Journal of the Mineralogical Society of Korea (한국광물학회지)

The Mineralogical Society of Korea (한국광물학회)
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Be Age-dating of Marine Sediments from NE Pacific

북동태평양 해저퇴적물의 Be 연대측정

  • Choi, Hun-Soo (Petroleum and Marine Research Division, Korea Institute of Geoscience and Mineral Resources (KIGAM)) ;
  • Kong, Gee-Soo (Petroleum and Marine Research Division, Korea Institute of Geoscience and Mineral Resources (KIGAM)) ;
  • Um, In-Kwon (Petroleum and Marine Research Division, Korea Institute of Geoscience and Mineral Resources (KIGAM)) ;
  • Kim, Ji-Hoon (Petroleum and Marine Research Division, Korea Institute of Geoscience and Mineral Resources (KIGAM))
  • 최헌수 (한국지질자원연구원 석유해저연구본부) ;
  • 공기수 (한국지질자원연구원 석유해저연구본부) ;
  • 엄인권 (한국지질자원연구원 석유해저연구본부) ;
  • 김지훈 (한국지질자원연구원 석유해저연구본부)
  • Received : 2011.06.16
  • Accepted : 2011.09.22
  • Published : 2011.09.30
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Abstract

In order to investigate absolute age of marine sediment in the KR5 region, northeastern Pacific, we measured the Be isotope ($^{10}Be$ and $^{9}Be$) of box core (BC08-02-13) sediment with depth. Core sediment is divided into three sedimentary facies (Facies I, Facies II, FaciesIII). Facies I mainly consists of brown to dark brown (10YR4/3) homogeneous mud with high water content. Facies II shows brownish yellow (10YR6/6) color. The unconformity is recognized at the boundary between Facies I and Facies II, Facies III consists of very dark brown (10YR2/2) mud. Many bioturbated burrows are observed at FaciesII and FaciesIII. Based on Be dating results, FaciesIII and Facies II had been deposited before 3.7 Ma and 2.3 Ma, respectively. After 2.3 Ma, the upper part of Facies II was eroded due to the change of sedimenary environment. Facies I has been deposited since 1.8 Ma. The unconformity located at the boundary between Facies I and Facies II may be driven by the envrionmental change due to the migration of Intertropical Convergence Zone.

북동태평양 우리나라 광구 KR5지역의 해서퇴적물 퇴적연대와 퇴적환경의 변화를 살펴보고자, 상자형 코아 시료에 대해 심도에 따른 Be 동위원소 분석을 실시하였다. 분석 코아 시료(BC08-02-13)는 상부에서부터 Facies I, Facies II, Facies III 세 개의 암상으로 구분된다. Facies I은 갈색/암갈색을 띠는 (10YR4/3) 균질한 머드로 높은 함수량을 보이는 것이 특징적이다. Facies II 는 갈황색을 띠고(10YR6/6), Facies I과는 부정합적인 관계를 보이며, Facies III는 암갈색을 띠는 머드층이다. Facies II과 FaciesIII 생교란작용에 의한 서관구조가 발달되어 있다. Be 연대측정 결과에 의하면 BC08-02-13 코아의 FaciesIII는 3.7 Ma 이전에 퇴적되었으며, Facies II 는 2.3 Ma 이전에 퇴적되었고, 그 후 환경변화에 의해 Facies II 상부가 침식을 받은 후 약 1.8 Ma 이후 현재까지 Facies I이 퇴적되었다. Facies I과 Facies II 경계의 부정합은 적도수렴대의 이동에 의한 환경변화에 의한 것으로 보인다.

Keywords

Acknowledgement

Grant : 심해저 광물자원의 광물.지화학적 요인연구

Supported by : 한국지질자원연구원

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