Weapons are broken up this way.
Magical Damage : Wands, Staffs, Bow using elemental arrows
Physical Damage : Everything Else
Yes, your int character can use a two handed sword/axe. However, it will do physical damage, not magical. If the sword/axe has elemental damage on it, it gets augmented by your proficiency in the elemental ability. For example a two handed sword with bonus poison damage, would do physical damage, augmented by your strength and skill in warefare and any skill you have in Two Handed. It would also do magical damage from the bonus poison damage. Because you are focusing Geomancy, the bonus poison damage will be augmented by your skill level in Geomancy.
In your case, being and INT based character, you are most likely best off going staff, dual wand or wand and shield. However, you would need to go with staff if you intend to use any Warfare skills like Battering Ram and Battle Stomp.
