海洋地中的道化流体流调和了热流和透性数据
1Earth Sciences Department, University of California, Santa Cruz 95064, USA. afisher@es.ucsc.edu
Nature
|January 19, 2000
概括
海底地中的热水流体循环对于海洋和地的组成至关重要. 区域透率高于钻井数据所表明的水平,这表明旧海洋地中的通道流.
科学领域:
- 地球科学 地球科学 地球科学
- 海洋学 海洋学 海洋学
- 地质物理学 地质物理学
背景情况:
- 水热流体循环显著影响海洋地和海洋化学.
- 脊侧面的循环 (地年龄大于1亿年) 在地质时间尺度上推动了大量的热量和流体流动.
- 海洋地的透性决定了流体流动的程度,影响了热量和化学交换.
研究的目的:
- 为了研究海洋地年龄,透性和流体流动之间的关系.
- 为了调和钻孔透度测量和大规模热流观测之间的差异.
- 了解成熟海洋地中控制热水循环的机制.
主要方法:
- 全球数据集的分析,用于测量海洋上层地的钻井透性.
- 对透性趋势与地震速度数据和依赖年龄的地特性进行比较.
- 开发和应用横流模型来估计区域范围的透度.
主要成果:
- 钻孔透度测量显示,随着年龄的增长,出现了趋势,这表明,在几百万年以上的地中,液体流量减少.
- 这种年龄透性趋势似乎与热流数据不一致,这些数据表明旧地中持续的附带热损失.
- 计算显示,区域范围的透度明显高于钻井测量,特别是在较古老的地中.
结论:
- 海洋地中的热液流很可能是通过岩石体积的一小部分进行的.
- 这种道化流量使测量到的低透率与较旧地的高区域热量损失相协调.
- 流体对流的几何形状和流体岩石相互作用的性质受到这种集中流动的深刻影响.
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