TedM

Hi. A few years ago I became convinced that evolution was the best explanation for the fossil record based on 1. the further you dig, the older the fossils. 2. dating methods that confirm #1 and 3. the ridiculousness of the Flood explantion for the fossil sequence we find.

I recently got out a book I have calledTornado in a Junkyard, by J. Perloff, and am now a bit concerned that these ideas are shakier than I have thought. Can anyone here help answer these objections from the book?

1. on page 146 he quotes evolutionist William Stansfield "It is obvious that radiometric techniques may not be the absolute dating methods that they are claimed to be. Age estimates on a given geological stratum by different radiometric methods are often quite different (sometimes by hundreds of millions of years). There is no absolutely reliable long-term radiological "clock."

How true is this objection? How could such differences exist within the same stratum? How meaningful is this? How consistent are the readings overall--ie out of 100 geological stratums, how many times are multiple measurements within say 10% of each other?


2. p 143 "Seventy-five percent of the geologic column's rock is sedimentary..Radiometric methods do not work on sedimentary rock. They are effective only with "igneous" rock (that which was once hot and molten, like lava or deep granites) and "metamorphic" rock (that transformed by heat or pressure, such as marble). Since most fossils are lodged in sedimentary rock, they cannot be radiometrically dated. And for the relatively few fossils in igneous and metamorphic rock, even if the dating technique works, it doesn't necessarily reveal the fossil's age--only the age of the minerals, which may have formed long before the fossil"

How valid is this objection? How do we verify the ages of fossils without assuming evolution if we can't use an independant dating method on the type of rock they are in?


3. Have radiometric methods overwhelmingly and consistently shown that the deeper you go into the earth, the older the rocks? It seems obvious, but I'm not so clear now: on page 146 he writes "Geologist Steven A Austin dated samples from the Uinkaret Plateau, which contains some of the highest rocks in the Grand Canyon (making them positionally young). Using the rubidium-strontium method, he obtained an age of approximately 1.3 billion eyars. Lead dating has put the rocks at 2.6 billion years, and potassium-argon at anywhere from 100,000 to 117 milion years. If the rubidium or lead methods are correct, these high rocks would be older than those lying near the canyon's base (the Cardenas basalt, dated by different techniques from 9.7 to 1.1 billion years old)"

How can the dating yield such positional results? How consistent do radiometric methods validate the top-young, bottom-old paradigm?


4. Regarding the column, he writes on p 154 "The Grand Canyon, which offers the best view of strata, contains only five of the major systems. Evolutionists try to explain missing layers by saing they must have eroded away. But sings of erosion are often lacking. And if uniformitarianism is true, and erosion is almost always slow, how could it eiliminate rock layers formed over tens of millions of years?"

Are these fair questions?


5. While I"m at it, although this isn't related to radiometric dating either, I'm curious about what he writes regarding a theory that I thought had been long disproven: The Flood model p156-7 he writes "Those that dwell at the lowest levels; clams and other invertebrates on the ocean floor (would be buried first). ..who lives over the marine inverebrates? Fish. Their ability to swim above the sediments would exceed that of invertebrates. ..The next creatures buried would probably be those living at water's edge: amphibians. Then would come terrestrial animals. The ones with the least mobility for escape? Reptiles. Above them, one woudl find mammals; and at the greatest height, the most resourceful being of all: man" He says the fossil record reflects this trend. He also says that "Countless billions of fossils are in the Earth. But today, millions of fish die daily, and, with very rare exceptions, they don't leave any fossils. Neither do other animals." He sees the Flood as an explanation for the millions of such fossils found.

Is this at all realistic?



Any answers would be greatly appreciated,

ted

hagiograph

Ted,

My comments to your questions asked in the S&S Forum:

http://www.iidb.org/vbb/showthread.p...90#post2834890

g-21-lto

The principle of superposition, which basically states that younger strata will overly older strata and so the strata will get older deeper into the geologic column, applies to sedimentary rocks due to the circumstances of their formation -- they are basically accumulated sands, muds, etc. with the most recently accumulated lying on top. For igneous rocks, such is the case only for volcanic rocks, in which successive flows will overly the older lava flows, or older country rocks. Magmas will form far beneath the surface and rise, cooling along the way to form igneous rock bodies, which means that there won't necessarily be any neat older-to-younger trend in the vertical direction.

Sedimentary strata can be dated relatively to these igneous rock bodies on the basis of cross-cutting relationships, wherein, for example, a body of igneous rock cuts across a layer of sandstone -- we know that the sandstone must have formed first for this body of magma to intrude into it, and so the sandstone must be older than whatever numerical date we get for the igneous body.

As for this quote:
I'm highly skeptical of Austin's conclusions. For one thing, we've been told nothing about the type of rock he is dating -- the principle of superposition doesn't apply to these rocks if they are igneous intrusions, which I assume they are if he is dating them. The Cardenas Basalt is a formation I'm not familiar with; from the (I assume?) .97 to 1.1 billion-year age I assume it is stratigraphically beneath the rest of the canyon strata? Does the book indicate this? (If so, then an igneous intrusion in the plateau stratigraphically above it would, indeed, of necessity be younger).

As for the different dating techniques yielding different ages, the ages have come out exactly as could have been expected -- the U/Pb, Rb/Sr, and K/Ar systems will all "close" within a mineral grain at progressively lower temperatures. That means that basically, each "clock" is going to be recording time since the grain cooled below a specific temperature called its closure temperature. Within the same rock sample, U/Pb will record an older age than Rb/Sr, which will record an older age than K/Ar. The book would have also been much more helpful if it had given the specific minerals on which these radiometric dating techniques were performed. Is there any way Austin could have picked up xenocrysts, which are foreign crystals from pre-existing rocks that the magma has moved through? This would definitely skew the results.

There is also apparently no discussion of the methods used to date the Cardenas Basalt, which could be quite important.

More on geochronology here from the University of Idaho.

If you completely skew the meaning of uniformitarianism, then I guess they are. In all seriousness, uniformitarianism is simply the concept that processes and physical properties we observe in the present were ongoing, or had analogous processes, in the past. Erosion rates vary greatly. If you accumulate a mound of sediment in an ocean and then lower sea levels to where that sediment pile is exposed, then a lot of it is going to erode. I don't see the author's hangup with erosion and deposition rates.

And as for the statement "signs of erosion are often lacking", this is overcome by correlating sedimentary strata from one outcrop with strata from other outcrops in the region -- often erosional surfaces (or time periods of non-deposition) can be shown in one locale by comparison to a fuller record in other locales.

No, it's not. In the author's model, there would be no (or almost no) possibility of bottom-dwelling species to be found in the middle and top strata of the geologic column, while there would have been opportunities for "more mobile" creatures to have been stunned, taken off their guard, etc., and buried with the bottom-dwellers. We could expect a fossil record in which bottom-dwelling and less-mobile species are found at the base of the column, occasionally interspersed wiht the unlucky or sick reptiles, mammals, birds, etc.

Instead, what we see is bottom-dwelling species throughout the geologic column -- of course, different species of shellfish, corals, etc. will appear and disappear from the record, but the basic bodyplans -- and bottom-dwelling life strategy -- have been well-represented since their first appearance. We don't see the reptiles, mammals, etc. until further up the column. Strangely as if they didn't exist at the beginning. :Cheeky:


Hope I've been helpful! There are bona fide geologists on the board who will be infinitely better sources of information than I.

OC1

Ted-

all your questions are answered here:

http://www.talkorigins.org/

A few comments:

The overall accuracy of radiometric dating has been verified by comparisons to non-radiometric dating methods, such as tree-rings, modern and ancient varves, annual ice layers in glaciers, long-term astronomical cycles in sedimentary sequences, and daily growth rings in ancient corals.

WRT the corals, the growth-ring pattern in fossil corals dated at 400 million years old indicated a year was 400 days long when the corals were alive. Independantly, astonomers predicted that the year was 400 days long 400 million years ago.

There are certainly some erroneous radimetric dates out there, but the overall accuracy of radiometric dating has been proven beyond any doubt.

The geologic time scale (i.e., the various periods, like Cambrian...Triassic, Jurassic...etc.) is based on fossil assemblages. The basic geologic column was devised before "Origin of Species". There is absolutely no assumption of evolution in the geologic time scale, only the observation that fossil assemblages have varied in a systematic way through time.

No. A few (of the many) reasons:

doesn't explain the fossil record for plants (which can't run away from the flood);

doesn't explain the fossil record for the numerous planktonic microorganisms (foraminifera, diatoms, ostracodes...), which are found throughout the fossil record;

doesn't explain the fossil record for flying critters. Why aren't flying reptiles (like pterodactyls) found alongside birds and bats? Wouldn't they all have been able to fly to higher ground? How did flightless birds (like moas) outrun the flying reptiles??

mosesnoses

This section shows the absolute lack of any real understanding of sedimentology or paleontology by the author. First of all, why is it that in the early Paleozoic sediments, no trace, no matter how minute, of any vertebrates are found? Not so much as a fish tooth or otolith? If fish had been living in the seas at that time, certain highly preservable bones would be included with the bottom dwelling inverts, no matter what. Otoliths and teeth are incorporated in the modern sea floor sediments worldwide. Further, the idea that there are only inverts living on and within the sea floor is wrong. There are plenty of bottom dwelling fish in modern oceans.

How about trace fossils? In the Grand Canyon there are many layers of sedimentary rocks that bear the trackways of bottom-dwelling inverts including trilobites. If the Grand Canyon sediments were deposited quickly as a single, unlithified package, how could multiple trackway horizons be present? The tracks were formed on the sediment-water interface in somewhat firm mud (soft enough to take the impressions, but firm enough to hold them). The environment had to be benign enough that the trilobites could live, walk around, and feed (rusophycus are a common feature). These trackway layers had to be gently buried by subsequent sedimentation, then a new sea floor surface established and consolidated enough to take a subsequent series of tracks. This cycle is repeated many times. The catastrophic deposition of 1000's of feet of sediment in a short time cannot have produced the sedimentary conditions and environments condusive to happy trilobites! Higher in the section are found vertebrate tracks made on emergent land. How is it that a flood produces emergent land over the ocean? If you flood an ocean, it gets deeper, not shallower. So how is it that dinosaurs were able to leave tracks in the same places that were clearly oceans only days or weeks before according to the Noah's Flood proponents? The dinosaurs must have had scuba gear, eh?

Finally, that line about how no fossils are forming today is just wrong. It show a total lack of understanding of how and where fossils form. It is as though he thinks that when a fish dies it should lay on the bottom and magically become a fossil for all to see. With regards to fish, in the majority of cases, the only place that body fossils would be forming is within thick packages of quickly deposited sediments that interred unlucky organisms to a depth that bioturbation can't act on the remains. The seds must then become lithified. Of course this process would not be visible at the sed surface, in fact anything you see on the surface certainly won't be fossilized in any oxygenated water (anoxic conditions may provide rare exceptions). Have these creato-geologists ever looked in the subsurface in a systematic way to see if fossils are forming? Have they read or done any taphonomic studies? No. They just say "We don't see any new fossils laying around" and point to that as proof. They haven't even looked. In many places relatively young fossils abound. Shelled molluscs are preserved along many seashores. Storms pile up sediments with shells included and if subsequent storms don't erode them, they quickly fossilize. In the tropics, snails like Cerion are often found in beach rock that lithifies so quickly it sometimes includes bottle caps as well. Fossils are forming all around us all the time, but you'll only know it if you care to look.

None of the paleontologic or sedimentary evidence in the Grand Canyon supports the flood theory at all. There are dozens of lines of evidence that very clearly refute all of their assertions in this regard.

buckshot23

I have been wondering how we can tell the difference between different sediments? Are Paleozoic sediments compositionally different than Eocene sediments? Other than fossils found in them.

Oolon Colluphid

Sediments will vary in subtle chemical composition from place to place, but not, AFAIK, from time to time as such, though the atmosphere at one time may be different from another, and that might affect it too. But no, basically a limestone is a limestone, a chert is a chert, and so on.

Apart from the fossils found in them, of course . Look up 'zone fossils'.

mosesnoses

I know what you're angling at and the fossils are the key. According to the ideas proposed above that clams (and I guess that includes brachiopods, since true clams were much less common in the early Paleozoic) were fossilized in the lowest strata. There is one HUGE problem with that proposal...none of the species of bivalves found in the Paleozoic sediments are around in modern seas...not a single one of them out of the hundreds of fossilized species. Further, none of the modern species are preserved in these ancient sediments...none. How does the creationist flood model account for that?

Jeffahn

Noah liked clam soup.

g-21-lto

There are some long-term global compositional trends that can be useful, such as the ratios of 13C/12C and 18O/16O in marine carbonates throughout the Phanerozoic. However as the trend is a rough oscillation, you'd need a section of limestone strata in order to correlate to some section of the global trend. And there are always local conditions which can offset values for a particular location.