Soot on throttle body

[DownUnder]

Okay, so what is going on here? I can't tell where this black soot, on the throttle body is originating from. Any ideas ..

 

[Scott]

Looks to me like it is from the cracked or old gasket there in the picture.

 

[DownUnder]

Looks to me like it is from the cracked or old gasket there in the picture.

I had thought about that, but I had to question it, because their should only be clean air passing through the TB.