Terraces and Paleo Sea Level Estimates at Marine Isotope Stage 3 in the Lower Isumi River Basin, Boso Peninsula, Central Japan.

• Kuwabara Takuichiro

  Department of Geography, Tokyo Metropolitan University

• Kikuchi Takao

  Department of Geography, Tokyo Metropolitan University

• Suzuki Takehiko

  Department of Geography, Tokyo Metropolitan University

• Kiyonaga Jota

  Tokyo Metropolitan Government, Bureau of City Planning

Bibliographic Information

Other Title

• 房総半島，夷隅川下流域における酸素同位体ステージ３の段丘面と当時の古海面高度
• ボウソウ ハントウ イスミ カワシモ リュウイキ ニ オケル サンソ ドウイタイ ステージ 3 ノ ダンキュウメン ト トウジ ノ コ カイメン コウド

Abstract

Marine terraces formed during the relatively low sea level epoch after 125ka BP can be found out on land in the lower Isumi River basin, Boso Peninsula, Central Japan, because uplift rate is remarkable during the Quaternary in this area. A geomorphologic and geologic investigation into the terraces of this area identified three terraces, named Taitozaki, Nagasaka, and Yoshifu in descending order, as terraces formed in the estuary environment at marine isotope stage 3 (MIS 3).<br>Four characteristics in particular indicate that Yoshifu terrace was formed in the estuary environment revealed by a transgression at about 30ka: (1) the projected profile of the terrace surface along the lower reaches of the Isumi river is flat and horizontal; (2) part of the terrace deposits bury the drowned valley; (3) the terrace surface is covered by tephric soil deposits including Aira-Tn tephra (24-25ka), but not by Hakone-Tokyo tephra (52ka); and (4) the ¹⁴C ages of terrace deposits are 31-34ka. Moreover, the result of pollen analysis for these terrace deposits do not conflict with the environment at about 30ka that has been described in previous works.<br>Mean uplift rates in this study area calculated using Shimosueyoshi terrace (MIS 5e, 125ka) and Holocene terraces (MIS 1, 6ka) are about 2.0∼2.2m/ka, which is nearly equal to the rates at Huon Peninsula, Papua New Guinea, where there are several coral terraces formed at MIS 3. Under the assumptions that uplift rate of 2.1m/ka has been constant and that Yoshifu, Nagasaka, and Taitozaki terraces were emerged at 28∼29, 37∼40, and 44ka respectively-the times at which the marine oxygene isotopic curve developed by Shackleton (1987) shows peaks of transgressions- their paleo sea level estimates are -29∼-31, -28∼-34, and -22m. These values do not agree with recent estimates deduced from raised coral terraces at Huon Peninsula (e. g. Chappell et al., 1996).

Journal

• The Quaternary Research (Daiyonki-Kenkyu)

  The Quaternary Research (Daiyonki-Kenkyu) 38 (4), 313-326, 1999

  Japan Association for Quaternary Research

Keywords

• 最終氷期
• 酸素同位体ステージ3
• 房総半島
• 夷隅川
• 海成段丘
• 古海面高度

Details

• CRID: 1390282681473296896
• NII Article ID: 10004720867
• NII Book ID: AN0034136X
• DOI: 10.4116/jaqua.38.313
• ISSN: 18818129
• ISSN: 04182642
• NDL BIB ID: 4819018
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I4819018
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed