Decoupled Lithospheric Folding, Lower Crustal Flow Channels, and the Growth of Tibetan Plateau

Abstract

The growth mechanism of the Tibetan Plateau, postulated by a number of hypotheses, remains under intense debate. Our analysis of recent satellite‐based gravity model reveals that Tibetan lithosphere has been decoupled and folded. It is further evidenced by the existence of crustal melts and channel flow that have been observed by seismic and magnetotelluric explorations. Based on 3D geodynamic simulations, we elucidate the exact buckling structures in the upper crust and lithospheric mantle: at mixed wavelengths between ∼240 and ∼400 km, the lower crustal viscosity is smaller than ∼1019 Pa·s, implicating weak lower crustal flow beneath the Plateau. This mixed wavelength is consistent with the result of our inverse gravity modeling. Our results facilitate a new plausible hypothesis that the decoupled lithospheric folding mechanism can explain the growth mechanism of the anomalously thick and wide Tibetan Plateau by conflating our idea and contemporary hypothesized scientific findings.

Present‐Day Three‐Dimensional Crustal Deformation Velocity of the Tibetan Plateau Due to Multi‐Component Land Water Loading

“…The Tibetan Plateau (TP; Figure 1), known as “the roof of the world”, is widely accepted as a natural laboratory for studying continental collision and orogenic movement (Ding et al., 2022; Molnar et al., 1993; Royden et al., 2008; Wang et al., 2014). Many studies focusing on the crustal kinematic characteristics and uplift mechanism of the TP have been conducted based on the physical constraint from modern geodetic data (Jiao et al., 2019; Shin et al., 2022; Sun et al., 2009; Wang et al., 2019; Wu et al., 2022; Yi et al., 2016), especially the high‐accuracy three‐dimensional GPS (Global Positioning System) crustal deformation velocity field (Liang et al., 2013; Wang & Barbot, 2023; Wang & Shen, 2020; Zheng et al., 2017). However, GPS observes an integrated geophysical signal, including both tectonic and atectonic deformations, out of which the land water loading has been proven to be an important signal source (Amos et al., 2014; Chanard et al., 2014; Hao et al., 2016; van Dam et al., 2001; White et al., 2022; Zhu et al, 2023).…”