THE CUMULATE PARADIGM AFFIRMED

McBirney and Hunter's conclusion that the cumulate paradigm or theory is an impediment to progress is unjustified because they did not demon strate that the original cumulate terminology cannot be adapted; neith er did they question the fundamental cumulate assumption of bottom upw ard solidification for many large mafic intrusions. Because the decoup ling of mineral, modal and whole rock chemical compositions may reflec t either the failure of cumulate theory or may be an artifact of sampl ing of large mafic intrusions on scales smaller than the scale of the heterogeneities produced by the irregular distribution and migration o f intercumulus liquids, we conclude that a compelling case to abandon cumulate theory has not been made. We suggest that the determination o f whether cumulus and intercumulus phases were in equilibrium with eac h other, and whether disequilibrium textures might yield a complete re cord of the crystallization history of the cumulus plagioclase, are li kely to be among the approaches that will influence the future develop ment of cumulate theory.