Fig 3. Investigators of the Subduction Factory seek to answer several fundamental questions: (i) How are volatiles cycled through the subduction factory? What is the relationship between subducted input (e.g., carbonate) and volcanic output (e.g., CO₂)? (ii) What is the rate and mechanism of crustal growth at convergent margins? How do input variables such as convergence rate, volatile content and crustal structure affect magma production rates and composition? (iii) How much sediment and crustal material is recycled to the deep mantle? Do residual slab compositions feed mantle plumes?