영양소분지에 분포하는 경상누층군에 대한 고지자기 연구

• 발행기관: 대한자원환경지질학회
• 저자명: 도성재 석동우 김범철
• 간행물 정보: 『자원환경지질』32권 2호, 189~201쪽, 전체 13쪽
• 주제분류: 자연과학 > 지질학
• 파일형태: PDF
• 발행일자: 1999.04.30

영문 초록

Paleomagnetic and rock magnetic investigations have been carried out for the Cretaceous Hanyang Group, exposed in the Yongyang Sub-Basins within the Kyeongsang Basin, eastern South Korea. A total of 452 oriented core samples was drilled from 31 sits for the study. The in-situ site mean direction is more dispersed than the mean direction after bedding correction, indicating that the fold test is positive at 95% confidence level. In addition, the stepwise unfolding of the characteristic remanent magfold test is positive at 95% confidence level. In addition, the stepwise unfolding of the characteristic remanent magnetization reveals that a maximum value of k is observed at 90% unfolding. Furthermore, the rock magnetic investigations and electron microscope observations of the representative samples show that the main magnetic carrier of the Hayang Group is the detrital specular hematite of single and pseudo-single domain sizes with negligible contribution of pigmentary hematite grains. These results collectively imply that the ChRM direction is the primary component acquired at the time of the formation of the strata. Provided the primary nature of the ChRM, a magnetostratigraphic correlation between polarities of the studied formation and the Geomagnetic Time Scale indicates that the Hayang Group in the Yongyang Sub-Basin can be correlated to the Cretaceous Long Normal superchron. The paleomagnetic pole position from this study is significantly different from those of the Hayang group in the Euiseong the Milyang sub-Basins. Rather the paleomagnetic pole position of the Hayang Group of the study area is closer to that of the Quaternary period or present time of the Korean Peninsula. It is hypothesized that the study area might be rotated about 25° aticlockwise with respect to the Euiseong and Milyang Sub-Basins after the formation of the strata and aquisition of the ChRM, although there is not enough geologic evidence supporting the rotation hypothesis.

키워드

영양소분지 경상누층군 고지자기 퇴적암류 화산암류 열쇠층 팔공산 시층서 의성소분지 밀양소분지