Say ahh Mr Dinosaur

[AstralTraveller]

I was pretty stunned to see this news item on the ABC site. The word 'palaoethermometer' jumped out as something I didn't expect on the ABC news page!

http://www.abc.net.au/news/stories/2010/05/25/2908426.htm

Here at UoW we are setting up equipment to use the same technique but we are a good year away from producing data (and so at least 2-3 years from having a paper). John Eiler who is mentioned in the article is one of the developers of the technique and he has been working on it for at least 5 years. They have hit upon a pretty good project - whether dinosaurs were warm or cold blooded is one of the ongoing controversies in science. We have our own pretty good project too but at the moment it's under wraps.

[renormalised]

It will be interesting to see the results of this study...no doubt it will throw up some new questions and (possibly) answer some old ones. It wouldn't surprise me if the results from the study were either inconclusive or in conflict with other data found using different techniques.

Mind you, if we had the technology to go back an literally take the temps of dinosaurs by shoving a thermometer up the clacker, I certainly wouldn't be the one stupid enough to volunteer for the job!!!:):P

"Mr T-rex, do you mind standing still for me whilst I shove my forearm up your you know where, so I can take your temperature??"...two seconds later you'd be the midday snack:eyepop::lol::P:D

[Ric]

A fascinating study, I'll be looking forward to seeing the results as well.

Hey Carl, where's your sense of adventure? Just give him a scratch behind the ears and say "who's a good boy" :D

It works with our cat at the vet's. :lol:

[renormalised]

Ric, I have a sense of adventure, not a death wish!!!!:):P

Besides, dinosaurs don't have external ears:)

[AstralTraveller]

Carl, there are no other techniques for determining a dinosaurs' body temperature. In fact there is no other method to determine the temperature of formation of any carbonate (mineral or biogenic) without knowing some other data, which we generally don't. The temperature record derived from deep-sea cores assumes that the temperature of the deep ocean hasn't changed and isotopic composition of ocean water is also constant. This is valid for a few million years but no further. In other environments the assumption isn't even valid for a few years. For instance we cannot determine the temperature of formation of even Holocene soil carbonates because we do not know the isotopic composition of the soil water from which they precipitate. Even if we try to guess the isotopic composition of rainwater, it is then subject to an unknown amount of evaporative enrichment (water containing only the light isotopes evaporates faster than that containing heavy isotopes). This is why my boss calls it the fourth revolution in stable-isotope mass spectrometry, and why he jumped straight in!

[renormalised]

I know about C12/14 and O16/18 isotopic analysis...I do have degrees in geology you know:)

I wasn't specifically talking about the dinosaurs literal body temperature, but more about the determination as to whether they were warm or cold blooded. You can determine if an animal was either warm or cold blooded by doing a thin section of their bones...especially large ones like the femur and looking at the structure and density of the blood vessels present in them. This is also possible for fossilised creatures, such as dinosaurs, where the internal structures of the bone are preserved. Actually, it has been done on a number of species of dinosaur, though the more prominent ones have been done on T-rex. Their bones show similar internal vascular structure as a turkey's, and where they've been lucky enough to find preserved blood cells, their shapes indicate the animal was warm blooded.

The big problem with this new type of isotope determination is you're going to have to take into account how these isotopic ratios have been modified over time by diagenetic and other geological process. Even though the isotopic ratios do get fixed in the bone/shell structures of the animals when they die, those bones/shells are affected by later processes and the ratios of the isotopes that maybe present in the newly found fossils aren't necessarily the same as when the animal died, or even when it was alive. So, just how accurate are these temperature determinations going to be in the first place. What you would have to find is either wholly unaffected bone, which by chance they have found on a few rare occasions, or bone that's been preserved in a manner that's also preserved the original isotopic balance within the bones. Very unlikely, but as I have mentioned, not unheard of.

[AstralTraveller]

Carl, I believe there are quite a few geologists who have never encountered stable-isotope techniques, though everyone knows about radioactive isotopes. (Very often when I tell people that i work on isotopes they think I am doing dating. Not at all.)

I think I may have heard of the blood vessel work but I had quite forgotten it. Obviously very good work and highly indicative but it doesn't produce a number.

Of course diagenetic alteration of material has to be considered and most material will not be suitable exactly for that reason. I've worked on recent (ie late Pleistocene) bone and, quite apart from any checks done outside my lab, we always measure the C:N ratio to check for diagenesis. Even the person working on corals only 5ka old checks for alteration of the aragonite to calcite. She used to just use XRD but has found thin sections to be more sensitive, even though it is more work and the section maker really 'loves' such soft porous material ("Hey Jose, at least it isn't a soil").

BTW did you hear about the Ichthyosaur found in a school vegie patch at Richmond Qld??

http://www.abc.net.au/news/stories/2010/05/26/2909511.htm

[Jen]

:lol::lol::lol: lol Ric :thumbsup:

[renormalised]

Very interesting article:) Plenty of fossils out around Richmond...especially fossils from the Jurassic and Cretaceous periods. Closer to home, you start to get into late Tertiary and Quaternary sediments...things like Diprotodon and such appear in fossil beds not far from here...about 80-100 miles or so from town.

Many geologists don't do very much physical geography....which I have, but I have encountered stable isotope analysis in geology before.