I considered the 'Halberd' style, but the apparent size is wrong, my Indian Sindh spike/dagger axe (the pommel unscrews into a dagger) looks about the right size head - some came with back spikes instead of spikey trunk elephants, but has a much longer haft. It's top spike is also fairly useless.
Doubt it's an Ankh, they were very specifically made with a spike and hook, no axe blade. The Hook was for guiding an elephant's trunk, while the spike was used to euthanize the elly if it went berserk and attacked its own side, it was driven into the elephant's spine just behind its head with a hammer which was part of an ankh weapon system. Again, OP's axe is too small & the haft end unsuitable for hammering and the spike wouldn't kill anything -it'd likely make an elly rather angry... The chain on a pommel ring is another anomaly. who want's a sharp axe with pointy spikes swinging around on the end of a chain near them? If it had a weight on the end of a longer chain, would it be a Japanese kusari-ono?
I add my French fire axe below, probably also of similar size to the OP one, it looks almost exactly like a french boarding axe, but doesn't have the belt hook and the haft is a few inches too short.
(don't have or want an ankh because it is sole purposed to kill elephants.)
All in all indeed an enigma hidden inside a conundrum.
p.s. - if the OP's axe turns out to be 2-3ft. long in the haft and weighs a kilo or so, I may be more inclined to refer to it as a 'battle axe'.
for now, i'll think of it as a Texas battle-tomahawk.