DogOnPorch Posted July 25, 2009 Report Posted July 25, 2009 Pretty cool. Looks like these little critters from the Early Jurassic lived in the desert with their tracks being preserved in an ancient sand dune. http://www.craigdailypress.com/news/2009/j...aur_national_m/ Quote Nothing cracks a turtle like Leon Uris.
Sir Bandelot Posted July 25, 2009 Report Posted July 25, 2009 Pretty cool. Looks like these little critters from the Early Jurassic lived in the desert with their tracks being preserved in an ancient sand dune.http://www.craigdailypress.com/news/2009/j...aur_national_m/ How do they know they are really 190 million years old? Quote
DogOnPorch Posted July 25, 2009 Author Report Posted July 25, 2009 How do they know they are really 190 million years old? Comes just after the Triassic boundry, I'd imagine. Quote Nothing cracks a turtle like Leon Uris.
Riverwind Posted July 25, 2009 Report Posted July 25, 2009 How do they know they are really 190 million years old?They know how old the rocks are. Quote To fly a plane, you need both a left wing and a right wing.
DogOnPorch Posted July 25, 2009 Author Report Posted July 25, 2009 They know how old the rocks are. Correct. Plus the Triassic-Jurassic boundry is easy to find if you're a geologist/paleontologist, et al. It took place about 199 million years ago for unknown reasons...the best theory in my opinion being carbon dioxide being released into the atmosphere suddenly...vulcanism or perhaps gas clathrate hydrates realeasing their bound molecules in a huge chemical reaction. Either way, few of the major life forms found in the Triassic in massive numbers are found above this layer. Quote Nothing cracks a turtle like Leon Uris.
Riverwind Posted July 25, 2009 Report Posted July 25, 2009 (edited) for unknown reasons...the best theory in my opinion being carbon dioxide being released into the atmosphere suddenly...That is not the 'best' theory. It is just the theory which happens to support the 'global warming' obsession which has taken over discussion of the paleo record. I don't understand why these extinction events are always assumed to be environment related. Seems to me a mutated virus could have the same effect and leave no evidence. Edited July 25, 2009 by Riverwind Quote To fly a plane, you need both a left wing and a right wing.
DogOnPorch Posted July 25, 2009 Author Report Posted July 25, 2009 That is not the 'best' theory. It is just the theory which happens to support the 'global warming' obsession which has taken over discussion of the paleo record. I don't understand why these extinction events are always assumed to be environment related. Seems to me a mutated virus could have the same effect and leave no evidence. Wouldn't some sort of virus kill only some while leaving others? Not only that, we're talking about a lot of different plants and animals that were affected by this virus. I'm not sure that would be possible. But, if you have an explanation, I'd like to hear it. Quote Nothing cracks a turtle like Leon Uris.
Riverwind Posted July 25, 2009 Report Posted July 25, 2009 (edited) Wouldn't some sort of virus kill only some while leaving others?That is what was observed. Some species survived. Others died out. Not only that, we're talking about a lot of different plants and animals that were affected by this virus.Our experience today suggests that viruses find it vey difficult to jump the species barrier but there is no reason to belive that was always true. In fact, the inter-species barrier could actually be an adaptation that the extinct species did not have. We have no way to verify this but it is at least as plausible as a theory which assumes that some unknown mechanism caused a massive increase in CO2 levels. Edited July 25, 2009 by Riverwind Quote To fly a plane, you need both a left wing and a right wing.
DogOnPorch Posted July 25, 2009 Author Report Posted July 25, 2009 That is what was observed. Some species survived. Others died out. Actually, I meant within the partcular plant/animal species. That is: wouldn't some Sellosaurus (a late Triassic dinosaur) have survived, immune to the virus? Our experience today suggests that viruses find it vey difficult to jump the species barrier but there is no reason to belive that was always true. In fact, the inter-species barrier could actually be an adaptation that the extinct species did not have. We have no way to verify this but it is at least as plausible as a theory which assumes that some unknown mechanism caused a massive increase in CO2 levels. I agree it's a plausible hypothesis. I'm just not sure about it being the best. A large comet for example, could have triggered such a release of methane or CO2...and as we saw with Jupiter last week...that happens more often than we'd like to admit. Quote Nothing cracks a turtle like Leon Uris.
Riverwind Posted July 25, 2009 Report Posted July 25, 2009 (edited) Actually, I meant within the particular plant/animal species. That is: wouldn't some Sellosaurus (a late Triassic dinosaur) have survived, immune to the virus?You could say the same about some being able to adapt to environmental changes too. A virus that affected multiple species would disrupt an ecosystem pretty badly. I agree it's a plausible hypothesis. I'm just not sure about it being the best. A large comet for example, could have triggered such a release of methane or CO2...and as we saw with Jupiter last week...that happens more often than we'd like to admit.The comet is plausible too. My pet peeve is the the circular logic that has infested this topic. i.e. people who believe in the "GHG as the main driver of climate" hypothesis go looking the paleo record for evidence to support their hypothesis. And given the lack of data it is not too hard to come up with a plausible CO2 linked hypothesis for many events in the past which they then use to bolster their GHG claims. After doing that someone else comes along and looks at the paleo and automatically favours the "GHG" hypothesis because it is consistent with what GHG alarmists keep repeating over and over again. What gets lost is the GHG explanation for these paleo events is no more plausible than others given the actual data available from that time. Edited July 25, 2009 by Riverwind Quote To fly a plane, you need both a left wing and a right wing.
Bonam Posted July 25, 2009 Report Posted July 25, 2009 I don't know who's trying to blame the dinosaur extinction on CO2 levels, but the asteroid impact theory of extinction is all but proven. The extinction occurred 65 million years ago, and there is a 180km diameter crater (the Chicxulub crater) of the same age, left by the impact of a body 10-15 km across. There is a distinctive layer of clay abnormally high in iridium, an element commonly found in high concentration in asteroids, that covers the entire world and all its continents, at a depth corresponding to that same timeframe. The immediate effects of the impact would have been wildfires and megatsunamis. Over the longer term, release of ash and dust into the atmosphere would have blocked out the sun's radiation, lowering temperatures dramatically. It is this long term (many years) drop in temperatures that is almost certainly responsible for the extinction of the dinosaurs. Quote
Riverwind Posted July 25, 2009 Report Posted July 25, 2009 I don't know who's trying to blame the dinosaur extinction on CO2 levels, but the asteroid impact theory of extinction is all but proven. The extinction occurred 65 million years ago...The extinction event being discussed here took place 200 million years ago. Quote To fly a plane, you need both a left wing and a right wing.
Bonam Posted July 25, 2009 Report Posted July 25, 2009 The extinction event being discussed here took place 200 million years ago. Ah oops, missed that. Quote
DogOnPorch Posted July 25, 2009 Author Report Posted July 25, 2009 Ah oops, missed that. No worries. Quote Nothing cracks a turtle like Leon Uris.
bush_cheney2004 Posted July 25, 2009 Report Posted July 25, 2009 I like the Roosevelt dime "In God We Trust" motto depicted next to the 190 million year old mammal footprint. Quote Economics trumps Virtue.
DogOnPorch Posted July 26, 2009 Author Report Posted July 26, 2009 I like the Roosevelt dime "In God We Trust" motto depicted next to the 190 million year old mammal footprint. Irony noted...good catch. Quote Nothing cracks a turtle like Leon Uris.
DogOnPorch Posted July 26, 2009 Author Report Posted July 26, 2009 (edited) You could say the same about some being able to adapt to environmental changes too. A virus that affected multiple species would disrupt an ecosystem pretty badly. I agree. It is a very clever hypothesis. The comet is plausible too. My pet peeve is the the circular logic that has infested this topic. i.e. people who believe in the "GHG as the main driver of climate" hypothesis go looking the paleo record for evidence to support their hypothesis. And given the lack of data it is not too hard to come up with a plausible CO2 linked hypothesis for many events in the past which they then use to bolster their GHG claims. After doing that someone else comes along and looks at the paleo and automatically favours the "GHG" hypothesis because it is consistent with what GHG alarmists keep repeating over and over again. What gets lost is the GHG explanation for these paleo events is no more plausible than others given the actual data available from that time. One factor we haven't mentioned is that there was less coastline during the Triassic than at any time in history. This greatly affected marine evolution as shallow coastal shelves were relatively rare compared to other ages. Perhaps this could have rebounded up the food chain onto land creating a global food shortage. Just a thought. We actually know very little about the Triassic oceans since they were long since recycled by plate tectonics...very few solid exaples exist for study. Edited July 26, 2009 by DogOnPorch Quote Nothing cracks a turtle like Leon Uris.
Wild Bill Posted July 26, 2009 Report Posted July 26, 2009 I heard that if you look at the tracks they appear to be those of white mice. 42 of them, actually! Quote "A government which robs Peter to pay Paul can always depend on the support of Paul." -- George Bernard Shaw "There is no point in being difficult when, with a little extra effort, you can be completely impossible."
DogOnPorch Posted July 26, 2009 Author Report Posted July 26, 2009 I heard that if you look at the tracks they appear to be those of white mice.42 of them, actually! They certainly would have been 'mouse-like'. Quote Nothing cracks a turtle like Leon Uris.
Riverwind Posted July 26, 2009 Report Posted July 26, 2009 We actually know very little about the Triassic oceans since they were long since recycled by plate tectonics...very few solid exaples exist for study.I am always amazed at what we do know about the distant past with reasonable certainty. Quote To fly a plane, you need both a left wing and a right wing.
DogOnPorch Posted July 26, 2009 Author Report Posted July 26, 2009 I am always amazed at what we do know about the distant past with reasonable certainty. That's for sure. The Triassic layers (three of them, of course) are very distinct. Sandstone for the most part, I believe. It's the Carboniferous period that I'm rather facinated with lately. With O2 levels up around 30%+, it would have made for some facinating flora...100' horse tails and such. Not to mention lightining storms would be akin to an airstrike. Note to self: Must build time machine. Quote Nothing cracks a turtle like Leon Uris.
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