Is area of effect, and the abilites that are associated with it, only created during ranged attacks?

It is not specific to ranged attacks, so there could be some melee SP that would call for it.

It's created whenever a power instructs it to be created. Generally they'll be associated with ranged attacks but that's not a rule or anything.

There's nothing preventing a power from being an AoE during a close combat attack. For example, it would be perfectly comic accurate and game acceptable Mr. Fantastic to have a power that creates an AoE with a close combat attack. He is all stretchy and can punch someone a mile away.

You could refer to the new chase Colossus' SP as having an area of effect:

PHOENIX EFFECT: When Colossus hits a character with a close combat attack and that character isn't knocked back, after actions resolve, deal 1 penetrating damage to that character and each other character along that direct line of fire.