Here's a THEORY with an LDS perspective. Copied from another thread. (Just one possibility.)
Before the fall of Adam there was no death, so the dinosaurs had to either exist with Adam, or after him. I think they existed much later, even after the flood. During, and for a while after the flood, the earth was in geologic turmoil, with things happening much faster than usual. Like when we read about the continents moving, or at Christ's death, which are other examples of periods of geologic turmoil.
So did Noah then have the dinosaurs on his arc? Yes, but they were obviously not the size as we think of them. (I do have to sneak evolution in here a bit.) Evolution does exist within species. Humans today are larger than they were a few centuries ago. If conditions are favorable for a particular species, it will thrive and evolve larger. So possibly the conditions on the earth, immediately after the flood, favored the original dinosaur species so well that it thrived and rather quickly evolved to be quite huge.
But the earth was still in its rapid change-mode, conditions continued to change and eventually the dinosaurs died out. With such a large earth and so few people here (because of the flood) they could have well stayed out of each other's way.
So... you accept that gradual change can occur, but don't believe it can lead to new species? How, then, do you explain
ring species?
Ring species show exactly the same mechanisms that Creationists say can't exist, just spread over distance instead of time. Have a look at the example on the link I provided (sorry it's from Wikipedia, but it's the clearest explanation that I know of) of
Larus gulls: starting in northern Europe with the Lesser Black-backed Gull, we have adjacent populations that can interbreed freely, somewhat like dog breeds - they look a bit different, but the two groups can mate and produce viable offspring, so they're the same species, by the conventional definition.
Now... look what happens when the chain comes back around again: by the time we get back to Britain, the variation from group to group has built up to the point where what you've ended up with (the Herring Gull) is so unlike what you started with (the Lesser Black-backed Gull), that they can't interbreed - they're no longer the same species.
When this process occurs over time instead of distance, you have the evolution that you claim doesn't happen.
Science says the earth is millions of years old. This is using a dating system that is based on assumptions. The assumption is that everything has always aged at the rate that it ages now. Or that those factors that the rate of aging is based on, are not always consistent.
You're starting from a false assumption. The age of the Earth has been established by many different methods, in widely different disciplines using different evidence, and they all agree.
Some of these methods do assume uniformity, but many do not. The ones that do assume uniformity do so for good reason - for example, if radioactive decay were to occur at different rates at different times for the same element, then this would contradict a huge body of evidence that has shown the opposite, as well as a large number of well-understood and well-supported scientific principles. Radiometric dating only assumes that decay is constant because it has been demonstrated that it actually
is constant.
"And unto Eber were born two sons: the name of one was Peleg; for in his days was the earth divided" (Gen 10:25)
Also in the Doctrine and Covenants 133:24 (non-LDS, please bear with me) "And the land of Jerusalem and the land of Zion shall be turned back into their own place, and the earth shall be like as it was in the days before it was divided."
Sounds like a reference to the Tower of Babel to me more than anything else. Why do you think it's referring to geological division and not cultural division?
So is it possible that at different times in the history of this earth, things happened at different rates and sometimes much more rapidly than today? If so, this would really throw the rate of aging totally out of whack. If continents can move and oceans formed in one lifetime, the measurements taken many centuries later might appear that it took millions of years.
No, it's not possible for things to happen as you describe. For one good example of this, consider
geomagnetic reversal. There are other reasons, but I'm a bit of a geology geek so I'm going to go with this one.
Rocks have crystal structure. When molten lava forms and cools into solid rock, its crystals are aligned with the Earth's magnetic field... as it is at the time. This is undebatable; this effect can be replicated in the lab, it happens consistently and repeatably, and the mechanisms behind the phenomenon are well-understood.
Now... from time to time, the poles flip. North becomes south, and south becomes north (note: this doesn't mean that whole planet actually rotates, just that things change in the Earth's mantle, and when the process is complete, a compass that used to point north would point south instead). We know that this happens because of that crystal structure I talked about before - as we look at the geologic record, we see that every single igneous rock that's formed points to where north was when it was formed, and then they all switch back and forth together, regardless of where on the planet the rock is.
We also have a very good, continuous record of all these geomagnetic reversals thanks to
sea floor spreading: the ocean floor is formed in a constant process where it wells up from mid-ocean spreading ridges, slides across the mantle, then is subducted beneath the continental plates. Every sea floor on the planet shows the same pattern of geomagnetic reversals in their crystal structure. These also agree with igneous rock formations on land (from volcanos, usually).
Because oceanic, i.e. sea floor, plates are constantly being created at the spreading ridges and then destroyed at the continental boundaries, oceanic plates are much younger than the Earth itself. Still, the oldest sections of sea floor have been dated at 160 million years old.
In the geological record of the sea floor, we can see approximately 200 geomagnetic reversals. If this happens over 160 million years, this poses no problems - they'd happen every 800,000 years on average (though the time between reversals can vary widely - have a look at
this graph - every black/white switch is a geomagnetic reversal). Our best estimate is that it's been about 50,000 years since the last one - long enough ago that it would have happened before any human had a compass, so it would have passed unnoticed.
Now... you want to compress the geologic history of the Earth into a much shorter time. This would mean that most of those geomagnetic reversals would have happened since human civilization began, and many of them since the development of the compass.
In all recorded human history, how many instances have there been of every single compass suddenly pointing in the opposite direction?
