Study on the chemical state of the Earth's deep interior based on chemical and isotopic compositions of kimberlites and mantle materials

基于金伯利岩和地幔物质的化学和同位素组成研究地球内部深处的化学状态

基本信息

批准号：
15340183
负责人：
KANEOKA Ichiro
金额：
$ 10.18万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

In this study, we aimed to reveal the chemical state of the Earth's deep interior by analyzing kimberlites and various mantle-related materials and examine some models on the chemical structure of the Earth's interior. To collect in-situ kimberlites, we performed sampling in China and Brazil, but found them to have been much altered. We could get a knowledge that fresh kimberlites might have been only found in a limited place where kimberlite magmas were intruded at a depth like sills. By analyzing noble gases in fresh kimberlites from West Greenland, which we had got from foreign investigators, we have revealed that their magma sources are similar to those of ocean-island basalts and probably derived from the lower mantle based on their high ^3He/^4He ratios. Since kimberlites are enriched in volatile elements and show unfractionated platinum-group element patterns relative to those of chondrites, it can be inferred that the lower mantle might have been less degassed and more reduced … More state compared to the upper mantle. However, we could not identify the difference in tungsten isotope ratios between kimberlites and mantle-related materials of the upper mantle origin.On the other hand, we observed ^3He/^4He ratios lower than that of the air in mantle xenoliths from Far Eastern Russia, which suggests the effect of subducted slabs to the mantle in that area. For xenoliths of lower crust and upper mantle origin from the Indian Ocean area, we observed ^3He/^4He ratios similar to those of MORBs and ^<40>Ar/^<36>Ar ratios affected by the air. Furthermore, we have revealed that basalts of less than 1 Ma from Mauritius Island, which belongs to the Reunion hotspot, show Sr, Nd and Pb isotope ratios which are closer to MORB values than those of older basalts. This can be explained by increasing of the effect of plume magmas by the upper mantle materials of MORB types with time. Such tendency can also be observed in noble gas isotopes in alkaline basalts taken from the ocean floor around the Hawaiian Islands and it suggests a possibility that upper mantle materials might have been affected by the ocean-island basalts. Less

在这项研究中，我们旨在通过分析金伯利岩和各种与地幔相关的材料来揭示地球深内部的化学状态，并检查有关地球内部化学结构的一些模型。为了收集原位金伯利特人，我们在中国和巴西进行了抽样，但发现它们发生了很大改变。我们可以知道，新鲜的金伯利特可能只在有限的地方发现了金伯利特岩浆像窗台一样深度侵入的。通过分析我们从外国调查人员那里得到的西格陵兰新鲜金伯利岩中的贵重气体，我们透露，它们的岩浆来源与海洋 - 岛玄武岩的岩浆源相似，并且可能是根据其高 ^3He/ ^4he比率衍生出来的。由于金伯利岩具有挥发性元素的富含，并且相对于软骨的铂群元素模式显示出未分离的铂群元素模式，因此可以推断出，与上地幔相比，下层的较低的地幔可能较少，并且降低了。但是，我们无法确定金伯利岩与上地幔起源的地幔相关材料之间的钨同位素比的差异。另一方面，我们观察到 ^3he/ ^4he比率低于俄罗斯远东俄罗斯的地幔Xenoliths中空气的比率，这暗示了Subduct subducted Slabs of the slabs to n of the n of the n of the n of。对于来自印度洋地区的下地壳和上地幔起源的异种石，我们观察到 ^3he/ ^4He比与Morbs相似， ^<40> ar/ ^<36> ar比率受空气影响。此外，我们已经透露，属于团圆热点的毛里求斯岛的玄武岩少于1 mA，显示了比较旧的玄武岩的底层sr，nd和Pb同位素比。这可以通过随着时间的流逝，MORB类型的上地幔材料增加李子岩浆的影响来解释。从夏威夷群岛周围海底的酒精玄武岩中的贵族同位素中也可以观察到这种趋势，这表明上地幔材料可能会受到海洋矿山玄武岩的影响。较少的

项目成果

期刊论文数量（65）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Ocean-island basalt-like source of kimberlite magmas from West Greenland revealed by high ^3He/^4He ratios

高 ^3He/^4He 比率揭示了来自西格陵兰岛的类似海岛玄武岩的金伯利岩岩浆源

DOI：
发表时间：
2006
期刊：
Geology 34・4
影响因子：
0
作者：
Tachibana;Y.;I.Kaneoka;A.Gaffry;B.Upton
通讯作者：
B.Upton

Meteoric ^<10>Be in volcanic materials and its behavior during acid-leaching.

火山材料中的流星^<10>Be及其在酸浸过程中的行为。

DOI：
发表时间：
2004
期刊：
Nuclear Instruments and Methods in Physics Research (NIM), Section B 223/224
影响因子：
0
作者：
Shimaoka;A.;M.Sakamoto;H.Hiyagon;H.Matsuzaki;I.Kaneoka;M.Imamura
通讯作者：
M.Imamura

Kumagai, H., H.J.B.Dick, I.Kaneoka: "Noble gas signatures of abyssal gabbros and periodotites at an Indian Ocean core complex."G-cubed. 4(12). 1-16 (2003)

Kumagai, H.、H.J.B.Dick、I.Kaneoka：“印度洋核心复合体中深海辉长岩和周期岩的惰性气体特征。”G 立方。