10 bubble nucleation exsolution of gas from magma

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Unformatted text preview: tion of new phase (bubbles) and consequently, the formation of an interface between this phase and the existing liquid phase. This interface has an interfacial or surface free energy, σ, associated with it, which must be be overcome in order for a bubble to grow. O v e r c o m in g th is s u r fa c e fr e e e n e r g y r e q u ir e s a d e g r e e o f s u p e r s a tu r a tio n Energetics of Bubble Nucleation !Gtot = 4" r 2# + 4 3 !Gr "r 3 V 11 Bubble Nucleation & Growth Rates S u r fa c e fr e e e n e r g y b e tw e e n g a s a n d s ilic a te m a g m a is fa ir ly la r g e , r e q u ir in g s ig n ific a n t d e g r e e o f s u p e r s a tu r a tio n . This will result in rapid bubble formation once the necessary ∆Gr is attained necessary S u r fa c e fr e e e n e r g y c o r r e la te s w ith v is c o s ity , s o n u c le a tio n w ill b e m o r e d iffic u lt in r h y o lite th a n in b a s a lt. C r y s ta ls p r o v id e a p o te n tia l s ite o f b u b b le n u c le a tio n w h e r e s u r fa c e fr e e e n e r g y is lo w e r Because finite surface free energy already exists between the crystal and liquid. Bubble Nucleation & Growth Rates O n c e it b e g in s , n u...
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This document was uploaded on 03/04/2014 for the course EAS 458 at Cornell University (Engineering School).

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