连接地幔羽毛,大型火山地带和环境灾难
Stephan V Sobolev1, Alexander V Sobolev, Dmitry V Kuzmin
1Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, 14473, Potsdam, Germany. stephan@gfz-potsdam.de
Nature
|September 17, 2011
概括
巨大的火热区域 (LIP) 从地幔羽毛中形成,可能导致大规模灭绝. 新的模型显示,回收的海洋地在羽毛中解释了LIP并引发了环境灾难.
科学领域:
- 地质科学 地质科学
- 地质化学 地质化学
- 地力学是什么?地力学是什么?
背景情况:
- 大火山区 (LIPs) 与大规模灭绝有关,但它们的形成机制,特别是来自地幔羽毛,是有争议的.
- 西伯利亚陷,一个主要的LIP,在厚厚的大陆岩层上形成,缺乏羽毛头抬起或拉伸的证据.
- 现有的模型很难解释LIP的形成和相关环境危机的规模,CO2脱气估计不足.
研究的目的:
- 为了研究回收海洋地在地幔羽毛头中的作用.
- 开发一个与地质观测相一致的LIP形成的热力学模型.
- 评估源气体排放可能导致大规模灭绝的潜力.
主要方法:
- 石矿学分析,以在羽毛头模型中识别回收的海洋地.
- 开发一个模拟羽毛-石质层相互作用的热力学模型.
- 整合模型预测与来自LIP的地平面和地质年代数据.
主要成果:
- 石矿学证据表明,在羽毛头内,密集的回收海洋地的重量成分 (15%) 是很重要的.
- 热力学模型预测LIP的形成在没有 magma 前提升或石质层延伸的情况下.
- 模型结果显示了大量的羽毛融和厚厚的岩石层的异质侵蚀.
- 大规模的二氧化碳和化合物从回收的地中的大规模脱气被确定为大规模灭绝的潜在触发因素.
结论:
- 在地幔羽毛中回收的海洋地提供了一个可行的机制,用于在厚厚的岩层上形成LIP.
- 羽驱动的大规模气体释放,而不仅仅是火山活动,可以解释与LIP相关的环境影响和大规模灭绝.
- 主要火山阶段之前的气体释放时间与西伯利亚陷和其他LIP的地质证据一致.
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