地石英在控制 Cordilleran 变形中的作用
Anthony R Lowry1, Marta Pérez-Gussinyé
1Department of Geology, Utah State University, Logan, Utah 84322-4505, USA. Tony.Lowry@usu.edu
Nature
|March 18, 2011
概括
大陆地的石英丰富程度影响温度和变形,解释了大陆山脉带的形成和地震活动. 这项研究揭示了一个反循环,涉及富含石英的地,热量和减弱.
科学领域:
- 地质物理学 地质物理学
- 构造学 构造学 构造学 构造学
- 矿物物理 矿物物理
背景情况:
- 大陆的变形机制在板块构造革命后的几十年里是不太了解的.
- 强度和密度等岩石特性会影响应力,但复杂地取决于温度,水和岩石类型.
- 山脉带和裂区的周期性形成表明,大陆变形的潜在控制.
研究的目的:
- 研究地石英丰度在大陆温度和变形中的作用.
- 了解地震速度比率 (vP/vS) 与变形区域的地特性之间的联系.
- 解释大陆变形的静止性和空间分布.
主要方法:
- 利用EarthScope地震接收器功能,重力和热流数据在美国西部.
- 估计的大陆地的厚度和地震速度比 (vP/vS).
- 分析了低vP/vS,高石层温度和地变形之间的相关性.
主要成果:
- 在低地的vP/vS与高的岩层温度和 Kordillera 的变形之间发现了强烈的相关性.
- 地震速度比 (vP/vS) 对石英丰富度敏感,这是岩石软弱的一个关键因素.
- 低的vP/vS表示大陆地富含石英.
结论:
- 地石英的丰富性显著影响了大陆的温度和变形.
- 提出了一种动态反机制:柔性菌株定位在薄弱的,富含石英的地中,促进变暖,水合,并进一步减弱.
- 这种反解释了大陆变形,热升起和流体活动的空间分布和时间.
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