Multistage lithospheric drips control active basin formation in the Central Anatolian Plateau: insights from analogue and numerical modelling

Geological and geophysical studies suggest that plateau uplift in regions such as Tibet, Colorado, the Andes, and Anatolia may be in part related to ‘lithospheric dripping’; a process whereby dense lithosphere is removed as a viscous instability. Recent satellite-based measurements and crustal isostasy studies, reveal an interesting tectonic puzzle at the Central Anatolian Plateau in Turkiye since the data indicate rapid subsidence of the Konya Basin within the overall uplifted plateau. Here, we combine results from 3D analogue/laboratory experiments and 2D numerical models with quantitative analyses to study lithospheric drip processes which may be responsible for this local basin subsidence within the plateau. 3D analogue models were built in the laboratory using materials such as polydimethylsiloxane (PDMS), clay, and sand to model lithospheric drip instabilities. Image correlation techniques such as Particle Image Velocimetry (PIV) and digital photogrammetry were used to monitor material flow and changes in topography of the analogue model. In conjunction, similar 2D numerical models were developed using viscoplastic rheologies with the ASPECT geodynamics code. In reconciling the models with the observations, we interpret that the Konya Basin is subsiding due to a secondary localized lithospheric dripping event following a larger scale primary dripping event that was responsible for the broad uplift of the Central Anatolian Plateau. Furthermore, the numerical and analogue experiments suggest that the local secondary drip is `asymptomatic’, in that it drives subsidence but no appreciable tectonic deformation (shortening or extension) of the crust. The findings indicate that multistage lithospheric foundering may be characteristic of the episodic development of orogenic systems.