various aspects of the geochemistry o-f ga in upper mantle—derived garnet, iherzolite xenoliths (from the bult-fontein floors mine dump in kimberley, south africa), spinel iherzolite xenoliths (from mount porndon, australia), and continental alkaline volcanic rocks (from the freemans cove, balcones, urach and hegau suites of canada, the u.s.a., and germany, respectively) have been investigated. ga abundances were determined by rnaa. the feasibility of using epithermal inaa to generate accurate ga data was investigated. analysis of u.s.g.5. standard granite g—2 suggests 72 that epithermal inaa utilizing 630.1 kev72ga data has the potential to produce geologically useful ga data. (see document for full abstract)