Abstract Zealandia was once located at the active Gondwana margin and experienced complicated tectonic evolution from continental breakup to subduction and oblique slipping along the plate boundary. Here, we investigate the lithospheric thermal and rheological properties via spatial variations in effective elastic thickness (Te). Using the topography, sediment thickness and gravity data, the fan wavelet coherence method is employed to recover Te values. The effects of dynamic topography and gravity in the subduction zone on the estimated Te are considered and removed. The final results reveal that the Te variation pattern generally coincides well with the tectonic regimes. Relatively high Te values up to 22 km are observed in North Island and the southernmost part of South Island, while central and northern South Island are dominated by smaller Te values (~15 km) similar to those of the surrounding submerged plateaus. We interpret the relatively high Te values as indicating the combined lithospheric strength due to the contacting plates in the subduction zone. To the north along the Tonga-Kermadec subduction zone, the lithosphere surprisingly exhibits anomalously high Te values, ranging from 22 to 36 km, which contradicts the geological evidence of normal faults developed in the incoming Pacific Plate and the magmatism in the overlying Australian Plate that generally contribute to low lithospheric strength. We speculate that the high-Te zone is related to the large bathymetry and gravity anomalies in the bending plate and controlled by non-isostatic factors. Finally, we find widespread low Te values covering the entire arcs and oceanic basins in northern Zealandia, which may indicate that regional lithospheric thinning associated with delamination weakened the integrated strength of the lithosphere.

中文翻译：

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西兰的有效弹性厚度及其对岩石圈变形的影响

摘要 西兰洲曾位于活动的冈瓦纳大陆边缘，经历了从大陆破裂到俯冲和沿板块边界斜滑的复杂构造演化。在这里，我们通过有效弹性厚度 (Te) 的空间变化来研究岩石圈的热学和流变学特性。利用地形、沉积物厚度和重力数据，采用扇形小波相干方法恢复 Te 值。考虑并去除了俯冲带中动态地形和重力对估计 Te 的影响。最终结果表明 Te 的变化模式通常与构造制度很好地吻合。在北岛和南岛最南端观察到高达 22 公里的相对较高的 Te 值，而南岛中部和北部则以较小的 Te 值（~15 公里）为主，类似于周围的淹没高原。我们将相对较高的 Te 值解释为表明由于俯冲带中的接触板块而产生的组合岩石圈强度。在汤加-克马德克俯冲带以北，岩石圈出人意料地表现出异常高的 Te 值，范围为 22 至 36 公里，这与进入的太平洋板块中发育的正断层的地质证据和上覆澳大利亚板块的岩浆作用相矛盾。通常导致岩石圈强度低。我们推测，高碲带与弯曲板中大的水深和重力异常有关，并受非等静压因素的控制。最后，