Proceedings of the Korean Geotechical Society Conference (한국지반공학회:학술대회논문집)
- 2002.11b
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- Pages.3-17
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- 2002
Tertiary basin in Korean peninsula and the study of geologic structure at Pohang basin
한반도의 제3기 분지와 포항분지내 지질구조 연구
- Lee, Byung-Joo (Principal Researcher, Geology Division, Korea Institute of Geoscience and Mineral Resources)
- 이병주 (한국지질자원 연구원 지질연구부 책임연구원)
- Published : 2002.11.01
Abstract
Tertiary Pohang basin distributed in south weatern part of the korean peninsula, is composed of Chunbuk formation as the basal conglomerate, Hakjon formation, Duho formation and intrusive basalt which is 15 Ma by absolute age data. The basement of the basin is represented by Cretaceous sedimentary rocks, Hakjon welded tuff and Chilpo welded tuff and rhyolite. The fault systems at the basement of the Pohang basin are consist of NNE direction fault, WNW to EW trend fault. NNE fault is not only strike-slip fault but also normal fault. n fault has sinistral strike-slip sene and the EW fault is strike-slip and normal fault. In the Tertiary basin, the fault system is represented by nm strike-slip fault, EW normal fault and NNE thrust fault. By these fault relationships and geometries, it is interpreted that NNE sinistral strike-slip fault and nomal fault have acted at Creceous times. At Tertiary tines, NNE dextralstrike-slip fault and EW normal fault has created. Progressively Tertiary Pohang basin was influenced by the trenspression to make thrust fault and fold, namely as inversion tectonics.