It is common knowledge that the Earth’s rigid upper layer called lithosphere is composed of moving plates. But just what mechanism first set plate tectonics into motion still remains a mystery. A team of researchers led by ETH professor Taras Gerya has now come up with one possible answer by using simulations.
When tears begin to spread throughout the lower crust, large slabs of the heavier rigid lithosphere plunge into the soft mantle, and the first plate margins emerge. The tension created by the plunging slabs ultimately sets the plates in motion. Subduction has begun – and with it, plate tectonics. Water acts as a lubricant and is an absolute necessity in the initiation of a self-sustaining subduction.
The Earth’s lithosphere is divided into several plates that are in constant motion, and today’s geologists have a good understanding of what drives these plate movements – heavier ocean plates are submerged beneath lighter continental plates along what are known as subduction zones. Once the movement has begun, it is perpetuated due to the weight of the dense subducting plate.