Would a combination of positionals and appropriately cycling through the elements to build up to something bigger be appropriate as well? I personally only used Earth, Water, and Wind because with white mage going pure holy (and the implication from the AST storyline that Geomancy is a variation of conjury) but theres little reason other elements can be added as well. Perhaps properly cycling through the elements allows you to generate a geo-field effect based on the elements, something like.

Fire- 1% Damage
Earth- 2% Crit
Wind- 3% Skill/Spell Speed
Water-3% Dhit

I know that I just blatantly copied brd songs with one addition. But make the numbers to high and you risk making the support way too powerful.