沿着地球最长的大陆热点轨道对岩组成的岩层控制
D R Davies1, N Rawlinson2, G Iaffaldano1
1Research School of Earth Sciences, The Australian National University, Canberra 2601, Australia.
Nature
|September 15, 2015
概括
石化层的厚度控制着大陆热点的岩组成和体积. 较厚的石化层会导致火山间隙或独特的白石含火山,这表明它对地幔羽融化的影响.
科学领域:
- 地质科学
- 火山学
- 地质化学
背景情况:
- 热点是与板块边界无关的火山区域,通常由地幔羽毛解释.
- 地幔羽毛是从地球深层带来的热物质浮出水面.
- 石质层厚度被认为会影响升高度和岩地质化学,但证据有限.
研究的目的:
- 在澳大利亚的Cosgrove轨道上调查岩层厚度与岩组成之间的关系.
- 通过综合地质和地质物理数据来确定大陆热点轨道下的层融化深度.
- 提供关于岩层厚度对羽毛衍生的岩的影响的观测约束.
主要方法:
- 表面地质学,地球时间学和板块运动重建的整合.
- 分析地质化学数据,包括微量元素度.
- 解读地震数据以评估岩层厚度.
主要成果:
- 沿着Cosgrove轨道的岩层厚度和岩组成之间存在强烈的相关性.
- 岩层<110公里的地方形成了岩岩;岩层>150公里的地方出现了火山间隙.
- 中级岩层厚度与低体积,含有白石的火山活动相关.
结论:
- 石化层厚度是地幔层部分融化程度的主要控制因素.
- 这项研究提供了第一个关于亚大陆羽毛融化深度的观察约束.
- 石质层的厚度对火山活动的体积和化学成分有很大影响.
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