Present-day uplift of the European Alps: Evaluating mechanisms and models of their relative contributions

Recent measurements of surface vertical displacements of the European Alps show a correlation between vertical
velocities and topographic features, with widespread uplift at rates of up to ~2–2.5 mm/a in the North-Western
and Central Alps, and ~1 mm/a across a continuous region from the Eastern to the South-Western Alps. Such a
rock uplift rate pattern is at odds with the horizontal velocity field, characterized by shortening and crustal
thickening in the Eastern Alps and very limited deformation in the Central and Western Alps. Proposed mechanisms
of rock uplift rate include isostatic response to the last deglaciation, long-term erosion, detachment of
the Western Alpine slab, as well as lithospheric and surface deflection due to mantle convection. Here, we assess
previous work and present new estimates of the contributions from these mechanisms. Given the large range of
model estimates, the isostatic adjustment to deglaciation and erosion are sufficient to explain the full observed
rate of uplift in the Eastern Alps, which, if correct, would preclude a contribution from horizontal shortening and
crustal thickening. Alternatively, uplift is a partitioned response to a range of mechanisms. In the Central and
Western Alps, the lithospheric adjustment to deglaciation and erosion likely accounts for roughly half of the rock
uplift rate, which points to a noticeable contribution by mantle-related processes such as detachment of the
European slab and/or asthenospheric upwelling. While it is difficult to independently constrain the patterns and
magnitude of mantle contributions to ongoing Alpine vertical displacements at present, future data should
provide additional insights. Regardless, interacting tectonic and surface mass redistribution processes, rather
than an individual forcing, best explain ongoing Alpine elevation changes.