I need to write a 500- to 750-word explanation regarding the role of plate tectonics in the origin of igneous rocks. Can someone help me get started with this and on the right track? Thanks

http://www.tulane.edu/~sanelson/eens211/igneous_rocks_plate_tectonics.htm

http://www.cliffsnotes.com/study_guide/Igneous-Rocks-and-Plate-Tectonics.topicArticleId-9605,articleId-9475.html