Wow, I just read the thread and saw quite a few logical fallacies thrown around.
Argument form Incredulity: "I cannot imagine how this could be true, therefore it must be false."
Argumentum ad hominem: Attacking the poster. (veiled insults about each others intelligence being thrown around.)
Proof by verbosity (argumentum verbosium, proof by intimidation) — submission of others to an argument too complex and verbose to reasonably deal with in all its intimate details. (respond to this massive thread before I'll take you seriously)
False dilemma (false dichotomy, fallacy of bifurcation, black-or-white fallacy) — two alternative statements are held to be the only possible options, when in reality there are more. (salt formations can only happen this one way.)
Fallacy of many questions (complex question, fallacy of presupposition, loaded question, plurium interrogationum) — someone asks a question that presupposes something that has not been proven or accepted by all the people involved. This fallacy is often used rhetorically, so that the question limits direct replies to those that serve the questioner's agenda. (lots of stuff on both sides.)
In any debate that seeks out the truth, using logical fallacies only muddies the search.
Edit: The salt could have formed by underground heat evaporating the moisture which escaped in near microscopic vents (which are quite common). That's my unresearched response just off the top of my head.