Re: what is a fossil

[Andrea Spreafico <sprea@linknet.it>]

At 14.12 21/06/97 -0500, Sam J. Hogan wrote:

>Unless you carefully define  "fossilization",  this sounds like circular
>definition to me:
>1.  Fossil:  an artifact resulting from the process of fossilization
>2.  Fossilization:  the process of producing a fossil

The above definitions are circular; but the main part of the definition in
my message is "everything remains of animal and vegetal organisms that lived
in the past geological times"; then it's specified that they are mantained
up today because of physical-chemical processes: these are referred to
several ways of mineralization, incrustation, carbonification, distillation,
inclusion in amber, etc., as a whole called "fossilization".

At 00.10 24/06/97 -0700, Betty Cunningham wrote:

>then this might not include some of our own extinct hominid ancestors?
>The need to have them in "past geological times"

>What of hybrids or cladistic descendants of things where the last parent
>is now extinct but this is still recent?
>If you found a quagga (perhaps mummified in the Sahara) would this be a
>fossil?
>If not a fossil then what would you clasify the remains as?
>Perhaps in terms of archeological nomenclature rather than GEOLOGICAL?

If we consider the age of an organism (or of a track), the question is how
much it must be old to be defined as fossil, and this may pose some
problems. If we refer to past geological times we exclude holocene, so every
dead organism from 10.000 years ago up today is not defined as a fossil: in
this case bivalves that are found in Miocene layers are fossils, but
individuals of the same species found dead in a roman-age-site or in a 5000
y.a.-layer are not. The same applies also to organisms that become extinct
in historical ages.
I agree that also this kind of definition lets some gap and could unsatisfy
some points of view. I only say that I prefer it to the definition n. 1
reported by Bonnie Blackwell.

Eugenio Spreafico