Journal of the Korean earth science society (한국지구과학회지)

The Korean Earth Science Society (한국지구과학회)
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Detrital Zircon U-Pb Ages of the Cretaceous Muju Basin: Implications for the Depositional Age and Provenance

백악기 무주분지의 쇄설성 저어콘 U-Pb 연대를 이용한 퇴적시기와 퇴적물 기원지 연구

  • Yong-Un Chae (Department of Geological Sciences, Pusan National University) ;
  • Youhee Kim (Department of Geological Sciences, Pusan National University) ;
  • Sujin Ha (Department of Geological Sciences, Pusan National University) ;
  • Hyoun Soo Lim (Department of Geological Sciences, Pusan National University)
  • 채용운 (부산대학교 지질환경과학과) ;
  • 김유희 (부산대학교 지질환경과학과) ;
  • 하수진 (부산대학교 지질환경과학과) ;
  • 임현수 (부산대학교 지질환경과학과)
  • Received : 2024.02.20
  • Accepted : 2024.02.28
  • Published : 2024.02.29
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Abstract

Detrital zircon U-Pb dating was performed to determine the depositional age and provenance of sediments in the Cretaceous Muju Basin in Muju-gun, Jeollabuk-do. Six samples were collected from the Seolcheon Tuff (SCT), Bangyiri Formation (BYR), Gobang Member of the Gilwangri Formation (GWR-G), Seochang Member of the Gilwangri Formation (GWR-S), Bukchang Member of the Gilwangri Formation (GWR-B), and Jeogsangsan Formation (JSS). Based on the dating results, the sedimentary strata of the Muju Basin were deposited for approximately 105.6-90.4 Ma corresponding to the Albian to Turonian. The youngest single zircon ages of about 94.4 Ma and 89.6 Ma were confirmed in the samples from the Bangyiri Formation and the Gobang Member of the Gilwangri Formation, respectively, distributed in the western part of the Muju Basin. The relative and numerical ages previously estimated based on the lithostratigraphic correlation of the Gilwangri conglomerate need to be revisited in further research. The results also suggest that most of the sediments filling the Muju Basin were supplied from a limited area adjacent to the basin.

전라북도 무주군에 분포하는 백악기 무주분지의 퇴적시기 및 퇴적물의 기원지를 파악하기 위해 쇄설성 저어콘 U-Pb 연대측정을 수행하였다. 시료는 설천응회암(SCT), 방이리층(BYR), 길왕리층의 고방층원(GWR-G), 서창층원(GWR-S), 북창층원(GWR-B), 적상산층(JSS)으로 총 6개가 채취되었다. 연대측정 결과 무주분지의 퇴적층은 약 105.6-90.4 Ma에 걸쳐 퇴적되었고, 지질시대로는 알바절에서 투로니아절에 해당한다. 무주분지 서쪽에 분포하는 방이리층과 길왕리층 고방층원 시료에서 각각 약 94.4 Ma와 89.6 Ma의 단일 저어콘 최소연령이 확인되어, 기존에 길왕리층 역암을 기준(암층서)으로 설정된 상대연령에 대해 추가연구를 통한 재확인이 필요하다. 그리고 무주분지를 채우고 있는 대부분의 퇴적물들이 무주분지와 인접한 제한된 지역에서 공급되었을 것으로 판단된다.

Keywords

Acknowledgement

이 연구는 한국연구재단의 지원(NRF-2023R1A2C1006945)에 의해 수행되었습니다. 좋은 심사의견을 주신 두 분의 심사위원과 편집위원께 감사드립니다.

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