MATERIAL AND THERMAL ROLES OF BASALT IN CRUSTAL MAGMATISM - CASE-STUDY FROM EASTERN NEVADA

Thousands of cubic kilometres of calc-alkaline intermediate to silicic magma erupted in eastern Nevada at similar to 35 Ma. On the basis of petrologic models, crustal contribution to magmatism is slightly great er than basaltic input. The volume of crystals generated during differ entiation is roughly twice that of erupted magma, implying that intrus ive complements are enriched in accumulated crystals. The amount of ba salt needed to drive the system thermally can be derived from the volu me of crust that is heated and assimilated, and is about twice the vol ume of basalt needed materially.