The Journal of the Petrological Society of Korea (암석학회지)

The Petrological Society of Korea (한국암석학회)
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Geochemical Characteristics and Quaternary Environmental Change of Unconsolidated Sediments from the Seokgwan-dong Paleolithic Site in Seoul, Korea

서울 석관동 유적의 미고결 퇴적층의 지구화학적 특성 및 제4기 지표환경변화

  • Lee, Hyo-Min (Geoanalysis Center, Korea Institute of Geoscience and Mineral Resources) ;
  • Lee, Jin-Young (Geo-Environmental Hazards & Quaternary Geology Research Center, Korea Institute of Geoscience and Mineral Resources) ;
  • Kim, Ju-Yong (Geo-Environmental Hazards & Quaternary Geology Research Center, Korea Institute of Geoscience and Mineral Resources) ;
  • Hong, Sei-Sun (Geo-Environmental Hazards & Quaternary Geology Research Center, Korea Institute of Geoscience and Mineral Resources) ;
  • Park, Jun-Bum (Seoul Institute of Cultural heritage)
  • 이효민 (한국지질자원연구원 지질자원분석센터) ;
  • 이진영 (한국지질자원연구원 지질환경재해연구센터) ;
  • 김주용 (한국지질자원연구원 지질환경재해연구센터) ;
  • 홍세선 (한국지질자원연구원 지질환경재해연구센터) ;
  • 박준범 (서울문화유산연구원)
  • Received : 2016.11.30
  • Accepted : 2016.12.29
  • Published : 2016.12.31
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Abstract

To understand human activity in the past, the information about past environmental change including geomorphological and climatic conditions is essential and this can be traced by using age dating and geochemical analysis of sediments from the prehistoric sites. The sedimentary sequence of Seokgwan-dong Paleolithic Site located in Seoul was 5m long unconsolidated sediments and consists of lower part bedrock weathering sediments, slope deposits and upper-part fluvial deposits. In this study, upper part sediments were used to reconstruct past environmental change through age dating and various physical and chemical analyses including grain size, magnetic susceptibility and mineral and elements. The fluvial sediments can be divided into 4 units including three organic layers. Grain size analysis results showed that the sediments were very poorly sorted with fining upward features. Magnetic susceptibility was relatively high in the organic layers, indicating environmental changes causing mineral composition change at that times. The mineral and major element composition are similar to Jurassic biotite granite which mainly consists of quartz, K-feldspar, biotite and muscovite. The radiocarbon age of $14,240{\pm}80yr$ BP was obtained from the lower most organic layer of Unit III(O), suggesting that the fluvial sediments formed at least from the early stage of deglacial period after the end of Last Glacial Maximum. Subsequent wet and warm climates and resultant fluvial process including slope sedimentation during the Holocene may have been responsible for the sedimentary sequence in Seokgwan-dong paleolithic site and surrounding area. The observed organic layers suggests frequent wetland occurrence combined with natural levee changes in this area.

과거 인간활동과 유적형성에 대한 이해를 위해서 과거 환경변화 정보를 수집하고 구체화 하는 것은 매우 중요하다. 이러한 환경변화 정보는 유적지에 형성된 퇴적물을 대상으로 연대측정과 지화학 분석을 통해서 추적할 수 있다. 석관동 구석기 유적지 퇴적층은 약 5 미터의 미고결 퇴적층으로 크게 하부 기반암 풍화층, 그 위의 사면퇴적층 그리고 상부 하천퇴적층의 3부분으로 나뉠 수 있다. 이 가운데 상부 하천퇴적층을 대상으로 입도분석, 대자율 분석, 유기지화학, 광물조성분석, 주성분 원소분석, 방사성탄소연대측정 등을 실시하였다. 시료를 채취한 퇴적층 구간은 4개의 퇴적단위로 구분되며, 3개의 유기물 함량이 높은 퇴적층들이 포함되어 있다. 입도분석 결과 퇴적물 입자의 평균 크기가 일정하지 않고, 분급이 매우 불량하게 나타나며, 여러구간에서 상향 세립화 경향을 보인다. 또한 대자율 측정결과 3개의 유기물층에서 값이 증가하였고, 이러한 특징은 환경변화에 따른 광물의 조성과 관련된 것으로 추정된다. 주성분 원소와 광물조성은 기반암인 쥐라기 흑운모 화강암을 구성하는 주요광물과 유사하였으며, 기반암의 석영, K-장석, 운모 등에서 기인한 것으로 생각된다. 방사성 탄소연대측정결과 최하부 유기물층은 $14,240{\pm}80yr$ BP로 나타났으며, 이는 이 퇴적층이 최후빙하기 이후의 점차 온난해지는 시기에 형성된 것으로 추정된다. 그리고 상부의 퇴적층은 플라이스토세 후기부터 홀로세에 이르는 기간에 형성된 것으로 해석된다. 결론적으로 연구지역인 석관동 유적은 계곡을 형성하는 하천활동과 사면퇴적 작용에 의해 퇴적물이 쌓이고, 자연제방과 같은 환경 또는 소규모 소택지 형태의 환경이 3 차례에 걸쳐 교대되었던 것으로 해석된다.

Keywords

References

  1. Delvanx, Bruno, Herbillon, Adrien and Vielvoye, Leon, 1989, Characterization of a weathering sequence of soils derived from volcanic ash in Cameroon Taxonomic, mineralogical and agronomic implications. Geoderma, 45, 375-388. https://doi.org/10.1016/0016-7061(89)90017-7
  2. Fedo, C.M., Nesbitt, H.W. and Young, G.M., 1995. Unraveling the effects of potassium metasomatism in sedimentary rocks and paleosols, with implications for paleoweathering conditions and provenance. Geology, 23, 921-924. https://doi.org/10.1130/0091-7613(1995)023<0921:UTEOPM>2.3.CO;2
  3. Folk, R.L., 1980. Petrology of sedimentary rock. Austin, Tex.:Hemphill Pub Co. 182p.
  4. Folk, R.L. and Ward, W, 1957, Brazos River bar: a study in the significance of grain size parameters. Journal of Sedimentary Petrology, 27, 3-26. Google Earth, 2016, http://www.google.com/earth https://doi.org/10.1306/74D70646-2B21-11D7-8648000102C1865D
  5. Kim, J-Y, Lee, Y-J, Woo, J-Y, Yang, D-Y, Hong, S-S, Oh, K-C and Kim, J-K, 2006, Environment and Chronology of fluvial Deposits in Yulryang-dong Site, Cheongju County, Korea. Journal of the Korean Ancient Society, 24, 29-51.
  6. Lee, B-J, Kim, Y-B, Lee, S-R, Kim, J-C, Kang, P-C, Choi, H-I and Jin, M-S, 1999, Geological report of the Seoul-Namchonjeom sheet (1:250,000). Korea Institute of Geoscience and mineral resources, 35p.
  7. Lee, M-B, Lee, G-R, Kim and N-S, 2007, The Origin of Paleo-Lacustrine Deposits at Yeoncheon in Chugaryeong Rift Valley, Central Korea. Journal of the Korean Geographical Society, 42(1), 15-26.
  8. Lee, S and Kim, J-Y, 2009, Pollen Indication of Holocene Vegetation and Environments in the Sacheon-dong Archaeological Site, Cheongju, Chungbuk Province. Journal of Paleontological Society of Korea, 25(1), 63-76.
  9. Lee, Y-I and Yi, S-B, 2002, Characteristics of Pyeongchangri paleolithic-site paleosols, Yongin-si, Gyeonggido, Korea: implications for archaeogeological application. Journal of the Geological society of Korea, 38(4), 471-489.
  10. Nam, K-S and Cho, K-S, 1993, Relative Movement of Major Elements on the Weathering of Rocks. Journal of Korean Institute Mining Geology, 26, 1, 67-81.
  11. Nesbitt, H.W. and Young, G.M., 1982. Early Proterozoic climates and plate motions inferred from major element chemistry of lutites. Nature 299, 715-717. https://doi.org/10.1038/299715a0
  12. Parker, A., 1970. An index of weathering for silicate rocks. Geological Magazine 107, 501-504. https://doi.org/10.1017/S0016756800058581
  13. Reimer PJ, Bard E, Bayliss A, Beck JW, Blackwell PG, Bronk Ramsey C, Buck CE, Edwards RL, Friedrich M, Grootes PM, Guilderson TP, Haflidason H, Hajdas I, Hatte C, Heaton TJ, Hoffman DL, Hogg AG, Hughen KA, Kaiser KF, Kromer B, Manning SW, Niu M, Reimer RW, Richards DA, Scott M, Southon JR, Staff RA, Turney CSM and van der Plicht J, 2013, IntCal13 and Marine13 Radiocarbon Age Calibration Curves 0-50,000 Years cal BP. Radiocarbon, 55, 1869-1887. https://doi.org/10.2458/azu_js_rc.55.16947
  14. Shin, S-C, Park, J-B, Lim, Y-K, Baek, S-H, Lee, S-J and Han, J-T, 2007, Report of surface investigation in the Seokgwan-dong Paleolithic Site, Korea. Seoul Institute of Cultural heritage, 3-5.
  15. Shin, J-B, Yu, K-M, Toshiro Naruse and Akira Hayashida, 2004, Study on loess-paleosol stratigraphy of Auaternary unconsolidated sediments at E55S20-IV pit of Chongokni Paleolithic Site. Journal of the Geological Society of Korea, 40(4), 369-381.