Thermal history and dinamic process of a large-scale pyroclastic-flow deposit

大型火山碎屑流矿床的热历史和动力学过程

• 批准号: 08454142
• 负责人: KAMATA Keiko
• 金额: $ 4.86万
• 依托单位: KOBE UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08454142/
• 关键词: remanent magnetization; large-scale pyroclastic-flow deposit; Ata pyroclastic-flow deposit; Ito pyroclastic-flow deposit; annealing temperature; fission-track method; emplacement temperature; アニーリング温度; 大規模火砕流; 古地磁気; 堆積温度; 溶結

Remanent magnetization and field survey of the Ata large-scale pyroclastic-flow deposit clarified relationship between lithological facies and emplacement temperatures. Palaeomagnetic measurements showed emplacement temperatures of essential fragments and matrix of the pyroclastic-flow deposits higher than 560ﾟC based on the corresponding TRM directions. Three types are identified in the directions of remanent magnetization : (1) single component with the same direction, (2) two components, low and high temperature component, obtained during progressive thermal demagnetization, and (3) components with scattered directions. These results are different from those of the Ito pyroclastic-flow deposit which shows weaker welding than the Ata, suggesting that welding processes start before emplacement.Reheating process for the Ito pyroclastic-flow deposit was investigated by measuring the annealing temperature of each mineral through track age and length of fission-track method. The anealing temperature of zircon and apatite within granitic fragments in the Ito pyroclastic-flow deposit was estimated to have been between 150ﾟC and 500ﾟC based on the measurement of track length.

阿塔大型火山碎屑流存款矿床的剩余磁化和现场调查澄清了岩相和侵位温度之间的关系。古地磁测量表明，根据相应的TRM方向，火山碎屑流沉积物的主要碎片和基质的侵位温度高于560 ° C。在剩磁方向上可分为三种类型：（1）同向的单分量，（2）在渐进热退磁过程中获得的低温和高温两个分量，（3）方向分散的分量。这些结果与Ito火山碎屑流存款的结果不同，Ito火山碎屑流存款显示比Ata弱的焊接，这表明焊接过程开始于侵位之前。根据径迹长度的测量，估计伊藤火山碎屑流存款中花岗岩碎片中锆石和磷灰石的退火温度在150 ℃和500 ℃之间。

项目成果

Suzuki-Kamata, K.and Kamata, H.: "Subsidence structures of caideras with the diameter less than 10km." Proceeding.Oji Seminar Neogene Evalution Pacific Ocean Gateways. IGCP-355. 160-178 (1997)

Suzuki-Kamata, K. 和 Kamata, H.：“直径小于 10 公里的 caideras 沉降结构。”

Suzuki-Kamata,K.: "Subsidence structures of calderas with the diameter less than 10km" Proceedings of Oji-seminar on "Neogene Evolution of Pacific Ocean Getways"(IGCP-355). (1997)

铃木蒲田，K.：“直径小于10公里的破火山口的沉降结构”王子研讨会“太平洋通道的新近纪演化”论文集（IGCP-355）。

鎌田桂子: "新版地学事典" 平凡社, 1443 (1996)

Keiko Kamata：《新版地质词典》Heibonsha，1443（1996）

谷口宏充: "普賢岳火砕流の物理計測の試み" 月刊地球. 号外15号. 112-117 (1996)

Hiromittsu Taniguchi：“尝试对普玄岳火山碎屑流进行物理测量”月刊特刊第 15 期。112-117 (1996)。

谷口宏充: "火砕流温度と火山災害" 伝熱研究. vol.35. 11-20 (1996)

谷口宏光：“火山碎屑流温度与火山灾害”传热研究，第 35 卷（1996 年）。