There was never tar here originally, it only replaced the original landscape, it only happens as a result
of a zone loading issue and is temporary.
Sometimes you can go to places that used to have tar and because of the loading issue find tar
again. but not in this case because the spot in the screenshot never had tar.
This particular variation of the zone load error, spontaneously replaced the original resource
which was grass with tar.
Also last I saw on the test server terrain reversion only restores terrain to its orginal state,
it does not restore the resource. so it will fill holes dug by players but not put grass back or
forrest ground or any other resource, it also doesnt remove a road surface.
Unless Terra revrsion has been changed since the last time i saw it on the test server a year
ago.
Plus tar is worthless it is only used in one waterskin the pioneer one, thats the only thing its used
for. There are 3 other waterskins that are easy to make.