Tephrostratigraphy in the Ulleung Basin, East Sea: Late Pleistocene to Holocene
- 92 Downloads
Three sediment cores, obtained from the Ulleung Basin, reveal five tephra layers that are easily distinguished from the other core intervals by coarse grain size, density grading, and sediment color. The tephra layers are well correlated among the cores and show a systematic lateral decrease in thickness and grain size away from the source of the explosive volcanic eruption. Three marker tephra layers were derived from Ulleung Island and consist predominantly of white vesiculate pumices of phonolitic or trachytic alkali magma. The disorganized Ulleung-I tephra layer was due to the last explosive eruption in Ulleung Island. It consists of only white vesiculate pumices, disturbed by strong bioturbation. The Ulleung-II tephra (ca. 9300 yr B.P.), the most explosive one among the Ulleung Island-derived tephras, shows two units: a lower density-graded unit and an upper pumice-scattered unit. The Ulleung-II tephra layer shows little bioturbation and is characterized by pumice-scattered texture. An unnamed tephra layer shows a distinct density grading by dark fine-grained crystals and white vesiculate pumices. This marker tephra originated from a phonolitic alkali magma of unknown source. The Aira-Tanzawa ash (ca. 22000 yr B.P.), derived from the Aira Caldera in southern Japan, consists commonly of bubblewalled glass shards from rhyolitic subalkali magma.
During the Holocene period, sediments were accumulated at a rate of 17.5–24.7 cm/kyr, based on the Ulleung-II tephra, which increased toward the center of the basin. During the last glacial maximum (LGM) period which is represented by the interval between the Ulleung-II tephra layer and the Aira-Tanzawa ash, a very thick turbidite mud was deposited in the unchannelized Ulleung Basin plain with higher accumulation rate (mean 26.1 cm/kyr) than that during the Holocene period. The very thick turbidite mud of LGM period occurs only in the unchannelized Ulleung Basin plain, which is not correlated with other layers in the channelized basin plain.
Key wordsUlleung Basin marker tephra sediment accumulation rate
Unable to display preview. Download preview PDF.
- Arai, F., Oba, T., Kitazato, H., Horibe, Y., and Machida, H., 1981, Late Quaternary tephrochronology and paleo-oceanography of the sediments of the Japan Sea. The Quaternary Research, 20, 209–230. (in Japanese with English abstract)Google Scholar
- Bahk, J.J., Han, S.J., Chun, J.H. and Chough, S.K., 1996 Quaternary sedimentary processes in the Ulleung Basin. The 1996 Spring Meeting of the Korean Society of Oceanography (Abstract), Pusan, April 26–27, p. 12. (in Korean)Google Scholar
- Cas, R.A.F. and Wright, J.V. (ed.), 1987, Volcanic Successions. Allen and Unwin, London, 528 p.Google Scholar
- Chough, S.K., 1983, Marine Geology of Korean Seas. International Human Resources Development Corporation Boston, 157p.Google Scholar
- Chough, S.K., 1984, Fine-grained turbidites and associated mass flow deposits in the Ulleung (Tsushima) Basin, East Sea (Sea of Japan). In: Stow, D.A.V. and Piper, D.J.W. (eds.), Fine-Grained Sediments, Deep-Water Processes and Facies Geological Society (London), Special Publication, 14, 185–196.Google Scholar
- Chough, S.K., Lee, G.H., Park, B.K. and Kim, S.W., 1984, Fine structures of turbidite and associated muds, in the Ulleung (Tsushima) Basin, East Sea (Sea of Japan). Journal of Sedimentary Petrology, 54, 1212–1220.Google Scholar
- Chun, J.H., Han, S.J., Cheong, D.K., Shin, D.H. and Bahk, J.J., 1996, Distribution and sedimentary processes of tephra layers in Ulleung Basin, East Sea of Korea. The 1996 Spring Meeting of the Korean Society of Oceanography (Abstract), Pusan, April 26–27, p. 46. (in Korean)Google Scholar
- Cox, K.G., Bell, J.D. and Pankhurst, R.J., 1979, The Interpretation of Igneous Rocks. Allen and Unwin, London, 450 p.Google Scholar
- Fisher, R.V. and Schmincke, H.U., 1994, Volcaniclastic sediment transport and deposition. In: K. Pye (ed.), Sediment Transport and Depositional Processes. Blackwell Scientific Publications, Oxford, p. 351–388.Google Scholar
- Han, S.J., Kim, S.R., Kim, H.J., Woo, H.J., Lee, H.J. and Kim, S.H., 1996, Basin Structures and Past Changes in the East Sea, Korea (BASAPES-95/96). Report BSPN 00321-950-5, Korea Ocean Research and Development Institution, Ansan, 548 p. (in Korean)Google Scholar
- Kigoshi, F., Fukuoka, K. and Yokoyama, S., 1972,14C age of Tsumaya pyroclastic flow, Aira Caldera, southern Kyushu, Japan. Bulletin of the Volcanology Society of Japan, 17, 1–8. (in Japanese with English abstract)Google Scholar
- Lee, Y.D., You, H.S. and Kim, S.Y., 1996, Silicoflagellate biostratigraphy and sediment facies in Ulleung Basin, the East Sea. Journal of the Geological Society of Korea, 32, 73–90. (in Korean with English abstract)Google Scholar
- Machida, H. and Arai, F., 1976, Volcanic ashes distributed in wide area: a discovery and significance of Aira-Tn ash. Kagaku, 46, 339–347. (in Japanese with English abstract)Google Scholar
- Machida, H., Arai, F., Lee, B.S., Moriwaki, H. and Furuta, T., 1984, Late Quaternary tephras in Ulleung-do Island, Korea. Journal of Geography, 93, 1–14. (in Japanese with English abstract)Google Scholar
- Park, B.K., Han, S.J., Barg, E.J. and Southon, J., 1995, Late Holocene sedimentation rates from core sediments of the western part of the East Sea, Korea. Journal of the Korean Society of Oceanography, 30, 382–389. (in Korean with English abstract)Google Scholar
- Vallier, T.L. and Kidd, R.B., 1977, Volcanogenic sediments in the Indian Ocean. In: Heirtzler, J.R. (ed.), Indian Ocean Geology and Biostratigraphy, Studies Following Deep-Sea Drilling Legs 22–29, American Geophysics Union, p. 87–118.Google Scholar