The interaction of geological structures at different scales often results in complex three-dimensional geometries. This can especially be the case when interpreting progressively deformed multi-layer fold systems which can result in complex non-cylindrical geometries of varying scale and congruity. Curvature analysis methods have lately been developed to assist this for analysing three-dimensional geological surfaces which do not need to assume cylindricity, but these methods are often applied to three-dimensional seismic horizons which have specific considerations that can affect scale analysis. We show how the application of manifold harmonic analysis together with implicit geological modelling can assist in the interpretation of fold structures. This is demonstrated by developing a three-dimensional model of the Padtherung Syncline, central Hamersley province, Western Australia, and applying our manifold harmonic analysis methods. Our results show how the analysis can be used as evidence to re-interpret the polyclinal structure as progressively deformed rather than a superposed structure.

地质结构在不同尺度上的相互作用常常导致复杂的三维几何形状。当解释逐渐变形的多层折叠系统时，尤其可能是这种情况，这可能导致复杂的非圆柱几何体具有不同的比例和一致性。最近已经开发了曲率分析方法来辅助此方法来分析不需要假定圆柱度的三维地质表面，但是这些方法通常应用于具有特定考虑因素的三维地震视域，这些因素可能会影响尺度分析。我们展示了将歧管谐波分析与隐式地质建模一起应用如何能够帮助解释褶皱结构。通过开发Padtherung Syncline的三维模型可以证明这一点，西澳大利亚州哈默斯利省中部地区，并应用我们的多种谐波分析方法。我们的结果表明，该分析如何可以用作将多斜结构重新解释为逐渐变形而不是叠加结构的证据。