Magmatism and Geodynamics

Magnatism is the only true endogenic process for generating new material on the Earth's surface. Obviously magmatism and tectonic movements are reflections of geodynamics that is physical processes which occur in deep-seated environments. What are the interrelationships between magmatism and tectronics? How did the character of terrestrial magmatism change through time and are there any irregularities in this process?