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Activities and Origin of Hotspot Volcanoes in Indian Ocean

印度洋热点火山的活动和起源

基本信息

批准号：
06041026
负责人：
KANEOKA Ichiro
金额：
$ 10.94万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06041026/
关键词：
Reunion Island Mauritius Island Rodrigues Island Hotspot Piton de la Fournaise Piton des Neiges Volcanic activity Indian Ocean 火山ピトン・ド・ラ・フルネ-ズ火山ピトン・ド・ネージュ火山火山岩超塩基性捕獲岩かんらん石斑晶

项目摘要

(1) Before we started the preliminary survey of the Reunion and Mauritius Island in 1994, we had visited the scientists of the IPGP (Institut de Physique du Globe de Paris) and got sufficient information directly on the sites of rocks which we wanted to collect and others. Further, we surveyed the Reunion Island from the air by a helicopter. Through the survey in 1994 and 1995, we could collect almost all kinds of samples which we want to get from the Reunion, Mauritius and Rodrigues Islands. They cover samples which range in space and time and include basalts with olivine phenocrysts and ultramafic nodules.(2) Three of our group surveyed the Rodrigues Island in 1995 and found that the geology in this island is different between the eastern and western parts and the center of volcanic activity seems to have moved from the west to the east. The magmas do not seem to have been originated from the ridge system.(3) Through the cooperative works with the scientists of the IPGP,as a volcanophysical study, we investigated the coda Q and found that it depends on the frequency of seismic waves. The coda Q around the Piton de la Fournaise volcano has been found to be identical with those of the island are and collisional regions. The time-sequence analysis has revealed that the rhythm of volcanic eruption for the Piton de la Fournase volcano and Mt. Fuji is controlled by a simpler system than those of Izu-Oshima and Miyake-jima volcanoes.(4) For collected samples, thin sections were prepared and petrological, mineralogical, chemical and isotope analyzes including K-Ar dating are undertaken. After we accumulate such data, we will discuss the characteristics and origin of the Reunion hotspot.

(1)在我们于1994年开始对留尼汪岛和毛里求斯岛进行初步调查之前，我们拜访了IPGP（地球仪de巴黎）的科学家，并直接获得了我们想要收集的岩石和其他岩石地点的充分信息。此外，我们还乘坐直升机从空中勘察了留尼汪岛。通过1994年和1995年的调查，我们在留尼汪岛、毛里求斯岛和罗德里格斯岛几乎可以收集到我们想要得到的所有样品。它们涵盖了不同时空的样品，包括具有橄榄石斑晶和超镁铁结核的玄武岩。(2)1995年，我们的三个小组调查了罗德里格斯岛，发现该岛的地质在东部和西部之间是不同的，火山活动的中心似乎已经从西部移到了东部。岩浆似乎不是起源于洋脊系统。(3)通过与IPGP科学家的合作，作为火山物理研究，我们研究了尾波Q，发现它取决于地震波的频率。Fournaise火山周围的尾波Q与岛弧和碰撞区的尾波Q一致。时间序列分析表明，富尔纳塞火山和富尔纳塞火山的火山喷发节律性较强。富士山是由一个比伊豆大岛和三宅岛火山更简单的系统控制的。(4)对采集的样品制作了薄片，并进行了岩石学、矿物学、化学和同位素分析，包括K-Ar测年。在我们积累了这些数据之后，我们将讨论团聚热点的特征和起源。