrast, the parent body of NWA 3117 (Vesta) is smaller than that of NWA 2727 (the Moon), yet NWA 3117 appears more highly deformed than NWA 2727. One possible explanation is that NWA 2727 is from a relatively young part of the Moon, which has not been exposed to impacts as long as the surface of Vesta.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2003.05a
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• pp.80-80
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• 2003

포천-기산리 일대에 분포하는 쥬라기의 대보화강암류의 변형정도를 결정하기 위해 석영의 파동소광의 강도(IWE : Intensity of Wavy Extinction)를 편광현미경, 디지털 카메라, NIH Image로 측정하였다. 파동소광이 나타나는 석영입자의 한 부분이 편광현미경 상에서 최대 소광이 될 때 IWE를 측정하고, 이 때 나타나는 파동소광의 아입자경계에 수직한 방향으로 측정을 시도하였다 본 연구에 사용된 NIH Image는 파동소광을 보여주는 각 부분의 광도를 256단계의 흑백 농담변화로 나타낼 수 있다. 이를 이용하여 측정 길이에 대한 농담변화로 IWE를 구하였다. 이렇게 획득한 IWE를 5$^{\circ}$ 단위로 묶어 돗수분포표로 처리하였으며, 자료의 분포특성상 히스토그램의 최빈값과 중간값 사이의 중간값을 그 암석의 대표 IWE로 정의하였다. 이를 다시 5단계의 변형대(무변형, 저변형, 중변형, 고변형, 최고변형)와 각각의 변형지수(D1, D2, D3, D4, D5)로 묶었다. 본 연구지역에 분포하는 화강암류는 흑운모화강암(Gb), 동부의 석류석흑운모화강암(Ggb) 그리고 북부의 복운모화강암(Gtm)으로 구성되어 있는 바 본 연구에는 크게 포천읍을 기준으로 서부에 분포하는 Gb와 동부에 분포하는 Ggb에서 파동소광의 강도 측정이 이루어 졌다. 연구결과 Gb는 D2 이하의 낮은 변형도가 나타났고, Ggb는 D3이상의 고변형이 나타나, 전반적으로 조사지역의 북서부에서 남동부로 갈수록 변형도가 증가하는 양상을 보여주었다.