Board Thread:Naruto Discussions/@comment-4688597-20140828033453/@comment-3279282-20140828110710

I think the missing piece of information in this case is [What kind of chakra gained Kaguya by eating the fruit?]. If we assume that she gained Senjutsu chakra and this chakra stays Senjutsu chakra when she merged with the tree, then the TT was made up of Senjutsu chakra. And if it even stayed Senjutsu chakra when Hagoromo split it and formed the TB out of it, then the TB are made up of Senjutsu chakra, too. Probably.