Recently, I received the following interesting and encouraging message from K.A. in Northern Ireland:
About 9 months ago, I received a phone call from a man I had visited in one of the counties here about 5 or 6 years previously. He has a stone cutting and polishing business. At the time I wanted some samples of fossils trapped in rock, as I was teaching through Genesis at church. He gave me some lovely samples with fossils trapped in the local marble and other stone.
He took me into his sales room, showed me his marketing literature, and gave me his business card. I noticed that he stated on them both that the rock he supplied had formed many millions of years ago. I asked if he would like me to tell him an alternative version of how they were formed. He said yes and listened respectfully to my recounting the ‘literal’ Genesis version of creation and the Flood.
During his unexpected phone call he told me that for about 4 years he couldn’t get what I had said to him that day out of his mind. He began to read the Bible, came to faith, joined a church, and now runs a youth club in it! The kids have started to ask him questions about creation and evolution and he thought he would ring me to get good sources of information. He has since set up a library of books and tapes in the church (some of which I gave him) and has visited me with more fossil samples.
It’s good to see the truth about Noah’s Flood and the Word of God gradually spreading.
The theme is Can the Bible and Geology Agree?
He is keen to connect with students who are members of Christian groups on campus, to train and equip them at an advanced level in biblical geology and associated disciplines.
The intensive will run from 10 am to 1 pm daily from Monday 15 July to Friday 19th July 2013 inclusive.
The course presenters will be Dr Peter Hastie, principal of the Presbyterian Theological College in Melbourne and yours truly (Dr Tasman Walker, geologist with Creation Ministries International).
This is the proposed program:
Day 1 How Big Pictures direct our thinking. Tasman Walker
Day 2 Options in interpreting Genesis. Peter Hastie
Day 3 Geology and history. Tasman Walker
Day 4 Radio-isotope dating. Tasman Walker
Day 5 Landscapes, Google Earth, and your career. Tasman Walker
This is quite an ambitious undertaking. Some of the bullet points connected with this intensive are:
Discover how the Bible big picture relates to all your subjects.
See how the biblical worldview can sharpen your critical thinking skills.
Bring your questions and any Uni course notes you wish.
We welcome any questions you have (related to the event content) and will discuss them with you in an honest and friendly manner.
If you are interested, or if you know of anyone who is or could be, please contact firstname.lastname@example.org for more information.
I’m convinced it will be a great intensive for university students and professors from the various universities around the area. It will engage with a different worldview and deal with issues that are not touched on in standard university courses.
The intensive will also be be excellent for theological students and professors at the theological and Bible colleges in the area. There are a number of Christian groups connected with all these colleges and we want to get the word out. We are keen to see Christians studying at tertiary level to be better informed on this issue.
Some more bullet points:
Can Noah and the ice age fit together? And if so what is the relevance to modern debates on climate?
Does radiometric dating hold the key to the earth’s age? What about fossils, dinosaurs, and distant star light?
This intensive will be highly relevant to your university studies, irrespective of your course.
If you can help get the word around please do; that will be great.
Here is a pdf of a flyer (1.5 Mb) about the intensive.
The report explains that researchers analysed a long continental drill core that coveres the period of the Pleistocene ice age.
Analyses of the longest continental sediment core ever collected in the Arctic, recently completed by an international team led by Julie Brigham-Grette of the University of Massachusetts Amherst, provide “absolutely new knowledge” of Arctic climate from 2.2 to 3.6 million years ago.
As soon as they quote dates of this magnitude it confirms that they are looking at the evidence through the lens of uniformitarianism—they are extrapolating present processes into the past. It’s this assumption that leads to age-interpretations of hundreds of millions of years. This philosophy ignores biblical history and the global Flood of Noah’s time, some 4,500 years ago. Biblical geologists interpret the period covered by their drill core as early post-Flood. (The Pliocene they mention may be very late Flood—the closing weeks of it.) The post-Flood Ice Age lasted for a period of some 700 years. It was driven by warmer oceans that were heated by the volcanic activity that occurred during the Flood.
And not surprisingly Brigham-Grette et al. discover exactly what creationist geologists have been talking about for decades: the climate in the Arctic was warmer in the past.
“One of our major findings is that the Arctic was very warm in the middle Pliocene and Early Pleistocene [~ 3.6 to 2.2 million years ago] when others have suggested atmospheric CO2 was not much higher than levels we see today.
In other words, CO2 was not a factor in the higher ocean temperature.
The problem is that because uniformitarians deny that the biblical Flood happened and ignore its consequences, they cannot expalin the Pleistocene Ice Age, for which the geologic evidence is very clear. So, even though their research shows that the warm oceans were not correlated with CO2 levels, that is not what they concluded. Rather, the authors still maintained that CO2 was factor because they already believed it was.
“In other words, the Earth system response to small changes in carbon dioxide is bigger than suggested by earlier climate models,”
This conclusion is almost unbelievable.
The quality of scientific research into past climates and the factors that drive them would be greatly improved if researchers were better read on biblical geology. As it is, researchers do not seem to be able to see that their models do not work (see Noah’s Flood and global warming).
Creationist models of the post-Flood Ice Age have been discussed in creationist literature for decades, and are the only models that provide a plausible mechanism for the cause of the Ice Age. (For more information go to Creation.com and search for Ice Age.) According to these models, earth’s past climate was not driven by CO2. Rather it was a consequence of the enormous global thermal disturbance of the Flood. In the centuries after the Flood the earth’s heat balance returned to equilibrium, and its climate stablilsed.
Update 15 May 2013:
Originally the text said the researchers found “the oceans were warmer” but it now says they found “the climate in the Arctic was warmer in the past.” Thanks to Ashely Haworth-Roberts for pointing this out. Creation scientists have been talking about warmer climates in this area for a long time. See for example: The extinction of the Woolly Mammoths. And creationist scientists have long considered warm oceans as the cause of the warm climate. See for example Rapid changes in oxygen isotope content of ice cores which presents oxygen-isotope evidence from ice cores suggesting the oceans were warmer immediately after the Flood.
The ages, based on measurements made on new analytic equipment, were 80 million years older than previously believed for Castle Hill.
A friend in Townsville sent me the news report and asked if I could write a creationist response, which they sent to the paper. Not long after, Daniel Bateman contacted me, asked lots of questions about the geology of the area, and requested a photo of me. However, nothing has yet appeared in print, and I doubt that it will.
I’ve posted my article below (slightly modified), which was written as a news release for the newspaper’s lay audience.
Geologist questions age of Castle HillAn Australian geologist has claimed that Castle Hill, Townsville’s impressive landmark, is much younger than traditionally taught.
Geologist Tasman Walker, one of the scientists with Creation Ministries International said, “It may seem surprising, but all geological dates are assumed. None has been directly measured.”
Dr Walker was commenting on the announcement by Dr Carl Spandler from the James Cook University School of Earth and Environmental Sciences that Castle Hill was 80 million years older than previously thought. The measurements were based on new analytical equipment costing $500,000 that was installed at JCU.
Dr Walker said, “I’ve used this sort of equipment myself. There is no question that its accuracy and precision are impressive. However this equipment does not measure age. It only measures the concentration of various radioactive atoms in the rock, at the present time.”
“The big question is, ‘How many radioactive atoms were in the rock when it formed?’ Unfortunately researchers cannot measure this; they can only assume how many they think there were.”
“The 80-million-year discrepancy that the researchers reported is is not unusual,” Dr Walker said. “Radioactive dates are full of surprises. If the number is too far off the researchers will just drop it, but Castle Hill’s situation allows a wide range of acceptable ages.
“Castle Hill is composed of granite, a volcanic rock that solidified deep underground from molten lava. Geologists traditionally imagined granite formed slowly over millions of years, however modern granite researchers say that granite formation was catastrophic and sudden.”
“The molten ‘lava’ gushed in pulses up through long, narrow cracks in the earth, forming large pools on the way.
“The sudden formation of granite would mean the radioactive dates calculated according to traditional assumptions would need to be hugely corrected. When the granite minerals, such as zircon, crystallized, they would have already included radioactive atoms, and that greatly inflates the calculated dates.”
Dr Walker is one of a growing number of international geologists that connect earth’s rocks and landscapes to biblical history. According to their research, the Castle Hill granite formed deep underground in the first part of the global flood described in the Bible. Later in the flood, the overlying rocks were eroded away as the waters that had covered the continent of Australia receded. This immense erosion exposed the granite outcrops around Townsville, including Castle Hill.
“So, Castle Hill is Townsville’s monument to Noah’s flood,” Dr Walker said. “The date for that is established historically which is the only reliable way of dating events in the past.”
The meaning of porous dinosaur eggs laid on flat bedding planes, by Michael Oard
Helium-3 capture in lunar regolith and the age of the moon, by Andrew Sibley
Internal oceanic waves and sedimentation, by Michael Oard
Impacts and Noah’s Flood—how many and other issues, by Wayne Spencer
What do impacts accomplish in the first hour? by Michael J. Oard
Global tectonics—clarity, not confusion, by John Baumgardner
Why was the UK once totally under water? by John D. Matthews
Fossil jellyfish from the Pilbara, Western Australia, by Philip Worts
Geology indicates the terrestrial Flood/post-Flood boundary is mostly in the Late Cenozoic, by Michael J. Oard
Plus, there are many articles on all sorts of other subjects, including biology, genetics, information, archaeology, philosophy and theology. See contents page, from where you can subscribe.
How would the water from the “flood” erode sedimentary rocks quicker? Especially when such a flood would result in mass deposition of sediment such as our current oceans do. Because once a layer of water is formed there is no turbulence caused by rain or storms under a certain level. The deepest storm base observed was about 20 m; average is much less. Even then it doesn’t do much to erode, but rather kicks up sediment disrupting life much more than “eroding” anything at all. And if you are suggesting that the eroding took place during the rain “fall” period, I thought that only last 60 days and 60 nights? Surely that could never result in the erosion of so much material!?
As well did you ever get an education? If so where? (Just so I can tell everyone I know not to go there.) There are so many holes in your argument. As a geologist I am not doing this as hate mail, or ‘flaming’ but in hopes of helping you recover from this terrible ignorance, displayed only to suit a prior bias in your ’science’.
A concern human being.
You are right. Once sediment is deposited and is covered by a depth of water it will not be significantly eroded. However, if it is uplifted it will be. And the Flood was an incredible tectonic event that involved the repeated uplift of huge portions of the earth’s crust.
The early part of the Flood was the most catastrophic. Sediments were deposited and then they were uplifted, causing the rocks to be folded and fragmented, and huge volumes of water to move across their surface, eroding them. More sediments were deposited. These also were also uplifted but not folded as dramatically as occurred early in the Flood. This uplift caused the waters to flow off the continents and that eroded the sediments again, leaving the landscapes as we see them today. There is much evidence in the landscape for this last uplift and erosion.
This article about the geological history for eastern Australia explains this sequence of events. Note the uplifting and folding that occurred at different times.
This article about the geology of South Africa discusses the last uplift on that continent. Note the erosion that occurred on the surface during this uplift.
Computer simulations indicate that once the waters of the Flood covered the continents, extraordinary ocean circulation took place. Note how fast the water currents flowed because they were unimpeded by continents and mountains.
That the waters of the Flood covered the continents is identified by geologists but the significance of what they observe is missed because of their philosophy. They speak of eperic seas.
There is a paper in the latest Journal of Creation discussing evidence that the whole of the UK was under water. If you can afford it I would encourage you to subscribe.
You will find answers to many of your questions by browsing the articles on this site. You will also find lots of information about geology on creation.com by searching the site and consulting the Topics listed. The information on those sites is material that you have not been taught in your geology course.
Over the years, I have met many geologists who have spent a lot of time reading articles on geology on these sites and they have appreciated the new perspective that it brought to their work.
Where did you train as a geologist? Are you working as a geologist at the present?
If you have any genuine questions or discussion about geology I would be open to hearing from you again.
All the best,
In 2009, he published some of these ideas in the Journal of Creation 23(3):116–118.
His research shows that the salt pillars around the world are elegantly explained by the interaction of a melted salt magma with the waters of the worldwide Flood.
His Journal paper summarizes:
Large formations of rock salt are found on every continent around the world. Oil and gas are often associated with salt deposits, which can rise kilometers above the top of the main underground salt body. These salt deposits are commonly referred to as “evaporites” because they are considered to have been formed by the evaporation of sea water. The evaporite model requires the evaporation of hundreds of kilometers of depth of seawater, a process that would require vast periods of time, far longer than the biblical timescale. Consequently evaporites have been used as an argument against young-earth geology. However, there are major problems with the evaporite model such that it is totally inadequate to explain the thickness, volume, structure and purity of salt deposits. A more feasible model regards salt deposits as the product of igneous halite magma. Such magmas melt at geologic temperatures, flow readily, and account for the association of salt deposits with reserves of coal, oil and gas.
I like Stef’s model, and think it is far superior to the uniformitarian attempt to explain the evidence, which I was taught at university in my geology course. That model hypothesizes that hundreds of kilometres of seawater evaporated slowly in an enormous, shallow, secluded area of the coast, over millions of years.
Hi Tas, I thought you might be interested in these pictures of the border between the Coweeta River and its adjacent watersheds. The Cullasaja River is a tributaryof the Coweeta River, located to the east of it, and flows towards the north.
In the first image, the divide between the Coweeta River basin and the neighboring Savannah River waterhsheds is shown as a red line, with the Coweeta basin to the left of the divide. Elevations below 700 m are in pink, and below 630 m are in purple. The image shows a wind gap between the two basins. This is indicated by an arrow where a pink connection runs across the red line of the divide, demonstrating a former connectivity between the two basins.
The problem for Gallen et al. is explaining the formation of the wind gap in their model. The gap is erosional, that is, formed by water, though its orientation may have been influenced by faulting. In addition, the angle of tributary “A” suggests that it used to flow toward the gap, because tributaries have a V shape in the downstream direction, whereas this one is “V-ing” upstream. Similar V-shapes have been used by other geologists to argue for stream rearrangement to the north of this area.
It could be postulated that the Coweeta captured the tributary from the Savannah watershed, but stream capture is thought to be favored by a steep slope on the side of the capturing stream, which is not the case here. In fact, the steepest slope is on the Savannah side of the divide, which should suggest that it should be doing the capturing, not the other way around.A simpler explanation would be that as the landscape emerged from inundation (during Noah’s Flood), water currents caused the erosional gap. As they subsided, the flow divided into two currents, one flowing toward the Mississippi and the other to the Atlantic, leaving this and other features such as water gaps in their wake (see circled areas in the second image). The knickpoint retreat referenced in Gallen et al. could have been caused by a sudden steep base level fall as emergence continued, followed by a standstill as the majority of floodwaters reached the Gulf of Mexico. After that, normal stream erosion would have taken over.
Note in the second image that the Blue Ridge Escarpment does not coincide with the drainage divide—another problematic feature of the area (see this link on the Origin of the Blue Ridge Escarpment, southern Appalachians for more information).
Thanks for another informative blog post!
UPDATE 26 February 2013:
Following feedback from Sean Gallen and communication with JS, this article and the images have been updated to correctly identify the river shown on the images. What is now labelled as the Coweeta River was previously labelled as the Cullasaja River. The Cullasaja River is a tributary of the Coweeta River, located to the east of it, and it also flows towards the north.
I am the first author on the article “Miocene rejuvenation of topographic relief in the southern Appalachians”. While my coauthors and I appreciate Tas’ interest in our research, his comments and reinterpretations of our work merit clarification. I understand that most readers of this blog are unlikely to read the primary research article which is why I wanted to present rational for why Tas’ comments are incorrect. I want to make it clear that I am not opposed to Tas’ ideas. I encourage criticism and critique; however, as detailed below, there is reasonable suspicion that Tas is intentionally misleading and attempting to manipulate readers of his blog. I am simply responding to his blog post to point out critical flaws in his critique of our work that readers should find offensive. The take home message is that Tas’ reinterpretation of our work is inconsistent with the observations and finds of the study. Even without our estimates of timing, our findings argue against flooding as a mechanism for changes in the landscape, but are well described by a region that experienced uplift sometime in the past.
[Tas] Thank you for taking the time to respond to my article. I don’t think your claim that I am “intentionally misleading” is justified because it is clear to everyone that I interpret evidence from a biblical perspective, as the name of this blog says, and as I say in the article. Further, the evidence you published in your paper does support the reality of the biblical Flood, and I will deal with that below.
“I’ll post the abstract below with my lay-friendly comments interspersed”, is how the blog post opens. For those who are unaware, an abstract is the briefest summary of the research presented in the paper. It does not discuss the important details of the research, but simply touches on the main observations, arguments, and conclusions. It, therefore, should go without saying that evaluating and interpreting scientific work solely base on an abstract is inappropriate. An analogy is evaluating and interpreting the content and plot of a movie based on a movie trailer. It is impossible to do so.
[Tas] I have read your whole article and I found your abstract to be a good summary of your paper. It provided a good starting point for presenting an alternative explanation. It enabled me to keep my article short, and it ensured that I could not be accused of misquoting you.
“the idea of millions of years comes from evolutionary assumptions, which I don’t accept, and which I discuss a bit more later.”
Evolutionary observations are not the only piece of evidence used to determine that the region have been tectonically inactive for hundreds of millions of year. Radiometric dating as well as the slow and steady accumulation of sediments in ocean basins provides supporting evidence. To convincingly suggest that these age estimates are inaccurate you will need to explain those latter bits of evidence and provide evidence to the contrary. Neither of which are done in the blog post or elsewhere for that matter.
[Tas] When a new idea is presented, people will often say, “That can’t be right because of this, this and this.” In the article above I’ve provided a big-picture view of how the evidence can be explained by Noah’s Flood, and I think I showed that the processes and events are consistent with what you would expect during the Recessive stage of the Flood. Of course there will be questions from those who are used to looking at things from a different perspective. That is normal and good. You mention two sticking points here that require a lot of reading and a lot of thought, which is why I did not address them in the blog item. Concerning radiometric dating there are many articles that show that radioactive dating is not a problem for the time-scale of the Flood (See Q&A Radioactive Dating). Concerning the accumulation of sediments, the accumulation rate was not “slow” during the Flood.
“There are two competing explanations that geologists use to try to get around the problem.”
It isn’t a problem it is an observation.
[Tas] Indeed. And the purpose of your paper was to explain two apparently inconsistent ‘observations’. As you say in your paper “tectonic activity presumably ceased” but your paper solved that problem by showing it didn’t.
“One idea for the something that happened recently is a change in the climate. (Someone had to suggest that. It’s par for the course these days for climate change to be invoked somewhere.)”
The statement in parentheses is a red herring. It is intentionally and inappropriately inserted into the text to distract readers. In conflates the controversy over present-day climate change with the ice ages. In other word, the climate change referred to in our paper is the ice ages, which Tas mentions later in his blog post, and not modern climate change. It is very well documented that the ice ages had a profound and measurable impact on landscapes. This statement indicates to me that Tas is intentionally misguiding and manipulating readers, he is being dishonest.
[Tas] Attacking a person’s character by calling them “dishonest” is inappropriate among scientists. I agree the climate change reference was is a side issue. However, that is not what I focussed on.
“Here they describe the extent to which the land surface has become eroded to produce deep gorges and steep escarpments. It’s significant. And they put a time on it.”
Tas glosses over a very important part of our research in the last sentence of this quote. He does not describe to the reader how we estimated time. To estimate time we did not use fossil (evolutionary) evidence or radiometric dating. We simply calculate the volume of material eroded and divide that by the erosion rate of the landscape, which has remained slow and approximately steady over the millennia. Evidence to support the assertion of slow and steady erosion of the Appalachians comes from sediment in offshore basins and radiometric methods. It is my opinion that he either did not read the article in its entirety or he is intentionally misleading readers. I favor the latter because it is very difficult to argue that are age estimates are incorrect as they based on a simple yet effective calculation.
[Tas] I’m pleased to see you use the phrase “how we estimate time” because all ‘ages’ are estimates. They are all based on assumptions, as you are well aware. In your case, you used rates of erosion from Ahnert’s relationship to obtain a rate of mm of erosion per thousand years. However, Ahnert’s relationship is only valid in the post-Flood period. It is not valid for the Recessive Stage of the Flood. I notice that you compared the rate with the beryllium-10 estimates, but these beryllium estimates do not apply in Recessive Stage either.
“The sequence of events that unfolded during the biblical Flood easily explains what the authors have found.”
This statement cannot be any more wrong. It is entirely inconsistent with the data we present. Flooding would actually be more similar to the climate change hypothesis that we disprove in our paper. The flooding hypotheses would suggest that the rivers become very erosive as waters recede into the ocean. The climate change hypothesis suggests that the rivers become more erosive due to cooler and more rapidly fluctuating climate (ice ages). Evidence from the river and surrounding landscape, however, are inconsistent with either of these models for change. Further, we show compelling evidence that the landscape was uplifted. In other words, even if the timing of landscape change were wrong, the observations support uplift, not flooding, as the mechanism for change. Our research would actually argue against flooding. Tas misses this central point of our research either due to preconceived notions of how to explain our results or his general lack of knowledge about geology. In either case, it is clear that his is attempting to manipulate readers.
What is discussed above makes the following statements in Tas’ blog regarding time moot. Tas offers no observations or evidence to support his claims on his chronology of events. I encourage Tas to make some observations, collect some data, and support his statements. This is how science works. Claims supported by observations, data, evidence, and facts.
[Tas] The unfolding of the Recessive Stage of the biblical Flood is vastly different from the ‘climate change’ scenario. The Recessive Stage of the Flood involved the rising of the continents and the lowering of the ocean basins. You say I should provide evidence. Well, I point to your paper because that is exactly what you have found—epeirogenic uplift. The Recessive Stage began with a high base level (high sea level), and the base level dropped during the progress of the phase. There are papers on creation sites that discuss and quantify these things.
It seems to me (I’m speculating here) that the paleorelief level you mention in your figure 3 would represent the level as the Recessive stage transformed from the Abative phase to the Dispersive phase, perhaps a bit after. (These may seem like jargon terms, but as a geologist you would find it helpful to become familiar with them.)
“The biblical Flood provides a coherent model and elegantly explains the geological evidence in the Appalachians published in this recent GSA Today paper.”
It does not. It is actually inconsistent with observations in the region and a similar hypothesis (climate change) is disproven in the paper (see above for more details).
[Tas] As I said above, the climate change hypothesis does not represent the Flood scenario.
“When we examine the shape of the landscape (i.e. geomorphology) we have a powerful tool for understanding the sequence of large-scale geologic events and their relative timing.”
I agree with Tas here; however, it is unclear whether or not he is capable of carrying out such tasks.
[Tas] Yes, we agree. But resist the temptation toward ad hominem.
“stimulates ideas for how to explain the evidence that is being uncovered”.
It would be more helpful if Tas spent time collecting evidence rather than attempting to explain the work of others.
[Tas] I appreciate the evidence you have published. You would know that a very important role is that of the scientist who collects data from others and synthesises it.
In closing, I want emphasize again that I am not opposed to Tas’ ideas. I do, however, take issue with someone who intentionally misleads and feeds misinformation to readers, as Tas has done in this blog post. The reason why I responded to his post was that he misrepresents and incorrectly reinterprets our data and leaves out important details of our work. Tas is one of two things: 1) guilty of intentionally trying to manipulate readers, or 2) inadequately trained and incapable of evaluating geologic literature. In either case, content posted in his blog is untrustworthy and unreliable. I caution readers to take his posts with a grain of salt.
[Tas] Now, now, it’s inappropriate to attack a fellow scientist’s training, ability and integrity.
However, I am more than happy for readers to critically evaluate what I am proposing. Understanding the geological effects of Noah’s Flood is a work in progress and it will only be strengthened by rigorous debate. I don’t think your term “grain of salt” is a good one; it suggests to me that the ideas should be dismissed without proper consideration. Instead, I would encourage readers to critically evaluate, read widely, picture the processes, and come to their own considered conclusions.
So I thank you Sean for your reply and the opportunity to engage.
This title would not mean anything to most people, because like most geological articles in geological journals this one is written in technical language making it difficult for a lay person to follow. So I’ll post the abstract below with my lay-friendly comments interspersed.
Conventional wisdom holds that the southern Appalachian Mountains have not experienced a significant phase of tectonic forcing for >200 myr;
In other words, the Appalachians were uplifted over 200 million years ago and have not been uplifted since. This means the Appalachians are considered a very old mountain range that has been exposed to normal weathering processes (rain, snow, ice, erosion, landslides, etc.) for hundreds of millions of years. (I’m quoting their figures, but the idea of millions of years comes from evolutionary assumptions, which I don’t accept, and which I discuss a bit more later.)
yet, they share many characteristics with tectonically active settings, including locally high topographic relief, steep slopes, incised river gorges, and frequent mass-wasting events.
But the problem is that, although the Appalachians are thought to be old, they have lots of features that look really young: tall mountains and low valleys, steep escarpments and deep river gorges with steep sides.
Two competing hypotheses are commonly used to explain their modern topographic expression. One suggests that relief is largely controlled by variable lithologic resistance to weathering and that their modern form has long persisted in a dynamic equilibrium. The second postulates that their relief is a product of recent rejuvenation, driven either by climate change or the epeirogenic uplift of the land surface driven by mantle forcing.
There are two competing explanations that geologists use to try to get around the problem. The first is that the hardness of different rock strata varies in such a way that the landscape just happens to weather such that it looks young even though it has been weathering for hundreds of millions of years.
The second is that something happened recently to cause a new bout of weathering and erosion, and the features look young because whatever happened only happened recently (geologically speaking).
One idea for the something that happened recently is a change in the climate. (Someone had to suggest that. It’s par for the course these days for climate change to be invoked somewhere.)
Another idea for the something that happened recently is that the continent was recently uplifted. (That’s what epirogenic means, that an enormous area of land uplifted without much folding of the sediments upon it. It was not just the Appalachians that was uplifted, but a huge area around them. The area is considered to have been uplifted from below the continental crust by vertical upwelling of the mantle.)
Within portions of the Cullasaja River basin of the southern Appalachians, we show that relief has increased by >150% since the Miocene.
Here they describe the extent to which the land surface has become eroded to produce deep gorges and steep escarpments. It’s significant. And they put a time on it. It has occurred since the Miocene, which is somewhere around 15 million years ago, within the evolutionary worldview. That is much more recent than the 200 million years.
Evident within the basin are a set of retreating knickpoints that delineate a rugged, actively incising landscape from lower-relief relict topography. Constraints on the timing of knickpoint entry into the basin suggest that the process of landscape rejuvenation began well prior to the late Cenozoic (<4 myr) transition to a more oscillatory (glacial-interglacial) climate regime.
Here they describe how they have measured various slopes on the landscape and determined that the renewed erosion was active until about 4 million years ago—i.e. before the Ice Age. So they established that the time range for the erosion was from 15 million to 4 million years ago.
Furthermore, the geomorphology of the Cullasaja River basin is difficult to reconcile in the context of a transition to a more erosive climatic regime but is consistent with an epeirogenically uplifted landscape.
Here they dismiss the first explanation put forward to solve the problem. They say that the shape of the landscape is such that the erosion was not caused by climate change.
Consequently, these observations lend new support to the idea that the rugged topography of the southern Appalachians has developed in response to post-orogenic regional uplift in the Miocene.
In other words, the erosion of the landscape began long after the Appalachian Mountains themselves were pushed up. Further the erosion that produced the young-looking features was caused by the whole continent (or a large part of it) uplifting with minimal folding or disturbance of the geology.
DiscussionI found this article from the GSA Today interesting. The sequence of events that unfolded during the biblical Flood easily explain what the authors have found. Of course, within the biblical way of thinking we should not be put off by the ages quoted of millions of years. The timing has to be reinterpreted within the biblical model. When they speak of 200 million years it’s getting toward the middle of the Flood. When they say 15 million years it is toward the end. And 4 million years is around the beginning of the post-Flood period. These are rough numbers, but a clearer picture emerges when we consider each local area on its merits.
First, the strata that make up the Appalachians were deposited during the first half of Noah’s Flood as waters were rising. The Flood occurred 4500 years ago, and the first half lasted about 150 days.
Second, the Appalachian Mountains were folded and formed by the Appalachian Orogeny (i.e. the Appalachian mountain-building event) which occurred about half way through the Flood, or just before. By this stage or soon after the whole earth would have been covered by water, including the North American continent.
Third, the newly formed Appalachian Mountains were eroded as the waters that covered them began to recede into the Atlantic in the second ‘half’ of the Flood. The waters began to flow off the continent because the continent began to be uplifted and the ocean basins began to open up (or sink). The water initially flowed off the land in sheets, greatly eroding the surface. The resultant surface would be undulating to flat. Secular geologists, who do not believe in the Flood, have mistakenly interpreted the flat and gently undulating surfaces as caused by long periods of sub-aerial weathering. The second ‘half’ of the Flood (until Noah disembarked from the Ark) lasted some 220 days.
Fourth, as the waters continued to retreat from the continent, parts of the land surface emerged above the water, and the receding water then eroded valleys and gorges in the areas that remained submerged. As the water level continued to drop the valleys and gorges were eroded deeper. This explains why the river gorges in the Appalachians (and all other mountain ranges around the world) cut straight through the ranges (rather than going around them). These erosional features of the landscape look young because they are young. (See Do rivers erode through mountains and the pdf about the Eastern Structural Front of the Appalachian Mountains for more on rivers flowing through mountain ranges.)
The timing constraints in the GSA Today paper suggest that the landscape in this area emerged from below the retreating waters of Noah’s Flood somewhere around the Miocene (although we have to be careful in trying to make a one-for-one correlation with the geologic column).
Fifth, the Ice Age began to develop immediately after the Flood (which provides the only plausible explanation for it). The ice cover grew on the continents for some 500 years and then retreated for the next 200.
The biblical Flood provides a coherent model and elegantly explains the geological evidence in the Appalachians published in this recent GSA Today paper. When we examine the shape of the landscape (i.e. geomorphology) we have a powerful tool for understanding the sequence of large-scale geologic events and their relative timing. (Google Earth and Google Maps are remarkable tools that have recently become available and can be used for this purpose, but they need to be used in conjunction with geological maps.) The Flood model gives insights into the processes that were occurring, how these processes changed with time, and stimulates ideas for how to explain the evidence that is being uncovered.
Sean F. Gallen, Karl W. Wegmann, DelWayne R. Bohnenstieh, Miocene rejuvenation of topographic relief in the southern Appalachians, GSA Today 23(2):4–10, February 2013.