I’m feeling a rush of what seems to be nostalgia: I’m sure it’s been ages since we saw such a classic example of an attempt to prove that the Earth is young via the use of an overly simplistic understanding of geological processes as we have here in Counting Earth’s Age in Lightning Strikes, by Brian Thomas.
But first a look at the research that prompted his article. Certain angular fracturing in exposed rocks – like in the above picture from northern Sweden – is commonly credited to the freeze-thaw cycle, with the expansion of water forming ice over winter acting to expand existing weaknesses. Other options do exist, but they all follow a similar theme. As Brian’s source paper, Lightning as a geomorphic agent on mountain summits: Evidence from southern Africa, says:
The physical (mechanical), chemical and biological weathering processes most commonly cited as important in periglacial environments [i.e. where water freezes sometimes] are, in no particular order, frost shattering through ice crystal growth (gelivation), porewater migration, thermal expansion, and biochemical dissolution (formation of tafoni). The unifying theme of these weathering processes is that their occurrence and rate of operation are strongly climatically-mediated.
However, while apparently wandering around Lesotho with a magnetometer, the authors of this paper (Jasper Knight and Stefan W. Grab) have determined that lightning strikes are an under appreciated part of this process. Hitting rock with lightning can shatter it in a similar way, and this can be detected via its magnetic properties. When struck, parts of the rock will melt and re-solidify, and will take up the magnetic field of the Earth at that time as opposed to when it was originally formed. Frost-fracturing and other processes produce no such magnetic signature, and so the researchers were able to determine that a much greater proportion of the fractured rock debris that they found was caused by lightning than expected. This has two key implications: first, the presence of fractured rocks should not be taken to automatically mean that there is frost in the area; and second, that due to the faster process of weathering mountains are potentially a more dynamic place than thought.
It is worth remembering here the difference between weathering and erosion: blasting apart a rock with lighting or with frost is weathering, while transporting the fragments down a river would be erosion. These processes are linked, but they are not the same.
Having explained the research Thomas comes to his first claim:
How might this finding affect overall erosion rates estimated for entire continents? Geologists have studied erosion rates worldwide for decades. A 2011 meta study collated hundreds of data points, finding that land erodes on average at 40 feet every million years. At this rate, all continents reduce to sea level in only 50 million years—far too fast to accommodate the billion-year age assignments of so many exposed Earth rocks.
But those studies never took into account these new lightning data, a factor which would only accelerate the erosion rate, making Earth’s old age assignment even less credible.
He cites a 2011 DpSU, which I covered at the time. Erosion rates were calculated via a radiometric method (something which cannot reasonably be considered to be reliable in a young Earth creationist world) that allowed the determining of how long a particular piece of rock had been exposed to the surface and therefore the rate of erosion at that location. This does not need to take into account the lightning weathering data because it is irrelevant: an increase in the potential rate of weathering does not challenge observed rates of erosion.
Wolfram alpha helpfully informs me that 40 feet per million years is about 12 micrometres per year, but deriving an average in the way Thomas did is a meaningless exercise. Flat lowlands erode hugely slower than highlands, and highlands erode down to lowlands: Thomas’ calculations, which average involve averaging not only the erosion rate but the heights of the continents, are firmly detached from reality and cannot be used to date the Earth.
The Southern Alps down here in New Zealand are eroding at a truly phenomenal rate. Alluvial fans are a common feature in this country, and braided rivers, formed when there is more sediment being moved than the river can handle, wind across the Canterbury plains. But the rate of erosion in the Southern Alps appears to be matched by the rate of uplift, something which can be more directly measured: it comes out at 5-10 millimetres per year, nearly a thousand times faster than Thomas’ average erosion rate. This introduces uplift, the flipside of the erosion coin and something that Thomas is completely ignoring. He could just have easily ignored erosion and concentrated on uplift: in doing so he might have equally nonsensically come up with a maximum age figure of just 375,000 years on the grounds that this would be how long it would take to uplift Mt Cook at 10 millimetres/year.
As it happens I was too quick in jumping to volcanic processes for the addition of rock to replace erosion in my 2011 post that I previously linked. Uplift from beneath is the primary process here, and doesn’t just happen where tectonic processes are active. Continental crust floats in the mantle just like ice in water: a much larger volume has to exist hidden down below to support that which is exposed up above, and mountain ranges hide huge quantities of rock that has been forced down into the mantle just as the more visible rock is forced up into the sky. If you slice off the ice in an ice-cube that is exposed above the water the rest of the cube will rise until the ideal ratio of exposed to underwater ice is restored. The same goes for the continents: you may think that you only need to erode away the nearly 9 km height of Mt Everest, but you will find that you also need to get rid of much of the 75 km of crust beneath – and that’s even without taking into account the effects of the ongoing tectonic movements that act to thicken the crust. Continental plains – which being flatter erode much, much more slowly – don’t have such great volumes of rock supporting them, but we’re still talking about 10s of kilometres.
Again, saying that the Earth must be young because it should erode flat in just a few tens of millions of years is one of the most simplistic, and therefore most flawed, arguments in the young Earth creationist handbook. Which brings us to Thomas’ next claim:
Lightning-generated cracks may not be a well-known erosional process, but earth scientists are generally more familiar with fulgarites—long, branched tubes of quickly melted and re-solidified materials created when lightning strikes sand and other ground debris. Yet, Earth’s surface does not display billions or even millions of years’ worth of fulgarites.
Physicist Don DeYoung described this problem in the Spring 2013 issue of the Creation Research Society Quarterly: “With approximately one hundred lightning strokes [sic] per second occurring across the earth, throughout the alleged 4.6 billion years of earth history….there should be…more than 1,000 fulgarites per square meter of land everywhere.” And this is if only “1% of these land strikes resulted in fulgarite formation.”
Where are all the missing fulgarites? Why are continents and high mountains still standing despite dramatic lightning damage and relatively fast erosion rates? The answers to these questions are the same—the world is only thousands, not billions, of years old.
Thus Thomas concludes his article. The problem with the fulgarite argument as expressed above is that not a single pebble on the Earth’s surface has sat there continuously exposed to lightning for anything approaching the last 4.6 billion years. The above discussion of erosion should be proof enough, but there are other ways to drive this home. You may have noticed that archaeological sites are typically buried: sometimes sediment is deposited on land and not eroded away. If erosion was taking place in that spot the archaeology itself would be eroded and destroyed, leaving only the places where deposition has occurred in the hundreds or thousands of years since the sites were created. Places where not a leaf was deposited nor a sand grain blown away are rare to non-existent – exposed earth simply doesn’t sit around taking lightning strike after lightning strike for even thousands, let alone billions of years.
DeYoung must know this, that his calculation is too simplistic, but the full CRSQ article is not available to check if he went on to point this out. It’s possible, yes, that he doesn’t realise the problem – creationists have said plenty of similarly foolish things, not least Thomas himself in the above – but that seems very unlikely. But provided that he does then Thomas is falsely making him out to be a fool, a fellow ignoramus, in which case he should probably complain.