How did birds manage to survive the K-T Event?
In the 1980s, paleontologists and other scientists put together an elegant scenario accounting for the enormous mass extinction that took place at the end of the Cretaceous Period of the Mesozoic Era. That scenario entailed the following events:
1) A meteorite or comet some 6 miles (10 kilometers) in diameter plummeted to Earth in an area that is now the Yucatan Peninsula of Mexico. At the time, that area was covered with seawater, and the seabed there incorporated a vast amount of gypsum, a mineral containing sulfur.
2) As a result, several things happened:
a) An enormous amount of seawater, gypsum, and other materials from the ocean floor were lofted high in the atmosphere, to heights that were perhaps greater than 150,000 feet. This vast cloud began to spread out in all directions, as well. After a while, this material began to rain down on the planet, often far from the impact site. As it did so, it became red-hot due to air friction.
b) The impact also sent seawater and debris flying out sideways, relatively low to sea level and the continent beyond. As a result, a huge, hot mud tsunami flowed well inland on the North American continent, covering large tracts of land in mud to depths of many feet and fouling rivers and lakes. The tsunami also plowed through what would someday be the Gulf of Mexico, inundating the coastline of the northern part of South America (the Isthmus of Panama did not yet exist, as North America and South America were separated from each other by a long stretch of ocean).
c) In the meantime, the thermal pulse produced by the impact was radiating away from the impact point at nearly the speed of light -- infrared light -- slowed done somewhat by heat transfer among molecules of the atmosphere. Every living thing within several hundred miles that wasn't deep in a cave system with its mouth oriented away from the strike or otherwise protected from the thermal pulse was instantly fatally flash-boiled or roasted to death.
d) Now the incandescent blowback from the strike began raining out of the upper atmosphere in earnest. Those that fell to land became heated even more by air friction. While most of it consisted of small pieces of debris, between the initial heat of impact and heat energy gained by falling back through the atmosphere it was all heated up to extreme temperatures -- heat that was readily transferred to the atmosphere. World-wide, the atmosphere began to heat up until it was as hot as an oven set on Broil, 500-600 degrees Fahrenheit.
e) Animals tucked safely away in burrows and cave-systems, or deep in the oceans, or able to dive to the bottom of deep lakes and stay there for awhile, were safe from the atmospheric heat as well as the incandescent pieces of debris that were raining down everywhere. But everywhere else all vegetation burned, vast forest-fires turning into gigantic firestorms, scouring the land with fire, while all animal life was battered or roasted to death.
3) The fires went on for many days. In the meantime, enormous amounts of sulfur in the blowback began to rain down on the land in the form of sulfuric acid, an extremely acidic material. It ran off the continents into the oceans, killing off all life in the shallows that hadn't been battered and roasted to death by the fallout, in the process destroying the places that the great marine reptiles and many fish, marine arthropods, and other sea-life had used as nurseries for their young. There would be no future generations of those creatures, even if they had fled far out to sea and spent as much time underwater as possible. Only those creatures that lived in cold water deep in the ocean survived -- the blowback falling into ocean waters above them would have been cooled way down by the time they reached the levels where life survived, doing little harm there. On land, creatures that had somehow been spared the worst damage from preceding events were scarred and poisoned by acid rain.
4) An additional event was taking place at the same time: vast flows of basaltic lava were being churned out in the area that would someday become the Deccan Traps of India. The Traps -- mountains of cooled lava -- were created by this basalt event, which also released countless megatons of noxious gases into the atmosphere. The subcontinent that would eventually be called India had broken away from Gondwanaland, one of two enormous supercontinents which together had formed Pangaea, the great world continent of the Paleozoic Era. By 67-68 million years ago it had docked against Asia, and the momentum of that collision began to push up huge mountains that would someday be called the Himalayas. But the press of the tectonic plate on which it sat, plunging under the tectonic plate underlying Asia, caused vast outpourings of basaltic lava from vents that had opened up in the Deccan region as a result of tectonic stresses. The gases emitted by those volcanoes began to poison the air across the globe. Female dinosaurs inhaling the polluted air began to produce eggs whose embryos had been badly damaged during development within those eggs, and the shells of which were themselves damaged, becoming too thin or too porous or otherwise unable to protect the vulnerable chicks inside them during their gestation. So even before the impact, dinosaurs were already under heavy stress, their ability to reproduce suffering as a result. The resulting 1-2 punch -- the bolide impact plus the noxious gases from the volcanoes together sealed the fate of the non-avian dinosaurs and numerous other great Mesozoic lineages.
The survivors -- birds; mammals; crocodilians; many lineages of arthropods, such as insects, horseshoe crabs, and spiders; lizards, snakes, and other reptiles; some amphibians; and various marine and freshwater creatures, such as some nautiloids, various mollusks, sea cucumbers, bony fish, sharks, and so on -- consisted of those creatures which could burrow into the ground or go deep underwater or could find refuge in caves or cracks in the rocks and thus escape the rain of incandescent blowback. They also had to have ways of keeping their developing embryos and fetuses from being poisoned by volcanic pollution, and, in cases in which they laid eggs, laying eggs with shells of a proper thickness and porosity to protect and nurture their unhatched young until time to hatch.
So far, so good.
Now: what's wrong with this picture?
It turns out there's plenty. That a huge bolide impact did happen at the time the non-avian dinosaurs became extinct is certain -- for one thing, in rock strata around the world the rocks of that age have unusually high concentrations of iridium, a metal rare on Earth but prevalent in objects from space, such as meteorites. Clearly something huge hit the Earth then, and it was large enough, heavy enough, and invested with enough kinetic energy to splash vaporized bits of itself all over hell and creation. Mixed in with that iridium are unusually high concentrations of sulfur, as well -- sulfur from the gypsum bed where the bolide hit. Furthermore, a crater large enough to have been produced by such an impact, dating to the time of the K-T Event, was finally located when geologists working for petroleum companies in the Gulf of Mexico and nearby areas contacted scientists working on the K-T Event problem and contributed their information to the teams working on it. Finally, the Deccan Traps were clearly produced by a very large flood basalt event, and they, too, date to the time of the K-T event. All those have been confirmed scientifically, including the dating, and it all ties together.
However, we need to look at the survivors to see where holes appear in the currently accepted scenario for the K-T extinctions.
Birds: If non-avian dinosaurs died out as a result of toxic and polluted air from the Deccan Traps event poisoning their reproductive systems and causing their chicks to die in the egg due to toxins skewing their development or the eggshells becoming to thin and porous to nurture and protect them properly, then why didn't all birds then extant become extinct for the same reasons? We know they didn't, because their descendants are with us today, the numerous bird species populating the modern world. But how?
Furthermore, if the creatures that survived did so by burrowing underground or retreating to the bottom of lakes and pounds and the oceans, how could birds have survived? With few exceptions, they don't normally burrow into the ground -- those that fly need to be able to launch from platforms that aren't restricted in most directions, and those that don't are very often far too big to burrow. There could have been small, burrowing birds that survived that way. There were none that could dive deep underwater, staying there until the fallout was gone and the broiling heat died down to a reasonable level -- birds are air-breathers, and even diving birds have to come up for air every so often. So: how?
Mammals: Here we have another problem, and it has to do with the behavior of fire, superheated air, and combustion products from runaway global firestorms. Supposedly many mammals then lived in burrows underground or hid out in caves, only coming out at dawn and dusk to seek food when non-avian dinosaurs were asleep or too groggy from sleep to see and prey upon them. That's all very well until we consider the fact that according to the major scenario, forests and wildlands all over the world were embroiled in horrific firestorms. Plants everywhere had been set on fire by the heat of the blowback, and the result was great firestorms which expanded and expanded until all available fuel was involved in the fires.
Consider a fire, any fire. First of all, fires produce combustion products. The molecules of some of these, such as carbon monoxide, are lighter than molecules of oxygen, and will rise as the air grows hotter -- heat rises as high as it can. This by itself would leave the air close to the ground relatively cool as well as free of carbon monoxide, which is deadly when inhaled by animals, binding with the iron in hemoglobin molecules and preventing oxygen from doing so. Animals who inhale it rapidly die, unable to use the oxygen they are also inhaling. But if those animals are deep down in burrows or in cave-systems, far from the entrance, they could be spared asphyxiation by carbon monoxide, which tends to rise and would not be drawn far into a cave-system.
The problem is carbon dioxide. Each molecule of CO2 consists of two oxygen atoms and one carbon atom, for a molecular number of 6 + 8 + 8 = 22. This number is higher than that for molecules of oxygen (O2, with a molecular number of 8 + 8 = 16) and nitrogen (N2, with a molecular number of 7 + 7 = 14). Therefore, because of their various molecular weights, heating CO2 molecules have trouble competing successfully with heating O2 and N2 molecules for a place in the gas column, and thus are pounded down to the lowest layers of the gas column by the other molecules. (For gases at room temperature, where the equations of state are stable, this doesn't happen, except when extremely large amounts of carbon dioxide are released in an area by release of carbon dioxide from the bottoms of lakes or the like.) For that reason, CO2 released as a combustion product pools along the ground or floor of the area in which it is released. Animal bodies cannot break down CO2 to extract oxygen from it, and any animal in a burrow in an area where massive forest fires are burning will be asphyxiated by the CO2 suddenly filling the burrow.
Further, there is the matter of what firestorms do to atmospheric dynamics. In short, they create their own weather, and the winds generated by them can be extremely strong and very chaotic. Some of them could easily rip away topsoil and expose any creatures hiding in burrows, especially if those burrows are shallow, and could pick up and carry any small animals -- and Cretaceous mammals were generally very small -- into the firestorm as the firestorm ravenously feeds on all available fuel and sources of oxygen in the vicinity. Animals deep in cave-systems could avoid that -- but what would they feed on, and would they get enough oxygen, before the firestorms died out?
Then there's heat. A fire superheats the air around and above it to temperatures hot enough to roast the lungs if inhaled, hot enough to blister skin or worse. It also causes air turbulence as the atmosphere struggles to equalize heat across the affected area. It also becomes invested in combustion products, which include, among other things, particulate matter and even chunks of blazing wood or other fuel lofted into the air by the turbulence generated by the fire. It also heats the carbon dioxide flowing along the ground as well as other, lighter gases that have risen above the ground-level layers. As hot ash and other superheated materials fall to the ground, they heat the air up in their vicinity until it becomes unbreathable. The vagaries of wind can then push some of that material into the burrows, along with superheated gases -- and anything alive down there that hasn't gone extremely deep, with tunnels extending below well away from the burrow mouth, is going to be roasted alive. If large chunks of burning material fall on top of entrances to burrow that don't go deep enough and don't extend far enough away from the burrow mouth, anything alive down there is likely to be carbonized.
As for crocodilians, yes, they can dive down to the depths of a large lake and stay there for awhile, but they have to come up for air at some point. What happens to them then?
Then there are reptiles, such as lizards, snakes, turtles, and so on, and amphibians, such as frogs, toads, and salamanders. All, save for tadpoles and other baby amphibians, are obligate air-breathers. If they burrowed in to escape the fallout and the heat generated by it, how deeply could they have burrowed in? Some, like a 24-foot long Cretaceous snake whose fossils were recently discovered, were just too big to burrow. So were the monitor lizards living on land then.
Yet all of these survived to bequeath the world with their modern descendants -- including ourselves. Otherwise we wouldn't be having this discussion. So: how?
Well, perhaps the idea that the rain of incandescent blowback from the impact and the fires it started needs modification. Maybe it wasn't global. Maybe there were pockets of land free of the blowback, with few trees to burn and sparse brush. In fact, it's virtually certain that there were. Large amounts of heat suddenly injected into the atmosphere will do strange things. Such a burden of heat let loose in the atmosphere in a short period of time will generate hurricane-force winds, winds that could, in this case, push large amounts of the blowback out of an area before it hits there. It could also generate huge packs of tornadoes, of course, which would be deadly to anything living in their vicinity. But the overall result of such atmospheric upheavals would include protection of some areas from the fallout and superheating of the atmosphere.
Also, "rain shadows" of some mountain ranges might protect the areas on one side of those ranges from the fallout and the superheating. That would increase the areas not impacted by fallout and hearing.
Such things taken together could account for the survival of birds, mammals, and other animals living at the time of the K-T Event. The question is, did they? And what else could? The answers to these questions would depend on input from fire scientists such as Stephen J. Pyne, arson investigation experts and other members of fire departments with strong experience with fire and how it behaves, physicists whose specialties include thermodynamics and chaos science, and paleontologists, and geologists whose areas of expertise include in-depth knowledge of the late Cretaceous and early Paleogene. I would love to know what they come up with.
1) A meteorite or comet some 6 miles (10 kilometers) in diameter plummeted to Earth in an area that is now the Yucatan Peninsula of Mexico. At the time, that area was covered with seawater, and the seabed there incorporated a vast amount of gypsum, a mineral containing sulfur.
2) As a result, several things happened:
a) An enormous amount of seawater, gypsum, and other materials from the ocean floor were lofted high in the atmosphere, to heights that were perhaps greater than 150,000 feet. This vast cloud began to spread out in all directions, as well. After a while, this material began to rain down on the planet, often far from the impact site. As it did so, it became red-hot due to air friction.
b) The impact also sent seawater and debris flying out sideways, relatively low to sea level and the continent beyond. As a result, a huge, hot mud tsunami flowed well inland on the North American continent, covering large tracts of land in mud to depths of many feet and fouling rivers and lakes. The tsunami also plowed through what would someday be the Gulf of Mexico, inundating the coastline of the northern part of South America (the Isthmus of Panama did not yet exist, as North America and South America were separated from each other by a long stretch of ocean).
c) In the meantime, the thermal pulse produced by the impact was radiating away from the impact point at nearly the speed of light -- infrared light -- slowed done somewhat by heat transfer among molecules of the atmosphere. Every living thing within several hundred miles that wasn't deep in a cave system with its mouth oriented away from the strike or otherwise protected from the thermal pulse was instantly fatally flash-boiled or roasted to death.
d) Now the incandescent blowback from the strike began raining out of the upper atmosphere in earnest. Those that fell to land became heated even more by air friction. While most of it consisted of small pieces of debris, between the initial heat of impact and heat energy gained by falling back through the atmosphere it was all heated up to extreme temperatures -- heat that was readily transferred to the atmosphere. World-wide, the atmosphere began to heat up until it was as hot as an oven set on Broil, 500-600 degrees Fahrenheit.
e) Animals tucked safely away in burrows and cave-systems, or deep in the oceans, or able to dive to the bottom of deep lakes and stay there for awhile, were safe from the atmospheric heat as well as the incandescent pieces of debris that were raining down everywhere. But everywhere else all vegetation burned, vast forest-fires turning into gigantic firestorms, scouring the land with fire, while all animal life was battered or roasted to death.
3) The fires went on for many days. In the meantime, enormous amounts of sulfur in the blowback began to rain down on the land in the form of sulfuric acid, an extremely acidic material. It ran off the continents into the oceans, killing off all life in the shallows that hadn't been battered and roasted to death by the fallout, in the process destroying the places that the great marine reptiles and many fish, marine arthropods, and other sea-life had used as nurseries for their young. There would be no future generations of those creatures, even if they had fled far out to sea and spent as much time underwater as possible. Only those creatures that lived in cold water deep in the ocean survived -- the blowback falling into ocean waters above them would have been cooled way down by the time they reached the levels where life survived, doing little harm there. On land, creatures that had somehow been spared the worst damage from preceding events were scarred and poisoned by acid rain.
4) An additional event was taking place at the same time: vast flows of basaltic lava were being churned out in the area that would someday become the Deccan Traps of India. The Traps -- mountains of cooled lava -- were created by this basalt event, which also released countless megatons of noxious gases into the atmosphere. The subcontinent that would eventually be called India had broken away from Gondwanaland, one of two enormous supercontinents which together had formed Pangaea, the great world continent of the Paleozoic Era. By 67-68 million years ago it had docked against Asia, and the momentum of that collision began to push up huge mountains that would someday be called the Himalayas. But the press of the tectonic plate on which it sat, plunging under the tectonic plate underlying Asia, caused vast outpourings of basaltic lava from vents that had opened up in the Deccan region as a result of tectonic stresses. The gases emitted by those volcanoes began to poison the air across the globe. Female dinosaurs inhaling the polluted air began to produce eggs whose embryos had been badly damaged during development within those eggs, and the shells of which were themselves damaged, becoming too thin or too porous or otherwise unable to protect the vulnerable chicks inside them during their gestation. So even before the impact, dinosaurs were already under heavy stress, their ability to reproduce suffering as a result. The resulting 1-2 punch -- the bolide impact plus the noxious gases from the volcanoes together sealed the fate of the non-avian dinosaurs and numerous other great Mesozoic lineages.
The survivors -- birds; mammals; crocodilians; many lineages of arthropods, such as insects, horseshoe crabs, and spiders; lizards, snakes, and other reptiles; some amphibians; and various marine and freshwater creatures, such as some nautiloids, various mollusks, sea cucumbers, bony fish, sharks, and so on -- consisted of those creatures which could burrow into the ground or go deep underwater or could find refuge in caves or cracks in the rocks and thus escape the rain of incandescent blowback. They also had to have ways of keeping their developing embryos and fetuses from being poisoned by volcanic pollution, and, in cases in which they laid eggs, laying eggs with shells of a proper thickness and porosity to protect and nurture their unhatched young until time to hatch.
So far, so good.
Now: what's wrong with this picture?
It turns out there's plenty. That a huge bolide impact did happen at the time the non-avian dinosaurs became extinct is certain -- for one thing, in rock strata around the world the rocks of that age have unusually high concentrations of iridium, a metal rare on Earth but prevalent in objects from space, such as meteorites. Clearly something huge hit the Earth then, and it was large enough, heavy enough, and invested with enough kinetic energy to splash vaporized bits of itself all over hell and creation. Mixed in with that iridium are unusually high concentrations of sulfur, as well -- sulfur from the gypsum bed where the bolide hit. Furthermore, a crater large enough to have been produced by such an impact, dating to the time of the K-T Event, was finally located when geologists working for petroleum companies in the Gulf of Mexico and nearby areas contacted scientists working on the K-T Event problem and contributed their information to the teams working on it. Finally, the Deccan Traps were clearly produced by a very large flood basalt event, and they, too, date to the time of the K-T event. All those have been confirmed scientifically, including the dating, and it all ties together.
However, we need to look at the survivors to see where holes appear in the currently accepted scenario for the K-T extinctions.
Birds: If non-avian dinosaurs died out as a result of toxic and polluted air from the Deccan Traps event poisoning their reproductive systems and causing their chicks to die in the egg due to toxins skewing their development or the eggshells becoming to thin and porous to nurture and protect them properly, then why didn't all birds then extant become extinct for the same reasons? We know they didn't, because their descendants are with us today, the numerous bird species populating the modern world. But how?
Furthermore, if the creatures that survived did so by burrowing underground or retreating to the bottom of lakes and pounds and the oceans, how could birds have survived? With few exceptions, they don't normally burrow into the ground -- those that fly need to be able to launch from platforms that aren't restricted in most directions, and those that don't are very often far too big to burrow. There could have been small, burrowing birds that survived that way. There were none that could dive deep underwater, staying there until the fallout was gone and the broiling heat died down to a reasonable level -- birds are air-breathers, and even diving birds have to come up for air every so often. So: how?
Mammals: Here we have another problem, and it has to do with the behavior of fire, superheated air, and combustion products from runaway global firestorms. Supposedly many mammals then lived in burrows underground or hid out in caves, only coming out at dawn and dusk to seek food when non-avian dinosaurs were asleep or too groggy from sleep to see and prey upon them. That's all very well until we consider the fact that according to the major scenario, forests and wildlands all over the world were embroiled in horrific firestorms. Plants everywhere had been set on fire by the heat of the blowback, and the result was great firestorms which expanded and expanded until all available fuel was involved in the fires.
Consider a fire, any fire. First of all, fires produce combustion products. The molecules of some of these, such as carbon monoxide, are lighter than molecules of oxygen, and will rise as the air grows hotter -- heat rises as high as it can. This by itself would leave the air close to the ground relatively cool as well as free of carbon monoxide, which is deadly when inhaled by animals, binding with the iron in hemoglobin molecules and preventing oxygen from doing so. Animals who inhale it rapidly die, unable to use the oxygen they are also inhaling. But if those animals are deep down in burrows or in cave-systems, far from the entrance, they could be spared asphyxiation by carbon monoxide, which tends to rise and would not be drawn far into a cave-system.
The problem is carbon dioxide. Each molecule of CO2 consists of two oxygen atoms and one carbon atom, for a molecular number of 6 + 8 + 8 = 22. This number is higher than that for molecules of oxygen (O2, with a molecular number of 8 + 8 = 16) and nitrogen (N2, with a molecular number of 7 + 7 = 14). Therefore, because of their various molecular weights, heating CO2 molecules have trouble competing successfully with heating O2 and N2 molecules for a place in the gas column, and thus are pounded down to the lowest layers of the gas column by the other molecules. (For gases at room temperature, where the equations of state are stable, this doesn't happen, except when extremely large amounts of carbon dioxide are released in an area by release of carbon dioxide from the bottoms of lakes or the like.) For that reason, CO2 released as a combustion product pools along the ground or floor of the area in which it is released. Animal bodies cannot break down CO2 to extract oxygen from it, and any animal in a burrow in an area where massive forest fires are burning will be asphyxiated by the CO2 suddenly filling the burrow.
Further, there is the matter of what firestorms do to atmospheric dynamics. In short, they create their own weather, and the winds generated by them can be extremely strong and very chaotic. Some of them could easily rip away topsoil and expose any creatures hiding in burrows, especially if those burrows are shallow, and could pick up and carry any small animals -- and Cretaceous mammals were generally very small -- into the firestorm as the firestorm ravenously feeds on all available fuel and sources of oxygen in the vicinity. Animals deep in cave-systems could avoid that -- but what would they feed on, and would they get enough oxygen, before the firestorms died out?
Then there's heat. A fire superheats the air around and above it to temperatures hot enough to roast the lungs if inhaled, hot enough to blister skin or worse. It also causes air turbulence as the atmosphere struggles to equalize heat across the affected area. It also becomes invested in combustion products, which include, among other things, particulate matter and even chunks of blazing wood or other fuel lofted into the air by the turbulence generated by the fire. It also heats the carbon dioxide flowing along the ground as well as other, lighter gases that have risen above the ground-level layers. As hot ash and other superheated materials fall to the ground, they heat the air up in their vicinity until it becomes unbreathable. The vagaries of wind can then push some of that material into the burrows, along with superheated gases -- and anything alive down there that hasn't gone extremely deep, with tunnels extending below well away from the burrow mouth, is going to be roasted alive. If large chunks of burning material fall on top of entrances to burrow that don't go deep enough and don't extend far enough away from the burrow mouth, anything alive down there is likely to be carbonized.
As for crocodilians, yes, they can dive down to the depths of a large lake and stay there for awhile, but they have to come up for air at some point. What happens to them then?
Then there are reptiles, such as lizards, snakes, turtles, and so on, and amphibians, such as frogs, toads, and salamanders. All, save for tadpoles and other baby amphibians, are obligate air-breathers. If they burrowed in to escape the fallout and the heat generated by it, how deeply could they have burrowed in? Some, like a 24-foot long Cretaceous snake whose fossils were recently discovered, were just too big to burrow. So were the monitor lizards living on land then.
Yet all of these survived to bequeath the world with their modern descendants -- including ourselves. Otherwise we wouldn't be having this discussion. So: how?
Well, perhaps the idea that the rain of incandescent blowback from the impact and the fires it started needs modification. Maybe it wasn't global. Maybe there were pockets of land free of the blowback, with few trees to burn and sparse brush. In fact, it's virtually certain that there were. Large amounts of heat suddenly injected into the atmosphere will do strange things. Such a burden of heat let loose in the atmosphere in a short period of time will generate hurricane-force winds, winds that could, in this case, push large amounts of the blowback out of an area before it hits there. It could also generate huge packs of tornadoes, of course, which would be deadly to anything living in their vicinity. But the overall result of such atmospheric upheavals would include protection of some areas from the fallout and superheating of the atmosphere.
Also, "rain shadows" of some mountain ranges might protect the areas on one side of those ranges from the fallout and the superheating. That would increase the areas not impacted by fallout and hearing.
Such things taken together could account for the survival of birds, mammals, and other animals living at the time of the K-T Event. The question is, did they? And what else could? The answers to these questions would depend on input from fire scientists such as Stephen J. Pyne, arson investigation experts and other members of fire departments with strong experience with fire and how it behaves, physicists whose specialties include thermodynamics and chaos science, and paleontologists, and geologists whose areas of expertise include in-depth knowledge of the late Cretaceous and early Paleogene. I would love to know what they come up with.