[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: The Emperor's New Papers

My reason for interest in this is that I work for an environmental
consulting company (well, for another couple weeks anyway, before I
head off to grad school...) and the main part of my job is assessing
the sensitivity of a particular area where some sort of project is
going to happen for fossils.  Most areas don't have bones sticking out
of the ground, so my main interest is if there are potentially bones
at depth, i.e. is the backhoe going to slam into a mammoth tusk while
it's digging out the foundation.  The only way I can really do this is
to see what other fossils have been found in the formations that will
likely be encountered, and take into account any known fossil
localities that may be in the vicinity.

So you see, something like this, if it actually has any merit, would
be a huge advantage for this aspect of paleontology, where the more
hard numbers you can get the better.

On 7/23/07, franklin e. bliss <frank@blissnet.com> wrote:
Delurking for a moment.

I'm sorry, I am generally not a very negative peer reviewer
but........  Having done some stats over time, I appreciate their
usefulness in certain things however....... IMHO, there will never be
a substitute for an experienced pair of eyes (or in my case eye) in
the field.  Statistical methods in this matter could lead you to a
fossil-less gully while ignoring the grassy hillside nearby with
vertebra sitting on the surface.  Chance (pure luck) is only one way
statistical probability can account for the gauntlet of preservation,
position relative to the surface, and crossing of the two time lines
(the fossils and yours).  You have to go into the field to gather the
data to put into the stats which means you have already picked up the
neon signs that say dig here anyway.  Remote sensing will tell you
nicely that this 14 mile wide stretch of earth consists of Hell Creek
(for instance) and you may know that upper Hell Creek may have more
fossils than lower (around here anyway) but there is very limited
application to stats in this particular part of the section.  I
haven't read the paper and I am sure it is/was well done technically
but field work has to be done to acquire enough data to make it
useful.  If I mark down every occurrence of gar pike (fish) scales
around here, I will notice that lots of gar scales at a site means
that I will find other fossils too.  So I then go back to the
computer and put that in, out comes the result of the computer saying
dig there.  I could have saved the trip back to the lab and just dug
there in the first place.

Ok, gullies have more fossil exposures than hillsides generally.  The
uppermost Cretaceous Hell Creek Formation has more dinosaur fossils
than the Paleocene Formations above generally.  I guess the
statistical GIS system would tell me that.  Any GIS statistical
system would just as likely lead you on a wild fossil avian theropod
chase.  This kind of system is only as good as the field work that
gathered the data to create the layers of numbers.  In my experience,
the third standard deviation (or for that fact the second) doesn't
apply to fossil hunting very well.  Giving GIS it's due, the
interpolation of bed spatial geometry mixed with topographic data may
be (marginally) useful in pin pointing presence or absence of a
particular unit on the surface.  (Aerial photos do that too). But I
can't imagine how GIS stats can interpolate preservational bias,
exposure, degrees of weathering, vegetative cover, paleoenvironmental
specific et al in that particular bed without the field work that
would walk you to the fossils in the first place.  Heck, if the Angus
bulls are out in that pasture, the GIS system might just get you into
a foot race.

Fossil hunters of the world are not in danger of loosing their job to
a GIS system.  Being able to recognize color and texture of fossils
and being able to separate them from the visual noise of the
background sediments and vegetation will continue to be the way it is
done.  Covering ever square inch of terrain is called "paying your
dues and looking for clues".

Maybe I missed the point.

Frank (Rooster) Bliss
MS Biostratigraphy
Weston, Wyoming

On Jul 23, 2007, at 8:07 PM, Andy Grass wrote:

> Could someone send me a PDF of this, if anyone has it?
> thanks!
>> Oheim, K.B. 2007. Fossil site prediction using geographic information
>> systems (GIS) and suitability analysis: The Two Medicine
>> Formation, MT, a
>> test case. Palaeogeography, Palaeoclimatology, Palaeoecology
>> 251(3-4):354-365. doi: 10.1016/j.palaeo.2007.04.005.
>> ABSTRACT: Fossil site discovery has traditionally been the result of
>> educated guesswork followed by systematic searching of terrain.
>> This study
>> approached the issues of fossil site identification by looking at key
>> variables in a GIS setting. The data were analyzed to create a
>> predictive
>> model for finding fossils, thus facilitating the process of fossil
>> discovery
>> and saving time and money. Geospatial variables believed to be
>> most useful
>> for finding fossils were examined and ranked on a scale from 1 to
>> 4, with 4
>> being the most advantageous score for finding fossils. Weighted
>> sum addition
>> combined the layers to create a suitability surface. Field testing
>> and
>> subsequent analysis showed the model accurately predicted areas of
>> high,
>> medium, and low fossil likelihood. Field observations and
>> additional site
>> data led to model refinements and increased resolution of fossil
>> density
>> distribution. The final model explained a statistically
>> significant 90% of
>> fossil density variation in the Two Medicine Formation.