Meteorite Impact Craters and Apparent Age – An Addendum

As a way of simplifying yesterday’s rambling entry I offer the following comparison of two meteorite impact craters. The first, Victoria Crater, is from Mars and the second, Amguid Crater, is in Algeria, Africa.  Let’s compare the features and then ask if they can help us to evaluate the current young earth geology models and apparent age arguments.

Victoria Crater (Mars). Please click to see details in a must larger version of this picture.  This crater is about 750 meters in diameter and 90 meters deep. Notice that they walls shows layered rocks but the edges of the crater are completely flat.  100s of millions of years old. 

Above is a panoramic pictures of Victoria crater taken by the Opportunity rover. Below is Amguid Crater in Algeria, Africa.

Amguid Crater (Algeria, Africa – Earth).  Please click the picture for a much larger version of this picture so you can see the rocks that make up the crater wall.  The completely circular meteorite impact crater is 450 meter (1476 feet) in width and 30 meter (100 feet) deep (at the surface of the central deposits). The top of the edge is covered by blocks of sandstone.  Estimated age –  less than 100,000 years old.  B.Devouard, LMV, UBP

Victoria (Mars) is larger than Endurance crater, also from Mars, which I have talked about previously. Victoria crater is about 750 meters in diameter.  If you click on the picture to see the larger version you will notice that the rocks on the surface edges are almost completely flat and even most of the material on the sides of the crater are flattened.  There are a few cliffs or bluffs around the edge with steep walls.  It may be hard to see, but the bluff on the immediate left of the picture has layered rocks for the bottom 2/3  of the rock but the top 3rd which is not as steep and look looser are not layered in the same way.  In fact, closer images (see below)  of this part of the bluff show that the upper 1/3 of the that bluff is randomly assorted chunks of rock .   The  most probably explanation for this is that the top 1/3 of the rock/sediment around this crater is material that was ejected from the center and thrown over the top of the layered rocks.   What is really amazing is that what must have originally been a random assortment of rocks has been worn flat on top and the jumbled rocks smoothed off even on the slope down to the crater bottom.  Conventional geological theory and detailed research at this site including computer modeling of impact effects and erosion suggest that to arrive at this point would take a minimum of several hundred million years.*

Bluff at edge of Victoria crater showing multiple layers of sedimentary rock (light color and brown layers beneath (click for closer view). The light colored material represents the top layer of rock found further away from the crater and so all the material above that is debris thrown on top by the meteorite impact which has since settled, compacted and eroded.

Amguid crater is in a remote portion of southwestern Algeria.   This crater is about 450 meters across and so is a bit smaller than Victoria but the overall shape is very similar.   To appreciate the differences in rocks around the crater you should click on the picture for a close look.   Here the crater is filled with sand that has blown in over time.  But even that amount of blowing sand has barely caused any erosion of the rocks around the crater rim (see picture below) especially in comparison to those at Victoria crater.  This crater has been estimated to be less than 100,00 years old but more than 10,000 years old.*

Here is what the outside flanks of the Amguid crater looks like. You can see how much debris has been thrown out to form the crest of the crater.  You can see that the rocks are very loose and have few signs of significant erosion.

Based on gross appearance and a simple knowledge of geological principles Victoria appears much older than Amguid crater.   More detailed work with geochemistry, analysis of erosion patterns, other evidence about the history of weather patterns in the area etc.. would only lead to an increased confidence that this is the case.

Faced with the obvious significant erosion of Victoria crater, some young earth creationists have suggested that the Victoria was created as it appears (ie. created with apparent age).   Amguid crater, on the other hand, leaves no room for apparent age because of the nearly universal set of assumptions behind young earth creationism.  Even if someone want to hold to a young earth and creation with apparent age the reason to hold to a young earth in the first place is a particular literal translation of Genesis 1.  Given the hermeneutic principles which lead to that interpretation should be applied consistently to other portions of Genesis the young earth creationists will invariable submit that a global flood must have occurred.  The logical extension then is to say that had this crater been formed with apparent age then why would it have survived a global flood with the appearance that it has today.  Surely, a global flood would have eroded this feature or at least filled it with sediment.   So, here the young earth creationist does apply sound logic and deduces that this crater must have a post-flood origin.   In fact it should probably be argued that this crater had its origin well after the flood since the valleys around this crater must have been formed prior to the impact since the impact debris lies on top of a well eroded landscape.   Even so, the crater does not appear to be brand new by any means and is minimally thousands of years old even using the most optimistic, from a young earth perspective, set of assumptions.

For the sake of argument let us say that Amguid crater really is less than 4000 years old even if that stretches the most credulous means of estimating impact age.   If it is 4000 years old then what of the hundreds of other craters on Earth that appear to be much much older but also can’t be more than 4 to 6 thousand years old?  More importantly for our comparison here, what does the young earth creationist do with Victoria crater?  Well, there are several different responses:

1) Some have attempted to deny that Victoria crater is indeed a meteorite impact crater and try to claim it is a volcanic in origin.  I don’t know how that changed the obvious erosional age problem at all and so it is either still very old or created with the appearance of age, but was created with the appearance of having been a volcanic phenomena rather than an impact crater.

2) Some have posited Victoria crater as having been created just as it is (ie. creation with the appearance of age).   Some theological difficulties and additional problems it creates have been discussed by myself and others many times.

3) Some simply assert that Victoria had its origin in the past 10,000 years but that it has eroded  very quickly to this point by some so-far not understood means.   These means might include very different climatic pattern in the past like Mars being covered in water in the past when the crater was formed.   Maybe the layers of sediments were soft at the time of impact and thus erosion took place quickly prior to hardening in to rock.   Sounds plausible in a general sense but more detailed analyses will quickly dismiss this hypothesis. For example, there are other impact craters on Mars that have the appearance of having originated in softer possibly wet sediments but Victoria has none of those characteristics and the blocks of rocks jumbled up on top strongly suggested fractured rocks.

Response 1 and 3 are clearly ad-hoc proposals and not based on any evidence or analysis that would give anyone confidence that there is a good chance of them being correct. They are simply assertions to provide any response other than admitting that Victoria appears extremely old.

Critique of the creationist views of Walter Brown

I can’t help but expand on response 3 a bit more by detailing the folly of one young earth creationists who has specifically attempted to explain the presence of craters on Mars and the Moon.  This is Dr. Walter Brown of  creationscience.com.  I have mentioned him.  I don’t say this very often in my writing but I must say that Brown’s hypothesis are outright ridiculous and it is an embarrassment to me as a Christian that he should be quoted so often as providing such an admirable defense of Biblical creationism.   There is little in his book, In the Beginning,  that makes any sense which is made even more distressing when one considers that Brown has a Ph.D in mechanical engineering from MIT.  I mentioned yesterday that Brown advocates for a young earth flood theory that proposes that craters on the Moon and Mars are the result of rocks being thrown off the Earth during the breakup on the deep at the beginning of the Biblical flood.   These rocks he says coalesced in space to form the comets and meteorites that are in the solar system today. Eventually many of these migrated to form the comet field near Mars and have impacted Mars to create its cratered surface.   It has hard to contain my incredulity but I mention this idea again because I keep seeing it promoted in other web sites and so is used by many lay Christians when faced with questions about craters on the moon and  the surface of other planets.  Most who use his ideas are followers who do not know much about science and are trusting that he knows what he is talking about and thus are unaware of how ridiculous their use of such arguments sounds.

Back to Victoria crater.  So if we apply the principles learned from Brown’s book where he explains how science shows us the Earth and the Solar system are young, without needing the Bible for confirmation, we find that prior to the Biblical flood some 4-6 thousand years ago the surface of Mars didn’t have craters.  He doesn’t say this directly but explains how Mars got craters.  What does he think it looked like before being cratered, smooth?   And why should God have created it smooth. Is smooth somehow more “good” than lumpy or scarred?  So, these rocks get throw off the Earth and make their way to Mars which is 60 to 400 million miles away.  That has to take some time!  Then somehow thousands of these pieces of earth all ended up in the path of Mars.  There are more than 42,000 impact craters on Mars with diameters greater than 5 kilometers and hundreds of thousands that are smaller.   Don’t  forget that there are rocks that have been found in Antarctica that have been convincingly demonstrated to have originated from Mars and so for Brown he would have to say that a rock from Earth traveled to Mars, was large enough to strike Mars causing pieces of Mars to get thrown off into space and then drift back and land back on Earth.   So, Victoria crater according to all this, can I call it logic?, was formed sometime after a global flood on earth and thus in the past 4 to 6 thousand years and probably is much much younger than that.

While Victoria looks fairly old there are many craters that look much much older and many craters that look much younger on Mars.  Could they really all have their origin within the space of only a few thousand years and yet look so different.   The Amguid crater on Earth is at least thousands of years old and yet it looks very very “fresh” but for Brown Victoria is likely even younger and yet looks so much older.  I am at a loss to imagine what Brown actually thinks when he sees pictures of these craters.  I suspect he doesn’t let himself worry about specific sites such as these. He just wants to present a general theory that sounds plausible enough that he can give those that believe that they must believe the earth is young some level of comfort that there is a possible explanation for these geological features that seem to suggest a much longer chronology.   Brown is doing them no real service in providing a purely fanciful hypothesis couched in scientific certitude.

* Regarding conventional ages of the craters, I am certainly aware of the assumptions behind many of the dating methods.   Rates of erosion processes can certainly vary over time if there are significant climatic shifts.   Being aware of the possibility of changes in rates of some processes allows one to test many of those assumptions and to determine if it is reasonable to assume that such changes would dramatically change the estimates.  Rates are also effected by the rock composition.  It might be argued that the Amguid crater is composed of rocks that are much more resistant to erosion than the Victoria crater rocks thus explaining why they look “younger.”   I don’t have the full details for each site but I expect the opposite could be the case Amguid rock is sandstone which is not the hardest rock and will be eroded by water and abrasion.  The rock at Victoria crater is not likely very different and could be even more resistant to erosion. Given that no water is present on Mars and wind is less abrasive the rate of erosion under present day conditions clearly favors exponentially higher rate for Amguid.

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Comments

  1. Reading the numerous explainations offered by Young Earthers to explain the age of these craters, I am reminded of the fact that the one thing you can always count on from the creationists is their exhaustless supply of ad hoc explainations.

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  1. [...] The impact craters from various meteorites presents another difficulty for YEC. Dating these craters puts them well beyond the allowances of a young earth perspective, but the young earth explanations stretch credibility beyond the breaking point. [...]

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