旧山的地根中的浮力正在减弱
1Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA. Karen_Fischer@brown.edu
Nature
|June 28, 2002
概括
由于冷却,山地的根在数百万年内失去了浮力,减少了它们支地形的能力,因为侵蚀会磨损山脉. 这就解释了为什么古老的山脉相对于它们的地根具有较小的浮力.
科学领域:
- 地质地质地质地质地质地
- 地质物理学 地质物理学
- 构造学 构造学 构造学 构造学
背景情况:
- 山脉形成涉及地的加厚和深层地的根源,这些根源提供浮力来支持地形.
- 在构造活动停止后,侵蚀减少了表面的浮力,但对地根的长期反应不太了解.
研究的目的:
- 为了研究山脉的地根如何对地质时间尺度上的侵蚀性卸载做出反应.
- 了解山脉年龄,地表浮力和地根浮力之间的关系.
主要方法:
- 从古老和年轻的碰撞山带中分析重力数据.
- 表面浮雕与地根厚度的比较.
- 模拟长期冷却和变态反应对地根浮力的影响.
主要成果:
- 较老的山脉带表现出较小的表面缓解与地根厚度比较较年轻的山脉带.
- 这一趋势归因于地根浮力随着年龄的增长而下降,这与冷却引起的变形反应相一致.
- 质量平衡表明,大陆石化层在数百万年内仍然足够弱,足以进行根源挖掘.
结论:
- 由于地的冷却,地根的浮力随着地质时间的推移显著下降,影响了山脉支.
- 虽然侵蚀可以长时间挖掘地的根,但减少浮力限制了由此产生的提升.
- 了解这些过程对于解释碰撞山脉带的演变至关重要.
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