In addition to standard IALA region A marks in Norwegian fjords one can encounter non-standard navigtion marks in form of poles or mounds. They are located in dangerous spots like underwater rocks or shoals. In Nowegian they are called jernstake (jernstang), varde or bake. They may have a top mark to indicate safe water side.
More on navigation marks here: http://www.livredd.no/files_doc/livredd_kap6.pdf