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Dinosaur Mummy Found
sckienle writes "Although the dig was a year ago, MSNBC has an article about a very rare dinosaur find. It starts off with "A mummified dinosaur, unwrapped from the rocks of Montana, has revealed how the creature looked and how it lived 77 million years ago -- down to the texture of its skin and the contents of its stomach, scientists say." Unfortunately, the details are mostly missing in the article. This isn't the first mummified dinosaur found but it is the first in a long time."
"Also because of the way the dinosaur was mummified, it showed the contents of the stomach, which included conifer needles, seeds and twigs and proved that hadrosaurs led a terrestrial lifestyle rather than aquatic."
RTFA, don't you see the link. It's only a page, instead of firing off a comment as soon as you can.
You have it backwards. Radio carbon dating is good for maybe 40,000 or 50,000 years, nothing older than that. The closer we are to when it died, by a long shot the more accurate the dating is.
This would've been done by dating the strata they were found in. Dating rock strata is a very accurate method of determining age.
There's a lot of assumptions involved in radiometric dating (of which carbon dating is a type).
First, you pick an isotope of an element which has a nice long half-life. Then, you guess at how much of that isotope was in the environment (and therefore the object you are dating as well) at the time period you assume the object was made.
The other assumptions are that there is a constant decay rate of the isotope and that the object being dated becomes a closed system, not seeping or leeching any of that isotope from its surroundings.
So what you really have with dates like the 77 million years is a best guess from a bunch of scientists who want it to be around 100 million and then crunch the numbers to get a more precise answer.
Let the rebuttals begin... =)
~Chaltek
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(now how many geeks will read these dating articles thinking it might help this weekend with the GF problem?:-)...
No not carbon, the half-life is too short.
Here are two articles on how dinosaur finds ages are determined, the first in general, the second on radiometric dating specifically.
Dating Fossils
Radiometric Dating
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There were some tracks discovered in the Paluxy River bed that had man tracks and dinosaur tracks side by side, but of course you will not hear about this from the secular science establishment, which would just as soon cover it up.
Probably because it was determined long ago that they were not man tracks.
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What they eat says volumes about how a dinosaur is built. A dinosaur that can stoop to get ferns and reach the leaves of conifers obviously has a certain length of neck and articulation of the spine. One that eats plants may not be as muscled or quick as one that eats other dinosaurs or carrion, mostly because it doesn't need to be.
Just from stomach contents we can tell what it was fast enough to catch, what it was tall enough to reach, what it could bend down to reach, and how much energy it had to work with. The condition of the contents tells us if it had blunted teeth or sharp ones. We have some clues from a skeleton, but we have a lot more information with some extra context: "Oh. That's why that neck was built like that."
Contrary to FUD coming from young-Earth wackos, carbon dating has absolutely nothing to do with determining ages of dinosaur fossils. Carbon dating cannot be used to measure ages older than 10,000 years or so. It is totally inadequate for determining geological timescales. That's why other radiometric methods are used, such as potassium-argon dating or uranium-lead dating.
Scientists probably don't mention how they know the age of every fossil they find because it would get old really quickly. Hell, they'd probably be happy to explain it over and over again; but do you think the reporter's going to put it in the article every time? Not likely.
I'll tell you the basics; to learn more grab any Geology 101 textbook. The Earth's continental crust is stratified: it has many layers like an onion. Unlike an onion, the layers aren't uniform, but basically, there are easily discernible stratigraphic layers in the earth's crust, which you can see in cliff faces, canyons, or where rock has been cut away for a highway. The layers are caused by deposits made over the eons, so deeper layers are from epochs further in the past. Samples can be taken from different layers, and a variety of techniques can be used to calibrate how long ago that layer was deposited at the surface of the Earth (including potassium-argon dating and uranium dating, paleomagnetism, etc.).
Now, because of erosion and tectonic movement, the rocks that are currently exposed at some locations can be from very old layers, that are probably deep underground in most other places. For example, the surface rock in the US state of Montana is largely composed of layers of sedimentary rock that were deposited during the Age of Dinosaurs. That's why lots of dinosaur fossils are found there.
So, a paleontologist finds a fossil in rocks from layer X. He looks up the radiometric age for that layer (or a nearby layer), and associates its age with the fossil. He can also look for smaller fossils in the same rock layer as secondary age indicators (i.e., plant A lived between 100 Mya to 50 Mya, insect B lived between 70 Mya and 20 Mya; if both are found in the same layer as the dinosaur fossil, it probably lived between 70 and 50 Mya).
Or you could type your question into google, and follow the first link that it gives you.
Liberal (adj.): Free from bigotry; open to progress; tolerant of others.
Except that many different methods yield the same result for a single time event within their stated uncertainties.
Here is a comparison of different radiometric and non-radiometric methods used to date a string of craters formed in the Triassic Period.
Of course the methods of radioactive dating for objects that old have uncertainties of +/- a few million years but that's only a few percent of the total age.
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Paul Sereno, for instance, has led expeditions into places like Niger, Morocco and Patagonia. The politics add an extra variable which makes it a pain in the ass to dig in another country, some countries more than others, so most American palentologists stay here. Also, it's a bitch to transport the fossils long distances after they're dug up. There's plenty of stuff to find here, so it's not really a problem.
They were definitely not predominantly here.
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The other assumptions are that there is a constant decay rate of the isotope...
Well, yes, or rather in proportion to the number of isotopes around. Anyway, do you suggest that this might not be the case here?
I can think of few scientific findings that are as well established as this one. This pattern has been observed in all radioactive decays - involving 100s of isotopes with decay rates spanning from nanoseconds to millenia.
Tor
There are ways of testing the accuracy of at least some of these methods. Carbon-14 dating, for example, has been compared with tree ring dating methods going back 10K (IIRC) or so years. There have probably been similar attempts with other isotope based methods.
Primar on archeological dating methods
Archeologists date flakes.
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(1) the decay rate is exponential, not linear. You don't have to "guess" about this, it's simply the result of a stochastic radioactive decay process, with a fixed probability per parent atom present in the sample. The rate cannot be other than exponential, with a decay constant determined by the atomic physics, which we can safely presume is invariant.
(2) You are correct that radiocarbon dating suffers from the systematic uncertainty that we cannot know what the atmospheric C14/C12 ratio was at the time the sample died. Unfortunately (for your argument), carbon dating has nothing to do with measuring truly geologic timescales of millions or billions of years. For that, we rely on other radiometric processes like Potassium-argon or Uranium-Lead. These methods do not suffer from the same systematic error that radiocarbon dating does.
For example, radioactive Uranium crystallizes with other atoms in a way that is impossible to create with Lead atoms instead of Uranium. However, the Uranium then begins to decay into Lead. So, you find these crystals in rock. You know that when the rock cooled from magma, it formed these crystals with all Uranium and no Lead. Now, some fraction of it has decayed to Lead. Measure the fraction of Lead to Uranium, apply the known exponential-decay rate, and you can very accurately determine how long ago the rock was molten.
Hope that helps.
Liberal (adj.): Free from bigotry; open to progress; tolerant of others.
Might be a little bit of speculation, but they could do a bit of comparative studies. They could potentially know the size of infants (from nearly hatched egg fossils) and adults. Depending iftyou consider them warm or cold blooded you can roughly estimate their growth rate based on contemporary animals (say gators, birds and mammals) and extrapolate from there.
Also, some bones and teeth exhibit growth rings, like those of trees. Maybe this type of dino had bone growth rings that are clearly visible.
Age Determination of DinosaursBONE STRUCTURE AND HISTOLOGY
Dinosaur Metabolism
Bone Histology
Dinosaurs' metabolism
Dinosaur Growth and Behavior
Sea turtle bones bear rings that help scientists measure sexual maturity
It wouldn't be carbon dating. Carbon 14 has a half life of about 5700 years, so after ~6000 years, it's got about 1/1000th of what was originally there (which is rather low to begin with). After that, I'm guessing that there's just too little to get reliable statistics from (perhaps noise from other decay sequences??).
Besides the problem of the (relatively) short half-life of Carbon14, the fossilization process leaches most of the carbon out of the body anyways-- so there is (almost) no carbon to date. Even if it didn't 1/2^(77million/5700) => 1/(2e4066). In other words, if you started with a chunk of carbon14 the size of Jupiter, you'd be lucky to find 2 atoms of carbon14 after 60million years of radioactive decay)
There's a nice intro to carbon dating at howstuffworks.com, with even more data at c14dating.com. They mention that you can use carbon-14 style radioisotape dating with isotopes that have a longer halflife than carbon 14. These are the methods are what are used to date older rocks.
The reason why carbon 14 isn't useful for recent items is the nuclear age. In the early years of the nuclear age, the US and later 'nuclear club' members did atmospheric nuke tests that completely messed up (read: randomized) the isotope ratios for everything that's died since the late '40s. Cherbonyl didn't help much, either. Anything earlier than that (and recent enough that there's a statistically valid percentage of C14 left in the body) is a good candidate for Carbon dating.
Prior to nuclear fallout, the primary source of Carbon14 was atmospheric Nitrogen being bombarded by cosmic rays.
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First, you pick an isotope of an element which has a nice long half-life. Then, you guess at how much of that isotope was in the environment (and therefore the object you are dating as well) at the time period you assume the object was made.
Not exactly. Isochron dating takes a set of samples which formed at the same time from a common pool of materials (such as a rock including several minerals) and plotting points on a graph. Three things are measured - the abundance of a radioactive element (the parent) , one of its decay products (the daughter), and a different non-radioactive isotope of the same element as the decay product (the control). A graph is plotted, with the X axis being the ratio of parent to control, and the Y axis being the ratio of daughter to control. The correlation of the plotted points to a line indicate the accuracy of the date, which can be determined from the slope of the line. How it works is described in better detail at the link I gave.
The other assumptions are that there is a constant decay rate of the isotope
A fair assumption, since no counterexample has ever been shown.
and that the object being dated becomes a closed system, not seeping or leeching any of that isotope from its surroundings.
Changes in composition of the object will cause the points on the isochron plot to not be correlated to a line, and thus the contamination will be noticed and either the object will be declared unsuitable for dating, or a date can be given with big error bars.
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I don't think the colors of the "mummy" will be that of the live dinosaur. All of the animal's body has been replaced with minerals. So the color will be that of the mineral. However they should get a better idea of what the animal looked like when it was a live.
Its just you.
Dinosaur fossils have been found in many places, including europe, asia, africa, australia and antarctica.
In order to discover fossils, you need a very particular set of conditions:
1) Conditions must be right for the specimens to be buried.
2) They must then be preserved a long time.
3) They then have to be exposed, usually by weathering, so that they can be found.
The "badlands" of the U.S. and Canadian west meet these conditions for fossils of the dinosaur era, roughly 225 - 63 million years ago. The specific types of fossils will depend on the age of the strata being exposed. In Montana and Alberta, that means the Jurassic and the Cretaceous.
Paleontological exploration will occur more in countries that are politically stable and can spare funds for research.
Here: http://news.nationalgeographic.com/news/2002/10/10 10_021010_dinomummy.html
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