Again, let's look a little deeper.
You wrote, and responded to my reply:
>>> 3. The occurrence of ichnofossils (trace fossils like burrows, tracks,
>>> coprolites, root casts, etc.) seems difficult to understand in the
>>> context of a global flood with rapid sedimentation.
>>
>> They seem difficult to understand in the context of slow sedimentation,
>> too. If seafloor sedimentation were gradual, tracks and burrows would be
>> quickly destroyed by continuing bioturbation. The presence of tracks, etc.
>> indicates quick preservation before disintegration.
>
> So we have quick preservation, big deal. It rains, animals walk in the mud
>on a river bank and leave tracks, the river rises (it's raining) and sediments
>cover the tracks. It doesn't indicate a global flood and, most importantly,
>you're ignoring the fact that trace fossils occur THROUGHOUT the sedimentary
>record. How do animals stroll about in the middle of a flood after THOUSANDS
>of feet of sediment have ALREADY been deposited?
>
I don't mean to ignore that. Some of the trace fossils are in the
Cambrian, like trilobite tracks, suddenly covered by turbidites, or worm
burrows that go up and up and up through successive layers of silt (and I
suspect may be the same individuals hurridly trying to climb up out of
rapidly deposited layers, until they got out or gave out). The many tracks
and burrows higher in the column are also fascinating -- like the famous
amphibian tracks in the Coconino sandstone. Why would you think there
would be no amphibians left alive after
the first few minutes or days of the onset of a flood? Animals that float
don't mind how many thousands of feet of sediments are being deposited
below them.
>>> How does one deposit thousands of feet of sedimentary rock in a
>>>violent
>>> flood and then form a sandstone bed with dinosaur tracks on it?
>>
>> When the tide goes out, wouldn't one expect the remaining dinosaurs to make
>> tracks where they could?
>
> Tides? We're talking about a flood which may have already deposited several
>thousand feet of sediment! I would imagine there would be nothing left to
>make
>footprints after such an event!
>
After the event? We're talking about during the event, before even all the
land area is fully eroded. When it was fully eroded there would be no
place to make subaerial footprints, until the ocean floors sank and land
areas emerged. But during the rise of the waters, dinosaurs would be sure
to walk uphill whenever they could, including between tides. Wouldn't you
expect tides in a worldwide water catastrophe?
>>> Or develop a paleosol?
>>
>> Are you convinced that the silty layers called paleosols were actually
>> formed slowly, then preserved in situ (usually with no unconformity)? I
>> am not. Even those with root casts in them are not necessarily slowly
>> formed. If they were the roots would have decayed. Even vertical
>> petrified trees in growth position are, on closer inspection, by many
>> evidences, found not to be in growth location.
>
> Your strategy here is to mention a couple of examples where there may be
>debate as to whether or not a particular paleosol is indeed a preserved soil
>horizon. I would counter with "Are you convinced that ALL of the thousands
>of localities where paleosols have been recognized are not paleosols, indeed,
>that paleosols don't even exist?"
>
Although I have not looked at ALL of them, my simple answer is, until the
Neogene, yes. And many in the Neogene may not be true soils either.
Appologies to those who are convinced that they are, but I find it hard to
be so convinced.
Just one example -- on my table here some leaf fossils from Yellowstone
Fossil Forest, with as good preservation at the base of the "soil layer" as
on the top. No decay. Most of these fossiliferous silt layers are fairly
homogeneous, and less than 10 cm thick (many less than 1 cm thick), and
latterally they pinch out, or form lenses.... about what you would expect
in a silt layer at the bottom of a lake, before the next load of volcanic
breccia came in. Not soils, but silt layers. Give me you best documented
example of a real fossil soil.
>>> What about a limestone on top of thousands of feet of flood deposits
>>> containing an in situ coral reef with associated fragile crinoids or
>>> bryozoans preserved as well?
>>
>> In many such reef structures the fossils are not really organically bound,
>> but are suspended in the matrix. Capitan Reef, for example, has been
>> recognized as a gigantic debris flow. Some reefs that show organic
>> structure are oriented upside down. They were probably transported from
>> where they grew -- which would suggest high-energy water movement. The
>> reef problem is very interesting.
>
> Capitan reef has NOT been recognized as a giant debris flow (except maybe
>by young-earth creationists who, once again, cannot have even one in situ reef
>in the geologic record or their model collapses). I refer interested people
>to a neat web site at:
>
> http://www.science.ubc.ca/~eoswr/slidesets/guad/slidefiles/guadc0.html
Actually, I was indirectly quoting a person on a GSA fieldtrip to Capitan
Reef who looked at the evidences for turbiditic structure (classical Bouma
sequences) in the Yates formation (in the "backreef"), if I remember
correctly, one who believed in long ages but recognized evidence of rapid
emplacement of this whole
set of formations. That may not be the accepted view in the present
literature, but on that fieldtrip many of the men recognized it as such.
>
> I would also remind people that reefs are EXTREMELY common in Paleozoic
>carbonates around the world.
That's where the upside-down (obviously transported) one I mentioned is.
Bioherms like that one were clearly transported as a unit. Other "reefs",
without real organically bound fossils (apparently not in situ coral reefs,
but still called "reef structures" because of their shape) were transported
broken up in limey mud from the area(s) where the organisms had grown.
Funny thing how, if they're all transported,
>that only tabulate corals ended up in Devonian/Silurian age rocks while
>Cenozoic rocks just have scleractinian corals
Yes! While many other classes of Coelenterates (Porifera, Hydrozoa, and
even Alcyonarids (Octocorallia, the "soft corals") continue through the
permo- triassic transition fairly smoothly, the Tabulata and Tetracorallia
die out entirely, and Scleractinians (and other Hexacorallia) begin. To
me, this points to a possible sensitivity of the Tabulata and
Tetracorallia, which caused their extinction when conditions changed.
Perhaps the waters where they lived (with trilobites, brachiopods, and the
rest pf the Paleozoic marine organisms) were not as saline as our seas are
today, and these corals, in contrast to many of the other forms, could not
survive inundation with water of greater salinity (or some other
condition). Whatever it was, they did not survive. The lack of
scleractinian remains with them indicates to me that the scleractinians did
not live in the same place. They are found with Mesozoic (and Cenozoic)
fossils, so I believe they lived in the waters of areas inhabited by
"Mesozoic" animals, and they survived to speciate in the postflood seas.
(makes a lot of sense from
>an old-earth, evolutionary point of view,
Do you think the Scleractinians evolved from Tabulates? Or a common ancestor?
none whatsoever from a young-earth
>or flood-model view).
>
Depends on your viewpoint. Making sense out of the fossil record from a
flood perspective is a challenge and a joy to me. There is always more to
be learned.
Karen