I promised an article about fossil sorting; here it is. It is quite long. And it's Andrew

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From: cust_ts@kruuna.Helsinki.FI (Tero Sand) Message-ID: <2049qg$ces@kruuna.helsinki.fi> Newsgroups: talk.origins I promised an article about fossil sorting; here it is. It is quite long. And it's Andrew MacRae, not Andy McRae. -- Tero Sand ------------------------------------------------------------ Article 20512 of talk.origins: Newsgroups: talk.origins Path: klaava!hydra!news.funet.fi!fuug!mcsun!uunet!nntp1.radiomail.net!fernwood!aurora isaak From: isaak@aurora.com (Mark Isaak) Subject: Response to the Response to the Flood FAQ, part 2 Message-ID: <1992Dec31.184608.6523@aurora.com> Reply-To: macrae@pandora.geo.ucalgary.ca (Andrew MacRae) Organization: The Aurora Group Date: Thu, 31 Dec 92 18:46:08 GMT Lines: 279 [More contributions from Andrew MacRae, who himself can't post.] 3. FOSSIL SORTING and "STRATIGRAPHIC LEAK" > folta@cs.umd.edu (Wayne Folta) >>[fossil sorting] >This section of questions does raise difficulties. Oh? >But no more difficulties than that spores and wood are found in Cambrian >rocks (from Morris & Parker, quoting Weier, Stocking, and Barbour's >textbook). Oh, ok, you want to avoid the question, and talk about supposed "difficulties" in the conventional interpretation. Fine. Ha! If the original source of this information is what I think it is, [Stainforth, 1966, Nature, v.210, p.292-294.] it is a clear case of contamination. I will elaborate further if this is the case. Please let me know what the original source of the information is. I am a paleopalynologist - I study fossil pollen, spores, and microscopic algae. There are plenty of processes that can mechanically introduce palynomorphs (i.e. the spores you mention) into otherwise barren rock. You can find a good summary of this in Traverse, 1988 (for instance): [Traverse, A, 1988, Paleopalynology. Unwin Hyman:Boston, 600pp. The particular part that discusses contamination problems is p.428]. The basic problem is that spores and pollen are very durable and very small, so they can be transported into cracks within the rock, with little evidence of their transport. Sometimes I find _modern_ pollen in my sample preparations (easy to recognize because protoplasm is still present inside!) despite careful cleaning of samples. However, the "wood" is intriguing, and I would like to know more about what the authors claim. There are some Precambrian plant tissues reported from China, but they are not wood in the sense that they are from land plants - they are from marine plants - "algae". There are also "spores" (in a very broad sense) of marine algae in Cambrian and Precambrian rocks, but they are _very_ different from the spores of land plants. >Also, Morris claims that fossils are found out of order, with the >terminology "stratigraphic leak" applied to them. Yes, you and Morris are right, "stratigraphic leak" is a term for a host of contamination problems that are observed. However, you are implying that there is no explanation, and that the occurrence of "stratigraphic leak" somehow invalidates the majority of fossil occurrences that have no such problems. The explanation is simple, and even expected. There are two possible "out of order" conditions: 1) anomalously "old" fossils in young rocks, 2) anomalously "young" fossis in older rocks. The first is by far the most common. For example, if you find a dinosaur bone in a modern stream bed, it is condition 1. It is a fairly common occurrence, and happens because many fossils are durable (shells, bones, plant spores, etc.), and have the potential to be eroded out of an older rock sequence, and deposited in another, younger sequence. This process is called "reworking". You see this happening _now_ if you go to a bedrock outcrop where fossils are being eroded out of a cliff, and deposited in beach sediments. If the beach sediments are preserved, you will find reworked, older fossils mixed in the modern sediments - potentially very confusing if you are as simple-minded as Morris seems to think geologists are. However, notice four features of the reworked fossils: 1) They were embedded in older rocks, so they are probably preserved in a different fashion from modern shells. 2) They were eroded, so they should show signs of wear. 3) They will be _mixed_ with younger fossils of a definite age (i.e. the modern shells on the beach), so you will have fossils of two distinct ages in one rock sequence. 4) Since they have been eroded, many are destroyed before being redeposited. Usually the "in place" fossils are much more common than the reworked ones. The fact is, in cases of "stratigraphic leak" with "older" fossils in younger rock, some or all of these features are observed, and make it clear that the "anomalously old" fossils are reworked. Since you would expect fossils to be reworked (since it happens in modern environments), it is no surprise to geologists that it occurs in the past too. Reworking actually provides additional information to geologists, since it indicates erosion of older rocks nearby. This can be a useful tool for working out the history of uplift in a mountain range beside a depositional basin. As predicted, reworked fossils in such a situation have a reverse ordering because the youngest rocks at the top of the mountains are eroded first, then deeper and deeper rocks. Reworked palynomorphs (fossil pollen and spores) are commonly darker than the "in place" fossils, because they have been "cooked" in the sediments for a longer period of time. In my B.Sc. study [MacRae, R. A., 1989. Palynology and stratigraphy of an upper Cretaceous sedimentary-volcanic sequence, Emma Fiord, northwest Ellesmere Island, N.W.T., Canada. Unpublished B.Sc. thesis, Dalhousie University, Halifax, Nova Scotia, 159 pages, 24 plates.] , I examined palynomorphs that were deposited in Cretaceous sediments unconformably overlying a deeply weathered limestone of Permian age. I was not surprised to find a few very dark brown Permian palynomorphs mixed with the light coloured Cretaceous ones. In partial confirmation of this, conglomerates in the Cretaceous sediments contained chert pebbles that contained Permian age corals and foraminfera with identical preservation to the underlying, in-place Permian cherty limestones. The second condition, anomalously "young" fossils in older rocks, is _very_ uncommon. You don't, for instance, usually find Mesozoic dinosaur fossils mixed with Cambrian trilobites. In all the examples I have seen, contamination of lower rocks by material from higher up is the explanation. For example, some Ordovician or Silurian marine limestones in the central U.S. contain what appear to be Carboniferous-age land vertebrates (amphibians or reptiles, I can't remember). No doubt Morris or other flood creationists would jump on this as a clear anomaly. However, the explanation is again simple, since the land vertebrates occur in narrow vertical crevasses in the limestone, filled with reddish terrestrial sediments. The interpretation is that they fell into the crevasses from above, while the limestones were exposed to erosion during the Carboniferous. When spores are analyzed from the crevasse sediments, they too are Carboniferous. Another common example of this condition is in oil wells. As the well is drilled deeper, chips of rock fall from the walls higher in the borehole, and are eventually carried up the surface, and mixed with the chips from the level the drill bit is currently penetrating. This process is called "caving". When the microfossils in a sample of the chips are examined, younger ones could be mixed in. It is for this reason that paleontologists working in wells use the _youngest/highest_ occurrence of a fossil to work out the stratigraphy, rather than the oldest/lowest occurrence. So, yes, "stratigraphic leak" is a problem, but it is not very common, and it is easily recognizable because of other evidence left by the processes responsible. >Then there is the difficulty (for evolution) where tens or hundreds of >millions of years of rocks are missing with no trace of weathering or other >possible removal mechanism. The terminology for such occurences is >"paraconformity", that is, something that an unbiased observer would call >conforming, but which an evolutionist "knows" cannot be conforming because >of the fossil contents. Sure, a paleontologist may suggest a paraconformity, but other geologists will not blindly accept the interpretaton - they will test it. Note that a paraconformity (or any type of unconformity) does not have to be erosive - i.e. removal of rock. You can have a period of very low depositional rate, or non-deposition. This will produce a "gap" in the rock record (non-deposition), or a "compressed" interval (very low deposition). Actually, there are many examples of paraconformities that were initially recognized on the basis of fossils, and later confirmed by detailed examination of the contact (demonstrating, for instance, subaerial weathering of the sediments below the paraconformity); very fine biostratigraphy (finding the missing fossils in a very thin, "compressed" interval); or lateral tracing of the contact to demonstrate that the beds above and below the contact do intersect in an angular unconformity, but at a very low angle that is difficult to recognize in a single outcrop. A friend of mine here at the University of Calgary discovered a 2cm-thick limestone bed that contained two "missing" fossil zones in a section of Devonian limestone in Morocco. A significant paraconformity was originally interpreted for the horizon. The 2cm-thick limestone bed is now interpreted as a "compressed" interval that fills the "gap". 4. GREEN RIVER FORMATION AND OTHER VARVES >> How do you explain the formation of varves? The Green River formation >> in Wyoming contains 20,000,000 annual layers, or varves, >> identical to those being laid down today in certain lakes. >> [From: bill@bessel.as.utexas.edu (William H. Jefferys)] >In Whitcomb & Morris, ("The Genesis Flood"), pages 424-428 talk about the >Green River formation. The book was written in 1961, so things may have >changed, but it says that the only real study of the formation was made >more than thirty years before that by Bradley, with all other papers >pointing back to this one. The Green River Formation is still actively studied today. Especially because of the economic potential of the substantial oil shale deposits. >They say that the 6 million years (to deposit) figure was based on >Bradley's estimates of an ancient drainage basin's size, slope, character, >erosibility, drainage characteristics, and the amount of water available. Well, of course these affect it. So? Is there any evidence that the estimates Bradley made were off by, say, several orders of magnitude (6000 versus 6 000 000)? Or are we talking about a variation of "only" 50% (3 000 000 years)? >They also say that the Green River formation has layers that are too thin >and too uniform over too wide an area to have been deposited in a normal >lake bed. What an insight! Yes, it was a _big_, _deep_ lake, not a "normal" lake. The Green River Formation occurs over a very large area. >That is, there are no signs of any stirring up of the sediments or of any >deposits that reflect flooding conditions where large amounts of sediment >would have been dumped into the lake and would have sorted out in graded >series. Man, haven't these guys heard of "proximal" versus "distal" sedimentary environments? Proximal is nearshore, near the sediment sources. Distal is away from the shore, in the central, deep part of the lake, below the influence of waves, and well away from the front of active deltas. Think of proximal environments as "on the beach", and distal as "out to sea". Clearly the varves were deposited in the centre of the lake, in distal sedimentary environments - not near shore, because the wave activity and high sediment influx near the shore would interfere with the deposition of the thin, continuous layers. This still leaves a problem, since the normal lake infauna (worms, clams, etc.) would burrow in the sediments and disturb the varves. However, it is not uncommon for lakes (especially large, deep ones) to become stratified - that is, have an oxygenated, warm water layer near the surface; and a cool, anoxic (little or no oxygen) bottom layer. What happens to the infauna at the bottom of the lake in the anoxic layer - it dies. In fact, variations in the vertical position of the anoxic layer is thought to be the reason for the massive fish kills that periodically produced the beautiful fish fossils from the Green River Formation (they occur in the varved sediments). The anoxic conditions are perfect to suppress the decay of the animals that fall into the lake, allowing them to be preserved over thick intervals of rock. >They have pictures of true lake deposits and of the Green River shales, >and the difference in appearance is dramatic. From this, it seems to me >that the Green River deposits are not what they claim... That a lake sould >not have been so still and undisturbed form six million years that there >is no sign in the formations. See above. Their "dramatic difference" is the difference between proximal and distal lake environments. Note that in a small lake, all you may see is the proximal environments, because you are always close to shore. Morris et al. should go snorkelling in a large anoxic lake sometime. Besides, the Green River Formation is not just the varved shales (which really would be anomalous). It also contains the nearshore, more proximal facies (rock types), including terrestrial river channels and shallow lake deposits. The proximal facies laterally intertongue with the varved, distal shales, exactly as predicted. Also as predicted, the proximal deposits are better oxygenated, and contain bottom dwelling faunas, like snails and clams. You can see these deposits along the road cuts in Spanish Fork Canyon, Utah, southeast of Salt Lake City [Rigby, J.K., 1968. Guide to the Geology and Scenery of Spanish Fork Canyon Along U.S. Highways 50 and 6 Through the Southern Wasatch Mountains, Utah. Brigham Young University, Geology Studies, v.15, part 3, p.1-31]. A more serious problem with the short amount of time used by some flood models is the wide lateral area of deposition. There are millions of individual varve layers. It does not matter whether they are one year for each varve, you still must make millions of laterally continuous layers by some sort of event that takes a finite amount of time. The sedimentology puts some constraints on the rate. The varves are composed of very fine material - clay-sized organic and mineral grains - that is graded into alternating mineral-rich and organic-rich layers. The water must be slow moving for the fine-grained material to settle out, and in order to leave the underlying layers undisturbed. Additionally, you must spread this fine-grained layer over many hundreds of square kilometres, allowing the minerals (more dense) to settle first, followed by the organics (less dense). In modern environments, such laterally continuous laminations take months to form (at least). Even if you make a _ridiculous_ assumption, and say each varve could form in a few minutes over hundreds of square kilometres, you are still dealing with much longer than some flood creationist models propose. How many minutes in a year? 60X24X365=525600, i.e. about half a million. So, even with these _ridiculous_ assumptions, the deposition of 20 million Green River Formation varves took almost 40 years - and this is only one of many older and younger formations, including varved ones!! A good example is the mm-thick laminae of alternating, very fine-grained calcite and anhydrite ("dehydrated" gypsum) in the Permian Castile Formation, Texas [Anderson, R.Y., Dean, W.E., et al., 1972. Permian Castile varved evaporite sequence, west Texas and New Mexico. Geological Society of America, Bulletin, v.83, p.59-86]. Individual laminae are traceable over tens to hundreds of kilometres. Similar laminated carbonates and evaporites occur in Alberta. Producing these units by catastrophic, rapid processes is very difficult to envision - especially evaporites (anhydrite, gypsum, salt). If you start using reasonable lower limits on a varve's formation - say, a few hours, days, or even months - the duration for the formation becomes correspondingly much longer. So, it does not matter if 1 varve = 1 year exactly - the total duration is still a long time. In fact, in the Dead Sea, one varve lamina is deposited every three or four years. If you restrict the deposition of all the varves to the 1 year total duration of flood models, you must deposit a varve in a few seconds (assuming you have all year - not taking into account other, thicker rock formations). This does not jive with the physics of fluid mechanics. This sounds very supernatural to me. -Andrew macrae@pandora.geo.ucalgary.ca Article 20513 of talk.origins: Newsgroups: talk.origins Path: klaava!hydra!news.funet.fi!fuug!mcsun!uunet!nntp1.radiomail.net!fernwood!aurora isaak From: isaak@aurora.com (Mark Isaak) Subject: Response to the Response to the Flood FAQ, part 3 Message-ID: <1992Dec31.184814.6605@aurora.com> Reply-To: macrae@pandora.geo.ucalgary.ca Organization: The Aurora Group Date: Thu, 31 Dec 92 18:48:14 GMT Lines: 190 [Still more contributions from Andrew MacRae, who himself can't post.] 5. SALT FORMATION and DIAPIRISM > folta@cs.umd.edu (Wayne Folta) >> isaak@aurora.com (Mark Isaak) >> How could the flood deposit layers of solid salt --- sometimes meters >> in width. This apparently occurs when a body of salt water has >> its fresh-water intake cut off, and then evaporates. These layers >> occur more or less at random times in the geological history, and >> have characteristic fossils on either side. Therefore, if the >> fossils were themselves laid down during a catastrophic flood, >> there are, it seems, only two choices: >> (1) the salt layers were themselves laid down at the same time, >> during the heavy rains that began the flooding, or >> (2) the salt is a later intrusion. >> I suspect that both will prove insuperable difficulties for a >> theory of flood deposition of the geologic column and its fossils. >> [From: marlowe@paul.rutgers.edu (Thomas Marlowe)] >Whitcomb & Morris, pg 412-417. Two simplified explanations: 1) the > deposits were moved from elsewhere, where they had been since the > creation; or 2) they were created by a lot of heat in a short time >rather than a little heat over a long time (volcanic versus solar). For 1): But the salt deposits are interbedded with sediments containing marine fossils, sometimes at centimetre scale. Fossils were supposedly created before the flood, on one of the days of creation? When do the "creation" fossils end, and the "flood" fossils begin? For 2): But the salt deposits are interbedded with sediments containing marine fossils, sometimes at centimetre scale. You can't have the animals that made fossils living in molten salt. Salt is commonly crystallized into cubes with recessed faces called "hopper" crystals. These are observed in modern evaporative ponds. I do not think they can form from melts. >Also, salt domes are so large that a non-Flood explanation has problems, >too. They claim that there are salt domes 3000 feet deep and deeper, and >Europe has domes that may be 15,000 feet deep. To have evaporated in >place would create enormous difficulties. Um, wow, I aggree. In fact, domes up to several km high are common. But I do not aggree that a "non-Flood explanation has problems". >They claim that such large deposits are only explainable in terms of non- >sedimentary mechanisms. The later intrusion mechanism above, sounds like >this. Ooooooooo! How original of Whitcomb and Morris. What a coincidence - the "intrusive" mechanism they describe is exactly the same one that geologists theorized many decades ago. It is called "evaporite diapirism" (evaporite, since the domes usually contain more than just salt). Did they at least give credit to conventional geologists for the explanation? :-) :-) This mechanism causes its own problems for "flood" models, since the evaporites intrude the overlying sediments plastically - i.e. they do no melt their way into the sediments, they slowly push their way through, and the evaporites become highly deformed in the process. This type of plastic deformation takes a long time, because rapid deformation causes the rock to break (i.e. fault), not bend plastically. All of the intrusion and deformation must have occurred _after_ the flood, if the kilometres of overlying sediments were deposited by the flood. A few thousand years is not enough time to plastically intrude evaporites through kilometres of sediments! You will also be pleased to know that some evaporite diapirs are subsurface, and form angular unconformities with thick sequences of overlying rocks - also implying a more complex history than a single flood can explain. Besides these problems, you are still avoiding the basic question: how did the salt form in the first place? True, deformed "salt domes" are kilometres high, and must have formed by intrusive diapir processes, but undeformed salt beds are still many hundreds of metres thick in some areas _and_ are interbedded with limestones containing marine fossils, gypsum, terrestrial sediments, etc. _and_ occur at many different ages. Do Whitcomb and Morris mention the fact that evaporite diapirs merge into single beds at depth, and that therefore diapirism doesn't really answer the basic question?? -------------------------------- -------------------------------- -----/-\------------------------ -----|+|-------------/-\-------- + = salt -----|+|-------------|+|-------- --- = other sedimentary rocks -----|+|-------------|+|-------- (these would be deformed -----|+|-------------|+|-------- near the edges of the diapirs) -----|+|-------------|+|-------- -----|+|-------------|+|-------- -----|+|-------------|+|-------- ----/+++\-----------/+++\------- ---/+++++\--/+++\--/+++++\------ ++++++++++++++++++++++++++++++++ <---- originating salt layer ++++++++++++++++++++++++++++++++ -------------------------------- This is the normal condition for all "salt" diapirs. 6. FOSSIL FORESTS >> How could a one-year flood deposit the following: "In Yellowstone >> Park there is a stratigraphic section of 2000 feet exposed which >> shows 18 successive petrified forests. Each forest grew to >> maturity before it was wiped out with a lava flow." [J. Laurence >> Kulp, quoted in Strahler, _Science and Earth History_, pp >> 221-224.] >This is an easy one. These are not 18 separate petrified forests, but the >repeated, rapid, cataclysmic deposits of trees from elsewhere. The >"trees" found are in fact tree stumps, without extensive roots or >branches. It is well-known that tree stumps that are ripped up in floods >often are deposited roots-down. (For example, this month;s Science >magazine shows such an effect from a huge flood in Washington. Gish and >company have also found the same sort of event at Mt. St. Helens.) I've seen the Mt. St. Helens paper [Coffin, H.G., 1983. Erect floating stumps in Spirit Lake, Washington. Geology, v.11, p.298-299]. It is a good, if short, observational paper. The reason the roots are often deposited down is because of boulders that the roots have trapped. The author makes a good point, however, note that at least as many logs and stumps in the illustrations are _not_ upright [ibid. fig. 2, 3]. Also note that the transported nature of the trees can be tested by other methods. For instance, trees grow in soils. If you find a tree stump with roots embedded in a paleosol (fossil soil), it must be in place. Another test is whether leaves appropriate for the wood are found around the stump (i.e. leaf litter), and other evidence that you were dealing with a normal, "in place" forest floor at the horizon of the stumps. As you imply, an "extensive", delicate root system is more likely to be in place than transported. >Thus, what looks like "forest killed by volcano, tens of thousands of >years until new forest, which is killed by volcano, ..." could have >actually been entirely been deposited in rapid succession from a forest >at another location. In fact, I think they presented (at their seminar) >information that one of their group had gotten a Master's Thesis out of >looking into the different forest's tree rings and finding that the many >layers were from the same forest (tree rings corresponded). Now that would be interesting. Do you have a citation for the paper or thesis? Ok, instead of trying to find out more about the Yellowstone occurrence, for which your explantion is certainly a possibilty (without more data), lets look at some others. One that I am familiar with is the "Fossil Forest" on Axel Heiberg Island, Canadian Arctic: Cristie, R.L., and McMillan, N.J. (eds.), 1991. Tertiary fossil forests of the Geodetic Hills, Axel Heiberg Island, Arctic Archipelago, Geological Survey of Canada, Bulletin 403., 227pp. Here you find _mummified_ (i.e. non-mineralized) tree roots and trunks in an unlithified "leaf-litter" (needles, leaves, like you find in modern forests). Amber is common. And, you guessed it, there are paleosols: Tarnocai, C. and Smith, C.A.S., 1991. Paleosols of the Fossil Forest area, Axel Heiberg Island. IN: [see above], p.171-187. They recognize 15 paleosols in a 22m section at the site, including the ones with the tree stumps/logs. There is no evidence that this is a displaced occurrence. The stumps and leaf litter are exactly as it would be if you were walking through the forest today (except that the tree trunks have fallen over beside the stumps :-). The spacing between trees is similar to modern forests. You can even burn the wood :-) Explain that. And when you are finished, check out this reference: Carpenter, K., 1992. Behavior of hadrosaurs as interpreted from footprints in the "Mesaverde" Group (Campanian) of Coldorado, Utah, and Wyoming. Contributions to Geology, University of Wyoming, v.29, no.2, p.81-96. Which describes dinosaur footprints and large tree stumps in the roof of two coal seams in Cretaceous age sediments. And visit Joggins, Nova Scotia, which has many upright stumps of Carboniferous age giant lycopod trees in what look like river-deposited sediments. Giant lycopod trees are not woody, they are a tube of vascular tissues with a pith-filled centre. The root systems are branch into a system 1-1.5m in diameter, and have many small rootlets (about 1cm dia, 10cm long) projecting from the main root branches into the surrounding sediment - - it is very unlikely that the rootlets or the pithy trunk could be transported far without being crushed. There are many more "fossil forest" horizons of different age worldwide. -Andrew macrae@pandora.geo.ucalgary.ca


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