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Re: fossils



This may be getting tangential to our subject, and I will make this my 
last posting, no matter what anybody calls me. 

To repeat, my definition of fossil is "remains or direct indication of 
prehistoric life."

I guess some of you think that is too general, or that "prehistoric" is 
not a good definitive attribute.

Bonnie said (7/2/97; 8:20a):
>Should we not consider an insect encased in amber that is only 5 ka 
>to be not a fossil, but consider a Tr coral with its original aragonite
>to be a fossil, PURELY ON THE BASIS OF THEIR AGES?  Clearly, this is
>not good science.  In fossilization, age confers no special characters. 

Well, it is one way to sepcifiy in unequivocal terms, what a fossil is.  
Of course, you may like to specify what a fossil is in OTHER unequivocal 
terms. And it may be your goal to be very precise and make fine 
distinctions.  I think we should do that later, after everybody 
understands the more general term.

In Bonnie's original posting, alteration ("remineralization") was the one 
critical test.  I once taught a college-level course dealing with what is 
good science and what is not, and there is nothing in my background 
stemming from that or other experiences which show any procedural or 
conceptual reason to say that a definition in which age is the critcal 
factor is not as good as a definition in which alterations is the 
critical factor, hence that "age" is not good science, but "alteration" 
is.  Different, yes; better or worse as science, I don't think 
definitions can be so judged.
 
Who, then, is the final arbiter of the "correct" definition?  Well, it's 
what definition wins out by preference among those who use the term.  
It's like the question "What is science?"  It's what scientists say it 
is, or what they do.

Consider these published definitions for fossil:

"the remains, traces, or imprints of once-living organisms preserved in 
the earth's crust"  (Boardman, Cheetham, and Rowell, eds., FOSSIL 
INVERTEBRATES, 1987, Blackwell Scientific Pubs., p. 1)

"the remains of prehistoric life"  (McKinney, EVOLUTION OF LIFE, 1993, 
Prentice Hall, p. 122)

"remains of organisms that lived in the distant past and have been buried 
and preserved in sediments and sedimentary rocks"  (Stearn and Carroll, 
PALEONTOLOGY, 1989, John Wiley, p. 3)

"the preserve remains of past life on earth, or indirect traces of such 
life" (Lane, LIFE OF THE PAST, 1978, Merrill, p. 1)

"any remains, trace or imprint of a plant or animal that has been 
preserved, by natural processes, in the Earth's crust since some past 
geologic or prehistoric time"  (Goldring, FOSSILS IN THE FIELD, 1991, 
Longman, p. 204)

"remains of an ancient organism, or the trace of such an organism"  
(Nield and Tucker, PALAEONTOLOGY--AN INTRODUCTION, 1985, Pergamon, p. 1)

"any record of past life, such as actual bones, shells, teeth, but also 
including impressions, footprints, burrows, etc.  (Dott and Prothero, 
EVOLUTION OF THE EARTH, 1994, McGraw Hill, p. g-4)

OK, now I hope this doesn't spur a mad rush to look up all of the 
definitions available.  These are the references I had at this moment at 
arm's reach that included an explicit definition for "fossil," and I am 
confident that just about anybody could ferret out a definition that 
seems to be at odds in some way with these.  But note that at least all 
of the ones above, except the first, specify or imply that fossils are 
ancient, whereas none specify that they must be altered, or 
"remineralized."

I didn't cite the definition from the classic textbook by Moore, 
Lalicker, and Fischer (1952) because the book is so old, but they 
actually specify that very young objects are excluded from consideration 
as fossils.  In other words, great age is critical.

So, I rest my case, and note the truism(??) that all of the truly great 
ideas in science are simple (well, at least, I heard that somewhere).  I 
think the simpler we keep things, the better.

Bonnie also said (same posting): 
> . . . the insistence on 10 ka, is meaningless, as would an insistence
>on 1 Ma, or 1 Ga, as a 'prerequisite age'.

My opinion is that it is a matter of definition, and you simply define 
what is meaningful.  Clearly, this ("meaningfulness") is a highly 
subjective matter, whereas at least the definition is objective.  If you 
don't like the conventional definition, make your own and wait to see if 
it works, or if people jump all over it, as they did with the 
"remineralization" definition.  In this case, 10 ka is a guideline to the 
boundary between the Pleistocene and Holocene, hence to what is and what 
is not a past geologic age.  Harping on 10 ka as if it were a totally 
arbitrary cut-off, standing on its own, misses the point.


*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
Norman R. King                                       tel:  (812) 464-1794
Department of Geosciences                            fax:  (812) 464-1960
University of Southern Indiana
8600 University Blvd.
Evansville, IN 47712                      e-mail:  nking.ucs@smtp.usi.edu