Initially introduced in the context of twinning, zonal dislocations are seen nowadays as key dislocation in few complex intermetallics, such as MAX phases and Laves phases. Combining shear with shuffling, such dislocation propagates thanks to the mechanism of synchroshear, which remain to date debated. By focusing on Mg2Ca Laves phases, we propose a numerical exploration at the atomic-scale of mechanisms responsible for the propagation of zonal dislocations. In particular, we demonstrate that nucleation and propagation of kink pairs is the energetically favorable mechanism for the motion of the synchro-Shockley dislocation. Additionally, we investigated how vacancies and antisite defects assist kink nucleation and propagation. Ultimately, we explore the thermally activated nature of synchro-Shockley dislocations and demonstrate the crucial role of thermal assistance on the propagation of such a zonal dislocation. By the thorough investigation of the synchroshear mechanism in Mg2Ca Laves phases, our work aims to advance the understanding of the mechanisms of motion of zonal dislocations in complex crystals. REFERENCES (maximum 2 references) [1] Guénolé J., Mouhib F-Z., Huber L., Grabowski B., Korte-Kerzel S., Basal slip in Laves phases: The synchroshear dislocation, Scripta Materialia, Vol. 166, pp. 134-138, 2019. [2] Xie Z., Chauraud D., Atila A., Bitzek E., Korte-Kerzel S., Guénolé J., Unveiling the mechanisms of motion of synchro-Shockley dislocations in Laves phases, under review, arXiv:2205.02669, 2023.