Impact of Decelerating India‐Asia Convergence on the Crustal Flow Kinematics in Tibet: An Insight From Scaled Laboratory Modeling

The factors controlling the spatiotemporally varying deformation patterns in Tibet, a prolonged period (∼50 to 19 ± 3 Ma) of NNE-SSW shortening, accompanied by eastward flow and orogen-parallel extension later stage (19 Ma present-day), are still poorly constrained. Using viscous models, we performed scaled laboratory experiments with steady unsteady state collision kinematics address this issue. Our model Tibet under steady-state collision, irrespective high (5.5 cm/yr) or low (3.5 indentation rates fails produce present-day crustal velocity fields patterns, reported from GPS observations. An unsteady-state decelerating convergence (5.5–3.5 is found be necessary condition for initiation ESE-WNW extensional deformations. results also suggest that mechanical resistance offered rigid Tarim block resulted uplift at faster western setting west east topographic gradient, existing till present-day. This gradient eventually polarized gravity-controlled direction when decelerated ∼3.5 cm/yr around Ma. shows central follows nearly Poiseuille type profile, bounded Himalaya south basin northern Tibet. allows us explain preferential locations crustal-scale dextral sinistral faults southern respectively. Finally, crustal-flow velocity, strain-rates, variations validated geological field data.