Oath put your Salvager in play, then put the rest of the cards into the graveyard.
THEN, Gaea's Blessing triggers, which goes on the stack. This is the time someone could, say, Stifle it, or Tormod's Crypt/Coffin Purge your graveyard.
If you have the mana, you can certainly dig up the Lotus and the Pyrite Spellbomb before the Blessing Trigger actually resolves.
Well, for the sake of answering the question, you are correct, but the Blessing actually triggers during the resolution of the ability of the Oath, not after it. It is put on the stack after the Oath ability has resolved.