Re: Making Tracks

From: Steven M Smith <smsmith@usgs.gov>
Date: Thu Apr 08 2004 - 13:25:02 EDT

Discussing the Dakota Fm. dinosaur tracks I wrote:
>> First of all, no one has all of the answers. This is an area of new
research. I'll give you some of the current hypotheses. Researchers suggest
that this megatracksite may represent a general north-south migration route
along the western shore of the mid-continent Cretaceous sea. The sandy
shorelines would be a logical routes for long distant travel. These
individual tracksites are so trampled that only some of the last footprints
made at any level are preserved. It has been proposed that these sandy
layers were 'dinoturbated'. The idea that these sandstones were once
beaches is also supported by overlying and underlying layers with
'crocodilian' tracks, abundant ripple marks, and extensive burrowing. <<

Bill replied:
> I'll agree that your scenario is at first blush a logical explanation for
this data. However, it does have a bit of a "just-so story" flavor. I guess
a more diplomatic way to say that would be to say that you have a good
working hypothesis, we'll see how it fares as the data is accumulated. <

You're correct. As I said the migration idea is an hypothesis. It may or
may not be confirmed. We have lots of tracks associated with features
commonly found in a beach environment. And terrestrial herbivores don't
generally live on beaches. We know that migrating animals often follow
geographic features like shorelines and mountain ranges. The migration
hypothesis seems to fit with the facts and with known animal behavior. But
a "just-so story"? You would say that this is more of a "just-so story"
than ideas of floating vegetation mat rafts loaded with herds of
dinosaurs???

>> The picture that conventional geology would propose is that the sand was
trampled biannually by migrating dinosaurs for thousands of years.
Infrequently, the tracks would be covered and preserved. When the sea
levels would rise or lower, the trampled beach strand would move farther
west or east, respectively. In this manner, a 5-10 m thick sedimentary
package could be formed covering 1000's of square miles. It didn't happen
all at once. <<

> It didn't happen all at once under your scenario. That doesn't mean it
didn't happen all at once. <

The difference is that the conventional scenario only calls for normal
populations of dinosaurs in normal environments behaving normally for
generations. The all-at-once scenario calls for abnormally large
populations of dinosaurs (necessary to create all those tracks nearly
simultaneously - See Glenn's post) in a horrifyingly abnormal situation but
still behaving normally. I would opt for the simpler picture that explains
all the data.

>> I'm not going to address problems with the ICR Impact-370 article at
this time. <<

> Since you have access to and are familiar with the Morrison, why don't
you take some time and present a reasoned response? That might be helpful.
<

Sorry. I have enough projects at the moment. Fortunately, David Campbell
and Glenn Morton have already addressed several of the Morrison issues.
When I read the article, I didn't see many real problems - just another
listing of geologic features lacking complete explanations put forth with a
negative anti-conventional geology slant and the implied accusation that
geologists are hiding compromising data.

>> (Just let me know if you really want me to give you the entire sequence
of sedimentary rocks exposed here in Denver along with the potential
problems that each individual formation presents to the YEC paradigm.
<grin>) <<

> ...snip... At any rate, if you're game I would love to see the entire
sequence, along with any imagined ;-) problems for YEC. <

Someday but not now. I've been collecting photos and info and hope to
eventually write a comprehensive web-based virtual field trip through the
stratigraphy and features of Denver geology possibly for the Assoc. of
Christian Geologists Website.

> That brings up another question. You mention "plant fossils and organic
debris" and "minor interbedded layers of coal." Do you happen to have, or
would it be possible for you to get, a few good photos of the coal, or a
reference in the literature that describes the coal and plants? <

Sorry. I'm not getting into the coal issue right now. Most of the coal
around here was mined underground. The mines are now flooded. The
exposures are gone. Many mined areas are now housing developments. What's
left are mostly some small organic-rich, black, silty layers.

> My question is, do you have paleosols and bioturbated root zones? From
your descriptions of the organics it sounds like they may be - likely are -
allochthonous. <

The Dakota sandstone has a lot of plant debris. I assume that most of it
probably is allochthonous (jargon for transported as opposed to 'in situ')
-- especially associated with the beach environment. The simplest
explanation is that the transported plant debris is local and not washed in
from great distances.

You wrote:
> I really don't see where you have enough food production for the
herbivores. A few minor swamps (now interbedded layers of coal) won't
sustain a herbivore dino population. <
... and ...
> You still need to show the food source for the herbivores. From what
you've said so far, it's not there in situ - it looks as if it was all
rafted in. <
... and ...
> Before you blast me, you need to explain where/what they ate. <

When I read this argument in the ICR Impact article I felt that it was a
red herring. This argument is even more irrelevant with respect to this
part of the Dakota Formation. The tracksites are on a ancient beach. I
wouldn't expect to see food sources in a beach environment. Beach sand are
not very good at preserving plant material - too much life, water, and
oxygen. And besides, the conventional picture doesn't need huge
populations and lush food sources. All things considered, the Dakota Fm.
here seems to be exceptionally rich in organic plant debris. Despite my low
expectations, there seems to be a lot of available food for herbivores. So
what's the problem?

> Like so many others, you are assuming that the Flood was responsible for
all sedimentary rocks. I'm trying my best to follow the data where it
leads, or actually where it often forces me to go kicking and screaming. <

Actually, I'm not assuming that flood scenario must explain ALL sedimentary
rocks. However, you do have a problem when this Dakota megatracksite layer
is buried under 1.5 miles of black, marine shales plus marine limestone and
more beach sands. If you can't explain these Dakota features as a
mid-flood depositional event then you might as well abandon any version of
global flood geology.

Steve
[Disclaimer: Opinions expressed herein are my own (or perhaps slightly
modified from other people) and are not to be attributed to my employer]

_____________
 Steven M. Smith, Geologist, U.S. Geological Survey
 Box 25046, M.S. 973, DFC, Denver, CO 80225
 Office: (303)236-1192, Fax: (303)236-3200
 Email: smsmith@usgs.gov
 -USGS Nat'l Geochem. Database NURE HSSR Web Site-
  http://pubs.usgs.gov/of/1997/ofr-97-0492/

|---------+---------------------------->
| | Bill Payne |
| | <bpayne15@juno.co|
| | m> |
| | |
| | 04/05/04 09:30 PM|
| | |
|---------+---------------------------->
>-----------------------------------------------------------------------------------------------------------------|
  | |
  | To: smsmith@usgs.gov, ksharman@pris.bc.ca |
  | cc: asa@calvin.edu |
  | Subject: Re: Making Tracks |
>-----------------------------------------------------------------------------------------------------------------|

Hey there, Steve,

When I hit the reply button on your post, I got that vertical line along
the left side, which prevents me from being able to insert responses that
are set off from yours. Kevin was able to set his e-mail to give the
chevrons along the left side, which is more convenient if you are able and
care to do that.

First of all, no one has all of the answers. This is an area of new
research. I'll give you some of the current hypotheses. Researchers
suggest that this megatracksite may represent a general north-south
migration route along the western shore of the mid-continent Cretaceous
sea. The sandy shorelines would be a logical routes for long distant
travel. These individual tracksites are crocodilianso trampled that only
some of the last footprints made at any level are preserved. It has been
proposed that these sandy layers were 'dinoturbated'. The idea that these
sandstones were once beaches is also supported by overlying and underlying
layers with 'crocodilian' tracks, abundant ripple marks, and extensive
burrowing.

I'll agree that your scenario is at first blush a logical explanation for
this data. However, it does have a bit of a "just-so story" flavor. I
guess a more diplomatic way to say that would be to say that you have a
good working hypothesis, we'll see how it fares as the data is accumulated.
What we need is both YECs and OEs both going at the same data and trying to
fit it into their respective models, and critiquing each other's model.
Unfortunately, those two camps don't usually work together very well.

This megatracksite is a 5-10 meter (15 to 30 feet) thick layer of sandstone
in a sedimentary package that is 3,350 to 4,250 m (11,000 to 14,000 feet)
thick. In a one year global flood, we would have to deposit sediment at an
average of 10 meters (30 feet) per day to get this pile. (In actuality,
the rates have to be much higher since this doesn't include any sediment
compaction factors.)

It would probably be higher still. The sediment in the Gulf Coast
geosyncline, if we assume it all came from the current drainage basin
between the Rockies and the Appalachians and up into southern Canada, would
be enough to cover the entire basin to a depth of about 1 mile. When we
are driving around looking at outcrops we tend to forget that what we are
looking at, and where we are standing, was once under a mile of sediment.

  Under this paradigm, we would have only a few days (at the most generous
estimates) for an enormous herd of recently disembarked dinosaurs to
trample thousands of square miles of sand. The picture that conventional
geology would propose is that the sand was trampled biannually by migrating
dinosaurs for thousands of years. Infrequently, the tracks would be
covered and preserved. When the sea levels would rise or lower, the
trampled beach strand would move farther west or east, respectively. In
this manner, a 5-10 m thick sedimentary package could be formed covering
1000's of square miles. It didn't happen all at once.

It didn't happen all at once under your scenario. That doesn't mean it
didn't happen all at once.

Note that the tracksites also preserve dinosaur behavior. What we see is
several parallel trails of herbivore (iguanodontid) dinosaurs suggesting a
herd-like behavior. One trail has a large iguanodontid adult walking
slowly on all fours with a parallel trail of a juvenile iguanodontid
walking quickly on its hind legs. (I'm reminded of my kids running to keep
up with their long-legged dad.) The theropod tracks do not come in
parallel trails. These are the carnivores that probably preyed upon the
iguanodontids. I don't know if the theropod tracks represent the behavior
of lone hunters or cooperating pack hunters.

I'm not going to address problems with the ICR Impact-370 article at this
time.

Since you have access to and are familiar with the Morrison, why don't you
take some time and present a reasoned response? That might be helpful.

It is about the Jurassic Morrison formation at Dinosaur National Park in
Utah/western Colorado. Although we have the type-locality of the Morrison
Formation complete with footprints and dinosaur bones exposed at Dinosaur
Ridge (just a few hundred feet below the track site in the Dakota
sandstone) I chose to limit this discussion to just the one issue - the
extensive upper Dakota megatracksite. (Just let me know if you really want
me to give you the entire sequence of sedimentary rocks exposed here in
Denver along with the potential problems that each individual formation
presents to the YEC paradigm. <grin>)

When in grad school at the U of TN, I went to the U of KY field camp in
Crested Butte, CO, so I do have a little experience with some of these
formations - or at least I did 35 years ago. That was before Crested Butte
was so commercialized - it was an absolutely beautiful summer. At any
rate, if you're game I would love to see the entire sequence, along with
any imagined ;-) problems for YEC.

Since the tracksites are thought to represent migratory trails on beaches,
you might think that we have a problem with food for the herbivore herds.
Actually, in addition to the tracks, ripple marks, and burrows, the Dakota
sandstones contain a large amount of plant fossils and organic debris.
Many of these fossils are well-preserved imprints of wood. At one site, we
actually have the preserved track of a dinosaur stepping on a stick.
Incidentally, the very first discovery of dinosaur bones in the Morrison
Formation, responsible for starting the infamous fossil bone rush of the
late 1800s, was made right here on Dinosaur Ridge by Arthur Lakes while he
was exploring the Dakota Formation for plant fossils -- As he dropped off
the ridge into the Morrison Fm. he stumbled upon an exposed ~4 ft. long
sauropod femur. And finally, when it comes to swamp plants for herbivorous
dinosaur food, the Dakota Formation also contains some minor interbedded
layers of coal! (I'll defer to you and Kevin on the coal swamp origin
arguments.)

That brings up another question. You mention "plant fossils and organic
debris" and "minor interbedded layers of coal." Do you happen to have, or
would it be possible for you to get, a few good photos of the coal, or a
reference in the literature that describes the coal and plants? My
question is, do you have paleosols and bioturbated root zones? From your
descriptions of the organics it sounds like they may be - likely are -
allochthonous. I really don't see where you have enough food production
for the herbivores. A few minor swamps (now interbedded layers of coal)
won't sustain a herbivore dino population.

That's enough for this post. I'll bet that most people on this list have
already hit the delete button long before reading this far. I'll look
forward to hearing your explanations on how rafted dinosaurs can make all
those footprints during so short a time.

Like so many others, you are assuming that the Flood was responsible for
all sedimentary rocks. I'm trying my best to follow the data where it
leads, or actually where it often forces me to go kicking and screaming. I
do admit to taking a YEC approach to my investigations, but in spite of
what Kevin might say, I can be swayed, or will at least give assent to a
superior argument. As far as your "how rafted dinosaurs can make all those
footprints during so short a time", I would say that the Cretaceous and
later strata may be post Flood, and therefore the time frame may not be so
short. You still need to show the food source for the herbivores. From
what you've said so far, it's not there in situ - it looks as if it was all
rafted in.

At this point I don't know how many footprints there really are. If there
was a raft(s) of vegetation with dinosaurs and the dinos got separated as
the raft began to break up, and they landed in different areas, then widely
separated individuals could make tracks that are being interpreted as
migratory. Before you blast me, you need to explain where/what they ate.

Bill
Received on Thu Apr 8 13:25:39 2004

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