Constraints on the continental indentation process: High‐resolution thermotectonic analysis of the Dolomites Indenter (eastern Southern Alps)

Running title: Thermo‐tectonic evolution of the Dolomites Indenter

Start: 01.02.2020

Orogens like the Andes or the Himalaya show a notably consistent lithospheric architecture along strike. This consistency is in stark contrast to the distinct lateral variations in crust and lithospheric structure of the Alps that occur over comparably short distances and include, e.g., the subduction polarity of the underlying plates, east‐west extensional structures, and the Adriatic indenter. Indenters (strong lithospheric blocks that collide with weaker units) are a main reason for along strike variation in tectonics in many convergent zones and are therefore of special interest.

For the Adriatic Indenter the relationship of the deformation in the crust to the dynamics of the underlying mantle remains speculative due to a lack of a comprehensive thermochronological and structural dataset. But the few existing data loosely denote an exhumation pattern not linked to the known fault structures. Our hypothesis is that major changes in the lithospheric structure resulted in regional (large wavelength – low magnitude) variations in exhumation rates, the timing of exhumation within the Indenter, and the spatial and temporal shifts of its internal deformation.

We propose to collect a new and comprehensive dataset to constrain this history of exhumation and deformation of the eastern Adriatic Indenter (Dolomites Indenter) and to address its relationship to the dynamics of the underlying mantle lithosphere. It is this exhumation record that can provide a solution to the unresolved question: what is the role of deep‐seated mantle dynamics in controlling the geometry and internal deformation of the Adriatic Indenter? The latter will be investigated through the proposed physical analogue modelling, which will provide insight in the forcing and associated length‐scales of deformation. As part of the international AlpArray initiative, with its focus on seismological investigations of the subsurface, our study provides crucial data for an integrated geodynamic model of Alpine convergence.