北京大学王腾团队实现了从咸海干燥推断欧亚大陆内部下方的弱软流层。2025年4月7日，《自然—地球科学》杂志发表了这一成果。
下地壳和上地幔的流变学影响着地幔对流的板块构造风格，但其空间变异性很难得到解决，特别是在大陆内部。研究组使用卫星雷达干涉测量来绘制咸海干燥导致的延迟隆起图，自1960年以来，咸海已经损失了约1000立方公里的水。由此，他们通过弹性和粘弹性建模来约束下伏上地幔的流变性。
结果发现，2016年至2020年间，咸海出现了长达7毫米/年的长波隆起，并呈放射状衰减。这种抬升模式用强岩石圈地幔下软流层的粘弹性弛豫来解释最好。研究组估计，软流层在130-190 km深度以下的有效粘度为4-7×1019 Pa s ，略大于俯冲带震后变形推断的值，但比其他构造稳定地区冰川均衡调整估计的值小1-2个数量级。这种隆起突显了人类活动影响地球深部动力学以及地表和地幔过程相互联系的潜力。
附：英文原文
Title: Weak asthenosphere beneath the Eurasian interior inferred from Aral Sea desiccation
Author: Fan, Wenzhi, Wang, Teng, Barbot, Sylvain, Fang, Dong, Ran, Jiangjun, Luo, Heng
Issue&Volume: 2025-04-07
Abstract: The rheology of the lower crust and upper mantle influences Earth’s plate tectonic style of mantle convection, yet its spatial variability is poorly resolved, particularly in continental interiors. Here we use satellite radar interferometry to map the delayed uplift resulting from the desiccation of the Aral Sea, which has lost ~1,000km3 of water since 1960. From this we constrain the rheology of the underlying upper mantle by elastic and viscoelastic modelling. We find a long-wavelength uplift of up to ~7mmyr–1 between 2016 and 2020 that decays radially from the Aral Sea. This uplift pattern is best explained by viscoelastic relaxation of the asthenosphere below a strong lithospheric mantle. We estimate that the asthenosphere has an effective viscosity of 4–7×1019Pas below 130–190km depth, slightly larger than the values inferred from post-seismic deformation at subduction zones, but 1–2 orders of magnitude smaller than estimates from glacial isostatic adjustment in other tectonically stable regions. Such uplift highlights the potential for human activities to influence deep-Earth dynamics and the interconnectedness of surface and mantle processes.
DOI: 10.1038/s41561-025-01664-w
Source: https://www.nature.com/articles/s41561-025-01664-w