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在夏威夷的热点点上,有同位素证据证明了白纪晚期的羽毛-山脊相互作用
1College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis 97331, USA. rkeller@oce.orst.edu
Nature
|June 23, 2000
概括
8100万年前的夏威夷热点产生了与中洋脊玄武岩区分不开的火山活动. 这表明热点与蔓延的山脊相互作用,引入了被耗尽的地幔物质.
科学领域:
- 地质化学 地质化学
- 地质地质地质地质地质地
- 板块构造学是一种板块构造学.
背景情况:
- 地幔羽毛和中洋山脊相互影响.
- 相互作用可以导致浅水度,过度的火山活动,以及山脊的基岩成分变化.
- 热点火山活动可以被拉向山脊并经过化学修饰.
研究的目的:
- 为了研究早期夏威夷热点火山的同位素组成.
- 为了确定夏威夷热点在其早期历史中是否与中洋山脊相互作用.
主要方法:
- 在底特律海上山的火山样本中进行了sr-nd-pb同位素分析.
- 对同位素特征与中洋脊玄武岩和已知的夏威夷热点岩进行比较.
- 与板块重建数据的集成.
主要成果:
- 底特律海底山 (81亿年前) 的火山活动显示出与中海基岩相同的同位素特征.
- 这种同位素特征是夏威夷热点轨道的独特特征.
- 这些发现支持了热点在中海山脊附近的假设.
结论:
- 夏威夷热点与大约8000万年前的中洋山脊相互作用.
- 羽毛在扩散中心附近携带了耗尽的上层地幔物质,掩盖了其原始的化学特征.
- 这种相互作用表明,热点在它们的进化早期可以通过接近蔓延的山脊而受到显著的修改.
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