This project is aimed at establishing the relationship between Laramide magmatic activity and mineralization in southeastern and northwestern Arizona where there are differences in the nature and age of underlying crustal basement rocks. In addition, geochemical characteristics of mineralized and non- mineralized igneous bodies will be compared. These data will help determine why mineralization occurs where it does. The results will prove useful to conceptualization of mineral exploration models and to what extent the underlying crust serves as the ultimate source of metals.