带有的蛇形岩和圣安德烈亚斯断层的爬行部分
Diane E Moore1, Michael J Rymer
1US Geological Survey, 345 Middlefield Road, Mail Stop 977, Menlo Park, California 94025, USA. dmoore@usgs.gov
Nature
|August 19, 2007
概括
在圣安德烈亚斯断层蛇形岩中发现的石表明,它可能解释了断层爬行. 这一发现解决了弱断层行为与蛇形矿物质高强度之间的差异.
科学领域:
- 地质地质地质地质地质地
- 构造学 构造学 构造学 构造学
- 矿物学是什么?矿物学是什么?
背景情况:
- 加利福尼亚州中部的圣安德烈亚斯断层 (SAF) 呈现出显著的爬行 (高达28毫米/年).
- 蛇形矿石经常被认为是导致这种弱断层行为的原因,但蛇形矿物具有与观察不一致的摩擦强度.
- 以前的研究表明,一个弱断层嵌入在一个强大的地环境中.
研究的目的:
- 为了研究SAF沿线的蛇形矿石的矿物成分.
- 为了确定负责这一断段的低切削强度和稳定的爬行机制.
- 为了使蛇形岩的存在与观察到的断层弱点相协调.
主要方法:
- 来自圣安德烈亚斯断层深度观测站 (SAFOD) 主孔的蛇形岩切片的分析.
- 岩石样本的显微镜和矿物学检查.
- 基于地质背景的矿物形成过程的推断.
主要成果:
- 在SAF的蛇形岩样本中发现了滑石.
- 据推断,滑石粉是由蛇与富含二氧化的热水流体反应而形成的.
- 滑石是沿着断层痕迹的剪切蛇形岩中发现的.
结论:
- 滑石在高温下具有摩擦性能,与SAF的低切削强度相一致.
- 塔尔克的稳定滑动行为与观察到的断层爬行保持一致.
- 滑石可能是关键矿物质,将蛇形存在与圣安德烈亚斯断层上的断层爬行联系起来.
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