의성지역 백악기 암석에 대한 고자기 연구

• 영문명: Palaeomagnetism of cretaceous rocks in the Ŭisŏng area, Kyŏngsang basin, Korea
• 발행기관: 대한자원환경지질학회
• 저자명: 김인수(In Soo Kim) 이현구(Hyun Koo Lee) 윤혜수(Hyesu Yun) 강희철(Hee Cheol Kang)
• 간행물 정보: 『자원환경지질』26권 3호, 403~420쪽, 전체 18쪽
• 주제분류: 자연과학 > 지질학
• 파일형태: PDF
• 발행일자: 1993.06.30

영문 초록

The Cretaceous Kyŏngsang Basin is known to be composed of several tectonic blocks (or subbasins) with each distinct stratigraphic succession. The study area represents a major part of one of these blocks, i. e. the Ŭisŏng block. The area is charaterized by a suite of WNW-trending sinistral strike-slip faults as well as a number of ring faults. A total of 292 independently oriented core samples were drilled from 23 sites, covering virtually all the formations of the Cretaceous Kyŏngsang Supergroup. Alternating field and thermal demagnetization experiments were conducted to reveal the primary magnetization. Due to the homoclinal nature of the strata in the area, it was not possible to make use of the conventional fold test. It is, however, believed that the primary remanent components have been obtained from the majority of the formations, considering the similarity of the palaeomagnetic pole positions with those of contemporary strata of other blocks and the existence of antiparallel reversed remanence. It was found neither any significant difference in magnetic declination on each side of the strike-slip faults nor systematic change of magnetic declination with distance from the fault-line. This does not support such a block rotation hypothesis associated with the strike-slip faulting in the area as alleged by some authors. The samples from the outcrops on or near the fault-lines were severely overprinted by the recent magnetic fields regardless of age and lithology. Epithermal Au-Ag-Cu-Pb-Zn mineralizations are known along some fault lines in the area. It is interpreted that these two facts are closely related with fluid circulations along the fracture zones caused by fault activities. In regard to the age of the strata as deduced from the magnetostratigraphic consideration, the Chŏmgok formation and the lower strata should be older than Barremian or 124 Ma. The age of volcanics of the Yuch’ŏn Group sampled in this study should be younger than Campanian or 83 Ma.

목차

ABSTRACT

서언

지질개요

시료채취와 잔류자기 측정

자기세척실험

암상별 실험예

지층별 평균 특성잔류자기

토론

결론

참고문헌