Hi, I'm Vince from the Philippines, I was wondering a bout the proper use of the term, fossil since some seem to refer as the remains of all ancinet organisms as fossils. However, fossils are mostly defined as the remains or traces of organisms that are preserved in rock (sediment) or in other forms. When it is preserved, its organic composition is slowly replaced by minerals. Still, fossilized remains of more recent animals such as extinct mammals from the last ice age are called fossils despite the lack of the organic composition being replaced by minerals. And so, my question is: Is it correct to call the remains of more recent organisms as fossils despite these remains being too recent to be replaced by minerals, or should these remains be called something else?

Great question. We have some paleontologists on this site who can may give you a more authoratative answer but my understanding is that while there are lots of different types of fossils (see e.g.
http://australianmuseum.net.au/what-are-fossils), the process you are referring which leads to mineralised fossils is - just that - a process.

So if your question is (simplistically) when does an old bone become a mineralised fossil, I rather suspect there is no defined threshold of mineralisation.  More generally however a fossil is usually defined as the preserved remains or traces of past life, so I would think (but am prepared for a paleontologists to contradict me) it is appropriate to refer to these more recent remains as fossils irrespective of degree of mineralisation.