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RE: mass extinctions and technology



> From: Mark Harvey [mailto:mharvey@scu.edu.au]
>
> >Not so: organic (carbon isotope and other) geochemisty has been
> examined for
> >at least the K/T, and to a lesser degree some of the other events.
>
> Not from an environmental perspective ie.  PCB cogeners, DDT and it's
> metabolites or phthalates

I disagree that carbon isotopes and the like aren't "enivornmental"!!
However, I take your point on the particular byproducts of one particular
technological society.

> Granted, if the soft sediments adjacent to a densely
> populated area
> were to produce some distinctive techno-fossils, and the techno
> fossils had
> hard parts amenable to mineralization, and the sediment encasing these
> fossils were subsequently eroded away or other wise disturbed at
> a time and
> place convenient for their discovery by a the right individual....

Actually, as I was stating, the most likely preservation would be in the
fluvial and deltaic sediments, many of these downstream from the point the
material entered the record.  Furthermore, also as stated, the preservation
potential of a waxpaper wrapper, cardboard box, etc., would be comparable to
those of the plant tissues that routinely make their way into the fossil
record.  Futhermore, though only a few leaves out of millions get preserved,
even the fragments of these leaves are still recognizable as leaf fragments.

> So many factors.  How do you estimate the likelihood of fossilization of
> any macroscopic object existing at the earths surface for a given
> interval
> of time - natural or manmade.

[snip]

> I don't think this kind of estimation has ever been attempted.

Yes, or at least they have for organismal remains.  It is a discipline
called "Aktuopaleontologie" in German ("aktuo-" as in "actuary"); in English
it is regarded a subdiscipline of taphonomy.  Heck, I've got an undergrad
doing a senior thesis on aktuopaleontologie of seeds & leaves in a
particular environmental setting  I recommend starting out by checking the
literature by Jim Valentine, Susan Kidwell, Andrew Hill, A. Kay
Berhensmeyer, and Michael Voorhies.

> So we can
> probably argue all day the probability of us being recognized 60,000,000
> years from now.  The truth is we don't even have an estimate.  It may be
> more productive just to look for globally ubiquitous pollution tracers.

See above.  Again, I'm not saying that one *shouldn't* look for pollution
tracers per se, but only that the argument that only a chemical record would
be left does not match the copious knowledge of the processes of taphonomy
(both for solid tissue and trace fossils).


> Professor Webster from PSU writes to me in regard to what we would leave
> after 65 MY:
>
> "After 65 million years little or nothing is my guess, although a few
> artifacts of very imperishable materials (e.g. gold) would survive. One
> might be able to detect some big patterns in the ecosystem. For example,
> the microenvironments established over huge, human-modified urban centers
> such as New York might be very distinctive, but it might not be apparent
> why. Certain kinds of cultural contamination (particularly nuclear) would
> persist, and might be interpreted as human-related. But remember that 65
> million years is an extremely long time. Continental drift and
> geomorphological restructuring would create a world that was very
> different
> from today's, thereby destroying, burying, or reducing to gibberish the
> archaeological record. "

Yes, well Doc Holtz from UMd writes to you something different.  I don't
know Webster so I don't know if he has any particular training in
paleontological-scale taphomony, fluvial and marine sedimentology,
ichnology, and the like.  I will tell you that I *do* have some professional
familiarity with these fields, both in the class and in the field.

Also, I would expect that the preservablity of the various landfills around
NYC would have greater preservability than the city itself.

Nevertheless, since humans (at least) are bound to water we tend to build
our constructs near water.  Furthermore, since we have used water transport
for a couple of thousand years (at least), many of our biggest complexes are
in regions where neither the tide (for shores) nor currents (for rivers) are
too high.  In other words, many of the biggest complexes that humans have
constructed are in *depositional* rather than erosional environments (at
least on the long term).

Now one can construct ad hoc explanations for why a hypothetical PHC only
built in erosional environments: Larry Niven once wrote a story ("The Green
Plague") about a Precambrian race of intelligent technological creatures
that only lived along subduction zones...  These are fine for stories, but
if you want people to take you seriously you have to offer some serious
evidence.

> I concede I would expect see taxonomic some homogenization.  Perhaps the
> "introduced species" went extinct before they had a good window of
> opportunity for preservation (say <1000 years).  Perhaps those
> "introduced
> species" that did survive are not well represented in the fossil
> record.  In any case, lack of evidence does not always constitute
> evidence
> of a lack.  I would consider lack of industrial tracers in the
> geochemical
> record better evidence of a lack.

But only if the PHC produced industrial tracers which are recognizable as
such to us.  If you really want to investigate this, find the funding to do
it.

However, your dismissal of any contrary observations sounds a lot like
"counting the hits and ignoring the misses", only that there are at present
no "hits" to count which are not also explainable by other phenomena.

> >Actually, there are pretty good estimates for their
> distribution, abundance,
> >and resource size (as you can imagine, there are many vested interests in
> >getting this information!).  True, some of these resources were obviously
> >lost during erosion of the Appalachians and other regions.  Nevertheless,
> >there do not appear to be big erosional surfaces that one would
> expect if a
> >coal-based technology utilized substantial portions of this limited
> >resource.
>
> I wonder what the estimates are?  Also for oil, natural gas, copper, iron
> etc.  It would be nice to know the range of ages, geographical
> distribution
> and reserves of these resources.   I would be encouraged to see that most
> of our oil is too young to have been available in the late
> cretaceous.  Something to investigate.

Then start by checking out standard textbooks on Environmental Geology
(Montgomery, Keller, etc.) and follow the references therein: resource
abundance curves are common in this literature.  As for petroleum: while
some is post-Cretaceous, a substantial fraction is derived from early-mid
Late Cretaceous organic rich deposits and subsequently trapped by the
stratigraphically higher rudistid reef deposits of the equatorial
Cretaceous.  Rudists, of course, were one of the main victims of the K/T
extinction.

> Nothing is more costly than regret.  A correlation between
> mass-extinction
> and industrial civilization might be just the warning we need to clean up
> our collective act.

Would that it were so...  After all, we have abundant evidence of the
effects of global climate change, but many people are happy to keep up with
the present state of affairs regardless.

I wish you luck with your search.

However, some food for thought:
* The most important attribute of an unusual claim: Extraordinary claims
require extraordinary evidence.
* Early models of particular ideas are often wrong.  Wegener has been hailed
as a scientific prophet, but in point of fact his actual model of
continental drift is just plain wrong! He was correct in that the continents
move, but he was totally off as to the age and physical relationships
between the continents and the oceanic crust, the speed of movement, and
more.  In fact, "continental drift" proper is not accepted; it is plate
tectonics (the model that wedded continental drift with sea-floor spreading)
which turned out to be the supported case.
* Any terrestrial PHC had to have evolutionary precursors. Finding some of
these might help you case.  Note that (to be fair) I know something more
about any of the potential candidates running around in the Late Mesozoic
than did either of the researchers you mentioned, if (as you seem to
indicate) your idea is not merely general but is specifically aimed at the
K/T boundary.
* Any EXTRAterrestrially derived PHC requires an even bigger set of claims!

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796