太平洋海上山道中的异步曲线:扩展性火山活动的案例?
Anthony A P Koppers1, Hubert Staudigel
1Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0225, USA. akoppers@ucsd.edu
概括
吉尔伯特山脊和托克劳海底山表现出独特的曲,挑战了静止热点理论. 它们的年龄表明异步形成,可能表明热点运动或局部地质事件.
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
- 板块构造学是一种板块构造学.
背景情况:
- 太平洋有独特的海底山道:吉尔伯特山脊和托克劳海底山,以60度的曲而闻名.
- 这个曲类似于夏威夷-皇帝曲 (HEB),这是理解太平洋板块运动的关键特征.
- 静止热点模型预测同期曲,如果板块运动是唯一的因素.
研究的目的:
- 为了调查吉尔伯特山脊和托克劳海拔曲线的形成年龄.
- 为了测试静止热点模型在太平洋海底山脉轨迹形成的有效性.
- 探索异步曲形成的替代解释.
主要方法:
- 使用40Ar/39Ar测年技术来确定海底山脉形成的年龄.
- 分析了地质数据,将曲线形成时间与夏威夷-皇帝曲线进行比较.
- 应用板块构造模型来解释海底山的空间和时间关系.
主要成果:
- 新的40Ar/39Ar约会揭示了吉尔伯特山脊 (6700万年前) 和托克劳海底山 (5700万年前) 曲线的不同年龄.
- 这些年龄早于夏威夷-皇帝曲线 (4700万年前),表明异步形成.
- 这些曲线的异步性质挑战了传统的静止热点范式.
结论:
- 吉尔伯特山脊和托克劳海上曲线的形成与HEB的形成并不同步.
- 静止热点模型不足以解释这些海拔曲线的观察时间.
- 研究结果表明,潜在的热点运动或局部的石质层延伸是海上岩石和曲的替代原因.
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