Xie Yuan, Balázs Attila, Gerya Taras, Xiong Xiong
School of Geophysics and Geomatics, China University of Geosciences, Wuhan, China.
Department of Earth Sciences, Institute of Geophysics, ETH Zurich, Zurich, Switzerland.
Nat Geosci. 2024;17(7):683-688. doi: 10.1038/s41561-024-01473-7. Epub 2024 Jul 2.
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 4 km 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.
青藏高原的地球动力学演化仍然存在很大争议。其演化的任何模型都必须解释高原的生长情况,这受到古海拔研究、岩浆活动的时空分布以及从下地幔地震速度异常推断出的岩石圈地幔移除的限制。已经提出了几种相互冲突的模型,但这些模型都无法自洽地解释一级地形、岩浆和地震特征。在这里,我们提出并通过数值模拟测试了一个高原演化模型,该模型涉及岩石圈地幔从覆盖板块逐渐剥离,以及随之而来的地幔和地壳熔融与隆升。我们表明,该模型成功再现了高原表面连续隆升至海拔4公里以上的过程,并且与因印度板块俯冲和欧亚板块岩石圈地幔拆沉而观察到的岩浆活动迁移和岩石圈 - 软流圈边界几何形态一致。这些比较表明,覆盖板块的地幔拆沉是青藏高原隆升的驱动力,并且可能更普遍地是造山高原隆升的驱动力。