中国东北持续的岩石圈滴注过程及其对板内火山活动的影响，这一成果由北京大学Feiyu Lin和南方科技大学郭震的研究组合作取得。该项研究成果发表在2024年3月6日出版的《地质学》上。

为了阐明中国东北地区地下的地球动力学过程，该研究团队在区域重建、地震和火山研究数据的限制下，进行了数值模型模拟。根据模型推导的地幔对流和岩石圈部分熔融结构的垂直速度场表明，随着过渡带近水平板块的向西迁移，东北地区的地幔上涌和熔融中心由东向西迁移，最终导致了所观测到的火山迁移。因此，随着太平洋板块西北部的俯冲退缩和日本海的张开，长白山—牡丹江地区与松辽盆地之间形成了明显的岩石圈厚度差异，导致岩石圈不稳定滴水。

这种滴落结构阻止了岩石圈的部分熔融，但也促进了松辽盆地的沉降。此外，岩石圈滴注模型成功地预测了与层析成像模型一致的上地幔结构、观测到的莫霍面深度变化和地表地形变化。其中，岩石圈厚度差异引起的岩石圈滴水作用和太平洋板块的后退俯冲作用为东北地区独特的地球动力学过程提供了一个机制。

据悉，自渐新世以来，中国东北地区出现了独特的板内火山喷发和火山西移，其中一个上覆大陆带，在构造上受西北太平洋板块俯冲和日本海张开的控制。有趣的是，这些板内火山活动发生在沉降盆地(松辽盆地)周围，但在松辽盆地内未观察到火山活动。而且，造成这些火山的地球动力学机制尚不清楚。

附：英文原文

Title: An ongoing lithospheric dripping process beneath northeast China and its impact on intraplate volcanism

Author: Feiyu Lin, Liang Qi, Nan Zhang, Zhen Guo

Issue&Volume: 2024-03-06

Abstract: Unique intraplate volcano eruptions and westward volcano migration since the Oligocene have been observed in northeast China, where an overriding continental zone is tectonically controlled by the subduction of the northwestern Pacific plate and the opening of Japan Sea. Interestingly, these intraplate magmatic events occur around a subsiding basin (the Songliao Basin), but no volcanic activity has been observed within the Songliao Basin. The geodynamic mechanism responsible for these volcanoes remains unclear. To address the geodynamic process beneath northeast China, we conducted numerical models constrained by data from regional reconstruction and seismic and volcanic studies. The vertical velocity field of mantle convection and lithospheric partial melting structures derived from our models show that mantle upwelling and melting centers migrate from east to west in northeast China with the westward propagation of the sub-horizontal slab in the transition zone, leading to the observed volcano migration. Also, with the subduction retreat of the northwestern region of the Pacific plate and the opening of the Japan Sea, significant lithospheric thickness differences developed between the Changbaishan-Mudanjiang region and the Songliao Basin, leading to lithospheric unstable dripping. This dripping structure prevents the partial melting of the lithosphere but facilitates the subsidence of the Songliao Basin. Moreover, the lithospheric dripping model successfully predicts upper mantle structures consistent with the proposed tomography model, the observed Moho depth, and surface topography variations. Thus, lithospheric dripping induced by lithospheric thickness differences and the retreating subduction of the Pacific slab provides a robust mechanism for the unique geodynamic processes in northeast China.

DOI: 10.1130/G51861.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G51861.1/636009/An-ongoing-lithospheric-dripping-process-beneathredirectedFrom=fulltext