Re-examination of buried peat deposits at the Desaki Coast (Tamano City, Okayama Prefecture) in the central part of the Seto Inland Sea, with special reference to Mid-Holocene relative sea-level variation

• Sato Hiroshi

  Institute of Natural and Environmental Sciences, University of Hyogo Museum of Nature and Human Activities, Hyogo

• Suzuki Sigeyuki

  Graduate School of Natural Science and Technology, Okayama Universit

• Matsushita Mariko

  Nara Research Institute for Cultural Properties

• Momohara Arata

  Graduate School of Horiculture, Chiba University

• Ueda Yayoi

• Katoh Shigehiro

  Museum of Nature and Human Activities, Hyogo

• Maeda Yasuo

  Institute of Natural and Environmental Sciences, University of Hyogo

Bibliographic Information

Other Title

• 瀬戸内海中部・出崎海岸（岡山県玉野市）における埋没泥炭層の再検討—特に完新世中期の相対的海水準変動との関係について—
• 瀬戸内海中部・出崎海岸(岡山県玉野市)における埋没泥炭層の再検討--特に完新世中期の相対的海水準変動との関係について
• セトナイカイ チュウブ デサキ カイガン オカヤマケン タマノシ ニ オケル マイボツ デイタンソウ ノ サイケントウ トクニ カンシン セイ チュウキ ノ ソウタイテキカイ スイジュン ヘンドウ ト ノ カンケイ ニ ツイテ

Abstract

Peat deposits were found under the sand beach on the Desaki Coast (Tamano City, Okayama Prefecture) in the central part of the Seto Inland Sea. In this paper, we re-examined the paleoenvironmental data on the deposits reported by Matsushita et al. (2004). The results of analyses of sulfur contents, diatom fossils, and plant macrofossils in the deposits were used along with ¹⁴C ages and the eruption age (ca. 7,300 cal BP) of Kikai-Akahoya tephra to derive the depositional environments. Peat depositions occurred in a salt marsh developing in a tidal range between mean high water level and the highest water level (HHWL), closely related to mid-Holocene relative sea-level (RSL) variations. The peat layer at this site was formed during a period ranging mainly from ca. 7,000 to 6,600 cal BP, and its age corresponds to the period of mid-Holocene RSL highstand when a rate of RSL rise slowed down after ca. 7,000 cal BP. RSLs have risen with an amplitude more than 0.27-1.27 m during the period from ca. 7,000 to 6,600 cal BP (at a rate more than 0.7-3.2 mm/yr), and reached the highest position at ca. 6,700-6,600 cal BP. Using a RSL (HHWL) index point of transgressive overlap with an altitude of +0.22 m at ca. 7,000 cal BP, half of the present highest tidal range (1.40 m) near the Desaki Coast, and tectonically corrected sea-level position with an altitude of +1.0 m at ca. 7,000 cal BP along the coast of Harimanada in the eastern part of the Seto Inland Sea (Sato, 2007), tectonic subsidence is calculated as 0.2-0.3 mm/yr at this site. Thus, sea-level rise over the period concerned depends mostly on the eustatic factor. This study provides valuable information for mid-Holocene RSL variation along the coast of the Seto Inland Sea.

Journal

• The Quaternary Research (Daiyonki-Kenkyu)

  The Quaternary Research (Daiyonki-Kenkyu) 50 (1), 61-69, 2011

  Japan Association for Quaternary Research

Keywords

• Desaki Coast
• Mid-Holocene
• relative sea-level variation
• peat deposit
• diatom analysis

Details

• CRID: 1390282681473762560
• NII Article ID: 10029070479
• NII Book ID: AN0034136X
• DOI: 10.4116/jaqua.50.61
• ISSN: 18818129
• ISSN: 04182642
• NDL BIB ID: 10991447
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I10991447
• Web Site: https://www.jstage.jst.go.jp/article/jaqua/50/1/50_1_61/_pdf
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed