Ah, Yep

A while ago I gave my personal definition of what science is, why we use it, and touched briefly on what I think this means for "non-conflict" between science and religion. I also recently lamented the distorted view of the boundaries of science implicit in using the term "supernatural."

Although I still want to go into this subject in a little more detail myself, this posting by P.Z. Myers and this even better one by Jerry Coyne lay out the case against reconciliation between science and religion beautifully. Coyne goes into some interesting detail about the intellectual roots of creationism as well, and the uncomfortable similarities it has with the thinking of conciliatory evolutionists like Kenneth Miller.

LNJ

The Future of Upper Triassic Vertebrate Biostratigraphy and Biochronology

Bill is currently reviewing the most recent issue of Journal of Vertebrate Paleontology, which contains three papers that directly bear on Upper Triassic archosaurs: descriptions of the weird little basal archosauriform Doswellia (Dilkes and Sues, 2009) and the postcranial skeleton of the “rauisuchian” Batrachotomus (Gower and Schoch, 2009), and a methodological critique of Spencer Lucas’ “Late Triassic land vertebrate faunachrons” (Rayfield et al., 2009). This makes this possibly the BEST JVP EVER in spite of the fact that there is a f-ing shark on the cover.

The Rayfield et al. paper touches on a lot of the same issues I covered in my dissertation (and hope to get into print before too long), and I want to spend a few posts talking about it. It is a short but direct criticism of the way in which Lucas and his colleagues use Triassic vertebrates for intercontinental correlation. Specifically, how they squeeze alpha taxonomy to most conveniently fit their correlations (by lumping when it aids correlation and splitting when it helps subdivide superimposed strata), ignore the effects of endemism, cannot seem to keep track of their own reasoning about how stratigraphic units are correlated, and make arbitrary and largely unexplained decisions in resolving overlaps between supposed index taxa.

As I discussed in a previous blog, putting the events in the history of life in correct chronological order is the ultimate goal of the biostratigrapher. The Law of Superposition helps us with this goal when looking in particular study areas (in my case, the Dockum Group in southern Garza County, West Texas, and Petrified Forest National Park in northeastern Arizona). If the lithostratigraphy is correctly worked out by walking out contacts, and vertebrate localities have been correctly tied into the lithostratigraphic model, superposition allows us to place vertebrate occurrences, and therefore evolutionary, migratory, and/or extinction events, in the correct chronological order. However, it is far more problematic to work out the relative ages of strata and their constituent fossils in geographic areas too widely separated to physically walk out lithologic units in between. If you cannot place physically separated lithologic units in the correct superpositional order, how do you determine what their relative ages are?

The longest-utilized method, biostratigraphic correlation, relies on the fossils themselves. If you can identify the same individual taxa and/or faunas, and ideally the same succession of individual taxa and/or faunas in different areas, then it might be assumed that equivalent taxa and/or faunas (and therefore the strata containing them) are the same age. However, as wise and realistic biostratigraphers working on both invertebrates and vertebrates have regularly pointed out for the past century, this is sketchy assumption which comes dangerously close to treating biostratigraphic units as chronostratigraphic units. The ranges of taxa in different areas may be diachrononous, and if the fossil record is incomplete (as it always is), you run the risk of identifying incomplete ranges of taxa living in different areas as being exactly equivalent in age. In reality, the boundaries of lithostratigraphic, biostratigraphic, and chronostratigraphic units do not have to coincide with each other in any way.

Mammalian biostratigraphers largely have gotten around this problem thanks to the rampant volcanic activity in western North America during the Cenozoic, which has provided them with a plethora of radiometric dates, augmented by extensive magnetostratigraphic zonation of Cenozoic strata. They therefore have a system of correlating isochronous strata completely independent of biostratigraphic correlation, which can, and has, been used to determine whether or not biostratigraphic units are in fact isochronous.

Unfortunately, there are relatively few volcanic deposits in Upper Triassic rocks in western North America, and little work has been done on the magnetostratigraphy. Consequently, chronostratigraphic correlation has mostly relied on vertebrates and pollen. However, with current advances in radioisotopic dating techniques making it easier to extract absolute age dates from a wider variety of strata (and run the samples in less time for less money), biostratigraphic correlation as a way of determining time-equivalent strata is in danger of becoming passé. Why rely on biostratigraphic correlations hampered by pitiful sample sizes and questionable assumptions about isochronous taxon ranges on different continents when you can just use lots of radiometric dates, augmented by magnetostratigraphy, to determine which strata are the same age?

So this is the most likely (and most promising) future of chronostratigraphic correlation for Late Triassic vertebrate=bearing strata: Provincial lithostratigraphic and biostratigraphic models, in which the lithostratigraphy and biostratigraphy is worked out in detail for particular areas. The identification of isochronous strata is based almost entirely on radiometric dating and magnetostratigraphy, and the alpha taxonomy of vertebrate specimens is done solely based on morphological criteria regardless of the age or geographic distribution of specimens. In this way, the chronostratigraphic correlation of strata tells us whether or not the ranges of similar taxa on different continents was isochronous or not, alpha taxonomy tells us whether taxa were geographically restricted or widespread instead of being dictated by biostratigraphic convenience, and we avoid the sort of circularity in reasoning discussed in the Rayfield et al. paper. The age equivalence of vertebrates is derived from the ages of strata established by other methods, not vice versa. If the correlation of Upper Triassic terrestrial deposits indeed proceeds along these lines, this will make some of the issues discussed in the Rayfield et al. paper irrelevant.

Incidentally, marine invertebrate biostratigraphy is a bit more complicated, because it is intricately intertwined with the chronostratigraphic time scale. The current correlation of stage boundaries, at least those for which a boundary stratotype (“golden spike”) has NOT been driven in, is based almost exclusively on the biostratigraphic correlation using, particularly, ammonoid and conodont biozones. The correlation of ammonoid and conodont biozones is therefore tied directly to the correlation of chronostratigraphic units, and necessary to find the most suitable locations for chronostratigraphic boundary stratotypes. However, one a “golden spike” has been driven in, a geologic stage pulls free of biostratigraphy, and chronostratigraphic correlation can be based entirely on radioisotopic dating and magnetostratigraphy (if available).

How My Day Is Going

Just the other day, Parker and I were reminiscing about a bad bad bad case of food poisoning that he got from a Chinese restaurant in Lubbock, which resulted in him camping out on my bathroom floor during one of his visits to look at the TTU collections. I commented, perhaps a little too blithely, about how I have never had a severe case of food poisoning.

Well guess what, ha, ha! I woke in in Flagstaff this morning and realized that the mini-burgers I had eaten the previous evening had been a mistake. A bad bad mistake. I stopped off to visit every gas station bathroom between Flagstaff and Holbrook, wondering if I was actually going to remain conscious all the way home, and learning many amazing an unexpected things about what my digestive tract is physically capable of. Fortunately, the absolute worst was over by the time I got back.

I'm currently working on some ruminations on Upper Triassic biostratigraphy inspired by the Rayfield et al. (2009) paper in the last JVP, which is a good jumping off point for getting a couple dissertation chapters whipped into shape.

I also encountered this phenomenal motivational poster, giving me another reason to work on pseudosuchians:

LNJ

Why Is God Better Than Evolution?

I find myself linking to stories posted at Pharyngula more frequently than to other sites. This is not because I find P.Z. Myers' posts more interesting or relevant than what anyone else posts, or because I agree wholeheartedly with Myer's zero tolerance response to religious expression (I don't). It is simply that Myers' posts tend to deliver the most jolting full arm slaps to my brain. For example, see this recent post on an abstract with unconventional views on gene expression in venomous animals.

It is easy to just make fun of this kind of stuff, but it is far more fascinating for me to crawl inside of the headspace of someone who thinks about reality in a fundamentally different way than I do. The human brain's capacity for generating its own reality is absolutely mind-boggling. How vividly our perception of reality feels or appeals to us has little impact on how likely it is to be true (the reason why science uses evidence, critical thinking, and peer review), but I have no doubt that Mr. Wilson sees God flipping on the "evil" switch in poisonous animal gene expression in his head just as vividly as I see the evolution of Mesozoic reptiles and the deposition of fluvial and lacustrine deposits over millions of years.

However, the things about the abstract that really interest me are:

1) How well-written it is. In spite of his scriptural blinders, Wilson seems to be a reasonably bright guy, and clearly spent some time refining the text. The abstract is very clear, tightly written, and articulate.

2) How thoroughly he explores the various possible explanations behind the origin of "evil" genes, and how logically he tries to deduce the correct answer in light of what he "knows" about the Biblical creation story.

2) How completely he fails to explore the significance of his own conclusions towards God. Wilson concludes that "evil" genes must have been created by God due to a lack of "creative power and intelligence" on the part of Satan (and of course, the inadequacy of natural selection), even if they did not find expression until after the Fall. What he does not explore, however, is that his means that God intentionally incorporated tendencies into his designs that Wilson considers "evil." What does this tell us about God? Wilson falls short of one of the important steps that I think separates the good scientists from mediocre ones: he doesn't fully explore the significance of his own conclusions. God deliberately created "evil" genes, and every person that dies of a snake or spider bite does so because of a deliberate design choice on the part of God.

This brings me to one of the most interesting (to me) aspects of creationist opposition to evolution: the complete lack of any logic behind their moral horror of non-directed natural selection, given that, in their view, God is directly and deliberately responsible for the cruelty of the natural world.

Creationists are terrified of the idea that not only our bodies and brains, but our moral and cultural institutions, might have developed (and continue to develop) without the input of a higher power. However, this perception makes absolutely no sense when looking at the world that exists around us. According to creationists, this world was created by a being who is supposed to be our moral compass. Violent, callous, and cruel things irrefutably happen every day in nature...and according to creationists, God deliberately designed things this way.

Evolution doesn't see the prehistoric history of the human species, or any species, as being any worse than the modern natural world. It simply says that the same sort of things that are irrefutably happening every day have been going on for a long time, and that they have had long term effects. Moreover, no one has consciously caused these things to happen.

The irony of creationist moral opposition to evolution is that evolutionists do not blame the cruelty of nature directly on God, and creationists do. Moreover, they justify it as being part of some really great but incomprehensible plan. I find this morally permissive attitude toward God ironic given creationist accusations that evolution is leading society down a moral toilet.

LNJ

Reconstruction Of The Blue Mesa Member Depositional System

For the general public, most of whom do not have a geology background, it is very hard to understand how drastically what they can see before them may differ from what used to be there. When visitors look out over the Painted Desert from Kachina Point or one of the other overlooks in the north end of the Petrified Forest National Park and are told that the strata before them were formed in an ancient river system, a common response is "oh, yeah, there it is right there!" They are referring to modern day Lithodendron Wash. They do not understand that the modern topography is something carved out by modern drainages, and that an absolutely huge body of sediment was laid down in very different environments and subsequently carved out by post-Mesozoic erosion.

A few months ago, I posted on a reconstruction of the Upper Triassic Chinle Formation depositional system in Petrified Forest National Park, which was paid for years ago by the park service. Such reconstructions are extremely useful for educating the public, as they illustrate the relationship between sedimentary strata and the ancient environments that actually produced them by helping the public understand that they are looking at an irregular cross-section through a series of ancient depositional systems.

However, as I had discussed in my prior blog, this diagram has some inaccuracies. As a result, I decided to do a series of revised block diagrams for the park service, showing the different depositional environments which laid down the Chinle Formation strata, and then one or two others showing this same stratigraphic block diagram carved into modern-day topography.

This project is probably going to take forever to complete, as I have have other illustrations to produce for the park (as well as a lot of other paleontological and geological duties), but I have the first block diagram done. This one illustrates the depositional system of the Blue Mesa Member, the lowest unit of the Chinle Formation in the park which is well-exposed within the traditional park boundaries. Specifically, it shows the depositional system associated with the Newspaper Rock Bed, a prominent sandstone unit in the middle of the member. This reconstruction is based mostly on Tim Demko's work in his 1995 dissertation, and publications by himself and other discussing the Blue Mesa Member depositional system (Demko, 1995b; Demko et al., 1998). The block is a half-kilometer on a side (click on it to see a bigger version).

From Paleo Errata

The Newspaper Rock Bed was deposited by a meandering river system, which displays well-preserved lateral accretion bedding (these are beautifully illustrated by some nice exhumed scroll bars which are visible from the main park road driving south, just before dropping down into the Teepees), while the associated mudstones of the Blue Mesa Member represent overbank and lacustrine deposits. The drab coloration, and relative scarcity of pedogenic carbonate nodules compared to what is seen higher in the Sonsela and Petrified Forest Members, indicate relatively poorly-drained soils and possible wetland conditions. This is supported by the abundance of metoposaurs (large temnospondyl amphibians), in the Blue Mesa Member; these become relatively scarce higher in the section.

Demko's work on plant taphonomy is also very cool, as it allowed him to plausibly reconstruct the distribution of different types of plants around the channel, floodplain, and lacustrine settings. Conifers (which seem to have been a little smaller then those forming the spectacular agatized forests in the Sonsela Member) are mostly found in the channel deposits, and may have been mostly confined to riparian zones along the banks of the river. Cycadeoids (bennettitaleans), ferns, and seed ferns, with less common cycads, ginkos, and conifers, were the main plants growing on the floodplains. Giant horsetails (sphenopsids), as well as smaller horsetails and club mosses, mostly grew along along channels and around the margins of lakes.

The biggest problem with the block diagram is that it is difficult to make out plants and animals at that scale (the little green dashes around the lakes are giant lycopods three meters tall or more, and there is actually an 8 meter long Leptosuchus-grade phytosaur sitting on the point bar. Trust me). At some point, I may do blow ups of different parts of the diagram giving a close-up of the fauna and flora.

REFERENCES

Demko, T.M. 1995a. Taphonomy of fossil plants in the Upper Triassic Chinle Formation. Unpublished PhD dissertation, University of Arizona, Tuscon, 274 pp.

Demko, T.M. 1995b. Taphonomy of fossil plants in Petrifed Forest National Park, Arizona. Pp. 37-52 in D. Boaz (ed.) Fossils of Arizona, Proceedings of the Mesa Southwest Paleontological Society and Mesa Southwest Museum, Mesa AZ.

Demko, T.M., Dubiel, R.F., and Parrish, J.T. 1998. Plant taphonomy in incised valleys: Implications for interpreting paleoclimate from fossil plants. Geology, vol. 26, no. 12, pp. 1119-1122.

Open Letter To Supporters Of Teaching Intelligent Design In Public Schools, None Of Whom Actually Ever Read This Blog

Merciful Christ, people.

Let’s just pretend for a second that your blatant religious agenda is some kind of closely guarded secret, and let me give you a hypothetical scenario:

You are a heavy thinker with a college degree of some kind. You may be doctor or a lawyer or a mathematician or a philosopher. You are probably NOT a biologist, but nonetheless you think you may have developed a compelling alternative hypothesis to one of the most strongly supported and widely accepted theories in biology.

Fine! Absolutely, perfectly all right! Although biologists (and paleontologists) may look at your claim with some skepticism given your specialization in another field, there is nothing inherently absurd about this. Non-specialists have made contributions to fields outside of their expertise before.

So here is what you do. You bring your hypothesis to biologists and paleontologists. You attend their conferences, discuss your hypothesis at depth with professionals in the field, using their comments and criticisms to refine and modify your hypothesis. You become intimately familiar with the details of the theory you are criticizing so that you know what you are talking about when you question the claims of the biologists who support it. You write papers for publication in peer-reviewed scientific journals, and pay close attention to any additional comments or criticisms you receive in the peer review process. You use these to further improve your hypothesis, and either succeed in refining and bolstering it to the point that you can proficiently fend off the criticisms (an impressive achievement), or acknowledge that your hypothesis has collapsed under the weight of evidence and reason and hopefully receive the justified respect of the biological community for your brutal self-honesty and willingness to discard your failed hypothesis rather than clinging to it like a protective parent.

And oh yeah, I almost forgot…if you can actually convince the biological community of the validity of your hypothesis and it becomes established and accepted as a viable theory among biologists, it will, of course, trickle down into the K-12 curriculum.

This is what you do, right? It is what a scientist would do.

Well no, that isn’t what you did. You dodged the biologists and took your idea straight to the K-12 students and a general public who are generally painfully ignorant of the theory you are criticizing. And since your hypothesis emotionally appeals to a large chunk of them, a lot of them have backed you up and accepted your claims to have vanquished the established theory, or at least seriously challenged it, even though all you did was run past it really fast with your head down and pretend not to notice when it beat you so badly when you went by that you pissed yourself. Then you cried that “academic freedom” is being violated because supporters of the theory demand that come back and fight like a man instead if just trying to hide out in the churches and schoolhouses and earnestly tell all the K-12 kids and their parents about how you actually beat it fair and square.

This is not an impressive achievement.

It is however, a mind-blowingly arrogant one, and never better illustrated than in Mike Egnor’s outrageously pretentious open letter to the Society of Integrative and Comparative Biology. Egnor takes the usual tactic of speaking as though evolution is on its way out, in spite of the fact that it is accepted by the vast majority of biologists and paleontologists. However, it is his contemptible demagoguery, which PZ Meyers has already addressed, that really makes the letter a testament to the arrogance of the Discovery Institute.

So let me just close with a couple appeals:

To Egnor and the other pack leaders: There is little point in asking you to be better informed about evolutionary theory, as you must know something about it to distort its claims as spectacularly as you do…so please just ruminate on the bizarre contradiction of using lies and character assassination against (mostly) good people to try to encourage morality. Would Jesus really approve of this bullshit?

And to those of you that have been pulled in by the hysterics about eugenics and appeals for “academic freedom”: Please face up to the fact that you have been suckered. Egnor is absolutely right that “students are not learning about all of the science surrounding evolution”, as folks like him have made damn sure of it by making certain that you grew up too ignorant of evolutionary theory to know when it is being misrepresented. Learn what biologists have to say about how evolution is actually supposed to work, so that you will know whether or not evolution’s critics are bullshitting you. And also please sit down and actually read the Bible, for exactly the same reason.

Cordially,

Jeff

What The Hell Is This Rock?

I'm writing this on the clock, but as it is a work-related inquiry from a tax-paying American citizen, I feel justified.

This object was sent to Bill last month from a gentleman in Michigan. The only information available is that it was "discovered in a garden in a farming community of Michigan's thumb area." I took a couple blurry photographs without scale bars to aid in identification.

From Paleo Errata

From Paleo Errata

The thing is about 25 cm across. It is definitely not a fossil; or at least if it was, it isn't anymore. It has got to be some kind of precipitate, but I'm not sure of what; whatever mineral it is formed from is white and light pink, and is not calcite or dolomite (it failed to acid test) and I also don't think it is silica, although I could be wrong. It has a vaguely honeycomb structure with voids of variable size and shape, with a layering in the "cell" walls which looks to be precipitated, but there are also masses of tiny crystals growing in botyroidal masses (I took a close up of these in the second photo) in the voids of the honeycomb, and masses of larger crystals in some of the bigger voids. I can't really tell anything about the crystal structure.

In summary, the thing seems to be some king of mineral precipitate which formed as a honeycomb with large voids filled by botyroidal masses of tiny crystals and some masses of larger crystals. If anyone can tell me what this thing might be, I would appreciate it.

On an unrelated note, Bill's mother passed away very suddenly and unexpectedly this week. Visit Chinleana and say something nice.

LNJ