Another argument that creationists make regarding evidence for a global flood is the fact that some mountains have marine fossils on them. Such fossils could only be present if the land forming those mountains wasn’t under water at one time.
Doesn’t that show that there was once a global flood?
Actually, no it doesn’t.
The land on those mountains, indeed, was at one time under water. There are two competing explanations for this.
Creationists state that there was once a global flood that covered even the tallest mountains just as the Bible states in Genesis 7:19 - They [the flood waters] rose greatly on the earth, and all the high mountains under the entire heavens were covered.
Mainstream scientists have a very different explanation. They insist that the land forming the mountains was “pushed up” from under the water by something called “plate tectonics” over very long periods of time.
A quick explanation of plate tectonics is needed.
People have noted for quite some time how well the various continents seem to “fit together” as though they were pieces of a jigsaw puzzle. For example, the East coast of South America has a lot of geographic features that would fit quite well into the West coast of Africa. There seem to be too many places that the continents “fit together” for it to be simply a coincidence. Scientists have looked at how the Earth is constructed and developed the theory of plate tectonics.
In summary, the outermost portions of the Earth’s interior are the “crust” which is the uppermost layer of the mantle. This is also fairly rigid. (Together these form what is called the “lithosphere”.) These move around on top of something called the asthenosphere. While the asthenosphere is not liquid, it is more viscous than the lithosphere. There are gaps between parts of the lithosphere and, as a result, things that look like “plates” form. These move around, at least in terms of geological time.
Maybe the best way to think of this is that it is a little bit like cookies floating on top of jello.
When these plates collide with each other, land is pushed up and mountains form. Over geological time, these plates can also move away from each other instead of against each other and the mountains that had been formed in the distant past erode away instead. As a result, some mountains are going up in height. Others are diminishing in height.
In the United States, the Rocky Mountains are going up and the Appalachian Mountains are eroding away. Note that this happens in geological time. That means it happens over many, many human lifetimes.
Which of these two hypotheses – a global flood or plate tectonics - provides the better explanation for marine fossils on mountains?
Most objective people would say that plate tectonics is the better explanation.
First of all, there is a great deal of evidence that plate tectonics take place. The most obvious evidence is that it has been confirmed that some mountains are indeed getting taller. The tallest mountain on Earth, Mt. Everest, is one such mountain. As confirmation, in 1998, a GPS device was brought to the summit of Mt. Everest by a group of mountain climbers. The exact height of Everest had been difficult to gauge because the amount of snow cover on the peak varies more than the height of the mountain itself. This GPS device, however, was attached securely to a long steel bolt which was drilled well into the rocks at the summit. It legitimately measures any changes in the position of the summit of that mountain. Readings from that sensor after it was placed show that Everest grows 0.1576 inches (about four millimeters) each year. This sensor, along with similar sensors on other mountain peaks, shows horizontal movement as well – exactly as predicted by the hypothesis of plate tectonics. Based on that rate of elevation change, the top of Mt. Everest would have been under water about 22 million years ago. Based on other evidence, that happens to match the estimate for when the plates that are causing Everest to move first began to intersect.
But besides the evidence from the GPS sensor supporting plate tectonics, there is other evidence showing that it is not likely that these fossils are the result of a global flood.
For one thing, the marine fossils extend through the entire mountain – from top-to-bottom and from side-to-side. A single flood, especially on top of a mountain, should be expected to leave a single layer of such fossils. (The flood itself lasted for “only” a year.) Similarly there isn’t any evidence of erosion or other evidence of the actual land being underwater in the last few thousand years. The fossils are really the only evidence that the land making up Everest was EVER under water.
Another problem is that many of the marine fossils are of deep bottom dwellers. If there was a global flood, the mountain tops would be the shallowest parts of the oceans. These bottom dwellers would stay in the deeper waters.
Radiometric dating also confirms that the land on Everest containing the fossils is many millions of years old. Creationists don’t trust radiometric dating – only because it disagrees with their preconceptions. But the fact that the radiometric dates confirm the plate tectonic hypothesis is important, nonetheless.
Two other points are worth making about these fossils that don’t involve Mt. Everest directly.
One of them is that if this is all the result of a global flood, then we should see such fossils on top of all mountains, globally. In fact, we should see them everywhere! If you dig deep enough in your own backyard, you should run into such fossils. There are, of course, many places – including many mountains and probably your backyard – that completely lack marine fossils.
The final question on this subject is why wouldn't the receding flood waters pull most of the aquatic animals into the valleys around the mountains? Creationists give inconsistent answers to the question of how fast the flood waters receded after the flood (or even, as we discuss elsewhere, give consistent guidance of where the water went after the flood). But in any case, the marine fossils should be closer to the bottom of the mountains if they are the result of a global flood. If the waters receded quickly, then the currents would have pulled the organisms with it. If the waters receded slowly, then the organisms would have followed the waters down themselves, preferring to stay in the water rather than die exposed to air. It would seem that under any conditions the area at the base of the mountains should have the highest concentrations of marine fossils if they are the result of the Flood of Noah. Needless to say, that's NOT the case.
Therefore the argument that marine fossils on mountains indicate that they were covered by flood waters as described in the Bible fails completely. The evidence would look different and there would be more evidence than what we actually see.
This conclusion is actually more obvious than it would seem to be. Even Leonardo da Vinci, who was a devout Christian and who lived well before Darwin, knew that fossils of aquatic organisms on mountain tops were NOT evidence for a global flood. Among other things, Leonardo noted multiple layers of marine fossils with gaps in between on the mountains in Italy. He realized that this couldn’t come from a single global flood.
Leonardo summarized his thoughts on this by writing in his diaries of the “stupidity and ignorance of those who imagine that these creatures were carried by the Deluge to such places distant from the sea.”
It appears that there is no compelling evidence outside of the Bible supporting the idea of a global flood (which, by itself, is strong circumstantial evidence against the occurrence of such a global flood).
 http://www.nationalgeographic.com/features/99/everest/roof_content.html, referenced on June 2, 2008
 http://www.eduplace.com/science/hmsc/6/c/cricket/cktcontent_6c93.shtml referenced on May 31, 2008