I've been lurking around this forum for quite some time, and really enjoyed the debates; not only are they often informative, but they've provided me with some excellent information and sources that I've had plenty of occasions to use, especially concerning dating methods. I'm not a very intelligent person, but I'm always trying to learn more, and this debate's driven me to read up on a number of subjects I wouldn't have, otherwise.
A recent topic on the subject of impact craters on the Moon got me thinking about the impact craters on Earth. On another forum, I posed this question to the creationists in attendance
Something I’ve been pondering, recently.
Most people know about the meteor impact that ‘killed’ the dinosaurs. What they often don’t know is that many, many other things died out around this time, too - fish, plants, even certain mammals and birds - it was a worldwide extinction event, and it left its mark in the Yucatan.
That’s about 170 km wide - quite an impressive impact, and it would have had effects all over the earth, both immediate and longer-term. I’m absolutely not the person to tell you about them...I suck at math. But, fortunately, Purdue University developed this really cool website that actually lets you calculate such things. So we can see what effects such an impact would have, here.
What can happen to you would depend on your proximity to the object - for instance, I put in 1,000 km away, and it informed me of all sorts of pleasant things, like my clothes igniting, a fiery hellstorm raining death upon from the skies, and being drowned and/or crushed by the resultant tsunami. Really, really unpleasant stuff.
But the thing is, that’s not the first time this happened - most people also don’t know that the KT impact isn’t the only big impact the Earth’s taken, nor is it the biggest. There are two craters which are even bigger than the one in the Yucatan - the one in Sudbury is about 250 km, and the one in Vredefort is a whopping 300 km.
And keep in mind - these are just confirmed craters. There unconfirmed ones that we haven’t found yet, that could drawf even that, but for the sake of argument we’ll just stick to what’s been confirmed.
So, you’ll notice that there’s quite a few big impacts that would have done huge damage to the earth - not all as drastic as the top five, but still quite noticeable. Forest fire, tsunamis, tremors, et cetera. This would have been quite noticeable to anyone alive at the time.
Now, with an old-earth model, I don’t see it a major problem. When the big first two hit, life on Earth wasn’t still microbial, and wouldn’t have been affected by it too much, I don’t think. These impacts are few and far between - there are a lot of them, but that’s about what you’d expect if the planet’s been around billions of years. You can only dodge the bullet so many times.
I’m not sure how this works with a young-earth model, though, and I’m curious if any of the reside YECs could proffer an explanation. Obviously, these meteors haven’t hit since the flood - if they’d all struck within a relatively short amount of time, they would have utterly annihilated life on this planet. Just one big one, like the one in the Yucatan, is enough to cause mass extinctions worldwides. Two, within 4,000 years, would be utterly devastating. The top five largest craters are quite close to or exceeding the Yucatan’s in size, and there are dozens of smaller, but still significant craters around the globe.
Clearly, they haven’t hit in recorded history, so what does that leave us? Before the Flood? If they’d happened before the flood, there wouldn’t even need to be a Flood - everything would be dead, not to mention that it’s not given note anywhere in the Bible. I think I recall someone saying that the Flood could have caused the meteor impacts in the first place, but I don’t see how that make even a little sense, not to mention that the acid rain, massive fish extinctions, and fireballs raining all over the place are something that Noah would have made notice off.
So I’m curious what the YEC ‘interpretation’ is for these impacts.
I really didn't get much of a response - one of them talked about angels holding battles inside of protective barriers, but it wasn't very serious, and none of the creationists seemed interested in providing any real feedback, which is odd since they're usually a chatty bunch on that forum. So in interest of refining the argument, I thought I might bring it here to see how well it stacks up and what possible objections there might be.
quote:An impact crater believed to be associated with the "Great Dying," the largest extinction event in the history of life on Earth, appears to be buried off the coast of Australia.
Becker and her team found extensive evidence of a 125-mile-wide crater, called Bedout, off the northwestern coast of Australia. They found clues matched up with the Great Dying, the period known as the end-Permian. This was the time period when the Earth was configured as one primary land mass called Pangea and a super ocean called Panthalassa.
quote:To check, we need one single event which has been dated by several methods. A nice example is the Triassic multiple-impact event, which formed a 4500-kilometer-long chain of huge craters. (There must have been a train of big objects from space, which hit the spinning earth, one by one, across several hours. Much like the way comet Shoemaker-Levy hit Jupiter in 1994.)
Here are the five confirmed craters:
Million Years Ago
214 ± 1
U-Pb on zircons
219 ± 32
214 ± 8
Ar/Ar laser spot fusion
215 ± 25
200 ± 25
"Stratigraphic" dating means that the crater itself has not been dated. Instead, the rock strata above and below the crater was dated. (By now, the Red Wing crater is under 1.5 kilometers of sediment.)
The table shows five datings that are consistent with each other. However, there is a sixth dating involved: the one for drawing the map.
Today, the continents are moving about one inch a year. This is a simple fact which can be measured by anyone with good GPS equipment. So, in 214 million years, the continents could have moved three thousand miles. To get a map of that past world, geologists did K/Ar datings of ancient lava flows. As the article below shows, the three main craters form a dead straight line on that map.
These dates were obtained by several different radioactive methods, on rocks of several different kinds, by geologists from four different countries. But the dates are consistent. That is the usual case, so the article didn't bother to comment on it.
For more detail:
Evidence for a late Triassic multiple impact event on Earth, J. Spray, S. Kelley, and D. Rowley, Nature 392,171-173 (12 March 1998)
What a lot of people are not aware of either is that the K-T extinction did not "start" at the impact. Life, particularly marine life, had already started dying off millions of years leading up to the K-T impact event, likely resulting volcanic extrusion of the Deccan Traps. It appears that the K-T impact may have been the straw that broke the camel's back.
In addition, though I do not know if there have been others identified in the stratigraphic record (possibly Upheaval Dome in Utah), the Alamo Breccia in Nevada is evidence of an impact that was discovered to be within the Guilmette Limestone formation. The meteor impacted in what is now southern Nevada, a marine coastline at the time. Despite what Creationists want to believe, geologists can tell the difference between shallow water and deeper water depositional environments.