Magnetostratigraphic and Neotectonic Study of Plio-Pleistocene Widespread Tephra Deposits

上皮里奥-更新世广泛分布的火山灰矿床的磁性地层学和新构造研究

• 批准号: 14540431
• 负责人: HAYASHIDA Akira
• 金额: $ 2.05万
• 依托单位: DOSHISHA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540431/
• 关键词: Paleomagnetism; Widespread tephra; Quaternary; Neotectonics

We made paleomagnetic studies of widespread tephra deposits aiming to obtain magnetostratigraphic and neotectonic data for the Plio-Pleistocene sediments in central Japan. Magnetic measurements of the Ebisutoge-Fukuda tephra, which occurs just above the Olduvai subchronozone, provided the following results :1.The Fukuda volcanic ash layer and its correlative ash deposits in the Osaka-Kyoto area, near Lake Biwa and in the Mie and Niigata areas yielded identical site mean declinations of approximately -170°, while the source volcanic unit, Ebisutoge pyroclastic deposits in the Takayama area, showed a mean declination of approximately -l55°. These results suggest that no significant rotation occurred between the Osaka-Kyoto, Mie and Niigata areas, but that the Takayama area suffered a clockwise rotation in respect to the other areas during the Quaternary.2.The Kd38 and Kd39 ashes in the Boso Peninsula both showed reversed magnetic polarity, suggesting both postdate the Olduvai subchron. These volcanic ash layers showed discordant site mean directions even after tilt correction, which may be explained by differential tectonic rotations near the active plate margin.3.The O2 volcanic ash in Oyabe-Kanazawa area, The Gokenchaya volcanic ash of the Kobiwako Group, and the Ide volcanic ash of the Osaka Group provided paleomagnetic data, which are consistent with the Fukuda tephra.4.A stable magnetic component of normal polarity was found from the Ide volcanic ash. This component is carried by a high-coercivity magnetic mineral, which was formed secondary during a normal polarity period.

我们对宽度的Tephra沉积物进行了古磁研究，旨在获得日本中部Plio-Ple-pelyescene沉积物的磁性和新原型数据。发生在Olduvai subschronozone上方的Ebisutoge-Fukuda Tephra的磁性测量结果提供了以下结果：1。福生火山灰层及其相关的灰烬及其相关的灰烬在大阪 - 京托地区，在比瓦湖附近以及Mie和Niigata的相同地点均散发出大约-1700000000000000。高山地区的火山碎屑沉积物的平均下降约为-l55°。这些结果表明，大阪 - 凯托，Mie和Niigata地区之间没有发生明显的旋转，但是高山地区在第四纪期间对其他区域的顺时针旋转。22。这些火山灰层即使在倾斜校正后也显示出不一致的位点方向，这可以通过在活动板边缘附近的差异构造旋转来解释。3。Oyabe-Kanazawa地区的O2火山灰，Gokenchaya火山灰，gobiwako群的Gokenchaya火山灰和the the the Faper Ash fruk and osomag as osomag as osomag as osomag canselints conselints consectients and osomag assinty and osomag assints conselittient Tephra.4。从IDE火山灰中发现正常极性的稳定磁成分。该成分是由高顽固磁矿物携带的，该矿物在正常极性期间形成次级。

项目成果

H.Iwaki, A.Hayashida: "Paleomagnetism of Pleistocene widespread tephra deposits and its implication for tectonic rotation in central Japan"The Island Arc. 12. 46-60 (2003)

H.Iwaki，A.Hayashida：“更新世广泛的火山灰沉积物的古地磁及其对日本中部构造旋转的影响”岛弧。

林田 明, 岩城啓美, 山下 透, 奥野博子, 檀原 徹: "京都府城陽市高塚林道に露出する普賢寺火山灰の古地磁気方位とフィッション・トラック年代"同志社大学理工学研究報告. 43. 106-113 (2002)

Akira Hayashida、Keimi Iwaki、Toru Yamashita、Hiroko Okuno、Toru Danhara：“京都府城阳市高冢林路暴露的普源寺火山灰的古磁取向和裂变径迹年龄”同志社大学科学与工程研究报告43。106-。 113（2002）

H.Iwaki, A.Hayashida: "Paleomagnetism of Pleistocene widespread tephra deposits and its implication for tectonic rotation in central Japan"The Island Arc. Vol.12. 46-60 (2003)

H.Iwaki，A.Hayashida：“更新世广泛的火山灰沉积物的古地磁及其对日本中部构造旋转的影响”岛弧。

A.Hayashida, H.Iwaki, T.Yamashita, H.Okuno, T.Danhara: "Paleomagnetic Direction and Fission-Track Age of the Fugenji Volcanic Ash at Takatsukayama Road in Joyo City, Kyoto Prefecture"The Science and Engineering Review of Doshisha University. Vol.43,No.2.

A.Hayashida、H.Iwaki、T.Yamashita、H.Okuno、T.Danhara：“京都府城阳市高冢山路普源寺火山灰的古地磁方向和裂变径迹年龄”同志社的科学与工程评论