西太平洋雅浦-卡罗琳海区海山多尺度地形特征

Multiscale topographic features of the seamounts in the Yap-Caroline area of West Pacific

  • 摘要: 海山地形的多尺度特征研究,有助于理解海山形成与演化过程中的地貌过程,并为深入认识俯冲带地球动力过程提供新的线索。本文基于中国科学院海洋研究所“科学”号科考船近年来在雅浦-卡罗琳海区采集的高分辨率海底地形数据,利用统计学及频谱分析等方法,分析了研究区42座海山的形态及地形粗糙度特征,并对海山地形多尺度特征及其成因开展研究。结果表明,雅浦-卡罗琳海区不同构造环境下形成的海山群,在海山的形态参数和多尺度地形特征等方面存在显著差异。相比于索罗尔海槽,帕里西维拉海盆中的海山具有更大的宽高比与更小的平坦度。两区域内海山形态参数具有不同的线性相关关系,表明区域内海山存在不同的形态演化过程。对帕里西维拉海盆中海山地形的频谱分析显示,其大尺度特征信号不显著,意味着该区域内海山地形受小尺度地貌过程的影响更大。索罗尔海槽中海山的粗糙度与海山体积具有线性相关性,可能与不同海山形成过程的差异有关,较早形成的海山受到了更多构造活动及小尺度地貌过程的影响,进而形成了更加粗糙的表面特征。

     

    Abstract: Multiscale topography of seamounts is helpful for understanding the geomorphic processes on different scales in the formation and evolution of seamounts and may provide clues for the study on geodynamic processes relating to plate subduction. Based on the high-resolution bathymetric data of Yap-Caroline area collected by R/V “Kexue” of the Institute of Oceanology, Chinese Academy of Sciences, the morphologic features and surface roughness of 42 seamounts in the study area have been analyzed by statistical methods, with focuses on the phenomenon and genesis of multiscale features of seamounts. The result demonstrates that the morphologic parameters and multiscale features of seamounts in different tectonic environments vary significantly. Seamounts in the Parece Vela Basin have larger height-to-basal-radius ratio and smaller flatness than those in the Sorol Trough. Different linear relationships between morphologic parameters imply that seamounts in the two regions have undergone different morphologic evolution processes. Multiscale analysis results suggest that the amplitudes of large characteristic scale (6~14 km) of seamounts in the Parece Vela Basin is not significant, and small-scale geomorphological processes have greater influence on the modification of seamount landscapes in this region. The linear relationship between roughness and volume of seamounts in the Sorol Trough might result from the discrepancy in formation times. Seamounts formed earlier have gone through more tectonic activities and small-scale geomorphologic processes, which resulted in rougher surface characteristics.

     

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