Understanding plate tectonics is pivotal to development of an integrated understanding of Geoscience topics. However, geology is frequently introduced to students in lower secondary school by describing separate processes, such as sedimentary rock formation, rather than investigating the overall driving forces for change. This study investigated what Grade 8 students (N = 37) drew to explain plate tectonics in relation to convection currents and how they integrated their prior learning into a holistic understanding through the drawing process. Students' explanatory diagrams revealed challenges to students' sense-making of this dynamic process which have not previously been documented, such as integrating understanding of temperature, density and pressure into an explanation for bulk movement of material in convection currents; and interactions between convection currents in the mantle and the tectonic plates. Understanding students' alternative conceptions at these fundamental levels provides opportunities for teachers to address these conceptions earlier in the teaching cycle. The results suggest that introduction to geology through student-generated visual representations may support students to construct better scientific explanations of the dynamic, complex processes of plate tectonics.