aight so, note i may be wrong here, this is what i recall from various sites and the game so i may have a few details off.
fairly sure babylonia is more a fixed point in time, cause the way it works to my understanding, gaia looked into the future, saw a really great timeline and decided that that was the one we should get to, so she started shutting off the timelines that could never end up there (where we get lostbelts from) and making certain events fixed in time when they advance towards that future, and if one of those fixed points in time is broken somehow (if say somene gave gille de rais a grail and he ended up making jeanne alter who basically wiped all of france of the map) then you get a singularity cause now the proper human history (or sacred timeline if you will) has shifted course, now just doing minor things like making jeanne d'arc stay a farm girl won't accomplish that as some other person will do it in her stead, that's how the fixed point in time thing works to my knowledge, but if you ruin things so utterly that it cannot be done at all, then a singularity occurs, and even then they take a holy grail to prevent gaia from fixing, all the singularities are goetia effectively breaking time anchors to make time malleable enough that he can sacrifice humanity, use the energy to go back in time and alter history without gaia being able to do anything, the fixed points in time making it real hard to alter history in any meaningful way as while the specific events may not occur, the overall thing that has to happen, still happens. with babylon being one of those, to my knowledge goetia is traveling back way farther than babylon when the time comes.