[Arcane Spell Failure, roll of 43 on d%, success] You detect two auras on the door, one strong and one rather weak, [Spellcraft checks: roll of 7 on d20, +6 skilled, total 13, failure, roll of 17 on d20, +6 skilled, total 23, success] and identify the weaker of the two auras as some kind of conjuration magic. The stronger aura, for some reason (likely the complexity of the spell and skill of the caster) defies identification. You detect no other auras in the surrounding area.