Complex sentence: He is a graduate of University College, Oxford and Trinity Hall, Cambridge and is most noted for advancing understanding of how magmas are generated in the Earth's crust and mantle and of the processes that occur in volcanoes before they erupt.
Split into simpler sentences: He is a graduate of University College, Oxford and Trinity Hall, Cambridge. He has made many important contributions to the understanding of how magmas are generated in the Earth and the process that occur in volcanoes before they erupt.