Ichthyosaur Fossils (was Re: Ark size and animals) (Long)

[Keith littlejo@comm.net]

Subject: Ichthyosaur Fossils (was Re: Ark size and animals) (Long)
Distribution: world
From: litt...@comm.net (Keith Littleton)
Newsgroups: sci.skeptic , alt.atheism
Date: May 29, 1997

This thread was "Subject: Ark size and animals"

In article <Pine.A41.3.95.970613225700.97392A -100...@green.weeg.uiowa.edu>,
Erik Marksberry <mark...@blue.weeg.uiowa.edu> wrote:
>On 13 Jun 1997, karl wrote:
>> In article <5nmi1b$700$1...@shell6.ba.best.com>,
>> at...@best.comNOSPAM (Mark Isaak) wrote:
>>
>> I just received a magazine with a picture of a baby
>> ichthyosaur emerging from its mothers body. Talk
>> about a quick burial.

Consulting Kaufman (1981), I found that his paper quickly
and soundly refutes the claims of "quick burial" by the
evidence and data it provides.

The same or similar picture of a baby ichthyosaur emerging
from its mothers body is shown on page 8 of "Stones and
Bones" a creationist pamphlet by Wieland (1994). The
caption reads:

"Mother ichthyosaur (an extinct Marine reptile) trapped
in the process of giving birth. Such well-preserved
features could not have come from mother and baby
lying on the ocean floor through countless ages of
slow processes."

This same ichthyosaur "Stenopteryglus quadriscissus"
illustrated by Figure 1 of "Stones and Bones" on page 8
of (Wieland 1994) also appears in Wild (1990, Figure 4,
page 285). This and other vertebrate fossils come from
Jurassic black shale deposits, known both as the
"Posidonienschiefer" and "Posidonia Shale" which occur
in southwestern Germany. The best known outcrops of
the Posidonienschiefer occur near the town of Holzmaden
which is situated on the fringe of Schwabiche Alb, about
30 km southeast of Stuttgart, Germany (Wild 1990,
Kaufman 1981)

**** Preservation of the "Mother Ichthyosaur" ****

Actually, it was not a quick burial. The ichthyosaur died
in childbirth and sank down into anoxic bottom waters
full of hydrogen sulfide into anaerobic sediments. As
summarized by Kaufman (1981, p. 312), conditions
allowing for the preservation of fossils like the "Mother
ichthyosaur" were characterized by either:

1. Stagnant bottom waters, which with the underlying
sediments is severely oxygen depleted or anaerobic.
Sedimentation is low, not rapid, and hydrogen sulfide
levels very high, or
2. Periods of rapid sedimentation that bury organisms
in anaerobic to oxygen depleted, hydrogen sulfide-rich
sediments.

In the case of the Posidonienschiefer, Kaufman (1981)
argues for the former case, preservation despite slow
sedimentation.

Wild (1990) states:

"There are preserved females giving birth to young
(Fig. 4), or containing up to thirteen embryos, or in
association with an aborted fetus. The high percentage
of pregnant female ichthyosaurs, and of juveniles, may
be due to a 'spawning ground' to which the animals
migrated periodically over a long geological time to give
birth to their young."

If the area was populated by pregnant ichthyosaurs, as
their abundance indicate, then it is likely that their death
during childbirth would be a common event. Given the
environmental conditions, a fraction of these dead
ichthyosaurs would be preserved as fossils.

+++++ Typical Fossils +++++

The "Mother ichthyosaur" illustrated by Wieland (1994) is
grossly atypical of the normal marine reptile and fish
fossils found in the black shales of the Posidonienschiefer.
The pictures of very well preserved fossils shown by
Wieland (1994) are the exception, rather than the rules.
Wieland (1994) and other creationists deliberately distort
the evidence by failing to either show or acknowledge the
billions of disarticulated, weathered, corroded, and gnawed
bones that exist as fossils for every complete skeleton like
his "Mother ichthyosaur".

In case of the "Mother ichthyosaur," Wieland (1994)
misrepresents the evidence by failing to note that not all
of the fossils found in the Posidonienschiefer / Posidonia
Shale are as well preserved as the "Mother ichthyosaur"
that he shows on page 8.

As observed by Kaufman (1981, p. 373):
"Exceptional preservation among Posidonienschiefer
vertebrates has been overemphasized. An overwhelming
number of fish fossils occur as disarticulated debris,
and disarticulated reptile material is more common than
reported. In both cases, bacterial decay and scavenging
prior to burial are implied."

Kaufman (1981) describes a more typical ichthyosaur in
the caption to his Figure 12-18. This is the type of fossil
which the creationists, e.g. Wieland (1994), deliberately
ignore in order to fabricate favorable arguments where
none exist. The caption of Figure 12-18 from Kaufman
(1981) states:

"Figure 12-18 Interpretation or common preservation
patterns of marine reptiles, as prepared from lower
side; exemplified by B, the ichthyosaur Stenopteryglus
crassicostatus von Huene (from Hauff 1960, Plate 14b).
Note: broken backbone in middle with vertebrae arranged
en echelon in different directions on either side of break;
opposed curvature of ribs on either side of break; displaced
upper; ribs; position of upper paddles on outside of those
representing lower surface. "

As Kaufman (1981) explains, this is clear evidence of
partial decay and scavenging of a carcass. This certainly
not a carcass that was rapidly buried by a catastrophic
event of any sort.

Kaufman (1981, Figure 12-18) continues.

"The Interpretation: A. Bacterial decay and scavenging
of upper surface of carcass exposed above the
aerobic-anaerobic interface causes. C. Collapse of
upper part of carcass, breaking the backbone, splaying
of ribs and vertebrae, and shifting of upper paddles to
outside position; lower (exhibit) surface of carcass lay
within anaerobic zone from time of deposition of reptile
and remained well preserved."

Obviously, the stagnant environment that lead to preservation
of the "Mother ichthyosaur" were unusual even for the period
of time during which just the Posidonia Shale accumulated.
When the bottom waters were more oxygenated, limited
scavenging and decayed occurred. Similarly, fossils that
were encrusted exposed on the sea floor by other fossils,
e.g. Kaufman (1981 Figures 12-14, 12-15, and 12-16) are
also ignored because they are evidence of a stable sea floor
receiving little if any sediment. These fossils are ignored
by creationists, because they refute their claims of very rapid
burial by their Biblical Flood.

+++++ Fossil Feathers +++++

>> fossil jellyfish indicate a quick burial.
>> leaf fossils indicate a quick burial.
>> fossil feathers indicate a quick burial.

For an explanation of how feathers can be preserved either
with or without quick burial or processes, see:

Davis, P. G., and D. E. G. Briggs (1995) Fossilization
of feathers. Geology. vol. 23, no. 9, pp. 783-786.

Davis and Briggs (1995) note that a bacterial glycocalyx (a
network of exocellular polysaccharide fibers) help promote
the fossilization of feathers some cases. Sometimes surfcial
bacteria on the surface of the decaying feather are replicated
by authigenic minerals (bacterial autolithification). In case
of the Archaeopteryx, the feathers are preserved "mainly
by imprintation following early lithification of the substrate
and decay of the feather."

>> egg fossils indicate a quick burial.
>> fish swimming in formation indicate a quick burial.
>> footprints indicate a quick burial.
>> polystrate trees indicate a quick burial.
>> fossils of scales indicate a quick burial.

I have either discussed or cited references for these in
another post.

>> the list goes on and on but I think you get my point.

Yes, you refuse to read any scientific paper, article, or
book that contains perfectly reasonably explanations for
these fossils.

> For argument's sake, I'll grant you that these all
>demand a quick burial. Wouldn't local flooding bury
>things rapidly as well? What necessitates a GLOBAL
>flood for all of this?

You are incorrect about the fossil vertebrates that are
found in the Posidonienschiefer / Posidonia Shale. First,
as previously many of the fossils found in the
Posidonienschiefer show various stages of disarticulation,
decay, and scavenging which are inconsistent with quick
burial. Finally, fossils such as the "Mother Ichthyosaur" of
Wieland (1994) do not need quick burial to be preserved.
In offshore, modern deep-water environments similar
to those in which the "Mother Ichthyosaur" came to rest,
decay can take surprisingly long to occur. Modern, direct
observations support this claim and refute the off-repeated
creationist falsehood that quick burial is needed to
preserve these and any other fossil.

For example, Kaufman (1981) states:
"Much work has recently been done on aerobic bacterial
decay in marine benthic environments, especially in
offshore, deep-water sites equivalent to that of the
Posidonienschiefer paleoenvironment. Degens and Mopper
(1975) and Jannasch and Wirsen (1973), among others,
found that rates of bacterial decay on exposed or sediment
bound nutrients are remarkably slow in the presence of
normal oxygen and abundant bacteria and almost negligible
in subnormally oxygenated environments; the latter
environments also tend to exclude many benthic scavengers
(Rhoads and Morse, 1971) Even in well-oxygenated
waters, bacterial decay rates are surprisingly minute over
the course of a year A large carcass may take many years
to decay in these environments if no scavenging occurs
and may be covered with sediment, or partially, before
the effects of decay are obvious If covering or underlying
sediments were largely anoxic and hydrogen sulfide-
enriched, as proposed for the Posidonienschiefer and
typical of many basins with subnormal oxygen levels,
effective decay would cease on contact with the sediment
thus preventing breakdown and ultimate disarticulation
of carcasses In part, the preservation of large reptile
carcasses in the Posidonienschiefer may reflect these
processes and is not incompatible with the relatively
deep, subnormally oxygenated, benthic environments
suggested by invertebrate evidence."

++++ Conclusions ++++

The claim made by Wieland (1994) that:

"Such well-preserved features could not have come
from mother and baby lying on the ocean floor
through countless ages of slow processes."

is simply false.

Geologists don't claim that the "Mother ichthyosaur"
lay for "countless ages" on the sea floor. Given the right
combination of anaerobic sediments and stagnant bottoms
waters, such fossils can be formed as shown by the
fossil evidence and modern observations quoted above.
In fact, a careful examination of the fossils evidence,
which creationists like Mr. Wieland, appear loathe
to do, clearly shows a lack of evidence for the catastrophic
processes they claim must have created these and other
fossils.

References:

Kauffman, Erle G. (1981) Ecological reappraisal of the
German Posidonienschiefer (Toarcian) and the stagnant
basin model. In Communities of the past. J. Gray-Jane,
A. J. Boucot, and W. B. N. Berry, eds., pp. 311-381,
Hutchinson Ross Publ. Co.. Stroudsburg, PA,

Wieland, C. (1994) Stones and Bones. Creation Science
Foundation Ltd., Acacia Ridge, Australia.

Wild, R. (1990) Taphonomy; Taphonomy of fossil-
lagerstatten; Holzmaden. In Palaeobiology; a synthesis,
D. E. G. Briggs and P. R. Crowther, eds., pp. 282-28.
Blackwell Sci. Publ. Oxford, United Kingdom.

Other Citations About the Posidonienschiefer / Posidonia Shale

Bandel, K., and H. Knitter (1986) On the origin and
diagenesis of the bituminous Posidonia Shale (Toarcian)
of southern Germany. Mitteilungen aus dem Geologisch-
Palaeontologischen Institut der Universitaet Hamburg.
vol. 60, pp. 151-177.

Hauff, B., and R. B. Hauff (1981) Das Holzmadenbuch
[ Holzmaden. ] Dr. B. Hauff. Holzmaden, Federal Republic
of Germany. Pages: 136.
( http://www.fto.de/ftsehen/fthauff.htm )

Kauffman, E. G. (1978) Benthic environments and
paleoecology of the Posidonienschiefer (Toarcian). Neues
Jahrbuch fuer Geologie und Palaeontologie. Abhandlungen.
vol. 157, no. 1-2, pp. 18-36.

Keller, Thomas (1977) Frassreste im sueddeutschen
Posidonienschiefer [ Feeding remains in the southern
German Posidonia Shale. ] Jahreshefte der Gesellschaft
fuer Naturkunde in Wuerttemberg. vol. 132, pp. 117-134.

Martill, David M. (1987) Ichthyosaurs with soft tissues;
additional comments. Transactions of the Leicester Literary
& Philosophical Society. vol. 81, pp. 35-45.

Martill, David M. (1986) The preservation of ichthyosaur
soft tissues in the Jurassic of Europe. Proceedings -
North American Paleontological Convention. vol. 4,
pp. A30-A31.

Thies, D. (1991) Posidonienschieferfische aus NW
Deutschland [ Posidonia Shale fish of northwestern
Germany. ] Arbeitskreis Palaeontologie Hannover.
vol. 19, no. 3-4, pp. 55-87.

Royal Tyrrell Museum Tour: Ichthyosaurs
http://tyrrell.magtech.ab.ca/tour/ichthyo.html .

Introduction to the Ichthyosauria
http://www.ucmp.berkeley.edu/diapsids/ichthyosauria.html .

Yours,
Keith littleton
litt...@comm.net
New Orleans, LA

Hall's Laws of Politics:
(1) The voters want fewer taxes and more spending.
(2) Citizens want honest politicians until they want something
fixed.
(3) Constituency drives out consistency (i.e., liberals defend
military spending, and conservatives social spending in
their own districts).

Some polystrate fossil web pages:
http://www.geo.ucalgary.ca/~macrae/talk_origins.html ,
http://www.geo.ucalgary.ca/~macrae/t_origins/polystrate_trees.html ,
http://www.talkorigins.org/faqs/polystrate.html ,
http://www.talkorigins.org/faqs/polystrate/trees.html ,
http://www.talkorigins.org/faqs/polystrate/polystrate_trees.html ,
http://www.talkorigins.org/faqs/polystrate/yellowstone.html ,
http://www.talkorigins.org/faqs/polystrate/dawson_tree2.html , and
http://www.talkorigins.org/faqs/polystrate/coal.html .
http://www.megabaud.fi/~tsand/creationism/polystrate

polystrate , polystrate , polystrate , polystrate
Archaeopteryx , Archaeopteryx , Archaeopteryx