近日，瑞士苏黎世联邦理工学院Xie, Yuan团队报道了青藏高原的隆升是由地幔从上覆板块剥离所驱动的。2024年7月2日出版的《自然—地球科学》发表了这项成果。

该团队提出并测试了一个高原演化的数值模型，该模型涉及岩石圈地幔从上覆板块逐渐剥离，随后的地幔和火山口熔融和隆起。研究表明，该模型成功地再现了高原连续的地表隆升至海拔4km以上，并与观测到的岩浆活动迁移和印度板块俯冲和欧亚板块地幔岩石圈层离，导致的岩石圈—软流圈边界几何形状一致。这些比较表明，来自上覆板块的地幔剥离是青藏高原隆升的驱动力，更广泛地说，可能是造山带板块隆升的驱动力。

据悉，青藏高原的地球动力学演化至今仍有很大争议。其演化的任何模型都可以解释高原的生长受到古海拔研究、岩浆活动的时空分布和岩石圈地幔移动的限制，这些岩石圈地幔移动是从地幔的地震速度异常推断出来的。虽然以往的研究已经提出了几种相互矛盾的模型，但这些模型都不能自洽地解释一阶地形、岩浆和地震特征。

附：英文原文

Title: Uplift of the Tibetan Plateau driven by mantle delamination from the overriding plate

Author: Xie, Yuan, Balzs, Attila, Gerya, Taras, Xiong, Xiong

Issue&Volume: 2024-07-02

Abstract: The geodynamic evolution of the Tibetan Plateau remains highly debated. Any model of its evolution must explain the plateau’s growth as constrained by palaeo-altitude studies, the spatio-temporal distribution of magmatic activity, and the lithospheric mantle removal inferred from seismic velocity anomalies in the underlying mantle. Several conflicting models have been proposed, but none of these explains the first-order topographic, magmatic and seismic features self-consistently. Here we propose and test numerically an evolutionary model of the plateau that involves gradual peeling of the lithospheric mantle from the overriding plate and consequent mantle and crustal melting and uplift. We show that this model successfully reproduces the successive surface uplift of the plateau to more than 4km above sea level and is consistent with the observed migration of magmatism and geometry of the lithosphere–asthenosphere boundary resulting from subduction of the Indian plate and delamination of the mantle lithosphere of the Eurasian plate. These comparisons indicate that mantle delamination from the overriding plate is the driving force behind the uplift of the Tibetan Plateau and, potentially, orogenic plateaus more generally.

DOI: 10.1038/s41561-024-01473-7

Source: https://www.nature.com/articles/s41561-024-01473-7