北京大学学报自然科学版 ›› 2019, Vol. 55 ›› Issue (3): 437-444.DOI: 10.13209/j.0479-8023.2018.025

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海底地形对不同时间尺度岩浆供给变化的响应

贠晓瑞1,2, 李江海1,2,†, 吴桐雯1,2, 宋珏琛1,2   

  1. 1. 造山带与地壳演化教育部重点实验室, 北京大学地球与空间科学学院, 北京100871 2. 北京大学石油与天然气研究中心, 北京100871
  • 收稿日期:2018-04-14 修回日期:2018-05-07 出版日期:2019-05-20 发布日期:2019-05-20
  • 通讯作者: 李江海,E-mail:jhli(at)pku.edu.cn
  • 基金资助:
    国家重点研发计划(2016YFC0503301)和大型油气田及煤层气开发国家科技重大专项(2016ZX05033002-007)资助

Seafloor Bathymetry Response to Different Time Scale of Magmatic Supply Fluctuation

YUN Xiaorui1,2, LI Jianghai1,2,†, WU Tongwen1,2, SONG Juechen1,2   

  1. 1. Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, School of Earth and Space Sciences, Peking University, Beijing 100871 2. Institute of Oil and Gas, Peking University, Beijing 100871
  • Received:2018-04-14 Revised:2018-05-07 Online:2019-05-20 Published:2019-05-20
  • Contact: LI Jianghai,E-mail:jhli(at)pku.edu.cn

摘要:

利用有限差分数值模拟方法, 恢复洋中脊地形的形成过程, 模型中岩浆供给按一定的时间周期和幅度规律性地变化。结果表明: 只有当岩浆供给变化周期的时间尺度大于在洋中脊同一侧形成两条断层的时间间隔时, 才能影响海底地形的形成过程并被记录。结合数值模拟实验结果和不同类型洋中脊的地形特征, 认为快速扩张洋中脊是唯一可能在地形上记录到米兰科维奇气候周期(偏心率(100 ka)、倾斜度(41 ka)和岁差(23 ka)) 3个时间尺度岩浆变化周期的洋中脊类型, 中速扩张洋中脊和部分岩浆供给充足慢速扩张洋中脊的地形可能与100 ka尺度的岩浆供给变化周期有关, 大部分慢速扩张洋中脊海底地形不受100 ka及以下的岩浆供给变化周期影响。

关键词: 洋中脊, 断层, 岩浆供给, 气候变化周期

Abstract:

The finite-difference numerical simulation is used to reproduce the seafloor bathymetry near mid-ocean ridges. The magma supply in the model changes regularly with fluctuation period and amplitude. The results indicate that only when the magmatic supply fluctuation period is greater than the time interval between the formation of two faults on the same side of mid-ocean ridge, the formation process of the seafloor bathymetry can be influenced and recorded. Combined with numerical simulation results and different types of ocean ridge topography, this paper considers that the fast spreading mid-ocean ridge is the only ridges type that can record three magmatic supply fluctuation period of Milankovich cycles (eccentricity (100 ka), obliquity (41 ka) and precession (23 ka)) on the bathymetry. Bathymetry in mid-speed mid-ocean ridges and part of slow spreading midocean ridges with sufficient magmatic supply may be related to the magmatic supply fluctuation period on the 100 ka time scale. seafloor bathymetry in most of the slow-spreading mid-ocean ridges is not affected by magmatic supply fluctuation period of 100 ka or less.

Key words: mid-ocean ridge, fault, magmatic supply, climate change