Fig. 4: Transition in average crustal density of the Gangdese arc during the Late Cretaceous-Cenozoic.
From: Lower crustal foundering drove the uplift of southern Tibet during the Paleocene
a Cartoon illustrating parameters used for the crustal isostatic calculation. The mantle density (ρm) is assumed to be 3.35 g/cm3[,21. The reference standard crustal column has a crustal thickness (H0) of 70 km, elevation (h0) of 5 km, and crustal density (ρc0) of 2.87 g/cm3[,47, roughly corresponds to the present Tibetan Plateau. After removing the effect of thermal isostasy, the non-thermal elevation is controlled by crustal isostasy, then h = h0 + H(1−ρc/ρm)−H0(1−ρc0/ρm), where h, H, and ρc represent non-thermal elevation, crustal thickness, and crustal density, respectively. b Non-thermal elevation versus crustal thickness at ~80, ~55 and ~30 Ma (filled circles). Error bars represent the propagated errors. The unfilled circles and related errors are plotted using the mean elevations derived from the mean processing and error analysis of multiple measurements. The light green lines represent the crustal density (g/cm3) formulated from the isostatic equation. Global continental elevation and crustal thickness at 1° resolution (gray and black dots) from the CRUST1.0 model78 are also shown for comparison. The dark green line represents the theoretical best-fit correlation line between global continental elevation and crustal thickness assuming crustal isostasy. The black dots represent the present Tibetan Plateau.
