海洋地质与环境重点实验室知识库

随着高分辨率海底地形探测技术的进步，海山地貌特征分析已成为海底地貌学中的研究热点，且具有重要的科学意义。然而，目前对海山地形地貌的研究仍停留在定性或半定量程度，鲜有对海山的粗糙度及多尺度特征的讨论。基于高分辨率DEM数据，本研究对位于西太平洋卡罗琳海脊上的平顶海山M4进行了地貌学分类，并应用频谱分析和多重分形去趋势扰动分析（MFDFA）方法对其粗糙度及多尺度特征进行了分析。结果显示平顶海山M4具有0.3~1km和7~20km两个特征尺度，小特征尺度下的地形粗糙度与地形的坡度相关。M4的地形具有多重分形性，且多重分形强度因剖面位置的不同而改变。其多重分形谱的形态参数（最大奇异性指数α₀、谱宽度W和对称性指数B）可以较好地描述地形的多尺度特征。平顶海山及具有平坦顶面的海底台地使地形剖面具有较大的α₀，对于具有强烈小尺度扰动（如冲沟地貌）的地形剖面，其多重分形谱的B偏负。结合M4附近另一座海山M2、50座陆地火山和15座火星火山的DEM数据，本研究对不同地质环境中形成的火山地貌进行了类比分析。地球火山（包括海山与陆地火山）底面宽度d与高度h之间满足线性关系h=0.08d+1.72，且具有类似的特征尺度。MFDFA的结果显示，海山与火星火山具有相似的α₀；而海山与陆地火山具有相似的W，且二者的赫斯特指数H与坡度标准差σ_s之间具有线性关系σ_s=-8.46H+16。产生这些现象的原因可能与不同环境中沉积-侵蚀作用的差异有关。

Along with the development of high-resolution seafloor surveying technologies, the geomorphological analysis of seamounts has become a hotspot in submarine geomorphology, which possesses much scientific meaning. However, most studies on seamount geomorphology are still qualitative or half-quantitative, and the roughness and multiscale analysis of seamounts have seldom been discussed. Based on high-resolution DEM data, the geomorphological units of guyot M4 on the Caroline Ridge in West Pacific are classified in this research. Spectral analysis and Multifractal Detrended Fluctuation Analysis (MFDFA) were applied to obtain the roughness and multiscale features of M4. The result shows that there are two characteristic scales (0.3~1km and 7~20km) in the topography of M4, and the small-scale roughness is correlated with the slope gradients. The topography of M4 is multifractal and the strength of multifractality varies with the locations of topographic profiles. The multifractal features can be perfectly described by multifractal spectrum parameters (the maximum singularity exponent α₀, the spectrum width W and the degree of symmetry B). The guyot and other landforms with flat tops are featured by higher α₀, while areas with strong small-scale fluctuations (e.g. gullies) tend to have negative B. Combined with DEM data of an adjacent seamount M2, 50 terrestrial volcanoes and 15 Martian volcanoes, analogous analysis was applied on volcanoes in different geological environments. With similar characteristic scales, earth volcanoes (both seamounts and terrestrial volcanoes) have a linear relationship between the basal radii d and heights h: h=0.08d+1.72. The MFDFA result shows that seamounts and Martian volcanoes have similar values of α₀. Besides, seamounts and terrestrial volcanoes have similar values of W, and their Hurst exponents H and standard deviations of slope σ_s have a linear relationship σ_s =-8.46 H +16. These phenomena could be attributed to the discrepancies of erosional-depositional processes in different environments.

第1章  引言... 1

    1.1  研究意义及研究内容... 1

    1.2  地形粗糙度计算及多尺度分析... 2

    1.3  海山地貌及地貌学类比研究... 6

    1.4  研究技术路线... 8

第2章  研究区域概况... 10

    2.1  研究区位置... 10

    2.2  区域地质背景... 11

    2.3  区域构造背景... 13

    2.4  区域构造演化历史... 15

第3章  数据及研究方法... 17

    3.1  数据来源... 17

    3.2  频谱分析... 17

    3.3  多重分形分析... 20

    3.4  地形表面特征分析... 23

第4章  平顶海山M4的粗糙度及多重分形分析... 25

    4.1  平顶海山M4发育区域的地貌特征... 25

    4.2  平顶海山M4的二维粗糙度... 29

    4.3  平顶海山M4的多重分形强度特征... 32

    4.4  平顶海山M4多重分形谱的参数特征... 37

    4.5  小结... 38

第5章  海山地貌多尺度特征的类比研究... 40

    5.1  海山M2、陆地火山及火星火山的地貌特征分析... 40

    5.2  海山、陆地火山和火星火山间形态学特征的类比分析... 48

    5.3  海山、陆地火山和火星火山标准化功率谱的类比分析... 49

    5.4  海山、陆地火山和火星火山多重分形参数的类比分析... 52

    5.5  小结... 60

第6章  结论及展望... 61

参考文献... 63

致  谢... 73

作者简历及攻读学位期间发表的学术论文与研究成果... 75