JOE MEERT
Joe brings up several issues here. The Vc model, that was briefly
presented here, has the advantage over the “Traditional” YEC position in
that it does maintain the temporal proximity of the formation of the
Siberian traps and the Permian ice age and the much later event of the
Deccan traps and the Pleistocene ice-age. By contrast, the “traditional”
YEC view usually claims that both these events happened within one year,
and not necessarily in that chronological order. Despite this advantage,
Joe is concerned about two issues: (1) The rapid climate change, and (2)
the Precambrian ice-ages.
JM: It’s not just the Siberian and Deccan traps being erupted that I am
concerned about! For one, its your claim that the Siberian traps are
responsible for the Permo-Carboniferous glaciation. That’s quite a
trick since the glaciations precede the eruption of the traps!
[/quote]It needs to be mentioned that the eruption of both the Siberian
and
Deccan traps could well have happened rapidly. One school of thought
holds that these areas were formed as a result of massive impacts
penetrating the crust and releasing the basalt. This would have of
necessity been a rapid occurrence. As far as erosion goes, it should be
noted that these materials would be soft for quite a while and this
during times of geologic upheaval. So erosion processes would be
expected to take their toll in a short amount of time where these areas
are concerned. [/quote]
JM: You’re mixing and matching ideas here. There is evidence for a
meteor impact at about the same time as the Deccan trap volcanism, but
to my knowledge there is no evidence that a meteor caused the Deccan
trap volcanism. Evidence for an impact at the time of the Siberian
traps is less compelling. Why don’t we get down to some specifics
instead of throwing out a bunch of ‘well it mighta been this way’. How
long do you think it took to erupt both the Siberian and Deccan traps?
Your statement about erosion is rather naïve. Once the rock erupted it
would begin to solidify and given the sheer volume of volcanism in the
Deccan and given the short amount of time you allow for its eruption,
erosion is not going to occur more rapidly because you are constantly
piling fresh basalt on the old. Think about it, let’s say it all
erupted in one years time. That’s 8.2 x 10^6 km^3 of basalt pouring out
in that period. That’s about ~300 m^3 of basalt per second!! Once it
hardens (and there is clear evidence that a lot of the Siberian and
Deccan traps remain as rock), it takes time to erode. So, give me some
of your estimates of erosive rates since the time the Deccan and
Siberian traps eroded? I want you to tell me (a) when they were erupted
(within a few hundred years in the ye-scenario) and (b) relative to the
current volume of material left, how much eroded?
However, Joe appears to be looking at the eruption and erosion of
the
traps solely in relation to the cycling of CO2 as the cause of the
ice-ages, in line with current thinking.
JM: No, I am not. I am looking at the whole picture. You seem to be
glossing over details that are important in the discussion. Important
items such as when, how, how fast and how much!
What I pointed out in my
original post was that there are other concurrent factors, which Joe has
not included, that speed up the whole process. These were listed off in
the original post as high axis tilt (which makes the poles significantly
colder), high water vapour content in the atmosphere (which means rapid
precipitation over colder poles), and mountain upthrusting (which
significantly changes the atmospheric circulation pattern). On this
basis, both the precipitation and cooling processes would be more rapid.
JM: Are you joking? I cannot believe this is what you think happens
with increased tilt of the axis. That is simply wrong and I am
surprised that a physicist wouldn’t understand this! If you increase
the tilt of the axis--- a couple of things happen. First, the climatic
conditions on the poles change dramatically from summer to winter and do
not favor the formation of glaciers (see Williams, 2000). It is the
equatorial region that becomes susceptible to glaciation. Secondly, you
are now tossing in mountain upthrusting into the equation. The effects
of mountains on climate depends very much on where the mountains rise.
So, where did these mountains rise? When did these mountains rise and
at what rate did these mountains rise? Please give the details and
please review the effects of increasing the axial tilt. While you are
reviewing those effects, please tell me when this axial tilt changed, to
what degree and how it returned to 23 degrees. Please supply details
not ‘mighta been’ stories. For example, please explain the actual
physical mechanisms for changing the tilt in whatever period of time you
claim the tilt to have changed. What caused the tilting and what caused
it to return to ‘normal’?
[/quote]On the second issue regarding the Precambrian ice ages, I come
from
South Australia which has the type-section for the middle and upper
Pre-Cambrian[/quote]
JM: It does not contain the type section. That is still being discussed
although it is one of the favorites. Other candidates are in Siberia,
Namibia, China and North America.
which includes the tillite and other beds in question, as
well as strata from the Permian and Pleistocene ice-ages. On this basis,
as well as university training in geology and subsequent work in that
field, I have a reasonable understanding of what Joe is talking about.
JM: It contains ‘tillites’ (plural).
The first point that I want to make is the very different
appearance of
the Precambrian tillites and associated beds compared with those of the
Permian and Pleistocene events. The Precambrian tillites are like cement
with unsorted boulders, pebbles and gravels mixed into the solid matrix.
By contrast, the Permian and Pleistocene beds are certainly not
cemented, but closely resemble glacial sediments and associated debris
seen today, but merely compacted. Read and Watson in their introductory
text on Geology also state that the Precambrian strata were different
from that left from the other ice-ages on a world-wide basis. This
suggests that something different was happening in the Precambrian case.
Furthermore, on the basis of what is seen in South Australia, the
geologists at Adelaide University have trashed the current “snowball
earth” paradigm as the explanation for these Precambrian beds on at
least 10 counts in several journals.
JM: Who claimed there was a snowball? The Australian who is doing most
of the ‘trashing’ is George Williams because he favors an alternate
explanation for the glaciations. He is NOT arguing that the glaciations
don’t exist or that they did not happen, he is arguing for an
alternative mechanism!! By the way, if you are familiar at all with the
geologic literature, you would know that I wrote a 1994 paper called “No
More Snowball Earth” so I am hardly an ally for the snowball hypothesis!
I do not deny that the glaciations have occurred. However, what you are
alluding to is that the tillites (in Australia) are not glacial in
origin. Unfortunately, the debate does not include ‘all the Precambrian
tillites’. I just completed a field season working on the
Neoproterozoic tillites in Norway (from the type section for the
Varangian glaciation). These are indisputably glacial as are many other
tillites worldwide. I can’t think of a single Aussie geologist who
claims that all Precambrian tillites are mistakenly identified, nor do I
know of many who claim that the Aussie tillites are non-glacial. It’s easy to make
assertions on web pages like these, quite another thing to actually
publish your ideas (as you well know!).
The question then becomes, “What was the cause of these
Precambrian
tillites and associated strata?” They date, radiometrically, from about
750 million years to about 600 million years worldwide.
JM: Really? The dating on them is uniformly poor or
non-existent—tillites tend not to be dateable rock types (see Evans,
2000). The 750-600 Ma interval is most widely cited, because it is
clear that some of the glacial rocks occurred during this interval. One
of the best dated tillites, the Squantum tillite (Boston Basin) is
younger. Let me note here that the problem in dating tillites stems
from the fact that the rocks are found in sedimentary successions that
are difficult to date and contain few diagnostic fossils. This seems to
go against your assertion that they were deposited during the Noachian
flood (see next paragraph).
With the speed
of light correction, this period becomes the same as Noah’s worldwide
Flood. I believe that it may be profitable to reconsider the origins of
these strata in light of that.
JM: Of course, no one has yet conclusively shown that the speed of light
has varied! It is your
opinion that this COULD be the case and you have submitted your
arguments to your peers, but there are many notions out there that don’t
ever survive the critical eyes of science. Once it is published, we can
discuss its relevance to other issues, but I see no profitability in
adding another ‘mighta been this’ to a mountain of ‘mighta beens’. By
the way, I am glad to see that at least one creationist (you) is willing
to submit their publication through normal channels. Peer-review is a
tough process, but it is how good science gets done.
[/quote] The debris making up the tillites in the
Adelaide region have their source area some 500 km away to the west, yet
they are still angular, which is not good evidence for glacial
origin.[/quote]
JM: What makes you think glaciers round every clast? Glacial erosion is
highly variable. Glaciers entrain a lot of material after ripping it
off the ground or sides of mountains. These clasts tend to be angular
and while entrained, they will not be rounded. Glaciers deposit the
material as it moves down through the ice and into the meltwater stream
where it can be rounded or deposited as is. Glaciers also pulverize
rock (loess), so the deposits left by glaciers tend to be highly
variable. The fact that there are angular clasts in the Adelaide
deposits does not necessarily indicate a non-glacial origin.
[/quote]However a flood would cart and deposit this material very
quickly,
leaving the debris as sharp-edged as that which we see there. The
various phases of the Flood would give rise to the various phases of the
Precambrian “ice age” strata. [/quote]
JM: Well, since your argument about angular clasts is incorrect, I see
no need to argue about a flood. However, let’s now take your word for
it that the Precambrian marks the time of the flood of Noah. Now, how
long does that flood last? What strata globally mark the onset and
termination of the flood? Be specific.
[/quote]Joe then asserts that the Bible should mention multiple ice ages
in
order to be scientifically correct. This is not necessarily so. The
Bible is primarily concerned with God’s relationship with man and not
with geologic activity. [/quote]
JM: Darn tootin! That’s what I’ve been saying all along! The Bible is
not a scientific text, it is a book about salvation. No one (including
you and Helen and other ye-creationists) should try to force it to be
scientifically accurate because it (a) is not a science book and (b) was
never meant to be used (or misused) as a scientific text. I’ve said it
to others and I’ll repeat it again. It seems to me that young earth
creationists worship the Bible as God rather than the God of the Bible
when trying to force science to fit their interpretation of it.
It is only where this activity reflects this
relationship that the Bible comments upon it. Comments by some of the
Biblical authors do help us put some of the pieces together, but the
Bible itself is silent in terms of explanations.
JM: However, don’t you think that the massive eruptions of the Deccan
and Siberian traps along with the ensuing ice ages would deserve a bit
of mention in the Bible given your claim of severity? At 300 m^3/sec
don’t you think someone would take notice?
Cheers
Joe Meert