Gents. A few notes: 1.ALL dinosaurs had long, down-facing legs. ALL. You may question this, but it is, incredibly enough, true. You can check me on this very easily.
All reptiles were short-legged and their legs were OUT-FACING. Dinosaurs had long legs and those legs were DOWN-facing. Aside from some minor differences, long down-facing legs were the BIG DIFFERENCE. Why is this important?
The difference between dinosaurs and reptiles. Whether you believe the Growing Earth Theory, or the rather odd Pangea Theory, instead. 1. 200MYA, earth was sub=tropical from pole to pole. The Growing Earth Theory says, that this was because the crust was thin, and much of earth's heat came from the earth itself. Certainly we know the sun was dimmer at that time and provided less heat. Whatever you believe, the fact is, seasoning became more apparent and more profound over time. Earth was evolving from perennial to seasonal plants. It is reasonable to assume, in that case, that the dominant life forms migrated hemispherically, from the Northern hemisphere, to the Southern and then back again, since the land was connected, and there were no mountains to bloke any migration, seasonal or otherwise. This is supported by dinosaurs long legs, the abundance of fresh seasonal plants on opposite hemispheres, seasonally (more like today), the negative factor of the effects of a colder atmosphere on creatures that had no fur, slept with their bellies on the ground, laid eggs on the ground, and could not burrow or hibernate.
Evolution, made attempts to help out, by turning scales to feathers, and allowing some dinosaurs to evolve into birds. These would survive as the final actor would enter the play.
Sections of the outer crust pulled apart, (in both theories). Massive trackways, that reducing numbers of dinosaurs used to make their hemispheric migrations, began to be A. Shattered and B. Mountains began to rise up along these pathways, driving dinosaurs up into the bitter cold, and forbidding them passage.
The birds, learned to fly higher and higher as the mountains rose, migrating like all of their ancestors to opposite hemispheres. Because the rifting and spreading of the continents could be overcome by flight, the birds survived.
The 25 to 35 foot crocadillians, and other sea dinosaur, whose food stores depended on migrating dinosaurs, wading, around and through, the shallow seas, that covered 2/3 of the continental plate. They died-out.
While all of this makes perfect sense, there is one added factor that happened at this time.
For those of you who care to, please consult the crustal age map. You will discover that 60MYA, or there abouts, Australia broke free of Antarctica. As a result, the Australian plate, driven upward, crushed, and broke into massive pieces the young oceanic plate between Australia, Indonesia and Asia. You can see these broken oceanic plate pieces easily on the crustal age map. This same break-up of oceanic plate gave purchase for the first and only compressive subduction of the earth. (Meaning, compressive subduction began on the earth around 60MYA. You can measure it on your crustal age map).
So you have reversal of Australia's direction, rifting and spreading all around Antarctica, shoving up on Australia, the shattering of oceanic plate off of Asia, and the first subduction on earth. I would have to say, that this is a massive upheaval, probably much more massive than anything in a billion years. I don't think it can be ignored as a contributing factor to the expiration of the dinosaurs. Far more, than a small meteor hit, half under water at the Gulf of Mexico.
Neal Adams
