Quantitatively Tracking the Elevation of the Tibetan Plateau Since the Cretaceous: Insights From Whole‐Rock Sr/Y and La/Yb Ratios
Fangyang Hu, Fu‐Yuan Wu, James B. Chapman, Mihai N. Ducea, Wei‐Qiang Ji, Shuwen Liu
Abstract
Abstract Crustal thickness, elevation, and Sr/Y and (La/Yb) N of magmatic rocks are strongly correlated for subduction‐related and collision‐related mountain belts. We quantitatively constrain the paleo‐elevation of the Tibetan Plateau since the Cretaceous using empirically derived equations. The results are broadly consistent with previous estimates based on stable isotope and structural analyses, supporting a complex uplift history. Our data suggest that a protoplateau formed in central Tibet during the Late Cretaceous and was higher than the contemporaneous Gangdese arc. This protoplateau collapsed before the India‐Asia collision, during the same time period that elevation in southern Tibet was increasing. During the India‐Asia collision, northern and southern Tibet were uplifted first followed by renewed uplift in central Tibet, which suggests a more complicated uplift history than commonly believed. We contend that a broad paleovalley formed during the Paleogene in central Tibet and that the whole Tibetan Plateau reached present‐day elevations during the Miocene.