Tony Stark, is the armored avenger, a genius level intellect, possessing the Iron man suit. Tony designed the suit, to be impervious to anything short of a nuclear explosion, and also to survive in most environments. The suit is capable of many powerful blasts of energy, forcefields, flight at faster then sound speeds, and also great feats of strength, the armor may lift several hundred tons.
Aquaman is the King of the Sea, also capable of lifting several hundred tons, durable enough to withstand gunfire, and extreme impact forces. The Trident grants Orin sea and weather manipulation, godly blasts, and forcefields.
Tony and his suit can definitely stand against Aquaman, physically equal, and very versatile. Aquaman will be victorious in a epic battle, simply because Orin dose not need a suit of armor to be impervious, or physically strong, and the versatility of the Trident can not be matched.