K-Pg Extinction... Or Not?

[wings]

...None of this pandering and wandering around the topic meets the question..why are no dinosaur remains found within a nine foot (3 meter) gape of the iridium analomy that supposedly caused their extinction. The answer is simple, the dinosaurs were mostly long gone prior to the impact and the fossil record proves it quite well and thoroughly. In his 1997 book, " Digging Dinosaurs" Horner stated, that in something like 15 seasons of excavations in the what you are suggesting as the PRIME location for finding dinosaur remains close to the kill event, he never once uncovered a single BONE within nine feet of the analomy. That is pretty intense evidence isnt it? You dont get to have the analomy preserved and then whine the fossils somehow vanished...sorry...

Just a slight correction to this, remember the paper I listed from above? (the paper is called "Dinosaur extinction: closing the '3 m gap'" and its address is http://rsbl.royalsocietypublishing.org/content/early/2011/06/29/rsbl.2011.0470.full.pdf)

In the abstract:"...we report the discovery of...a ceratopsian brow horn found...located no more than 13 cm below the palynologically defined boundary....The in situ specimen demonstrates that a gap devoid of non-avian dinosaur fossils does not exist and is inconsistent with the hypothesis that non-avian dinosaurs were extinct prior to the K–T boundary impact event..."

I won't say too much about this since you probably can download the paper. I'm not saying they are declining or not but just to say that perhaps there is no 3 metres gap. This does not favor one way or another but just a fact that we know at this time.

[Himmapaan]

Just a note to say that this topic has been split off from the Hadrosaurs Found in Spain thread.

[amargasaurus cazaui]

...None of this pandering and wandering around the topic meets the question..why are no dinosaur remains found within a nine foot (3 meter) gape of the iridium analomy that supposedly caused their extinction. The answer is simple, the dinosaurs were mostly long gone prior to the impact and the fossil record proves it quite well and thoroughly. In his 1997 book, " Digging Dinosaurs" Horner stated, that in something like 15 seasons of excavations in the what you are suggesting as the PRIME location for finding dinosaur remains close to the kill event, he never once uncovered a single BONE within nine feet of the analomy. That is pretty intense evidence isnt it? You dont get to have the analomy preserved and then whine the fossils somehow vanished...sorry...

Just a slight correction to this, remember the paper I listed from above? (the paper is called "Dinosaur extinction: closing the '3 m gap'" and its address is http://rsbl.royalsocietypublishing.org/content/early/2011/06/29/rsbl.2011.0470.full.pdf)

In the abstract:"...we report the discovery of...a ceratopsian brow horn found...located no more than 13 cm below the palynologically defined boundary....The in situ specimen demonstrates that a gap devoid of non-avian dinosaur fossils does not exist and is inconsistent with the hypothesis that non-avian dinosaurs were extinct prior to the K–T boundary impact event..."

I won't say too much about this since you probably can download the paper. I'm not saying they are declining or not but just to say that perhaps there is no 3 metres gap. This does not favor one way or another but just a fact that we know at this time.

I did achknowledge the paper, Wings and also commented as to the one find that it mentions, as well as the material known from the San Juan valley. I appreciate your sharing that material with us, and found it a fascinating read.
My contention remains that if the meteor were responsible for mass kill, you would have the analomy and either intermixed with it, or directly above , the remains of millions of dinosaurs. In two hundred years of dinosaur findings and documentation around the entire world, we have a SINGLE triceratops horn found in association with the event.  We have the boundary layer, and iridium signature all preserved quite nicely, but virtually NOTHING in the fossil record to suggest the impact theory is remotely accurate. Evidence is what it is..there is nothing to prove the impact event was the PRIME canidate in dinosaur extinction, and the fossil evidence also proves this quite well. We instead find a layer or gap before the impact occurrs that shows the animals were gone long beforehand. I did make note of the single triceratops horn, and the claim it was not reworked. I do suggest if it were an original placement of an original fossil, we would have more of the animal, perhaps another horn or the actual dinosaur. That in itself suggests movement of the piece , despite the authors contentions. However, even if we accept the authors conclusions, and allow the specimen as unworked, you have a single piece in 200 years to suggest dinosaurs were anywhere near the K-pg terminal event.
  For an event supposedly responsible for the near instanteneous deaths of millions of lifeforms, that does seem just a bit odd, dont you think? Jack Horner did state in his book the lag line between the dinosaur remains and the impact signature was nine feet. While many of Horner's theories are a bit contentious, he has arguably spent more time and effort studying and mining the Hell creek setting for dinosaur remains than any other known authority on topic and i would hesitate to suggest he is lying.
  Someone said the evidence is there, and it is. It is quite present and quite indicative of what occurred. What it suggests is most dinosaur families were in decline and entire groups had simply vanished long before the impact event. The impact event was likely the coup de grace just as Greg Paul stated in one of his comments.

[wings]

My point was never about whether the animal is in a healthy population but about your point in saying "...why are no dinosaur remains found within a nine foot (3 meter) gape of the iridium analomy that supposedly caused their extinction...". At least "one" that we found is all I'm saying according to the paper. It is also fair to say that not finding the rest of the animal does not imply the specimen has been reworked from its original sediment setting, it could well be due to preservation processes (i.e. scavenger, erosion etc). Fossil finds are often incomplete, sometimes it could be a leg bone or just a toe bone so I just don't see how this would be much different if it is a brow horn or not. If you have a better reason for your hypothesis about this particular specimen being "reworked", I'm happy to listen to it since being incomplete is really not much of a reason (as in quite a lot of palaeontological finds).

[amargasaurus cazaui]

No Wings I was not stating the specimen itself suggests reworking, based on the locality or sediments itself. (although the authors of the paper did state one possible method the horn could be reworked, albeit dubious, themselves)

What I was attempting to put across was that if the specimen were MORE than just the horn, ie some articulated bones, or a more complete Post cranial assemblage, it would lend more credence to trying to close the gap, than a single horn found at that depth in an isolated find, apparently where it fell or was dropped by some passing dinosaur.  Given that it is indeed Triceratops and therefore one of the most COMMONLY found and well preserved dinosaurs, one might expect more from such a shallow and recent find.


A few of the points that make me ask questions about this find are... A)Given also it is a horn, it would be doubtful it was scavenged and carried away from the main animal carcass. An entire leg, or something more likely to be scavenged perhaps.....B) Erosion, from my understanding of the find as stated in the paper would be hard to explain given the analomy layer present directly above the fossil intact. That would be a rather selective form of erosion........  This places me in a position to wonder where the rest of the animal is or went to. .......is far easier to consider a single horn an analomy or isolated relic, over a complete animal or for that matter many of them, as Ceratopsian dinosaurs are often found. I am unsure if the possibility of being washed in was discussed in the paper, but that might be a more likely scenario for the questions I am asking, than perhaps reworking, and perhaps that is a better way to state my query and issue. Replace reworking with washed in then.....
   I did understand your point and the paper was quite useful Wings, and I did mention it throughout my comments. The nine foot figure I quoted came directly from Jack Horner's book, "Digging Dinosaurs" in which he did make the claim i stated.
    I just feel that if the case is being made the impact event destoyed dinosaurs as a dominant life form, there should be fossils. Millions of them....stacked , crammed and piled deep where they fell when they either were blasted with fire, frozen to death in a nuclear winter, or subsequently starved to death by the millions. We have a single horn......one. (1) That was my point, and again thanks for sharing the paper Sir.
  I believe from the onset of this discussion I have myself also stated I felt there were some dinosaurs present during the impact event. I am debating IF the meteor was the primary cause of their decline or there was a previous and more harmful event that lowered the dinosaur populace and made them a target for a rapid extinction .

[wings]

Depending on the age of the individual, skull bones might not be fused together firmly and the skull could easily fall apart. A good example are the sauropods, we have quite a number of their postcranials but we rarely find their skulls. Often the head was washed away by current, all we have is just the neck and the rest of the body. Then sometimes you find the head or part of the head (if the suture between bones aren't bind together completely) but not the rest of the animal. Could the brow horn be a "washed away" since it was found in a mudstone overbank deposit (which shows no disturbance at all which indicates no reworking as their reasoning), or could it be pull apart during the animal being eaten and dropped there? There are examples of partial skull find as well like Sinosaurus triassicus from China, all we have is part of its premaxilla (IVP AS V34). As for ceratopsians, yes we do have a lot of rather complete specimen but at the same time we also have a lot of bits and pieces of them. Unfortunately fossil finds are often by luck so I'm not sure whether I can say "...Given that it is indeed Triceratops and therefore one of the most COMMONLY found and well preserved dinosaurs, one might expect more from such a shallow and recent find...". Maybe there is but just we haven't found it yet.

[amargasaurus cazaui]

All well stated points Wings. I accept your logic as stated there. I would love to see it if they found the rest of the animal, that would be a clincher I think. I did wish to ask , as you find so many of these papers..have you found or see anything at all regarding the San Juan valley findings in Mexico. This is the site where they are claiming these dinosaurs existed ABOVE the K-pg event, in the news releases . I have not seen a serious paper or anything more substantive than this, and wondered if anything formal had been brought forward.

[Simon]

You are falling into a common seemingly logical fallacy ie:  if they all died together, where are the mass graves?  That's not how it works.

ALL animals alive today will be dead within 100 years, their lives overlapping with replacements.  the fossil finds therefore reach across tens of thousands of years or more.  Very few fossils are actually preserved.  If all the animals dies on the same day, the fossil record would simply END.  There would be no graveyard of bones because in the normal process of life very, very few animals are preserved (except in ocean sediment, hence the mass fish grave from the K-P boundary in Antarctica).

The terrestrial fossils of the cataclysm were burned at hundreds, even thousands, of degrees Fahrenheit, buried under tsunami debris, dissolved by acid rain.

Once again, you need to take a global step back and actually look at the mechanics of this asteroid apocalypse.  There are no fossil beds of the terrestrial animals at K-T because the cataclysmic conditions (see above) prevented the normal fossilization processes from being given a chance.

Again, the 'dead layer' is testimony to the apocalyptic consequences of the asteroid impact and have nothing whatever to do with any dinosaur winnowing out.  At the time of their annihilation, the dinosaurs were just as vibrant, successful, and dominant as at any time in the previous 200 MY.

[wings]

...have you found or see anything at all regarding the San Juan valley findings in Mexico. This is the site where they are claiming these dinosaurs existed ABOVE the K-pg event, in the news releases . I have not seen a serious paper or anything more substantive than this, and wondered if anything formal had been brought forward.

@amargasaurus cazaui, here is the paper (http://nmgs.nmt.edu/publications/guidebooks/downloads/56/56_p0395_p0407.pdf), it's published in 2005. I haven't read through it yet but I think it's recent enough for the purpose of this discussion.

[amargasaurus cazaui]

umm no, sorry. And no again. Remember your fossil beds of herds of Hadrosaurs and herds of Centrosaurs all killed in mass disasters and ALL preserved together? Sorry they do not vanish because they die together and the evidence again conflicts that explanation entirely. Otherwise we would not have the mass herds of duckbills and other animals we find all dead together.And no again, they were not buried under ocean sediments.
   All animals alive today will be dead in a 100 years yes, but they will die in various stages and ages, at differing localities . And yes, they will leave skeletons that will be buried and when exumed will show during this time on earth it was heavily populated and anaimls were dying constantly due to HIGH population. Just as the fossil record indicates for dinosaurs up until the last nine feet prior to the impact event. PRECISELY as the fossil layer indicates. The issue then becomes the gap or area between impact and the known dinosaur remains. There is a tremendous sparsity of such.
  Your ocean sediment argument was a nice way to explain the fossil fish bed, so what happens when those ocean sediments become part of your imagined tsunami and bury an entire population? Shouldnt they then be just as well preserved as your fish from the same sediments?
  Regarding these mass firestorms and major tsunamis......I am somewhat unsure how you are able to get them over every square inch so they remove all traces even far inland of these habitated areas.
  Here are a few more rather telling quotes from wiki..that I rounded up.

The impact may also have produced acid rain, depending on what type of rock the asteroid struck. However, recent research suggests this effect was relatively minor. Chemical buffers would have limited the changes, and the survival of animals vulnerable to acid rain effects (such as frogs) indicates that this was not a major contributor to extinction. Impact theories can only explain very rapid extinctions, since the dust clouds and possible sulphuric aerosols would wash out of the atmosphere in a fairly short time—possibly under ten years.
That does not at all sound like the bone dissolving, carcass removing agent you have summoned up for your kill event does it? As I stated quite far up thread, the very species that SHOULD have died in your impact scenario lived and debunk these claims.
   Google goes on to state this.........
Before 2000, arguments that the Deccan Traps flood basalts caused the extinction were usually linked to the view that the extinction was gradual, as the flood basalt events were thought to have started around 68 Ma and lasted for over 2 million years. However, there is evidence that two-thirds of the Deccan Traps were created within 1 million years about 65.5 Ma, so these eruptions would have caused a fairly rapid extinction, possibly a period of thousands of years, but still a longer period than what would be expected from a single impact event.[13][14
See the difference? They are demonstrating WHY the extinction was spread out over a much longer time, which does match the fossil record. We have already dismissed the imaginary acid rain so you cannot summon it to blame for the lack of fossils.
And google goes on to quote Walter Alvarez, whose father WROTE the impact scenario to begin with in stating.......
However, even Walter Alvarez has acknowledged that there were other major changes on Earth even before the impact, such as a drop in sea level and massive volcanic eruptions that produced the Indian Deccan Traps, and these may have contributed to the extinctions.[15]
  So they are saying the author of the entire impact scenario, has a son, also a well established scientist, who helped author the study, and he agrees with my stated chain of events as quite possible...............
Someone said change is a lazy excuse but here is another issue we have not yet dealt with, known from the actual and not surmised or guessed at fossil record. By that I mean this is something they know took place and can confirm from actual fossils, not guesswork.
Maastrichtian marine regression  Clear evidence exists that sea levels fell in the final stage of the Cretaceous by more than at any other time in the Mesozoic era. In some Maastrichtian stage rock layers from various parts of the world, the later ones are terrestrial; earlier ones represent shorelines and the earliest represent seabeds. These layers do not show the tilting and distortion associated with mountain building; therefore, the likeliest explanation is a regression, that is, a buildout of sediment, but not necessarily a drop in sea level. No direct evidence exists for the cause of the regression, but the explanation which is currently accepted as the most likely is that the mid-ocean ridges became less active and therefore sank under their own weight as sediment from uplifted orogenic belts filled in structural basins.[21][22]

A severe regression would have greatly reduced the continental shelf area, which is the most species-rich part of the sea, and therefore could have been enough to cause a marine mass extinction. However, research concludes that this change would have been insufficient to cause the observed level of ammonite extinction. The regression would also have caused climate changes, partly by disrupting winds and ocean currents and partly by reducing the Earth's albedo and therefore increasing global temperatures.
Marine regression also resulted in the reduction in area of epeiric seas, such as the Western Interior Seaway of North America. The reduction of these seas greatly altered habitats, removing coastal plains that ten million years before had been host to diverse communities such as are found in rocks of the Dinosaur Park Formation. Another consequence was an expansion of freshwater environments[23]
As you can see for yourself, the Deccan traps had already erupted, and with it the atmospherics that came with that. The damage to the environment had to be horrendous. Then throw in the cooling off trend we already know about, the marine regression I identified here and quite suddenly it does become quite obvious that yes, sure enough the dinosaur ecosytem was in a state of extreme distress and had been damaged badly. Proveable, fossil records show it
Change is not a lazy answer, it is a very proveable one. Then along comes a meteor to finish the dirty work...just as the fossil record indicates . Start to finish...no need to conjure up imaginary acid rainistorms and nuclear winters.
It is all there in simple print. Google the words yourself.  Even Walter Alvarez is stating the ideas I am throwing out there are quite possible

[amargasaurus cazaui]

...have you found or see anything at all regarding the San Juan valley findings in Mexico. This is the site where they are claiming these dinosaurs existed ABOVE the K-pg event, in the news releases . I have not seen a serious paper or anything more substantive than this, and wondered if anything formal had been brought forward.

@amargasaurus cazaui, here is the paper (http://nmgs.nmt.edu/publications/guidebooks/downloads/56/56_p0395_p0407.pdf), it's published in 2005. I haven't read through it yet but I think it's recent enough for the purpose of this discussion.

I took the time to read through that paper last night, it is an exceptional study of the stratiography and formations, as well as fossils found in the San Juan basin and the determinations they stated, I believe are quite well done and well supported. The short hand for their paper is they thoroughly and completely debunked the occurrence of any fossils associated with dinosaurs in the area being of a post impact date. The few fossils that were debate worthy could easily be stated as reworked based on parsimony and size. I will post for you the two main things I found of interest within the paper as they bring some bearing to our discussion...in the first they are discussing a  well preserved and complete hadrosaur femur found above a layer of fossils from the early Paleocene age. I found this portion of particular interest  following our discussion of the trike horn, especially as there is a single well preserved element involved.

Along the San Juan River near Farmington, at a location
dubbed the San Juan River site (Fig. 1), an essentially complete,
and well-preserved, hadrosaur femur was recovered from the
Kimbeto Member of the Ojo Alamo Formation (Fassett et al.,
1987). The occurrence of Paleocene palynomorphs stratigraphically
below this femur has continued to be a problem in interpreting
the age of the rocks and has added fuel to the notion that
some dinosaurs survived the K/T extinction event (Fassett et al.,
1987, 2000, 2002; Fassett and Lucas, 2000). However, despite
the bone's near-pristine appearance, we argue here, largely based
on parsimony, that the bone has been reworked, and not transported
any significant distance, thereby preserving the integrity
of the bone's outer surface. We note countless examples where
reworked specimens, such as upper Paleozoic brachiopods, found
among the pebbles of the Ojo Alamo Formation, preserve the
shell in great detail. We note, too, that no other dinosaur bones
have been discovered in this part of the section.
Fassett et al. (2002) further claimed that Paleocene pollen is
present in the uppermost bed of the De-na-zin Member, and thus
stratigraphically below the entire dinosaur fauna of the Naashoibito
Member of the Ojo Alamo Formation (Fig. 4). We present
data below that call into question this report of Paleocene palynomorphs
stratigraphically below dinosaur fossils (also see Sullivan
et al., 2002, 2003).

This is the one specimen in the entire debate I found worthy of sticking my hands in the fire for, as it is somewhat problematic and does pose questions.
The final conclusions they stated are quite telling however.


5. Vertebrate biostratigraphy, based on the occurrence of Alamosaurus
sanjuanensis as a datum (in the Javelina Formation),
suggests that the Naashoibito Member is of early Maastrichtian
age (Sullivan et al., 2005). Because the unit is relative thin, it
probably represents no more that 1 million years of deposition
(69-68 Ma).
6. Palynostratigraphy does not support assignment of a Paleocene
age to any dinosaur fossils in the San Juan Basin.

So they basically concluded due to multiple and massive errors over the past hundred years in paleo work, the two uncomformities in the basin have allowed Cretaceous era fossils to overide much later strata levels. They made a very solid case, and one I myself have to accept completely .I do not think the age of the study is relevent as they are fixing errors and mistakes as far back as Sternberg, Granger, and Brown, dating to as far back as 1906. The central point I think was made that the individual fossils that were in contention were not reworked, the entire layer they are encased in was forced upwards over a newer layer at some point, creating uncomformities. This for me explains why massive bones like those of sauropods are being found above younger fossils from the paleocene era. as well as associated elements of various tyrannosaurids and other Cretaceous dinosaur fauna.

[Simon]

You are regurgitating your earlier posts for the third and fourth time in the case of some of your points.  Reposting pages of the same arguments does not make your arguments any more persuasive. Neither does reposting them in highlights. I find your analytical ability shall we say somewhat lacking.

I will leave future replies to some of the capable members who have already chimed in earlier.

I WILL address one recurring patent absurdity in your last post. 

Re-read my post earlier upthread as to why the dinosaurs died out after the asteroid strike (can we agree that a rock the size of Manhattan is an asteroid and not a meteor???) and cold-blooded creatures did not. 

I will repeat my conclusion without reposting the reasons why as you can find them upthread easily enough:

Given the K-T impact and its known aftermath, the animals that died out were the ones expected to die out, and the ones that survived are the ones expected to survive.

You flippantly turn that on its head while offering no evidence nor even any semi-logical argument to address the reasons I specified as to why it IS so. 

Therefore I have nothing more to add.

Good night.

[amargasaurus cazaui]

Generally once someone reverts to insults, i think the value in a debate is lost or at least misplaced. There is a saying, wise men raise their arguments, and weak ones their voices. In that spirit I will address your comments Simon, despite your apparent attempts at insults.
   The reason I am repeating some of the information I am giving is I am addressing more than one posting member at a time. This means at times information does have to be repeated .My advice would be do not read anything you find repititious so as to save your eyes for future endeavors, perhaps in research.
     The use of highlights is to provide emphasis for quoted material , and making sure that it is credited to its proper source. This is considered proper forum etiquette, and does have its purpose despite your complaints. In all cases the quoted material that is highlighted was new and previously unposted material by myself at least. I suggest if this part is an issue for you, perhaps reduce the text size in your browser or moderate the areas of my postings you feel drawn to review.

I will next address your question that you have posed. And yes it will be in highlights so please be forewarned. I will extend you this courtesy despite your apparent misunderstanding of its purpose.

Re-read my post earlier upthread as to why the dinosaurs died out after the asteroid strike (can we agree that a rock the size of Manhattan is an asteroid and not a meteor???) and cold-blooded creatures did not.

The answer is no, we will not use incorrect and inaccurate terms to tailor this conversation to your incorrect terminology .  The proper term for the impacting agent would be bolide, as I began using at the outset of this conversation. However seeing your inability to understand current terminology and their use...ie the K-T/ K-P event, I altered the term I was using.
  Here is the actual set of definitions for your benefit, and yes they also will appear in bold, so you are forewarned.

Asteroids (from Greek ἀστεροειδής - asteroeidēs, "star-like",[1] from ἀστήρ "star" and εἶδος "like, in form") are a class of small Solar System bodies in orbit around the Sun.

So if you are stating you do not believe the impact occurred and the item is still orbiting the sun, we can use your definition..of course stating the impact never occurred...well that would be just Heretical wouldnt it?

Now if you can please follow along to the proper term...again in bold.

A meteorite is a natural object originating in outer space that survives impact with the Earth's surface. A meteorite's size can range from small to extremely large. Most meteorites derive from small astronomical objects called meteoroids, but they are also sometimes produced by impacts of asteroids. When a meteoroid enters the atmosphere, frictional, pressure, and chemical interactions with the atmospheric gasses cause the body to heat up and emit light, thus forming a fireball, also known as a meteor or shooting/falling star. The term bolide refers to either an extraterrestrial body that collides with the Earth, or to an exceptionally bright, fireball-like meteor regardless of whether it ultimately impacts the surface.

As you can see from the definitions, your impacting agent would be considered a meteor properly until it impacted, at which point it became a bolide. These are the two terms I have tried to work with. The term asteroid , as stated in your request is technically the least possible accurate description of the item that could be assigned. Therefore my answer has to be no, will not agree to further undermine the discussion with terms we understand to be incorrect. I hope the in depth explanation makes it simpler to understand for you.
To summarize....asteroid belongs with K-T, in the we do not use box.
  As for animals expected to die and what not, I quite clearly refuted that line of discussion regarding your phantom killing acid rain that failed to affect frogs. If you noticed it was in BOLD as I was quoting reference sources, and I solidly rebuffed that argument in its content and intent.There was of course nothing flippant about my response, I posted in sold bold ink the rebuttal to your acid rain and surviving aninals theory .
  I am glad we do agree to at least your last comment, nothing further to add, as apparently you did NOT. Nothing except insult and attempts to discredit based on posting style of all things?errm yes, good night and do rest well, please.

[Simon]

Amargasaurus, acid rain is not going to affect a creature buried underneath many feet of mud like an amphibian. 

It would kill animals floating around in water, but those animals were probably largely killed off by the 800+ degree temperatures first anyway.  The reason amphibians and Croc survived had to do with their ability to remain buried in deep mud for months, sometimes even years and still survive.  Of course the vast majority was wiped out in the K-T 'event' and its aftermath.

The point is that they had a survival strategy that larger warm blooded animals like dinosaurs did not.

This is the kind of logical connection that you have sometimes failed to make, or to understand (in my posts). 

I am sorry if the tone of my last post offended you, but I will note that some other members around here have grown equally weary after arguing with you on some topic or other, so I believe I am not alone in reaching that stage.   

You do get points for persistence, however.  I'm out.

[amargasaurus cazaui]

I did post for you the scientific rebuttal to the entire acid rain scenario. You are welcome to google and reasearch the topic for yourself, as you have an aversion to my repeating my information. Summary, scientific research has concluded the marker species for extermination in an acid rain scenario all survived, which suggests the acid rain was minimal or non existent due to buffering agents within the atmosphere, both above ground and stratigraphically.
  This then becomes the summoning of yet another extra terrestrial, non proven agent, which cannot be established nor reliably proven, to explain away the apparent  smart bomb level extinction of certain species and their remains.
  The constant need to insert that dinosaurs were warm blooded is another rather obvious issue here. The issue of blood temperature is vastly more complicated than just warm or cold blooded, and scientific study daily expands our understanding that there could be many different methods for temperature regulation in the dinosaurs. To date there exists little SOLID proof wether dinosaurs were warm blooded, cold blooded or employed some more antiquated method regulating body heat. There are behavioral aspects, as well as physical features that imply they had to be something more dynamic than basic reptiles in everyday life yes, but the smoking gun proof for warm blooded..similar to mammals, and cold blooded similar to the frog, at this point is non existent. There are many factors and much information on both sides of the discussion, but nothing definitive for proof is established yet. So what then becomes dogma is how you can state a turtle or frog could burrow and hibernate but another species of reptile that is at this point unknown, as to physical characteristics, could NOT. This is another case of assuming a characteristic existed, and using it for evidence, with nothing for proof to establish the base premise. Finally, if dinosaurs were most closely related to birds, and your contention is birds were able to burrow, and thus survive your impact.........do you yourself see the contradiction in terms you are implying?
      I do not believe that either reading my posts, nor commenting on them is required as a basis for attendance to the forum. I was led to understand there is actually a feature that allows one to ignore threads they find weary, or drull. I tested the feature with my own version of the forum and found it works perfectly. Generally this is what I employ if something offends, disturbs or annoys me.
  Even assuming that were not the case, this is a discussion forum based on theories and currently prevailing views. It is where you can state and offer your ideas, theories and beliefs, be they poorly formed or almost Einstein level in their proportions. The desired effect would be the absoprtion for all of more understanding and enlightment of any given topic. I do sometimes play the devils advocate, and avoid the "safe" and simple path purposely to provoke discussion and present a viewpoint that I myself may not fully accept so I can determine if it is in the least defensible. This has the effect of bringing more information to the table and improving everyone's understanding. I do not mind losing a debate, nor being wrong in the least. Because the information presented will insure that the next time I post, I will be more enlightened. The one thing I do try to work with, is the discussion is not about people, it is about ideas and science, where being insulting, rude, and attempting to undermine another is ill placed.
  Persistence.......I see no point in defending a view if you do not make a serious effort to bring to the table all of the things that viewpoint holds. Thanks.
  I almost forgot to mention, I find great admiration for this person Wings, as in each discussion and debate he pops up, and offers actual papers to read which are well researched and provide solid information to help form ideas. I appreciate all the papers Wings, and thanks for always bringing them for us to review.

[Simon]

Acid rain may or may not have happened and frankly it makes little difference because the boiling of the atmosphere to hundreds, even thousands of degrees, the resulting fires, followed by a global winter are by themselves more than sufficient to account for what happened.  I don't know who brought up acid rain, but if I mentioned first it it was only in passing because I had seen a reference to it somewhere.  In my view it would have been the smallest factor and not a necessary one in the least for the mass-extinction.

Yes, I realize that while theropod dinosaurs almost certainly were warm-blooded, the case for sauropods and other sepcies is much less clear and some midway system may have existed.  This in no way defeats my point because it was the size of the animals that died off that was apparently the biggest factor in who lived and died.

Re: birds - small, feathered.  dinosaurs - much larger, most probably not feathered.  Hence birds could hide and huddle together for warmth in their holes, while dinosaurs obviously did not. Many birds are also known to store food for the colder months and may have therefore had an additional supply to help them survive the long cold night.

http://en.wikipedia.org/wiki/Hoarding_%28animal_behavior%29

[amargasaurus cazaui]

Alright progress, so we admit the acid rain thing isnt working, and is not supportable..as you stated it does not matter. It does not leave you with an acid soloution to dissolve all those skeletons however.
     SO moving along to this immense firestorm, nuclear winter, that you state happened. Where is your evidence? You had stated the iridium layer is generally accompanied by a layer of ash, however most writings on the topic I have read suggest the layer is non-present and would have been indeed eliminated by global rain and washout., it it ever had been present.Generally above and below the iridium signature you have...........clay, and smooth sandstone. Clay is deposited in what fashion? Clay is created by the mixture of matrix and water...in this case apparently falling down in massive quantities as you would expect from a near shore/shore strike. Adding the ejecta from the crater into the atmosphere and mixing with steam and water from the impact and get mud rain....this is what the evidence shows, and what fits the impacting sites at both Shiva, where the iridum signature clay is a foot thick ,(thicker than anywhere else in the world ) and even deep into Mexico where there are exposed layers showing the iridium layer buried underneath a layer of...no not ash..MUD and clay.I have a picture of one of Alvarez's assistants walking along a stratiagraphical layer in Mexico. The view allows you to see the Iridium and clay layer...no ash, however a depth of two feet of mixed sandstone and clay. If there was a global storm, it was a storm of water and mud. Do you somewhat comprehend the concept of how long and how much rain and mud would have to drop to form a layer a foot thick over most of India, let alone the entire world?  If there is water and mud falling from the sky, how could the world be enveloped in a firestorm? The clay would land baked...not as particles to form bedded layers. Summary, no evidence for firestorm, much proof for mud and water dropping for a prolonged period from atmosphere.
  The nuclear winter scenario...evidence? Anything? No? Another specter summoned from the ranks of..the thing fell therefore it had to happen right? Altogether the entire BOLIDE impacting, destroying the ranks of the dinosaurs and thus ending their reign does sound like an act of god as you stated....quite similar indeed, one that had to happen but offers no proof.
   If size were the single detemining factor for the extinction we would have kept all dinosaurs below two feet correct? Many mammals and oceangoing species larger than that survived correct? If you use the criteria of size, you lose sharks, fish over a given size, and some species like crocs, alligators, and even larger birds. This extinction left the larger fauna in place that were not dinosaurian....almost entirely. There had to be a bit more at work here than just size...something that worked on principles that the extinct species required over others. ....perhaps the loss of oxygen in a marine regression as stated upthread?
   So we are stating now that the feathered dinosaurs were only smaller species and nothing larger had feathers? I am certain a few people like pixelboy here in the forum would love to read that. The concept of feathering has been used to explain many dinosaur lines and their ability to cope with heat loss . In addition the fossil record clearly shows some forms of fully grown larger dinosaurs with feathers, I can think of a tyrannosaurid for instance, just offhand. What of Gingantaraptor? Citipati? These were all feathered dinosaurs of rather decent size yes?Yutyrannus? Wait...read this last very carefully.
Hence birds could hide and huddle together for warmth in their holes, while dinosaurs obviously did not. Many birds are also known to store food for the colder months and may have therefore had an additional supply to help them survive the long cold night.
Just where is your evidence for any of those statements? How do YOU know? Dinosaurs might very well have done precisely that....the evidence shows them being caregivers to their young for instance in many cases. They are known to move in herds.  Evidence suggests some were pack hunters, or family units.  How do you KNOW dinosaurs did not store food? Dinosaurs are most like birds, and your posted reference shows birds hoarding food right?  Is it possible this, like migration, nest building and many other natural abilities would be ancestoral and passed down? again, speculation does not reinforce a point, it weakens it. Proof please...for any of those statements?

[wings]

...have you found or see anything at all regarding the San Juan valley findings in Mexico. This is the site where they are claiming these dinosaurs existed ABOVE the K-pg event, in the news releases . I have not seen a serious paper or anything more substantive than this, and wondered if anything formal had been brought forward.

@amargasaurus cazaui, here is the paper (http://nmgs.nmt.edu/publications/guidebooks/downloads/56/56_p0395_p0407.pdf), it's published in 2005. I haven't read through it yet but I think it's recent enough for the purpose of this discussion.

...I found of interest within the paper as they bring some bearing to our discussion...in the first they are discussing a  well preserved and complete hadrosaur femur found above a layer of fossils from the early Paleocene age. I found this portion of particular interest  following our discussion of the trike horn, especially as there is a single well preserved element involved...The central point I think was made that the individual fossils that were in contention were not reworked, the entire layer they are encased in was forced upwards over a newer layer at some point, creating uncomformities...

I suppose since the quote is referring to the link the I sent earlier then I will respond to it. Or if that is not intended for me to attend to then you can stop right here and not read the rest.

So, are you implying that the brow horn was based on an uplift? Personally I don't see the relevant of comparing the "San Juan" paper to the "3 metres gap" paper. Firstly, two different locations has been tested in both papers. Secondly, it is clear that the authors from the "3 m gap" paper don't think that the brow horn was placed there via an uplift (because this would very much defeat the purpose of their paper). Royal Society Publishing Biology Letters is a well known online journal, I would assume most if not all the articles have been peer reviewed. So if an in situ fossil in this case the brow horn is not a possibility then I would think that the referees would point it out and they wouldn't publish it (I haven't seen a rebuttal on this yet and if you really would like to get to the bottom of this and see how did they make such evaluation then I suggest you can write to the authors, I'm sure at least one of them would reply to your query). So for the time being I'll just have to take it as it is.

In closing, all I'll say is that I'm not well read on the topic (regardless of how interesting it might sounded...unfortunately I just have no interest on extinction theory at all). I don't have any intention to really join in the discussion, at the beginning I just happened to come across that "3 metres gap" paper so I just post it into this thread.

[amargasaurus cazaui]

No Wings you completely misunderstood what I was stating. I understand they are entirely different locations, finds and causes for such. I was not implying the one find had a thing in common with the other or that brow horn was "uplifted". What I was stating was ...as with the brow horn, we have another fossil that is a single element...if you remember me discussing that part with you. In this case, instead of a brow horn it is a single femur that shows no evidence of being moved or reworked. I found that somewhat an underlining of your paper, as it IS a single element, which i had found odd earlier if you remember. Just as with the brow horn, we have a nicely preserved single element from a late Cretaceous dinosaur, however the piece in the San Juan study showed indicators of being paleocene in age, due to the uplifed level of strata it is located within. I was not comparing nor trying to make a cause factor between the two beyond the obvious single element connection itself. Well that and the fact they were neither one reworked, the first being a mud bank deposit and the second being in an entire layer of uplifted strata.  .....I found both papers informative and helpful and was not trying to question either finding .

[Gryphoceratops]

I haven't really read most of this thread but rather skimmed the last few posts. 

"I do sometimes play the devils advocate, and avoid the "safe" and simple path purposely to provoke discussion and present a viewpoint that I myself may not fully accept so I can determine if it is in the least defensible. This has the effect of bringing more information to the table and improving everyone's understanding."

So before or during your playing the devil's advocate, do announce that you yourself don't fully accept the idea or do you just let them think that is indeed your understanding and belief of the matter to see their reactions?