Korean Journal of Mineralogy and Petrology (광물과 암석)

The Petrological Society of Korea & The Mineralogical Society of Korea (한국암석학회 & 한국광물학회)
권호 표지
DOI QR코드

DOI QR Code

SHRIMP Zircon U-Pb Ages of Basement Rocks in the Danyang National Geopark

단양 국가지질공원 기반암류의 SHRIMP 저어콘 U-Pb 연령

  • Cheong, Wonseok (Department of Earth & Environmental Sciences, Chungbuk National University) ;
  • Han, Giun (Department of Earth & Environmental Sciences, Chungbuk National University) ;
  • Kim, Taehwan (Division of Polar Earth-System Sciences, Korea Polar Research Institute) ;
  • Aum, Hyun Woo (Department of Earth & Environmental Sciences, Chungbuk National University) ;
  • Kim, Yoonsup (Department of Earth & Environmental Sciences, Chungbuk National University)
  • 정원석 (충북대학교 자연과학대학 지구환경과학과) ;
  • 한기운 (충북대학교 자연과학대학 지구환경과학과) ;
  • 김태환 (극지연구소 극지지구시스템연구부) ;
  • 엄현우 (충북대학교 자연과학대학 지구환경과학과) ;
  • 김윤섭 (충북대학교 자연과학대학 지구환경과학과)
  • Received : 2020.12.19
  • Accepted : 2020.12.26
  • Published : 2020.12.31
Download PDF
⟨ Previous Next ⟩

Abstract

We carried out the U-Pb age dating of zircon from basement rocks in the southern part of the Danyang National Geopark. Two migmatitic gneisses composed of biotite±sillimanite±garnet+feldspar+quartz were dated. Leucosomes in the samples were clearly distinguished from their melanosomes. The U-Pb isotopic compositions of zircon from sillimanite- and garnet-bearing migmatitic samples were measured using a secondary ion microprobe, yielding metamorphic ages, 1870±10 Ma (2σ)와 1863±6 Ma (2σ), respectively. 1.87~1.86 Ga metamorphic ages are consistent with those of the Paleoproterozoic low-P and high-T regional metamorphism (1.87~1.85 Ga) in the Yeongnam Massif. The maximum depositional age based upon the apparent 207Pb/206Pb ages of detrital zircon in the samples was estimated as 2.06 Ga, and thus sedimentation age of the protolith of the migmatitic gneisses ranges between 2.06 and 1.87 Ga.

단양 국가지질공원 남쪽에 분포하는 기반암에서 저어콘 U-Pb 연령측정을 수행하였다. 연령 측정은 2개의 시료에서 실시하였으며, 이들 시료는 우흑질과 우백질이 뚜렷이 구분되는 혼성암질 편마암으로 흑운모±규선석±석류석+장석+석영의 광물조합을 가진다. 함규선석 및 함석류석 편마암시료에서 각각 수집한 저어콘 결정들에 대해 고분해능 이차이온질량분석기(SHRIMP)를 사용하여 U-Pb 동위원소 성분비를 측정하였으며, 이로부터 1870±10 Ma (2σ)와 1863±6 Ma (2σ)의 변성 연령을 구하였다. 1.87~1.86 Ga의 변성 연령은 영남육괴고원생대 고온-저압의 광역변성작용의 시기(1.87~1.85 Ga)와 일치한다. 저어콘 결정들의 상속핵 연령을 기반으로 두 시료에서 얻어진 최고 퇴적연령은 2.06 Ga로 혼성암질 편마암 모암의 퇴적시기는 2.06~1.87 Ga 사이일 것으로 추정된다.

Keywords

References

  1. Aum, H.W., Kim, Y., Cheong, W., Hau, B.V., 2019, SHRIMP zircon U-Pb age and geochemistry of granites in the Gudambong-Sainam Geosite, Danyang Geopark. Journal of the Petrological Society of Korea, 28, 1-14 (in Korean with English abstract). https://doi.org/10.7854/JPSK.2019.28.1.1
  2. Cheong, C.S., Kwon, S.T. and Park, K.H., 2000, Pb and Nd isotopic constraints on Paleoproterozoic crustal evolution of the northeastern Yeongnam massif, South Korea, Precambrian Research, 102, 207-220. https://doi.org/10.1016/S0301-9268(00)00066-8
  3. Cheong, W., and Na, K.C., 2008. Origin and evolution of leucogranite of NE Yeongnam Massif from Samcheok area, Korea. Journal of Petrological Society of Korea, 17, 16-35 (in Korean with English abstract).
  4. Cheong, W., Sun, G-.M., Na, K.C., 2009, Relation between Metamorphic P-T Conditions and Boron Concentrations of Metasedimentary Rocks and Biotite Granitic Gneisses from NE Yeongnam Massif around Samcheok Area, South Korea. Economic Environment 42, 16-35 (in Korean with English abstract).
  5. Cheong, W., Cho, M., Kim, Y., 2013. An efficient method for zircon separation using the gold pan. Journal of the Petrological Society of Korea, 22, 63-70 (in Korean with English abstract). https://doi.org/10.7854/JPSK.2013.22.1.063
  6. Cho, M., Min, K., Kim, H., 2018. Geology of the 2018 Winter Olympic site, Pyeongchang, Korea. International Geology Review., 60, 267-287. https://doi.org/10.1080/00206814.2017.1340196
  7. Cherniak, D.J., and Watson, E.B., 2003, Diffusion in zircon.In: Hanchar, J.M., Hoskin, P.W.O. (Eds.), Zircon. Reviews in Mineralogy and Geochemistry 53, pp. 113-143. https://doi.org/10.2113/0530113
  8. Claoue-Long, J.C., Compston, W., Roberts, J., Fanning, C.M., 1995. Two Carboniferous ages: a comparison of SHRIMP zircon dating with conventional zircon ages and 40Ar/39Ar analysis. In: Berggren, W.A., Kent, D.B., Auberey, M.P., and Hardenbol, J. (eds.), Geochronology, Time Scales, and Global Stratigraphic Correlation. SEPM (Society for Sedimentary Geology) Special Publication, 4, 3-21.
  9. Cumming G.L. and Richards J.R., 1975. Ore lead isotope ratios in a continuously changing Earth. Earth and Planetary Science Letters, 28, 155-177. https://doi.org/10.1016/0012-821X(75)90223-X
  10. Hoskin, P.W.O., Schaltegger, U., 2003. The composition of zircon and igneous and metamorphic petrogenesis. In: Hanchar, J.M., Ho skin, P.W.O. (Eds.), Zircon. Reviews in Mineralogy and Geochemistry 53, pp. 27-62. https://doi.org/10.2113/0530027
  11. Kim, J., Cho, M., 2003. Low-pressure metamorphism and leucogranite magmatism, northeastern Yeongnam Massif, Korea: implication for Paleoproterozoic crustal evolution. Precambrian Research 122, 235-251. https://doi.org/10.1016/S0301-9268(02)00213-9
  12. Kim, N., Cheong, C.-S., Park, K.-H., Kim, J., Song, Y.-S., 2012. Crustal evolution of northeastern Yeongnam Massif, Korea, revealed by SHRIMP U-Pb zircon geochronology and geochemistry. Gondwana Research, 21, 865-875. https://doi.org/10.1016/j.gr.2011.10.003
  13. Kim, N., Cheong, C.-S., Yi, K., Song, Y,-S., Park, K,-H., Geng, J,-Z., Li, H.-K., 2014. Zircon U-Pb geochronological and Hf isotopic constraints on the Precambrian crustal evolution of the north-eastern Yeongnam Massif, Korea. Precambrian Research, 242, 1-12. https://doi.org/10.1016/j.precamres.2013.12.008
  14. Kretz, R.. 1983. Symbols for rock-forming minerals. American Mineralogist, 68, 277-279.
  15. Kwon, S.-T., Ree, J.-H., Park, K.-H., and Jeon, E.-Y., 1995. Nature of contact between the Ogcheon belt and Yeongnam massif and the Pb-Pb age of granitic gneiss in Cheongong-ri, Danyang. Journal of the Petrological Society of Korea, 4, 144-152 (in Korean with English abstract).
  16. Kwon, Y.W., Oh, C.W., Kim, H.S., 2003. Granulite-facies metamorphism in the Punggi area, northeastern Yeongnam Massif, Korea and its tectonic implications for east Asia. Precambrian Research, 122, 253-273. https://doi.org/10.1016/S0301-9268(02)00214-0
  17. Lee, S.-G., Asahara, Y., Tanaka, T., Kim, N.H., Kim, K.H., Yi, K., Masuda, A., and Song, Y.S., 2010, La-Ce and Sm-Nd isotopic sytematics of early Proterozoic leucogranite with tetrad REE pattern. Chemical Geology, 276, 360-373. https://doi.org/10.1016/j.chemgeo.2010.07.003
  18. Lee, S.R., Cho, K., 2012. Precambrian crustal evolution oh the Korean Penisula. Journal of the Petrological Society of Korea, 21, 89-112 (in Korean with English abstract). https://doi.org/10.7854/JPSK.2012.21.2.089
  19. Lee, Y., Cho, M., Cheong, W., Yi, K., 2014, A massif-type (-1.86 Ga) anorthosite complex in the Yeongnam Massif, Korea: late-orogenic emplacement associated with the mantle delamination in the North China Craton. Terra Nova, 26, 408-416. https://doi.org/10.1111/ter.12115
  20. Lee, Y., Cho, M., Cheong, W., Yi, K., 2018. Prolonged high-temperature, low-pressure metamorphism associated with -1.86 Ga Sancheong-Hadong anorthosite in the Yeongnam Massif, Korea: Paleoproterozoic hot orogenesis in the North China Craton. Precambrian Research, 307, 175-200. https://doi.org/10.1016/j.precamres.2018.01.018
  21. Ludwig, K.R., 2008. User's Manual for Isoplot 3.60: A geochronogical toolkit for Mirosoft Excel. Berkeley Geochronology Center Special Publication, Berkeley, 77p.
  22. Paces, J.B., Miller, J.D., 1993. Precise U-.Pb ages of Duluth Complex and related mafic intrusions, northeastern Minnesota: geochronological insights to physical, petrogenetic, paleomagnetic, and tectonomagmatic processes associated with the 1.1 Ga midcontinent rift system. Journal of Geophysical Research 98, 13997-14013. https://doi.org/10.1029/93JB01159
  23. Wan, Y.S., Xu, Z.Y., Do ng, C.Y., Nutman, A., Ma, M.Z., Xie, H.Q., Liu, S.J., Liu, D.Y., Wang, H.C., Cu, H., 2013, Episodic Paleoproterozoic (-2.45, -1.95 and -1.85 Ga) mafic magmatism and associated high temperature metamorphism in the Daqingshan area, North China Craton: SHRIMP zircon U-Pb dating and whole-rock geochemistry. Precambrian Research, 224, 71-93. https://doi.org/10.1016/j.precamres.2012.09.014
  24. Williams, I.S., 1998. U-Th-Pb geochronology bu ion microprobe. In: Mckibben, M.A., Shnakn, W.C.III., Ridley, W.L. (eds.), Applications of Microanalytical Techniques to Understanding Mineralizing Processes. Reviews in Economic Geology, 7, 1-35. https://doi.org/10.1080/07474938808800138
  25. Zhang, Z., Dong, X., Xiang, H., Ding, H., He, Z., Liou, J.G., 2015, Reworking of the Gangdese magmatic arc, southeastern Tibet: post-collisional metamorphism and anatexis. Journal of Metamorphic Geology, 33, 1-21. https://doi.org/10.1111/jmg.12107