ImagingGeek,
Revisiting your earlier reply to my stating that you were assuming the Earth’s surface gravity could not have changed, you stated that:
“It's not an assumption; I provided two papers - one analyzing paleomagnetic data, the other tidal sediments - to measure the mass of the earth over its history. They clearly showed there has been no change in the earths mass.”
I would agree that the Earth’s total mass has not changed significantly over the last few hundred million years. However you, and most people, don’t realize that there is another mechanism that could alter the surface gravity on the Earth. That method is the shifting of the Earth’s cores, either or both.
The Gravity Theory of Mass Extinction explains this. For hundreds of millions of years, continental land masses have formed various land mass configurations, quite different from today’s fairly balanced widespread distribution. Since the Earth is spinning, any unbalanced distribution of these land masses as in the case of Pangea, according to the theory, causes the core(s) to shift away from the center of mass of the consolidated land masses lowering the surface gravity on it. As Pangea broke apart and dispersed, the reverse process would increase surface gravity until the core(s) returned to their central position.
There is much circumstantial evidence to support the theory. An example which is relevant to the current discussion concerns the pterosaurs. The core, or cores, movement would create a gravitational gradient on Pangea, lower surface gravity near Pangea’s center of mass, which would be near but not always on the equator, and higher surface gravity (but not as high as present) as one moves closer to either pole
The pterosaurs started out small and gradually increased in size during the Jurassic, as did the sauropod dinosaurs. At the end of the Jurassic, not only did the largest sauropod dinosaurs disappear from North America, the Rhamphorhynchoid Pterosaurs went extinct. Why would the surviving pterosaurs continue to grow to such enormous proportions (i.e., wing surface area to body size) unless there was some other environmental pressure to do so? This indicates a significant increase in surface gravity on at least part of Pangea or possibly all of it. Either continental breakup or, as has been postulated, the entire Pangean supercontinent moved north during the late Jurassic. Also, since the theorized gravitational gradient would have resulted in lower surface gravity in near-equatorial regions (which would vary based on the movement of Pangea as a whole and the movement of individual continents during breakup), one would expect the largest creatures to live in this region. The largest pterosaurs, from what I have found, lived in these regions. The largest sauropod dinosaurs in N. America lived in what is now the southern USA during the Jurassic and the northward movement of Pangea shifted the lower gravity region into S. America during the Cretaceous, thus the giant titanosaurs.
Laze
