Willem Jan Bloom June 2022
Two times Heerema and van Heugten in the Journal of Creation
Introduction
Six months ago, the Journal of Creation published an article I wrote about the origin of salt layers and salt structures. This article was mainly a response to an earlier publication by the Dutch creationists Stef Heerema and Gert-Jan van Heugten. It was therefore expected that there would be a response from them, and that response was published last week in the Journal of Creation. An earlier edition of this year also featured an article by Heerema and Van Heugten about deserpentinization. For the sake of completeness, I will respond to both articles in chronological order in this blog post.
Deserpentinization
It is not really clear from the content why Heerema and Van Heugten have chosen to devote an article to deserpentinization. I myself have been the only one who has mentioned deserpentinization as a salt formation mechanism in a creationist context, but my JoC article is not mentioned by Heerema and Van Heugten. Earlier, when I was still a creationist myself, I pointed out deserpentinization to the Dutch creationist community. But because Heerema and Van Heugten do not mention this, its relevance for the Journal of Creation remains unclear. I do not intend to analyze every point that Heerema and Van Heugten make. I personally do not think that salt layers are formed by deserpentinization, so I certainly think that there are problems with the model. I do think it is a much more realistic model than Heerema's own hypothesis of volcanic salt. Therefore, I will briefly discuss a few points.
First of all, it should be mentioned that Heerema and Van Heugten do not provide a correct picture of the scientific literature on deserpentinization as a salt formation mechanism. They pretend that this only consists of an article by Debure et al. from 2019. But in doing so they are overlooking, among other things, an article by Scribano et al. from 2017. That's careless, because I pointed them to that article and it's also cited by Debure et al.
Heerema and Van Heugten are right that a deserpentinization model requires large quantities of serpentinite to be available. The question is how strong is that objection from the proponents of volcanic salt, who have to hypothesize enormous amounts of salt magma (something whose existence has never been established). The proponents of the deserpentinization model hypothesize that large amounts of serpentinite were collected at the crust-mantle boundary by planar subduction.
Another way to solve this problem is to assume that there is a continuous supply of new serpentinite. When a salt layer forms near a subduction zone, proponents of a deserpentinization model may hypothesize that the salt precipitates from water streams emanating from the subducting plate. Because the subducting oceanic plate is constantly being replenished at that spot, it is unnecessary for all the serpentinite to be present at one moment to allow the salt layer to form. For creationists, this solution is not really useful unless they assume that serpentinization is an extremely fast process. If need be, creationists may hypothesize that an extraordinarily large portion of the lithosphere was serpentinized prior to the Flood. That was my idea when I was still a creationist. Of course, that hypothesis is quite ad hoc, but as mentioned, the same applies to the assumption that enormous amounts of salt magma were present in the mantle prior to the Flood.
So far a few suggestions about deserpentinization in response to Heerema and Van Heugten, but I'll leave further elaboration of the model to those who actually believe that salt layers were formed in this way. Introducing the second article I will now discuss the second article by Heerema and Van Heugten (their response to my article) paragraph by paragraph. It is striking that they start their article with 'It is strange…'. What exactly is strange? That I have chosen to publish as a theistic evolutionist in the Journal of Creation, while I do not consider that a scientific journal at all. This opening of their article is quite unprofessional. Matters are added that are not relevant to the scientific discussion. But what's even more striking is that I simply explained why I published in the JoC. Heerema and Van Heugten could have mentioned that, and then they wouldn't have had to start with 'It is strange…'. I'll just quote it for completeness:
Why did you choose to publish an article in the Journal of Creation?
The decision to publish in JoC is the result of the fact that Stef Heerema refused to react to my criticisms (published on this blog) as long as they were not “peer-reviewed”, with which he meant a publication in, for example, JoC. Another consideration was that most English-speaking creationists and critics of creationism cannot read Heerema’s Dutch publications, so I thought that gave me some responsibility to address my criticisms to that community as well, especially since Heerema increasingly tries to reach the international creationist community. (Which has probably everything to do with the fact that his model is generally rejected by Dutch creationists.)
"Liquid, not solid"
Heerema and Van Heugten skip the section of my article on clues to sedimentary origin of salt deposits and jump straight to the simple model of salt pillar formation I presented. Before I go into the details, three things need to be mentioned:
1. My simple salt pillar model is in the context of a response to something Heerema and Van Heugten argued in their original JoC article. In it, they argued on the basis of tests with salt pillars that it is impossible for salt to flow from 25 kilometers away. My model only refutes that point: under the conditions that Heerema and Van Heugten indicated, it is indeed possible to form a salt pillar. My model was not created with the intention of being an extremely realistic simulation of how salt pillars form. So when Heerema and Van Heugten treat my model as such (which they do, while not defending their original criticism against my refutation), they are attacking a straw man.
2. Heerema and Van Heugten completely ignore the fact that I have placed all the necessary nuances in my model myself. Since they apparently have not been noticed, I will quote them again:
This simplified model can be made more realistic by adding several factors that enhance or resist salt flow. Instead of lifting up the overburden, the diapir can push its roof aside, which lowers the pressure above the diapir; erosion of the roof also lowers the pressure. Compressional tectonic forces, a lower viscosity due to lower grain sizes or higher temperature, an elevation head gradient, and thermal loading can also drive salt flow. Weak salts such as bischofite and carnallite can result in higher strain rates, lowering the overall viscosity of salt.
On the other hand, the strength of the overburden, the movement of the overburden in the opposite direction, and the presence of salts with a high viscosity (e.g. anhydrite) are factors that resist salt flow. Equation (1) shows that discharge is proportional to the cube of the salt layer thickness. As a result, salt flow decreases due to thinning of the salt layer. Numerical models that take these factors into account demonstrate the possibility of the formation of salt diapirs in millions of years.
3. If Heerema and Van Heugten had wanted to go further than what I already indicated in my article, they should have come up with a counter model. Just feed the extra equations to the model! Then they could have shown that they ensure that no more salt flow takes place. Instead, they have chosen to make some loose-handed critical comments, with no evidence to support the claim that they are enough to reject the model.
Now for the specific criticisms that Heerema and Van Heugten raise against my model. I will also discuss these point by point:
1. In a miraculous way, the underlying salt and the subsalt rock stayed undisturbed in the process of graben forming.
That's not at all what my model says. I challenge Heerema and Van Heugten to point out where in the model I should assume that the salt layer has remained 'undisturbed'. They seem to start from the schematic figure I put in my article, just to clarify what I mean by certain parameters.
2. With Blom’s supernaturally formed graben in place…
Uiteraard hoeft die niet op een bovennatuurlijke manier gevormd te zijn. Hadden Heerema en Van Heugten verwacht dat ik het ontstaan van een graben ging uitleggen? Ze hadden net zo goed kunnen schrijven: ‘With Blom’s supernaturally formed overburden in place…’ and that would have been as pointless.
3. Although the solid overburden rests upon the solid salt, Blom falsely believes that the salt layer can move without displacing it.
I think so, because that's the idea of Poiseuille flow, the mechanism of a fluid (a fluid, not a liquid) moving between two solid plates as a result of pressure differences. The speed at the edges is then 0, so there is no drag force against the layer above.
4. These enormous horizontal movements and the time path involved are neglected. Blom focuses on the rise of the vertical pillar only.
The whole model is almost exclusively about horizontal displacement of salt, see equation (1) in the model.
5. The whole model is almost exclusively about horizontal displacement of salt, see equation (1) in the model.
That seems to me to be the correct method. It would be more curious if I used unobserved processes to calculate observed processes.
These five points are either completely false (1, 4), or there is nothing remarkable about them at all (2, 3, 5).
According to Heerema and Van Heugten, it is wrong that I advise creationists to use tectonic forces to explain the formation of salt layers. According to them, tectonic forces on the "mud" of the Flood may not have had the right result. However, the geological records clearly show that bedrock tectonics must have occurred during periods that creationists place during the Flood. And, as I mentioned in my JoC article ([S]alt deposits often act as décollements in thrust belts, as is the case in the Pyrenees, which are called “a salt-based folded belt”), precisely during this deformation of solid rock rock salt appears to be the most smeared.
Finally, Heerema and Van Heugten mention the presence of anhydrite as a limiting factor for salt flow. I had already stated that in the JoC article. The presence of anhydrite makes salt flow more difficult, just as the presence of sylvite facilitates salt flow. Such effects are included in more complex models.
False suggestions
The last part of the article by Heerema and Van Heugten (the text fits on two pages) is about the density of rock salt in relation to the overburden. They begin this section as follows:
Another inaccuracy in Blom’s paper is that salt pillars are considered less dense than the overburden. He writes: “If the average density of the overburden is higher than the density of the salt (which is 2,200 kg/m3 or even lower9), the salt will even reach the surface and spread out.” He believes that salt pillars consist mainly of NaCl (2,160 kg/m3 ). The higher density salts such as anhydrite (2,970 kg/m3 ), which make up a significant portion, are ignored.
Although Heerema and Van Heugten include my footnote in their quote, they do nothing with it. In it I refer to an article with results showing that the Sedomdia Pier near the Dead Sea has a lower density than the overburden. I already gave more explanation in a previous blog post, so I'll just quote that part:
Overburden density was Heerema's main publication topic in 2014 and 2015, including a publication in the geology journal Grondboor & Hamer and a presentation at an American creationist conference. In this blog post I will mainly focus on Heerema (2014), because that is where the most information is available. Heerema writes about his research:
My work, which is the first research ever to include actual rock densities in the discussion of salt tectonics, is decisive. (Heerema 2016)
However, a designation as 'first research ever' is not entirely justified. Heerema has done little more than create a depth-density graph of the overburden. Such studies have been done before. His results are as follows:
I've signed in the same trendline as Stef Heerema, which I wonder why he hasn't improved it in the last six years. Of course, the density profile in the subsoil does not make such a strange kink. The density profile is determined by the compaction curve, which in turn depends on the sediment type and the average sedimentation rate (Fossen 2016, p. 418). The average density of rock salt is generally reached between 1500 and 3000 meters. In Heerema's curve, this density (2200 kg/m3) is reached at about 1500 meters, so at the lower end of the spectrum given by Fossen. In the Dutch geological literature, however, it is often mentioned that the turning point is already at 500 meters, which has been debunked by Heerema's research.
Heerema does not stop here, however. According to him, it is incorrect that the average density of rock salt is 2200 kg/m3. Based on a technical pocket book, he arrives at an average density of 2350 kg/m3. It is unknown what measurements this pocketbook is based on. If this value were correct, the tipping point would not be until 2400 meters, which is at the high end of the spectrum.
The diapers in the Gulf of Mexico contain between 95 and 99 percent halite (Warren 2016, p. 601, Fredrich et al. 2007). If we start from the lowest percentage and assume that the rest consists of anhydrite, we arrive at an average density of 2200 kg/m3. A cross-section of the Gorlebendiapier in Germany shows which layers of the Zechstein group comprise this diapier (Bäuerle et al. 2000). Based on the thicknesses in the Dutch drill core SLN-04, an average density of 2900 kg/m3 for anhydrite, 2700 kg/m3 for limestone, 2200 kg/m3 for halite and 2200 kg/m3 for claystone, I arrive at an average density in the diapier of 2219 kg/m3. A density study of the Sedomdia Pier shows an average density of less than 2200 kg/m3 (Weinberger et al. 2006). Based on these data from three different locations, we can determine that the average density of the rock salt in diapiers is about 2200 kg/m3.
The density of the overburden has also been determined in several studies. Again, there is the study on the area around the Dead Sea (Weinberger et al. 2006), where the turning point is already less than 1000 meters below the surface. In the Gulf of Mexico, the tipping point is around 2000 meters (Nettleton 1934). In Oman, the density of any stratigraphic group overlying the Ara Salt is greater than that of salt (Cooper et al. 2013).
There is thus ample support for the fact that the sediments above the salt have a greater density than the salt itself. Even with the numbers that Heerema works with, this creates an instability that leads to salt flow (Hardebol 2016). Most importantly, however, the low-viscosity salt can flow upwards along fractures due to pressure differences. According to Heerema (2014), this is beyond the scope of his research, meaning that his density research only attacks a small element of the current theory of salt tectonics. This attack, however, turns out to have failed: the overburden is heavier than the salt.
The Gorleben diapir, which I already discussed in my blog post, is again led by Heerema and Van Heugten. They estimate the proportion of anhydrite based on the image they show, but forget that much of the halite may have dissolved in the meantime because the diapier is so close to the surface.
An important word in the sentence that Heerema and Van Heugten quote from my article is 'average'. If the average density of the overburden is greater than that of the salt, the salt can come to the surface. This means that the density of the overburden at the surface can be less, as long as it is compensated for at a greater depth by rock that has a higher density than salt.
For example, if I calculate the average density of the overburden (between 0 and 3000 meters depth) on the basis of Heerema's own data, I arrive at about 2150 kg/m3. That can be enough for a diaper with a very low density to reach the surface purely by means of density differences. It is rare, however, for salt pillars to reach all the way to the surface. For example, it did not happen in the places where Heerema's density data comes from.
Finally, Heerema and Van Heugten note that it is remarkable that I continue to cling to the consensus theory about the formation of salt layers. “It is remarkable that he ignores the growing group of geologists that argue against it.” This suggestion is incorrect for several reasons. First off, I'm not ignoring this group at all. I mention the presence of hydrothermal models in the introduction, see footnote 8. And even more ironically, I myself suggest that creationists should turn to the geologists who use deserpentinization as an explanation, see footnotes 47, 48 and 49. In fact, I have been the first person to introduce this alternative hypothesis in creationist circles.
Second, the suggestion that the group of geologists moving away from consensus theory is growing is unfounded. There is the team of Hovland, Rueslåtten and Johnsen in Norway, the team of Scribano, Carbone and Manuella in Italy and the team of Debure and others in France. In addition, it is plausible that the American geologists Keith and Swan are sympathizers of an alternative salt model. I wouldn't know anyone else. In no way does it appear that these geologists are gaining more adherents to their model, or that they are gaining more influence in the scientific literature on salt deposits. The Utrecht geologists who are working on the Messinian Salinity Crisis are aware of the existence of the alternative hypotheses, but they play no part in the discussions they conduct about salt layers. Among geologists concerned with salt, the consensus theory is still extremely widely accepted.
Heerema and Van Heugten copy two further objections to the consensus theory from an article by Scribano et al. They do not provide detailed argumentation, nor can they be found in their source. Since it is up to the contributors of an argument to properly substantiate this, I will let these objections rest until further explanation follows.
Conclusion
Heerema and Van Heugten's response to my JoC article did not help the discussion. All the points they brought up were either obviously incorrect, or I had already discussed it in the article or previous blog posts. They have not bothered to further develop their model, introduce new arguments or refute arguments from my article in detail. More specifically, the following points from my JoC article are simply ignored:
1. The similarity between the morphology of salt crystals in salt layers and salt crystals that are formed by evaporation.
2. The alternation between salt layers and sedimentary rocks on several levels.
3. The presence of sedimented salt containing sedimentary structures.
4. The presence of salts that are unstable at high temperatures, including indications that these salts are primary.
5. The presence of clay minerals in and around salt layers that should have suffered the consequences of metamorphism at high temperatures.
6. The rebuttal of Heerema's objection that there is little siliciclastic sediment or fossils in the salt.
7. The role of salt layers in orogenic belts.
8. The fact that the conditions that, according to Heerema and Van Heugten, make salt tectonics impossible (a distance of 25 kilometers with the pressure difference of 20 MPa) yield a model in which salt tectonics do take place.
9. The connection between salt structures and fractures.
10. The implausibility of the idea that the magma of the Ol Doinyo Lengai can be related to a NaCl-rich magma.
11. The differences in δ34S between anhydrite in salt layers and volcanic anhydrite.
12. The differences between structures in salt layers and in ionic liquids.
13. The response to the claim that the similarities between the structure of salt pillars and liquids in a Rayleigh-Taylor instability indicates salt flow in liquid phase.
14. The presence of the original layering in diapers.
15. The implausibility that a salt magma could have reached the seabed due to density differences.
16. The absence of a metamorphic halo around salt pillars.
Of course you cannot discuss all the points that I have raised in my article in a published response. Nevertheless, Heerema and Van Heugten's reply resulted in a very meager harvest. In fact, they have only responded (in the wrong way) to my simple model, and to my claim that the mean density of the overburden is sometimes greater than that of the salt.