Paleo-environmental study on Late Quaternary fine-grained volcanic ash beds around Kagoshima University

鹿儿岛大学周边晚第四纪细粒火山灰层古环境研究

• 批准号: 04680248
• 负责人: MORIWAKI Hiroshi
• 金额: $ 1.02万
• 依托单位: Kagoshima University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04680248/
• 关键词: Kagoshima; Quaternary; Tephra; Fine-grained ash; Phreatomagmatic eruption; Paleo-environment; 完新世; 縄文海進; ベースサージ

Following problems on Late Pleistocene and Holocene tephra layrs were dicussed in the northern part of Osumi Peninsula in southern Kyushu, in which a lot of fine-grained volcanic ash layrs : Late Quaternary tepra stratigraphy, stratigraphic position of fine-grained volcanic ash layrs prtoduced by phreatomagmatic eruptions, and their distribution and source vents. In this region, 17 tephra layrs lie on Ito pyroclastic flow deposit, which is 22,000 yBP in age, 13 tephra layrs of them are derived from Sakurajuma Volcano or Aira caldera. They include 4 fine-grained volcanic ash layrs produced by phreatomagmatic eruptions :(1) Sakurajuma-Takatoge 4 tephra (age : 13,000 yBP),(2) Takano base surge (12,000 yBP),(3) Sakurajima-Satsuma tephra (11,000 yBP),(4) Sakurajima-Takatoge 1 tephra.Takano base surge deposit is not distributed near Wakamiko vent, which has ever been estimated to be the source vent, instead, it is thick in Ushine area north to Sakurajuma Volcano, suggesting that the source vent is situated south to Wakamiko vent.Satsuma tephra is often observed in Holocene marine deposits of Kagoshima lowland by the bore hole analysis. The tephra erupted at the time of low sea-level stand of Younger Dryas stage. The relative sea-level height in this age is 50 m below the present sea level, indicating that phreatomagmatic eruption of Satsuma tephra occured at the depth of more than 50m below the present sea level.

讨论了九州南部大美半岛北部晚更新世和全新世火山灰地层存在的以下问题：晚第四纪火山灰地层、云雾岩浆喷发产生的细粒火山灰地层位置、分布和物源喷口。该区有17个盖层位于伊藤火山碎屑流沉积之上，时代为2.2万年，其中13个盖层来自樱花火山或艾拉火山口。它们包括4个由云母岩浆喷发产生的细粒火山灰层：(1)Sakurajua-Takatoge 4 Tephra(年龄：13,000 yBP)，(2)Takano基潮(12,000 yBP)，(3)樱岛-SatSuma tephra(11,000 yBP)，(4)Sakurajima-Takatoge 1 Tephra。高野基流沉积并不分布在和歌宫喷口附近，而是Sakurajua火山以北的乌尔山地区，表明源泉位于和歌岛火山以南。特弗拉喷发于新仙女木阶段的低海平面阶段。该时代的相对海平面高度低于现代海平面50m，表明温州蜜柑的岩浆喷发发生在现代海平面以下50m以上的深度。

项目成果

MORIWAKI, H.(1992): "Late Quaternary phreatomagmatic tephra layrs and their relation to paleo-sea-levels in the area of Aira caldera, southern Kyushu, Japan." Quaternary International. Vol.13/14. 195-200

MORIWAKI, H.(1992)：“日本九州南部姫良火山口地区晚第四纪岩浆火山灰层及其与古海平面的关系。”

森脇 広: "屋久島における扇状地、斜面堆積物と長瀬状砕流との関係" 南西地域研究資料センター報告. 5号. (1993)

Hiroshi Moriwaki：“屋久岛冲积扇、斜坡沉积物和长濑状碎屑流之间的关系”南西地区研究资料中心报告第 5 号（1993 年）。

Moriwaki H.: "Late Quatornary Phreatomagmatic Thephra Layers and Their Relation to Paleo-sea levels in the Area of Aird caldera" Quatermary International. 13/14. 195-200 (1992)

Moriwaki H.：“晚第四纪风岩浆 Thephra 层及其与艾尔德火山口地区古海平面的关系”第四纪国际。

Moriwaki,H: "Late Quatermary Rhreatomagmatic Tephrd Layers and Their Relation to Paleo-sea Leuels in the Area of Aira Calalora,Soulhern Kyshis,Japan" Quatermary International. 13/14. 195-200 (1992)

Moriwaki,H：“晚第四纪流岩浆 Tephrd 层及其与日本 Soulhern Kyshis 地区 Aira Calalora 地区古海 Leuels 的关系”第四纪国际。

森脇広: "屋久島における扇状地・斜面堆積物と長瀬火砕流との関係" 南西地域研究センター報告. 5号. 8-12 (1994)

Hiroshi Moriwaki：“屋久岛冲积扇/斜坡沉积物与长濑火山碎屑流之间的关系”南西地区研究中心报告 5，第 8-12 期（1994 年）。