Insights into upper lithosphere detachment and exhumation through numerical modelling

The mechanisms underlying exhumation have been a topic of debate among researchers for many decades, prompting the development of numerous computational models aimed at elucidating the processes that initiate exhumation. However, a key gap in the literature lies in understanding how segments of the subducting lithospheric plate detach and subsequently exhumate after extended periods. Specifically, there has been limited investigation into whether material is stripped from the upper portion of the downgoing plate at relatively shallow depths, approximately 30 km, and, if so, whether these segments can eventually reach the Earth's surface. Furthermore, no existing model demonstrates that material can detach from the subducting plate as early as 15,000 years after the subduction is initiated. This study seeks to examine whether such a phenomenon occurs, using the subduction system of the Mediterranean Ridge as a case study. The process was simulated by extensively modifying an established thermomechanical visco-elasto-plastic code, named I2ELVIS, initially introduced by Gerya (2010). Lastly, macroscopic observations from the broader Hellenides region were employed to ascertain whether any such metamorphic rocks had indeed surfaced, thus confirming their exhumation. In conclusion, this research serves as a foundational investigation into a subject that warrants further exploration and detailed analysis in the future.