近日，中国科学院广州地化所刘亮和南方科技大学Jason P. Morgan合作取得一项新突破。他们研制了由上地幔热不均匀性驱动的长寿北半球幅合系统。这一研究成果发表在2024年2月21日出版的国际学术期刊《地质学》上。

研究人员认为上地幔热不均匀性，特别是异常冷的北半球上地幔，是这种长期辐合的根本驱动因素。通过考虑观测到的热不均匀性模式，研究的数值模型表明，即使在俯冲板块是漂浮的，流动诱导的不对称俯冲也将倾向于向冷地幔域发展。该模型可以通过包括拟议的俯冲前板块分布和/或性质，来再现在北半球观测到的各种俯冲样式。

据了解，板块重建显示，在欧亚大陆东部和北美洲下方不晚于200Ma形成了两个长期的辐合中心。这些幅合中心以特色的平坦俯冲、板块停滞和/或大陆边缘俯冲为特征，其成因仍然不确定。

附：英文原文

Title: Long-lived Northern Hemisphere convergence systems driven by upper-mantle thermal inhomogeneity

Author: Liang Liu, Zebin Cao, Jason P. Morgan, Hongyan Li, Fan Yang, Yi-Gang Xu

Issue&Volume: 2024-02-21

Abstract: Plate reconstructions reveal that two secular centers of convergence formed beneath eastern Eurasia and North America no later than 200 Ma. The cause of these convergence centers, which featured flat subduction, slab stagnation, and/or continental margin subduction, remains uncertain. Here, we propose that upper-mantle thermal inhomogeneity, particularly an anomalously cool Northern Hemispheric upper mantle, was a fundamental driver of this long-lived convergence. By considering the pattern of observed thermal inhomogeneity, our numerical models show that flow-induced asymmetrical subduction will tend to develop toward cold mantle domains, even when the subducting plate is buoyant. The models can reproduce the diverse subduction styles observed in the Northern Hemisphere by including proposed pre-subduction plate distributions and/or properties.

DOI: 10.1130/G51948.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G51948.1/635319/Long-lived-Northern-Hemisphere-convergence-systems